Antioxidants

11 pages, 1514 KiB

Open AccessArticle

Two Novel Lipophilic Antioxidants Derivatized from Curcumin

by Tao Liu, Xiaohan Liu, Tosin M. Olajide, Jia Xu and Xinchu Weng

Antioxidants 2022, 11(4), 796; https://doi.org/10.3390/antiox11040796 - 18 Apr 2022

Cited by 1 | Viewed by 2080

Tert-butyl curcumin (TBC), demethylated tert-butylated curcumin (1E,6E-1,7-bis(3-tert-butyl-4,5-dihydroxyphenyl)hepta-1,6-diene-3,5-dione, DMTC), demethylated curcumin (DMC), and Cur were synthesized from the starting compound, 2-methoxy-4-methylphenol. TBC and DMTC are two novel lipophilic compounds, and Cur and DMC are polar and hydrophilic. The antioxidant activities [...] Read more.

Tert-butyl curcumin (TBC), demethylated tert-butylated curcumin (1E,6E-1,7-bis(3-tert-butyl-4,5-dihydroxyphenyl)hepta-1,6-diene-3,5-dione, DMTC), demethylated curcumin (DMC), and Cur were synthesized from the starting compound, 2-methoxy-4-methylphenol. TBC and DMTC are two novel lipophilic compounds, and Cur and DMC are polar and hydrophilic. The antioxidant activities of Cur, TBC, DMC, and DMTC were evaluated by using the methods of 2,2-diphenyl-1-(2,4,6-trinitro-phenyl)-hydrazinyl (DPPH), deep-frying, and Rancimat. Tert-butylhydroquinone (TBHQ) and Butylated hydroxytoluene (BHT) were used as comparison compounds. Both Rancimat and deep-frying tests demonstrated that DMTC was the strongest antioxidant, and TBC also had stronger antioxidant activity than Cur. In the DPPH assay, DMC showed the highest scavenging activity, followed by DMTC, TBHQ, Cur, and TBC. DMTC and TBC can be potentially used as strong antioxidants in food industry, especially for frying, baking, and other high temperature food processing. DMTC is the strongest antioxidant in oil to our knowledge. Full article

(This article belongs to the Special Issue Antioxidants in Foods II)

► Show Figures

Figure 1

34 pages, 5743 KiB

Open AccessReview

Carotenoids: Dietary Sources, Extraction, Encapsulation, Bioavailability, and Health Benefits—A Review of Recent Advancements

by Ramesh Kumar Saini, Parchuri Prasad, Veeresh Lokesh, Xiaomin Shang, Juhyun Shin, Young-Soo Keum and Ji-Ho Lee

Antioxidants 2022, 11(4), 795; https://doi.org/10.3390/antiox11040795 - 18 Apr 2022

Cited by 107 | Viewed by 11279

Abstract

Natural carotenoids (CARs), viz. β-carotene, lutein, astaxanthin, bixin, norbixin, capsanthin, lycopene, canthaxanthin, β-Apo-8-carotenal, zeaxanthin, and β-apo-8-carotenal-ester, are being studied as potential candidates in fields such as food, feed, nutraceuticals, and cosmeceuticals. CAR research is advancing in the following three major fields: (1) CAR [...] Read more.

Natural carotenoids (CARs), viz. β-carotene, lutein, astaxanthin, bixin, norbixin, capsanthin, lycopene, canthaxanthin, β-Apo-8-carotenal, zeaxanthin, and β-apo-8-carotenal-ester, are being studied as potential candidates in fields such as food, feed, nutraceuticals, and cosmeceuticals. CAR research is advancing in the following three major fields: (1) CAR production from natural sources and optimization of its downstream processing; (2) encapsulation for enhanced physical and chemical properties; and (3) preclinical, clinical, and epidemiological studies of CARs’ health benefits. This review critically discusses the recent developments in studies of the chemistry and antioxidant activity, marketing trends, dietary sources, extraction, bioaccessibility and bioavailability, encapsulation methods, dietary intake, and health benefits of CARs. Preclinical, clinical, and epidemiological studies on cancer, obesity, type 2 diabetes (T2D), cardiovascular diseases (CVD), osteoporosis, neurodegenerative disease, mental health, eye, and skin health are also discussed. Full article

(This article belongs to the Special Issue The Role of Carotenoids in Human Health (2021))

► Show Figures

Figure 1

Figure 1
The molecular structure of chromophore of (all-E)-β-carotene (A), responsible for the absorption of light in the visible range. The absorbance spectrum of (all-E)-β-carotene (B) is from carrots recorded using a diode array detector (DAD) in the solvent system previously used in our study [<a href="#B29-antioxidants-11-00795" class="html-bibr">29</a>] (unpublished data). Full article ">Figure 2
The lipid peroxyl radical (LOO•) scavenging/detoxification by carotenoids (CARs). The carotenoid radical cation (CAR•+) can be regenerated in the presence of tocopherol (vitamin E), ascorbate (vitamin C), and glutathione. Full article ">Figure 3
The marketing trends of carotenoids. Source: <a href="https://www.bccresearch.com" target="_blank">https://www.bccresearch.com</a>, accessed on 25 February 2022. Full article ">Figure 4
The dietary carotenoids obtained from the major fruits and vegetables. From top to bottom, (1) green leafy vegetables, (2) pumpkin and carrot, (3) tomatoes, (4) red paprika, and (5) orange. Full article ">Figure 5
The presence of two unmodified β-ionone rings in one molecule of β-carotene can provide two molecules of retinol (vitamin A; 100% provitamin A activity), while α-carotene and β-cryptoxanthin contain only one β-ionone ring structure (50% provitamin A activity). Full article ">Figure 6
The antioxidant (in normal cells) and pro-oxidant properties of carotenoids regulate the reactive oxygen species (ROS) and modulate the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB); nuclear factor-erythroid 2-related factor 2 (Nrf2), responsible for apoptosis of cancer cells; and survival of normal cells. Abbreviations: BAX, B-cell lymphoma 2 associated X; Bcl-2, B-cell lymphoma 2; PARP, poly (ADP-ribose) polymerase; PGE2, prostaglandin E2; TNF-α, tumor necrosis factor-alpha. Full article ">Figure 7
Carotenoids block the phosphoinositide 3-kinase (PI3K)/phosphorylated protein kinase B (PKB or Akt)/mechanistic target of rapamycin (mTOR) signaling pathways, thus reducing tumor cell initiation, progression, and metastasis. Abbreviations: Bcl-2: B-cell lymphoma 2: IGF: Insulin-like growth factor: MMP9: Matrix Metallopeptidase 9. Full article ">

32 pages, 1900 KiB

Open AccessReview

Does Plant Breeding for Antioxidant-Rich Foods Have an Impact on Human Health?

by Laura Bassolino, Katia Petroni, Angela Polito, Alessandra Marinelli, Elena Azzini, Marika Ferrari, Donatella B. M. Ficco, Elisabetta Mazzucotelli, Alessandro Tondelli, Agostino Fricano, Roberta Paris, Inmaculada García-Robles, Carolina Rausell, María Dolores Real, Carlo Massimo Pozzi, Giuseppe Mandolino, Ephrem Habyarimana and Luigi Cattivelli

Antioxidants 2022, 11(4), 794; https://doi.org/10.3390/antiox11040794 - 18 Apr 2022

Cited by 16 | Viewed by 4126

Abstract

Given the general beneficial effects of antioxidants-rich foods on human health and disease prevention, there is a continuous interest in plant secondary metabolites conferring attractive colors to fruits and grains and responsible, together with others, for nutraceutical properties. Cereals and Solanaceae are important [...] Read more.

Given the general beneficial effects of antioxidants-rich foods on human health and disease prevention, there is a continuous interest in plant secondary metabolites conferring attractive colors to fruits and grains and responsible, together with others, for nutraceutical properties. Cereals and Solanaceae are important components of the human diet, thus, they are the main targets for functional food development by exploitation of genetic resources and metabolic engineering. In this review, we focus on the impact of antioxidants-rich cereal and Solanaceae derived foods on human health by analyzing natural biodiversity and biotechnological strategies aiming at increasing the antioxidant level of grains and fruits, the impact of agronomic practices and food processing on antioxidant properties combined with a focus on the current state of pre-clinical and clinical studies. Despite the strong evidence in in vitro and animal studies supporting the beneficial effects of antioxidants-rich diets in preventing diseases, clinical studies are still not sufficient to prove the impact of antioxidant rich cereal and Solanaceae derived foods on human Full article

(This article belongs to the Special Issue The Role of Antioxidant Foods and Nutraceuticals in Ageing)

► Show Figures

Figure 1

Figure 1
The flavonoid biosynthesis and its regulation in cereal and Solanaceae crops. Scheme of the pathway leading to the production of flavonoids and phenolic acids in monocots (a) and dicots (b). Phenylalanine is first deaminated by PAL to produce cinnamic acid, then converted by C4H into p-coumaric acid, which can enter the synthesis of hydroxycinnamic acids (i.e., chlorogenic acid and other phenolics) or it can be conjugated with coenzyme A to produce 4-coumaroyl-CoA by 4CL. CHS catalyses the condensation of p-coumaroyl-CoA with three molecules of malonyl-CoA to naringenin chalcone, then converted to the flavanone naringenin by CHI. Indeed, naringenin may be converted to flavones by FNSI/FNSII (e.g., maysin in maize), to the red phlobaphenes, derived from condensation of the 3-deoxy flavonoids apiferol and luteoforol (a) and to dihydroflavonols, such as dihydrokaempferol (DHK), which can then be used by F3′H to produce dihydroquercetin (DHQ) or by F3′5′H to form dihydromyricetin (DHM) (b). Dihydroflavonols are then converted to flavonols (e.g., kaempferol, quercetin, and myricetin) by FLS. Downstream, DFR reduces the dihydroflavonols to their respective colourless leucoanthocyanidins, which are then converted into the coloured anthocyanidins (e.g., cyanidin, pelargonidin, and delphinidin). The main enzymes catalyzing the reactions in the pathway are reported in violet. Regulatory proteins belonging to diverse classes of transcription factors are marked with coloured dots. Branches leading to different classes of flavonoids and anthocyanins are indicated with diverse colours; in B, thicker purple and red arrows highlight the branch leading to the most abundant derived anthocyanins. The name of the enzymes is detailed in the abbreviation list. Full article ">Figure 1 Cont.
The flavonoid biosynthesis and its regulation in cereal and Solanaceae crops. Scheme of the pathway leading to the production of flavonoids and phenolic acids in monocots (a) and dicots (b). Phenylalanine is first deaminated by PAL to produce cinnamic acid, then converted by C4H into p-coumaric acid, which can enter the synthesis of hydroxycinnamic acids (i.e., chlorogenic acid and other phenolics) or it can be conjugated with coenzyme A to produce 4-coumaroyl-CoA by 4CL. CHS catalyses the condensation of p-coumaroyl-CoA with three molecules of malonyl-CoA to naringenin chalcone, then converted to the flavanone naringenin by CHI. Indeed, naringenin may be converted to flavones by FNSI/FNSII (e.g., maysin in maize), to the red phlobaphenes, derived from condensation of the 3-deoxy flavonoids apiferol and luteoforol (a) and to dihydroflavonols, such as dihydrokaempferol (DHK), which can then be used by F3′H to produce dihydroquercetin (DHQ) or by F3′5′H to form dihydromyricetin (DHM) (b). Dihydroflavonols are then converted to flavonols (e.g., kaempferol, quercetin, and myricetin) by FLS. Downstream, DFR reduces the dihydroflavonols to their respective colourless leucoanthocyanidins, which are then converted into the coloured anthocyanidins (e.g., cyanidin, pelargonidin, and delphinidin). The main enzymes catalyzing the reactions in the pathway are reported in violet. Regulatory proteins belonging to diverse classes of transcription factors are marked with coloured dots. Branches leading to different classes of flavonoids and anthocyanins are indicated with diverse colours; in B, thicker purple and red arrows highlight the branch leading to the most abundant derived anthocyanins. The name of the enzymes is detailed in the abbreviation list. Full article ">Figure 2
A simplified overview of carotenoid pathway in cereal and Solanaceae crops. The first step in carotenoid biosynthesis is the condensation of two GGPP molecules to form phytoene catalysed by PSY, which is the main rate-limiting step in solanaceous fruits and cereal grains. Further, the conversion of phytoene to lycopene via sequential desaturation and isomerization reactions is catalysed by a set of four enzymes (PDS, ZISO, ZDS, and CRTISO). Lycopene is at the branch point of carotenoid synthesis since it can be cyclized to ß-carotene or α-carotene by LCYB and LCYE. Downstream, the sequential hydroxylation and epoxidation of these carotenes leads to the production of diverse xanthophylls (e.g., lutein and zeaxanthin). Regulatory proteins belonging to diverse classes of transcription factors are marked with coloured dots. The name of the enzymes is detailed in the abbreviation list. Full article ">

21 pages, 1389 KiB

Open AccessArticle

The Butterfly Effect: Mild Soil Pollution with Heavy Metals Elicits Major Biological Consequences in Cobalt-Sensitized Broad Bean Model Plants

by Raimondas Šiukšta, Vėjūnė Pukenytė, Violeta Kleizaitė, Skaistė Bondzinskaitė and Tatjana Čėsnienė

Antioxidants 2022, 11(4), 793; https://doi.org/10.3390/antiox11040793 - 18 Apr 2022

Cited by 1 | Viewed by 2479

Abstract

Among the heavy metals (HMs), only cobalt induces a polymorphic response in Vicia faba plants, manifesting as chlorophyll morphoses and a ‘break-through’ effect resulting in the elevated accumulation of other HMs, which makes Co-pretreated broad bean plants an attractive model for investigating soil [...] Read more.

Among the heavy metals (HMs), only cobalt induces a polymorphic response in Vicia faba plants, manifesting as chlorophyll morphoses and a ‘break-through’ effect resulting in the elevated accumulation of other HMs, which makes Co-pretreated broad bean plants an attractive model for investigating soil pollution by HMs. In this study, Co-sensitized V. faba plants were used to evaluate the long-term effect of residual industrial pollution by examining biochemical (H₂O₂, ascorbic acid, malondialdehyde, free proline, flavonoid, polyphenols, chlorophylls, carotenoids, superoxide dismutase) and molecular (conserved DNA-derived polymorphism and transcript-derived polymorphic fragments) markers after long-term exposure. HM-polluted soil induced a significantly higher frequency of chlorophyll morphoses and lower levels of nonenzymatic antioxidants in Co-pretreated V. faba plants. Both molecular markers effectively differentiated plants from polluted and control soils into distinct clusters, showing that HMs in mildly polluted soil are capable of inducing changes in DNA coding regions. These findings illustrate that strong background abiotic stressors (pretreatment with Co) can aid investigations of mild stressors (slight levels of soil pollution) by complementing each other in antioxidant content reduction and induction of DNA changes. Full article

(This article belongs to the Special Issue Environmental Stress and Antioxidant Defences)

► Show Figures

Figure 1

Figure 1
Results of PCA using quantitative characteristics of broad bean plants grown in polluted soils with different extents of heavy metal pollution. DF1–DF8—polluted soil from different sites of the drill factory. Full article ">Figure 2
Phenotypic groups (A) and frequencies (B) of Co-induced chlorophyll morphoses (NG—normal green, LG—light green, Y—yellow) observed in V. faba plants grown in soil possessing different pollution levels. DF1,4,6,7,8—polluted soil from different sites of the drill factory. Full article ">Figure 3
Biplot of the first two principal components (PCs) (accounting for 88.3% of the variance) obtained by including two chemical analysis-based soil indices (Zs and RI), germination rate, and frequencies of Co-induced morphoses in V. faba plants grown in soils with different industrial pollution levels. Phenotypes of morphoses: NG—normal green, LG—light green, Y—yellow; C—plants grown in control soil; DF1,4,6,7,8—plants grown in soil collected from different sites of the drill factory. Full article ">Figure 4
Distribution of phenotypic groups (A) and content of free proline (B), ascorbic acid (C), and flavonoids (D) in Co-pretreated V. faba plants after one month of exposure to the mildly polluted soil mix. Phenotypes of morphoses: NG—normal green, LG—light green, Y—yellow; C—plants grown in control soil; DF—plants from soil collected from different sites of the drill factory. Significance level: a p < 0.05, b p < 0.01, c p < 0.001 compared with the respective phenotypic group from control soil; 1 p < 0.05, compared with Co-untreated plants grown in the same soil variant. Full article ">Figure 5
Biplot representing the first two principal components (PCs) (accumulating 72.5% of variance) generated using all tested biochemical parameters (ROS generation, antioxidants, and photosynthetic pigments). Ellipses enclose the same treatment and phenotypic groups of V. faba plants grown in control and polluted soils. Phenotypes of morphoses: NG—normal green, LG—light green, Y—yellow; C—plants grown in control soil; DF—plants from soil collected from different sites of the drill factory. Full article ">Figure 6
UPGMA dendrograms were generated using the conserved DNA-derived polymorphism (CDDP) (A) and variation in the profiles of transcript-derived fragments (TDFs) (B). The Nei and Li genetic distances are presented on the axis, and bootstrap values from 1000 iterations are shown at the branch nodes. Full article ">

16 pages, 897 KiB

Open AccessArticle

Evaluating the Nutritional and Immune Potentiating Characteristics of Unfermented and Fermented Turmeric Camel Milk in Cyclophosphamide-Induced Immunosuppression in Rats

by Thamer Aljutaily

Antioxidants 2022, 11(4), 792; https://doi.org/10.3390/antiox11040792 - 18 Apr 2022

Cited by 8 | Viewed by 3146

Abstract

Antioxidative, nutritional, and immune-boosting characteristics of turmeric-camel milk (TCM) and fermented turmeric-camel milk (FTCM) were investigated. A cyclophosphamide-induced immunosuppression rat model consisting of six experimental groups was carried out to study the effects of TCM and FTCM on weight gain, antioxidant status, immunoglobulin [...] Read more.

Antioxidative, nutritional, and immune-boosting characteristics of turmeric-camel milk (TCM) and fermented turmeric-camel milk (FTCM) were investigated. A cyclophosphamide-induced immunosuppression rat model consisting of six experimental groups was carried out to study the effects of TCM and FTCM on weight gain, antioxidant status, immunoglobulin (Igs), pro-inflammatory and anti-inflammatory cytokines, and oxidative stress biomarkers. TCM or FTCM were orally administrated at 10 or 20 mL Kg⁻¹ rat weight to CYP-immunosuppressed rats for 2 weeks in the presence of negative (NR) and positive (CYP) control groups. The phytochemical analysis and antioxidant capacity results indicated that TCM and FTCM contained considerable phenolic content with super antioxidant activities. CYP injection affected the rats’ weight directly during the first week and then, a low weight gain percentage was recorded in treated groups at the end of the experiment. The most efficient treatment for recovering rats’ weight was administering TCM and FTCM at 20 mL kg⁻¹. Feed efficiency significantly increased with feeding TCM and FTCM in a dose-dependent manner. A significant improvement was found in WBCs, lymphocytes, and neutrophils count, suggesting that both TCM and FTCM alleviated the CYP-induced immunity suppression in a dose-dependent manner. IgG, IgA, and IgM concentrations in the CYP + TCM at 10 or 20 mL kg⁻¹ and CYP + FTCM at 10 or 20 mL kg⁻¹ groups were increased significantly. Concentrations of IL-1 beta, IL-6, IL-10, IL-13, and IL-TNF-α in the CYP group were significantly lower than in the NR group. Interestingly, both TCM and FTCM, especially with high doses, significantly enhanced cytokines production. Administrating FTCM was more potent than TCM, indicating that TCM with probiotics fermentation potentiated the immunological activity in immunosuppressed rats. Treated rats with TCM and FTCM can reverse CYP inhibition of antioxidant enzyme activities, significantly increase GSH, CAT, and SOD, and decrease MDA levels in a dose-dependent manner. In conclusion, these observations indicated that FTCM exhibits better improvements in weight gain, increased immune biomarkers in terms of WBCs, enhanced pro-inflammation and anti-inflammation responses, and accelerated antioxidant activity in immunosuppressed rats compared with TCM. It could be beneficial and profitable for boosting immunity and protecting against oxidative stress. Full article

► Show Figures

Figure 1

17 pages, 2144 KiB

Open AccessReview

The Antioxidant Effect of the Metal and Metal-Oxide Nanoparticles

by Xuemei Ge, Zhaoxin Cao and Lanling Chu

Antioxidants 2022, 11(4), 791; https://doi.org/10.3390/antiox11040791 - 18 Apr 2022

Cited by 49 | Viewed by 4335

Abstract

Inorganic nanoparticles, such as CeO₃, TiO₂ and Fe₃O₄ could be served as a platform for their excellent performance in antioxidant effect. They may offer the feasibility to be further developed for their smaller and controllable sizes, flexibility [...] Read more.

Inorganic nanoparticles, such as CeO₃, TiO₂ and Fe₃O₄ could be served as a platform for their excellent performance in antioxidant effect. They may offer the feasibility to be further developed for their smaller and controllable sizes, flexibility to be modified, relative low toxicity as well as ease of preparation. In this work, the recent progress of these nanoparticles were illustrated, and the antioxidant mechanism of the inorganic nanoparticles were introduced, which mainly included antioxidant enzyme-mimetic activity and antioxidant ROS/RNS scavenging activity. The antioxidant effects and the applications of several nanoparticles, such as CeO₃, Fe₃O₄, TiO₂ and Se, are summarized in this paper. The potential toxicity of these nanoparticles both in vitro and in vivo was well studied for the further applications. Future directions of how to utilize these inorganic nanoparticles to be further applied in some fields, such as medicine, cosmetic and functional food additives were also investigated in this paper. Full article

► Show Figures

Figure 1

Figure 1
Scale-up platform currently in development and inorganic particle species formed on-chip. (A) Flow schematic of high-throughput assembly. The structure of microfluid platform with insets of disposable positive displacement pumps and cartridge holder that does not require manual fluidic connections. (B) TEM images of ZnO particles prepared by using LGD variant at FRR of 1:1, 1:6, and 1:20. Iron oxide particles fabricated at a TFR of 10.5 mL/min and FRR of 1:2. Full article ">Figure 2
(A) Structure of a nanoparticle of ceria showing 111, 110 and 100 surfaces. The structures of “perfect” 111, 110 and 100 surfaces of nanoceria simulated using DFT are consistent with the structures of the surfaces exposed by the nanoparticle. (B) One of the nanoparticle’s 111 surfaces after nanoceria has been reduced. Ce4+ is in white, Ce3+ is in blue and oxygen is red. (C) Interaction energy of phosphate with nanoceria for three compositions of nanoceria in a living cell. Interaction energy (kJ/mol) of phosphate at nanoceria surfaces 111 (blue triangles), 110 (green circles) and 100 (red squares). Full article ">Figure 3
Examples of the fabrication process of the iron oxide nanoparticles. (A) Schematic representation of biosynthesis of FeONPs. (B) Surface modification of the nanoparticles. L−PEOXA−FexOy and C−PEOXA−FexOy NPs show different stability in HSA. Cyclic PEOXA shells could quantitatively prevent the formation of a protein corona. Linear brush shells cannot be entirely prevented. Full article ">Figure 4
(A) The preparation process of SeNPs-C/C. (B) The SEM image and distribution of CTS-SeNPs as well as SeNPs-C/C.) [<a href="#B126-antioxidants-11-00791" class="html-bibr">126</a>]. Full article ">Figure 5
(A) The formation of the corona around the TiO2 nanoparticles with the protein from foods. (B) CD spectra of protein (glutenin, gliadin, soy protein isolate, zein) and protein−nanoparticle coronas. Full article ">

20 pages, 4301 KiB

Open AccessReview

Overview of Research on Vanadium-Quercetin Complexes with a Historical Outline

by Agnieszka Ścibior

Antioxidants 2022, 11(4), 790; https://doi.org/10.3390/antiox11040790 - 17 Apr 2022

Cited by 11 | Viewed by 2625

Abstract

The present review was conducted to gather the available literature on some issues related to vanadium-quercetin (V-QUE) complexes. It was aimed at collecting data from in vitro and in vivo studies on the biological activity, behavior, antioxidant properties, and radical scavenging power of [...] Read more.

The present review was conducted to gather the available literature on some issues related to vanadium-quercetin (V-QUE) complexes. It was aimed at collecting data from in vitro and in vivo studies on the biological activity, behavior, antioxidant properties, and radical scavenging power of V-QUE complexes. The analysis of relevant findings allowed summarizing the evidence for the antidiabetic and anticarcinogenic potential of V-QUE complexes and suggested that they could serve as pharmacological agents for diabetes and cancer. These data together with other well-documented biological properties of V and QUE (common for both), which are briefly summarized in this review as well, may lay the groundwork for new therapeutic treatments and further research on a novel class of pharmaceutical molecules with better therapeutic performance. Simultaneously, the results compiled in this report point to the need for further studies on complexation of V with flavonoids to gain further insight into their behavior, identify species responsible for their physiological activity, and fully understand their mechanism of action. Full article

► Show Figures

Graphical abstract

14 pages, 594 KiB

Open AccessArticle

Rosemary Extracts Improved the Antioxidant Status of Low-Fat Yoghurt Sauces Enriched with Inulin

by Magdalena Martínez-Tomé, Cristina Cedeño-Pinos, Sancho Bañón and Antonia M. Jiménez-Monreal

Antioxidants 2022, 11(4), 789; https://doi.org/10.3390/antiox11040789 - 16 Apr 2022

Cited by 5 | Viewed by 2714

Abstract

Yoghurt sauces are considered fatty products which are quite susceptible to oxidation and must be stabilised using antioxidants. Novel formulations for yoghurt sauces often involve replacement of fat with dietary fibres and use of natural preservatives. The aim of the present research was [...] Read more.

Yoghurt sauces are considered fatty products which are quite susceptible to oxidation and must be stabilised using antioxidants. Novel formulations for yoghurt sauces often involve replacement of fat with dietary fibres and use of natural preservatives. The aim of the present research was to design healthier formulations for yoghurt sauces based on the replacement of sunflower oil (SO) with chicory inulin (IN) and the use of rosemary extracts (RE) as natural antioxidants. Different sauces were developed by adding IN at 2 and 5% w: w and/or 300 mg/kg lipo- and/or water-soluble rosemary extracts (RLE and/or RWE) containing 120 and 146 mg polyphenols per g extract, respectively. Nutritional value (proximate composition and caloric contribution), some physical properties (pH and CIELab colour) and antioxidant status (deoxyribose, DPPH radical scavenging, Rancimat, lipid peroxidation and linoleic acid assays) were assessed in the sauces. Replacement of SO with IN (5%) reduced fat content by 30%, roughly 15% low calories, thereby obtaining healthier sauces. As expected, the RLE was more effective than the RWE in improving antioxidant activity in lipidic environment. Using RLE enhanced the antioxidant capacity of lipid peroxidation by 44%. In the Rancimat test, this increased the oxidative protection of the sauce made with and without IN (5%) by around 20% or 45%, respectively. Similarly, using RLE doubled protection against linoleic acid oxidation. Application of IN in yoghurt sauce has nutritional (replacement of lipids with dietary fibre) and technological interest (foaming agent) and can be combined with RE of high polyphenol content as a potential functional ingredient capable of stabilising the sauces against oxidation. Full article

► Show Figures

Figure 1

22 pages, 544 KiB

Open AccessReview

Neonatal Anesthesia and Oxidative Stress

by David A. Gascoigne, Mohammed M. Minhaj and Daniil P. Aksenov

Antioxidants 2022, 11(4), 787; https://doi.org/10.3390/antiox11040787 - 16 Apr 2022

Cited by 9 | Viewed by 3388

Abstract

Neonatal anesthesia, while often essential for surgeries or imaging procedures, is accompanied by significant risks to redox balance in the brain due to the relatively weak antioxidant system in children. Oxidative stress is characterized by concentrations of reactive oxygen species (ROS) that are [...] Read more.

Neonatal anesthesia, while often essential for surgeries or imaging procedures, is accompanied by significant risks to redox balance in the brain due to the relatively weak antioxidant system in children. Oxidative stress is characterized by concentrations of reactive oxygen species (ROS) that are elevated beyond what can be accommodated by the antioxidant defense system. In neonatal anesthesia, this has been proposed to be a contributing factor to some of the negative consequences (e.g., learning deficits and behavioral abnormalities) that are associated with early anesthetic exposure. In order to assess the relationship between neonatal anesthesia and oxidative stress, we first review the mechanisms of action of common anesthetic agents, the key pathways that produce the majority of ROS, and the main antioxidants. We then explore the possible immediate, short-term, and long-term pathways of neonatal-anesthesia-induced oxidative stress. We review a large body of literature describing oxidative stress to be evident during and immediately following neonatal anesthesia. Moreover, our review suggests that the short-term pathway has a temporally limited effect on oxidative stress, while the long-term pathway can manifest years later due to the altered development of neurons and neurovascular interactions. Full article

(This article belongs to the Special Issue Oxidative Stress and Neurodegenerative Disorders II)

► Show Figures

Figure 1

19 pages, 3343 KiB

Open AccessArticle

Loss and Recovery of Glutaredoxin 5 Is Inducible by Diet in a Murine Model of Diabesity and Mediated by Free Fatty Acids In Vitro

by Sebastian Friedrich Petry, Axel Römer, Divya Rawat, Lara Brunner, Nina Lerch, Mengmeng Zhou, Rekha Grewal, Fatemeh Sharifpanah, Heinrich Sauer, Gunter Peter Eckert and Thomas Linn

Antioxidants 2022, 11(4), 788; https://doi.org/10.3390/antiox11040788 - 15 Apr 2022

Cited by 3 | Viewed by 3217

Abstract

Free fatty acids (FFA), hyperglycemia, and inflammatory cytokines are major mediators of β-cell toxicity in type 2 diabetes mellitus, impairing mitochondrial metabolism. Glutaredoxin 5 (Glrx5) is a mitochondrial protein involved in the assembly of iron–sulfur clusters required for complexes of the respiratory chain. [...] Read more.

Free fatty acids (FFA), hyperglycemia, and inflammatory cytokines are major mediators of β-cell toxicity in type 2 diabetes mellitus, impairing mitochondrial metabolism. Glutaredoxin 5 (Glrx5) is a mitochondrial protein involved in the assembly of iron–sulfur clusters required for complexes of the respiratory chain. We have provided evidence that islet cells are deprived of Glrx5, correlating with impaired insulin secretion during diabetes in genetically obese mice. In this study, we induced diabesity in C57BL/6J mice in vivo by feeding the mice a high-fat diet (HFD) and modelled the diabetic metabolism in MIN6 cells through exposure to FFA, glucose, or inflammatory cytokines in vitro. qRT-PCR, ELISA, immunohisto-/cytochemistry, bioluminescence, and respirometry were employed to study Glrx5, insulin secretion, and mitochondrial biomarkers. The HFD induced a depletion of islet Glrx5 concomitant with an obese phenotype, elevated FFA in serum and reactive oxygen species in islets, and impaired glucose tolerance. Exposure of MIN6 cells to FFA led to a loss of Glrx5 in vitro. The FFA-induced depletion of Glrx5 coincided with significantly altered mitochondrial biomarkers. In summary, we provide evidence that Glrx5 is regulated by FFA in type 2 diabetes mellitus and is linked to mitochondrial dysfunction and blunted insulin secretion. Full article

(This article belongs to the Special Issue Thioredoxin and Glutaredoxin Systems II)

► Show Figures

Figure 1

Figure 1
Experimental setup of the animal experiment. Male C57BL/6J mice were divided into the experimental (Exp) and control (Ctrl) groups at the age of 7 weeks after 2 weeks of adaption to our animal housing. Control animals were fed a control diet (CD, ca. 3514 kcal/kg, 10% of energy from fat, 66% from carbohydrates, and 24% from protein) throughout the study period. The experimental group was fed a high-fat diet (HFD, ca. 5389 kcal/kg, 70% of energy from fat, 14% from carbohydrates, and 16% from protein) from 7 to 20 weeks of age, followed by rescue feeding with the CD for 3 weeks, and another cycle of the HFD for 4 weeks. Euthanasia was carried out in both groups at 7, 20, 23, and 27 weeks of age. Full article ">Figure 2
Fasting and dynamic blood glucose levels, body weight, free fatty acid levels, and pancreas weight of the research animals. IPGTT and euthanasia was conducted before dietary changes and at the end of the experimental procedure at 7, 20, 23, and 27 weeks of age. Fasting blood glucose levels and body weight were monitored every two weeks until 20 weeks of age, and then weekly. (A) Body weight and (B) fasting blood glucose values at 7, 20, 23, and 27 weeks of age; n = 5–33 mice/timepoint/group. (C) Blood FFA levels as determined by ELISA; n = three mice/timepoint/group. (D) Pancreas weight; n = six mice/timepoint/group. (E–H) IPGTT results at (E) 7, (F) 20, (G) 23, and (H) 27 weeks of age; n = five mice/timepoint/group. For each graph, the white bars represent the controls, and the black bars represent the experimental group. *** denotes p < 0.001, ** p < 0.005, and * p < 0.05 ((A–D): two-way ANOVA, (E–H): unpaired t-test). Full article ">Figure 3
Immunohistological and Ins1 and Glrx5 mRNA expression analysis. The immunohistological staining patterns of insulin and Glrx5 were analyzed at 7, 20, 23, and 27 weeks of age. Glrx5 staining was quantified by calculating the ratio of the Glrx5/insulin staining area. The mRNA expression of Ins1 and Glrx5 was studied using qRT-PCR. (A–F, J–O, S–X, AB–AG) Representative images taken from the immunohistological analysis of insulin and Glrx5 presenting size-matched representative islets of both groups of mice ((A–C) controls, 7 weeks; (D–F) HFD, 7 weeks; (J–L) controls, 20 weeks; (M–O) HFD, 20 weeks; (S–U) controls, 23 weeks; (V–X) HFD, 23 weeks; (AB–AD) controls, 27 weeks; (AE–AG) HFD, 27 weeks). Green = insulin, red = Glrx5, blue = nuclei. Scale bars represent 100 µm. Images were taken at 200× magnification. n = 33–67 islets of three to four mice/timepoint/group. (G,P,Y,AH) The quantification of Glrx5 staining. (H,Q,Z,AI) The islet mRNA expression of Glrx5 and (I,R,AA,AJ) of Ins1 given as fold change controls vs. HFD for each time point. n = six mice/timepoint/group. For each graph, the white bars represent the controls, and the black bars represent the experimental group. **** denotes p < 0.0001, ** p < 0.005, and * p < 0.05 (two-way ANOVA). Full article ">Figure 4
Pancreatic islet ROS production and glucose stimulation. ROS were quantified in pancreatic islets from animals of both groups at 7, 20, and 23 weeks of age by DCFH-DA staining and analysis with a confocal microscope. The glucose stimulation and consecutive measurements of insulin in islet lysates and the medium were conducted in both groups at 27 weeks of age. (A) The ROS production of primary islets at 7, 20, and 23 weeks of age. n = 63–65 islets of three mice/timepoint/group. (B,C) The amount of insulin in the (B) lysates and (C) culture medium of the islets before and after stimulation with 300 mg/dL glucose. n = five islets of three mice/timepoint/group, four runs. For each graph, the white bars represent the controls, and the black bars represent the experimental group. **** denotes p < 0.0001, ** p < 0.005, and * p < 0.05 (two-way ANOVA). Full article ">Figure 5
MIN6 Glrx5 level and insulin secretion. (A,B) Diabetic conditions were modelled in MIN6 cells employing a 48 h period of pre-incubation with 400 µM palmitic acid (PA) followed by 1 h of starvation and exposure to increasing concentrations of glucose for 24 h. (C,D) Furthermore, we employed a treatment with 0.75, 1.5, or 3 mM oleic acid for 24 h, (E,F) and a 2 h period of starvation followed by exposure to 5, 10, 20, or 30 mM glucose for 24 h, or (G,H) a cytokine mix (10 ng/mL TNF-α, 5 ng/mL IL-1β, and 100 ng/mL IFN-γ) for 24 or 48 h, respectively. The protein level of Glrx5 in lysate and insulin in the culture medium of β-cells exposed to (A,B) glucose for 24 h after and without pre-incubation with 400 µM palmitate and 1h of starvation; (C,D) oleic acid for 24 h; (E,F) glucose for 24 h after 2 h of starvation; and (G,H) a mix of 10 ng/mL TNF-α, 5 ng/mL IL-1β, and 100 ng/mL IFN-γ for 24 or 48 h. Insulin and Glrx5 were measured by ELISA and normalized by total protein. The white bars represent the controls, and the black bars represent the (pre)-treated cells. n = 3–5. **** denotes p < 0.0001, *** p < 0.001, ** p < 0.005, and * p <0.05 (one-/two-way ANOVA). Full article ">Figure 6
Cytological analysis of MIN6 insulin and Glrx5 content. MIN6 cells exposed to 1.5 mM oleic acid for 24 h were stained for insulin and Glrx5 and compared with the controls. Staining was quantified by measuring the integrated density using ImageJ software. The values for insulin and Glrx5 were correlated. (A) The correlation of insulin with Glrx5 in the control cells and (B) after treatment with 1.5 mM oleic acid for 24 h. n = 4 (9–35 cells/run, Pearson). Full article ">Figure 7
ATP production and the O2 flux in the respiratory chain after FFA treatment. Cellular ATP levels were analyzed employing a luciferase-based bioluminescence assay. Respiratory states were measured with an Oxygraph and an O2 probe. (A) ATP after exposure to oleic acid for 24 h or (B) after pre-incubation with 400 µM palmitate, 1 h of starvation, and exposure to glucose. (C–H) The O2 flux in the respiratory chain after exposure to 0.75 mM oleic acid for 24 h. The white bars represent the controls, and the black bars represent the (pre-)treated cells. n = 12. **** denotes p < 0.0001, *** p < 0.001, ** p < 0.005 and * p < 0.05 (one-way ANOVA/unpaired t-test). Full article ">

18 pages, 7691 KiB

Open AccessArticle

Antioxidant and Anticancer Activities of Synthesized Methylated and Acetylated Derivatives of Natural Bromophenols

by Hui Dong, Li Wang, Meng Guo, Dimitrios Stagos, Antonis Giakountis, Varvara Trachana, Xiukun Lin, Yankai Liu and Ming Liu

Antioxidants 2022, 11(4), 786; https://doi.org/10.3390/antiox11040786 - 15 Apr 2022

Cited by 3 | Viewed by 2319

Abstract

Natural bromophenols are important secondary metabolites in marine algae. Derivatives of these bromophenol are potential candidates for the drug development due to their biological activities, such as antioxidant, anticancer, anti-diabetic and anti-inflammatory activity. In our present study, we have designed and synthesized a [...] Read more.

Natural bromophenols are important secondary metabolites in marine algae. Derivatives of these bromophenol are potential candidates for the drug development due to their biological activities, such as antioxidant, anticancer, anti-diabetic and anti-inflammatory activity. In our present study, we have designed and synthesized a series of new methylated and acetylated bromophenol derivatives from easily available materials using simple operation procedures and evaluated their antioxidant and anticancer activities on the cellular level. The results showed that 2.,3-dibromo-1-(((2-bromo-4,5-dimethoxybenzyl)oxy)methyl)-4,5-dimethoxybenzene (3b-9) and (oxybis(methylene))bis(4-bromo-6-methoxy-3,1-phenylene) diacetate (4b-3) compounds ameliorated H₂O₂-induced oxidative damage and ROS generation in HaCaT keratinocytes. Compounds 2.,3-dibromo-1-(((2-bromo-4,5-dimethoxybenzyl)oxy)methyl)-4,5-dimethoxybenzene (3b-9) and (oxybis(methylene) )bis(4-bromo-6-methoxy-3,1-phenylene) diacetate (4b-3) also increased the TrxR1 and HO-1 expression while not affecting Nrf2 expression in HaCaT. In addition, compounds (oxybis(methylene)bis(2-bromo-6-methoxy-4,1-phenylene) diacetate (4b-4) inhibited the viability and induced apoptosis of leukemia K562 cells while not affecting the cell cycle distribution. The present work indicated that some of these bromophenol derivatives possess significant antioxidant and anticancer potential, which merits further investigation. Full article

(This article belongs to the Special Issue Antioxidant and Chemopreventive Activity of Natural Compounds)

► Show Figures

Figure 1

19 pages, 4100 KiB

Open AccessArticle

In Silico Identification of Novel Inhibitors Targeting the Homodimeric Interface of Superoxide Dismutase from the Dental Pathogen Streptococcus mutans

by Carmen Cerchia, Emanuela Roscetto, Rosarita Nasso, Maria Rosaria Catania, Emmanuele De Vendittis, Antonio Lavecchia, Mariorosario Masullo and Rosario Rullo

Antioxidants 2022, 11(4), 785; https://doi.org/10.3390/antiox11040785 - 15 Apr 2022

Cited by 3 | Viewed by 2301

Abstract

The microaerophile Streptococcus mutans, the main microaerophile responsible for the development of dental plaque, has a single cambialistic superoxide dismutase (SmSOD) for its protection against reactive oxygen species. In order to discover novel inhibitors of SmSOD, possibly interfering with [...] Read more.

The microaerophile Streptococcus mutans, the main microaerophile responsible for the development of dental plaque, has a single cambialistic superoxide dismutase (SmSOD) for its protection against reactive oxygen species. In order to discover novel inhibitors of SmSOD, possibly interfering with the biofilm formation by this pathogen, a virtual screening study was realised using the available 3D-structure of SmSOD. Among the selected molecules, compound ALS-31 was capable of inhibiting SmSOD with an IC₅₀ value of 159 µM. Its inhibition power was affected by the Fe/Mn ratio in the active site of SmSOD. Furthermore, ALS-31 also inhibited the activity of other SODs. Gel-filtration of SmSOD in the presence of ALS-31 showed that the compound provoked the dissociation of the SmSOD homodimer in two monomers, thus compromising the catalytic activity of the enzyme. A docking model, showing the binding mode of ALS-31 at the dimer interface of SmSOD, is presented. Cell viability of the fibroblast cell line BJ5-ta was not affected up to 100 µM ALS-31. A preliminary lead optimization program allowed the identification of one derivative, ALS-31-9, endowed with a 2.5-fold improved inhibition power. Interestingly, below this concentration, planktonic growth and biofilm formation of S. mutans cultures were inhibited by ALS-31, and even more by its derivative, thus opening the perspective of future drug design studies to fight against dental caries. Full article

(This article belongs to the Section Antioxidant Enzyme Systems)

► Show Figures

Graphical abstract

19 pages, 1214 KiB

Open AccessReview

Role of Oxidative Stress in Diabetic Cardiomyopathy

by Bart De Geest and Mudit Mishra

Antioxidants 2022, 11(4), 784; https://doi.org/10.3390/antiox11040784 - 15 Apr 2022

Cited by 72 | Viewed by 6200

Abstract

Type 2 diabetes is a redox disease. Oxidative stress and chronic inflammation induce a switch of metabolic homeostatic set points, leading to glucose intolerance. Several diabetes-specific mechanisms contribute to prominent oxidative distress in the heart, resulting in the development of diabetic cardiomyopathy. Mitochondrial [...] Read more.

Type 2 diabetes is a redox disease. Oxidative stress and chronic inflammation induce a switch of metabolic homeostatic set points, leading to glucose intolerance. Several diabetes-specific mechanisms contribute to prominent oxidative distress in the heart, resulting in the development of diabetic cardiomyopathy. Mitochondrial overproduction of reactive oxygen species in diabetic subjects is not only caused by intracellular hyperglycemia in the microvasculature but is also the result of increased fatty oxidation and lipotoxicity in cardiomyocytes. Mitochondrial overproduction of superoxide anion radicals induces, via inhibition of glyceraldehyde 3-phosphate dehydrogenase, an increased polyol pathway flux, increased formation of advanced glycation end-products (AGE) and activation of the receptor for AGE (RAGE), activation of protein kinase C isoforms, and an increased hexosamine pathway flux. These pathways not only directly contribute to diabetic cardiomyopathy but are themselves a source of additional reactive oxygen species. Reactive oxygen species and oxidative distress lead to cell dysfunction and cellular injury not only via protein oxidation, lipid peroxidation, DNA damage, and oxidative changes in microRNAs but also via activation of stress-sensitive pathways and redox regulation. Investigations in animal models of diabetic cardiomyopathy have consistently demonstrated that increased expression of the primary antioxidant enzymes attenuates myocardial pathology and improves cardiac function. Full article

(This article belongs to the Special Issue Mitochondrial Dysfunction and Oxidative Stress in Diabetes and Associated Diseases)

► Show Figures

Figure 1

16 pages, 1106 KiB

Open AccessArticle

Effect of Dietary Phenolic Compounds on Incidence of Cardiovascular Disease in the SUN Project; 10 Years of Follow-Up

by Zenaida Vázquez-Ruiz, Estefanía Toledo, Facundo Vitelli-Storelli, Leticia Goni, Víctor de la O, Maira Bes-Rastrollo and Miguel Ángel Martínez-González

Antioxidants 2022, 11(4), 783; https://doi.org/10.3390/antiox11040783 - 14 Apr 2022

Cited by 17 | Viewed by 3163

Abstract

The health benefits of plant-based diets have been reported. Plant-based diets found in Spain and other Mediterranean countries differ from typical diets in other countries. In the Mediterranean diet, a high intake of phenolic compounds through olives, olive oil, and red wine may [...] Read more.

The health benefits of plant-based diets have been reported. Plant-based diets found in Spain and other Mediterranean countries differ from typical diets in other countries. In the Mediterranean diet, a high intake of phenolic compounds through olives, olive oil, and red wine may play an important role in cardiovascular prevention. Prospective studies carried out in Mediterranean countries may provide interesting insights. A relatively young Mediterranean cohort of 16,147 Spanish participants free of cardiovascular disease (CVD) was followed (61% women, mean (SD) age 37(12) years at baseline) for a median of 12.2 years. Dietary intake was repeatedly assessed using a 136-item validated food frequency questionnaire, and (poly)phenol intake was obtained using the Phenol-Explorer database. Participants were classified as incident cases of CVD if a medical diagnosis of myocardial infarction, stroke, or cardiovascular death was medically confirmed. Time-dependent Cox regression models were used to assess the relationship between (poly)phenol intake and the incidence of major CVD. A suboptimal intake of phenolic compounds was independently associated with a higher risk of CVD, multivariable-adjusted hazard ratio for the lowest versus top 4 quintiles: 1.85 (95% CI: 1.09–3.16). A moderate-to-high dietary intake of phenolic compounds, especially flavonoids, is likely to reduce CVD incidence in the context of a Mediterranean dietary pattern. Full article

(This article belongs to the Special Issue Antioxidant Activity of “Polyphenolic-Food” and Human Health – 2nd Edition)

► Show Figures

Figure 1

26 pages, 6123 KiB

Open AccessArticle

HO-1 Upregulation by Kaempferol via ROS-Dependent Nrf2-ARE Cascade Attenuates Lipopolysaccharide-Mediated Intercellular Cell Adhesion Molecule-1 Expression in Human Pulmonary Alveolar Epithelial Cells

by Chien-Chung Yang, Li-Der Hsiao, Chen-Yu Wang, Wei-Ning Lin, Ya-Fang Shih, Yi-Wen Chen, Rou-Ling Cho, Hui-Ching Tseng and Chuen-Mao Yang

Antioxidants 2022, 11(4), 782; https://doi.org/10.3390/antiox11040782 - 14 Apr 2022

Cited by 14 | Viewed by 2947

Abstract

Lung inflammation is a pivotal event in the pathogenesis of acute lung injury. Heme oxygenase-1 (HO-1) is a key antioxidant enzyme that could be induced by kaempferol (KPR) and exerts anti-inflammatory effects. However, the molecular mechanisms of KPR-mediated HO-1 expression and its effects [...] Read more.

Lung inflammation is a pivotal event in the pathogenesis of acute lung injury. Heme oxygenase-1 (HO-1) is a key antioxidant enzyme that could be induced by kaempferol (KPR) and exerts anti-inflammatory effects. However, the molecular mechanisms of KPR-mediated HO-1 expression and its effects on inflammatory responses remain unknown in human pulmonary alveolar epithelial cells (HPAEpiCs). This study aimed to verify the relationship between HO-1 expression and KPR treatment in both in vitro and in vivo models. HO-1 expression was determined by real time-PCR, Western blotting, and promoter reporter analyses. The signaling components were investigated by using pharmacological inhibitors or specific siRNAs. Chromatin immunoprecipitation (ChIP) assay was performed to investigate the interaction between nuclear factor erythroid-2-related factor (Nrf2) and antioxidant response elements (ARE) binding site of HO-1 promoter. The effect of KPR on monocytes (THP-1) binding to HPAEpiCs challenged with lipopolysaccharides (LPS) was determined by adhesion assay. We found that KPR-induced HO-1 level attenuated the LPS-induced intercellular cell adhesion protein 1 (ICAM-1) expression in HPAEpiCs. KPR-induced HO-1 mRNA and protein expression also attenuated ICAM-1 expression in mice. Tin protoporphyrin (SnPP)IX reversed the inhibitory effects of KPR in HPAEpiCs. In addition, in HPAEpiCs, KPR-induced HO-1 expression was abolished by both pretreating with the inhibitor of NADPH oxidase (NOX, apocynin (APO)), reactive oxygen species (ROS) (N-acetyl-L-cysteine (NAC)), Src (Src kinase inhibitor II (Srci II)), Pyk2 (PF431396), protein kinase C (PKC)α (Gö6976), p38 mitogen-activated protein kinase (MAPK) inhibitor (p38i) VIII, or c-Jun N-terminal kinases (JNK)1/2 (SP600125) and transfection with their respective siRNAs. The transcription of the homx1 gene was enhanced by Nrf2 activated by JNK1/2 and p38α MAPK. The binding activity between Nrf2 and HO-1 promoter was attenuated by APO, NAC, Srci II, PF431396, or Gö6983. KPR-mediated NOX/ROS/c-Src/Pyk2/PKCα/p38α MAPK and JNK1/2 activate Nrf2 to bind with ARE on the HO-1 promoter and induce HO-1 expression, which further suppresses the LPS-mediated inflammation in HPAEpiCs. Thus, KPR exerts a potential strategy to protect against pulmonary inflammation via upregulation of the HO-1. Full article

(This article belongs to the Special Issue Pharmacological and Clinical Significance of Heme Oxygenase-1 2022)

► Show Figures

Graphical abstract

18 pages, 3454 KiB

Open AccessArticle

Antioxidant Effects of Korean Propolis in HaCaT Keratinocytes Exposed to Particulate Matter 10

by In Ah Bae, Jae Won Ha, Joon Yong Choi and Yong Chool Boo

Antioxidants 2022, 11(4), 781; https://doi.org/10.3390/antiox11040781 - 14 Apr 2022

Cited by 9 | Viewed by 2938

Abstract

Air pollution causes oxidative stress that leads to inflammatory diseases and premature aging of the skin. The purpose of this study was to examine the antioxidant effect of Korean propolis on oxidative stress in human epidermal HaCaT keratinocytes exposed to particulate matter with [...] Read more.

Air pollution causes oxidative stress that leads to inflammatory diseases and premature aging of the skin. The purpose of this study was to examine the antioxidant effect of Korean propolis on oxidative stress in human epidermal HaCaT keratinocytes exposed to particulate matter with a diameter of less than 10 μm (PM₁₀). The total ethanol extract of propolis was solvent-fractionated with water and methylene chloride to divide into a hydrophilic fraction and a lipophilic fraction. The lipophilic fraction of propolis was slightly more cytotoxic, and the hydrophilic fraction was much less cytotoxic than the total extract. The hydrophilic fraction did not affect the viability of cells exposed to PM₁₀, but the total propolis extract and the lipophilic fraction aggravated the toxicity of PM₁₀. The total extract and hydrophilic fraction inhibited PM₁₀-induced ROS production and lipid peroxidation in a concentration-dependent manner, whereas the lipophilic fraction did not show such effects. High-performance liquid chromatography with photodiode array detection (HPLC-DAD) analysis showed that the hydrophilic fraction contained phenylpropanoids, such as caffeic acid, p-coumaric acid, and ferulic acid, whereas the lipophilic faction contained caffeic acid phenethyl ester (CAPE). The former three compounds inhibited PM₁₀-induced ROS production, lipid peroxidation, and/or glutathione oxidation, and ferulic acid was the most effective among them, but CAPE exhibited cytotoxicity and aggravated the toxicity of PM₁₀. This study suggests that Korean propolis, when properly purified, has the potential to be used as a cosmetic material that helps to alleviate the skin toxicity of air pollutants. Full article

(This article belongs to the Special Issue Antioxidant Activity of Honey Bee Products)

► Show Figures

Graphical abstract

17 pages, 1499 KiB

Open AccessArticle

Creeping Wood Sorrel and Chromium Picolinate Effect on the Nutritional Composition and Lipid Oxidative Stability of Broiler Meat

by Mihaela Saracila, Arabela Elena Untea, Tatiana Dumitra Panaite, Iulia Varzaru, Alexandra Oancea, Raluca Paula Turcu and Petru Alexandru Vlaicu

Antioxidants 2022, 11(4), 780; https://doi.org/10.3390/antiox11040780 - 14 Apr 2022

Cited by 6 | Viewed by 2366

Abstract

The study investigates the efficacy of Cr in broilers, aiming to evaluate the effects of Chromium picolinate (CrPic) in association with creeping wood sorrel powder (CWS) on the proximate composition, fatty acids profile, bioactive nutrients and lipid oxidative stability of broiler meat. A [...] Read more.

The study investigates the efficacy of Cr in broilers, aiming to evaluate the effects of Chromium picolinate (CrPic) in association with creeping wood sorrel powder (CWS) on the proximate composition, fatty acids profile, bioactive nutrients and lipid oxidative stability of broiler meat. A total of 120 Cobb 500 chickens were assigned into three treatments: a control diet (C) and two test diets, including 200 µg/kg diet CrPic (E1), and 200 µg/kg diet CrPic +10 g CWS/kg diet (E2). Dietary supplementation with Cr + CWS significantly improved the concentration of n − 3 polyunsaturated fatty acids (PUFAs), while its n − 6/n − 3 ratio decreased in comparison to the group receiving Cr and the conventional diet. The concentration of docosahexaenoic acid (DHA) significantly increased in the breast meat collected from the E2 group than that from the C group. Dietary administration of Cr and CWS improved lutein and zeaxanthin content, decreased Fe and Zn levels of the breast, and increased Zn deposition in the thigh samples. Malondialdehyde (MDA) concentration decreased more in the thigh meat of the supplemental groups (E1, E2) than in that from the C group. In conclusion, the current study suggests that Cr together with CWS can be a viable option as antioxidant sources for broiler diets, promoting the nutritional quality of meat. Full article

(This article belongs to the Special Issue Antioxidants in Foods II)

► Show Figures

Graphical abstract

Graphical abstract
Full article ">Figure 1
Nutritional quality indices of the lipids in breast meat. Main effects of diet are presented in each graph (Prism Graph 9.02). Data are presented as mean SEM (n = 6 broilers/group). Asterisks denote statistical significance (p > 0.1234 ns; * p ≤ 0.0332; ** p ≤ 0.0021); AI = atherogenic index; TI = thrombogenicity index; SI = saturation index; h/H = hypo/hypercholesterolemic index; HPI = health-promoting index; C—control diet; E1 = experimental diet supplemented with 200 µg/kg diet CrPic; E2 = experimental diet supplemented with 200 µg/kg diet CrPic + 10 g creeping wood sorrel powder (CWS)/kg diet. Full article ">Figure 2
Nutritional quality indices of the lipids in thigh meat. Main effects of diet are presented in each graph (Prism Graph 9.02). Data are presented as mean SEM (n = 6 broilers/group); AI = atherogenic index; TI = thrombogenicity index; SI = saturation index; h/H = hypo/hypercholesterolemic index; HPI = health-promoting index; C—control diet; E1 = experimental diet supplemented with 200 µg/kg diet CrPic; E2 = experimental diet supplemented with 200 µg/kg diet CrPic + 10 g creeping wood sorrel powder (CWS)/kg diet. Full article ">Figure 3
TBA reactive substances (TBARS) of broiler breast and thigh meat during seven days of storage. Main effects of diet are presented in each graph (Prism Graph 9.02). Data are presented as mean SEM (n = 6 broilers/group). Asterisks denote statistical significance (p > 0.1234 ns, * p ≤ 0.0332; ** p ≤ 0.0021); C—control diet; E1 = experimental diet supplemented with 200 µg/kg diet CrPic; E2 = experimental diet supplemented with 200 µg/kg diet CrPic + 10 g creeping wood sorrel powder (CWS)/kg diet. Full article ">Figure 4
Heat map showing Pearson’s correlations between bioactive nutrients content, TAC and TBARS in breast (A) and thigh meat (B). Abbreviations: TPC, total phenolic content; TAC, total antioxidant capacity; TBARS, thiobarbituric reactive substances. Blue colors correspond to positive correlation coefficients, red colors correspond to negative correlation coefficients. The saturation of colors reflects the absolute value of the correlation coefficient. Asterisks indicate a significant correlation between respective parameters: * p < 0.05 if the correlation is significant at alpha = 0.05 level; ** p < 0.01 if the correlation is significant at alpha = 0.01 level; p < 0.001 if the correlation is significant at alpha = 0.001 level. Full article ">

13 pages, 2588 KiB

Open AccessArticle

Natural Polyphenols May Normalize Hypochlorous Acid-Evoked Hemostatic Abnormalities in Human Blood

by Tomasz Misztal, Agata Golaszewska, Natalia Marcińczyk, Maria Tomasiak-Łozowska, Małgorzata Szymanowska, Ewa Chabielska and Tomasz Rusak

Antioxidants 2022, 11(4), 779; https://doi.org/10.3390/antiox11040779 - 14 Apr 2022

Cited by 1 | Viewed by 2018

Abstract

During pathogen invasion, activated neutrophils secrete myeloperoxidase (MPO), which generates high local concentrations of hypochlorous acid (HOCl), a strong antimicrobial agent. Prolonged or uncontrolled HOCl production may, however, affect hemostasis, manifesting in inhibition of platelet aggregation and thrombus formation and in elevated fibrin [...] Read more.

During pathogen invasion, activated neutrophils secrete myeloperoxidase (MPO), which generates high local concentrations of hypochlorous acid (HOCl), a strong antimicrobial agent. Prolonged or uncontrolled HOCl production may, however, affect hemostasis, manifesting in inhibition of platelet aggregation and thrombus formation and in elevated fibrin density and attenuated fibrinolysis. In this report, we investigated whether three plant-derived polyphenols with well-known antioxidant properties, i.e., quercetin (Que), epigallocatechin gallate (EGCG), and resveratrol (Resv), at concentrations not affecting platelet responses per se, may normalize particular aspects of hemostasis disturbed by HOCl. Specifically, Que (5–25 μM) and EGCG (10–25 μM) abolished HOCl-evoked inhibition of platelet aggregation (assessed by an optical method), while the simultaneous incubation of platelet-rich plasma with Resv (10–25 μM) enhanced the inhibitory effect of HOCl. A similar effect was observed in the case of thrombus formation under flow conditions, evaluated in whole blood by confocal microscope. When plasma samples were incubated with HOCl, a notably higher density of fibrin (recorded by confocal microscope) was detected, an effect that was efficiently normalized by Que (5–25 μM), EGCG (10–25 μM), and Resv (5–25 μM) and which corresponded with the normalization of the HOCl-evoked prolongation of fibrinolysis, measured in plasma by a turbidimetric method. In conclusion, this report indicates that supplementation with Que and EGCG may be helpful in the normalization of hemostatic abnormalities during inflammatory states associated with elevated HOCl production, while the presence of Resv enhances the inhibitory action of HOCl towards platelets. Full article

(This article belongs to the Special Issue Heme Peroxidases in (Patho)Physiological Reactions and Disease Progression)

► Show Figures

Figure 1

Figure 1
Effects of quercetin, epigallocatechin gallate, and resveratrol on platelet aggregation and on HOCl-evoked inhibition of aggregation. Samples of PRP were incubated with quercetin (Que), epigallocatechin gallate (EGCG), or resveratrol (Resv) for 5 min (A) followed by the addition of collagen (arrow, 5 μg/mL), and platelet aggregation, measured as light transmittance through platelet suspension, was recorded. (B) PRP samples were supplemented with HOCl (200 μM, for 5 min) or with indicated concentrations of Que, EGCG, or Resv added 1 min before HOCl. Next, aggregation was triggered by the addition of collagen (arrow, 5 μg/mL). Control samples contained an appropriate volume of vehiculum: ethanol (used as a control for Que and Resv) or water (used as a control for EGCG). Representative aggregation curves from one experiment (out of six) and extent of aggregation are presented. Aggregation obtained in the presence of only collagen was considered as maximal aggregation. Data are means ± S.D. from n = 6 experiments. * p < 0.05; ** p < 0.01; *** p < 0.001 vs. control (sample supplemented with collagen, (A,B)). # p < 0.05; ## p < 0.01 vs. sample supplemented with HOCl 200 μM (B). Full article ">Figure 2
Effects of quercetin, epigallocatechin gallate, and resveratrol on thrombus formation under flow and on HOCl-mediated reduction of thrombus formation. PPACK-anticoagulated whole blood samples (supplemented with DiO to visualize platelets) were incubated with appropriate vehiculum (ethanol or water) or with indicated concentrations of Que, EGCG, or Resv (for 5 min, upper panel). Next, samples were perfused over collagen-coated surfaces at a shear rate of 1000 s−1 to form thrombi. Surface coverage area was calculated from end-stage confocal pictures. Lower panel: samples were incubated with HOCl (500 μM, for 5 min) or with Que, EGCG, or Resv added 1 min before HOCl and thrombus formation was performed under conditions as in upper panel. Representative thrombi obtained in the presence of HOCl or combinations of HOCl with selected concentrations of Que, EGCG, or Resv are presented in lower panel. Data are means ± S.D. from n = 3 experiments. * p < 0.05; ** p < 0.01 vs. control. Distance bar is 10 μm. Flow direction was from left to right. Full article ">Figure 3
Effects of quercetin, epigallocatechin gallate, and resveratrol on HOCl-related increase in fibrin clot density. Plasma samples were incubated with appropriate vehiculum (ethanol or water) or with HOCl (250 μM for 5 min) or with indicated concentrations of Que, EGCG, or Resv, added 1 min before HOCl. Afterward, samples were supplemented with AF488-fibrinogen (to visualize fibrin formation) and clotting was triggered by recalcification (20 mM CaCl2, final conc.). Result fibrin clots were analyzed under confocal microscope toward fibrin density. Structures representative of six independent experiments are presented. Bars are means ± S.D. from six experiments. * p < 0.05 vs. control. Distance bar is 30 μm. Full article ">Figure 4
Effects of quercetin, epigallocatechin gallate, and resveratrol on HOCl-evoked attenuation of fibrinolysis. Plasma samples were incubated with appropriate vehiculum (ethanol or water) or with HOCl (125 μM for 5 min) or with indicated concentrations of Que, EGCG, or Resv, added 1 min before HOCl. Coagulation was triggered by the addition of CaCl2 (to 20 mM final concentration). The time to 50% and 100% of lysis was determined as the time required for a decrease in absorbance (of 50% or 100%, respectively) after reaching the maximal turbidity, measured in the presence of tissue plasminogen activator (200 ng/mL final concentration). Representative lysis profiles from six experiments are presented. * p < 0.05 vs. control. Full article ">Figure 5
Effects of quercetin, epigallocatechin gallate and resveratrol on HOCl-produced decrease in free sulfhydryl groups in plasma. Samples of plasma were incubated for 10 min at 37 °C with HOCl (125 μM) without (control) or with, preincubated or not with studied antioxidants (for 1 min) at indicated concentrations. The content of reduced thiol (-SH) groups in plasma was measured using the DTNB assay. The total free-SH group content in plasma was about 533.5 ± 83 μM. Data are mean values ± S.D. from three independent experiments (each in triplicate). * p < 0.05. Full article ">

20 pages, 5367 KiB

Open AccessArticle

P2X7 Receptor Augments LPS-Induced Nitrosative Stress by Regulating Nrf2 and GSH Levels in the Mouse Hippocampus

by Duk-Shin Lee and Ji-Eun Kim

Antioxidants 2022, 11(4), 778; https://doi.org/10.3390/antiox11040778 - 13 Apr 2022

Cited by 2 | Viewed by 2427

Abstract

P2X7 receptor (P2X7R) regulates inducible nitric oxide synthase (iNOS) expression/activity in response to various harmful insults. Since P2X7R deletion paradoxically decreases the basal glutathione (GSH) level in the mouse hippocampus, it is likely that P2X7R may increase the demand for GSH for the [...] Read more.

P2X7 receptor (P2X7R) regulates inducible nitric oxide synthase (iNOS) expression/activity in response to various harmful insults. Since P2X7R deletion paradoxically decreases the basal glutathione (GSH) level in the mouse hippocampus, it is likely that P2X7R may increase the demand for GSH for the maintenance of the intracellular redox state or affect other antioxidant defense systems. Therefore, the present study was designed to elucidate whether P2X7R affects nuclear factor-erythroid 2-related factor 2 (Nrf2) activity/expression and GSH synthesis under nitrosative stress in response to lipopolysaccharide (LPS)-induced neuroinflammation. In the present study, P2X7R deletion attenuated iNOS upregulation and Nrf2 degradation induced by LPS. Compatible with iNOS induction, P2X7R deletion decreased S-nitrosylated (SNO)-cysteine production under physiological and post-LPS treated conditions. P2X7R deletion also ameliorated the decreases in GSH, glutathione synthetase, GS and ASCT2 levels concomitant with the reduced S-nitrosylations of GS and ASCT2 following LPS treatment. Furthermore, LPS upregulated cystine:glutamate transporter (xCT) and glutaminase in P2X7R^+/+ mice, which were abrogated by P2X7R deletion. LPS did not affect GCLC level in both P2X7R^+/+ and P2X7R^−/− mice. Therefore, our findings indicate that P2X7R may augment LPS-induced neuroinflammation by leading to Nrf2 degradation, aberrant glutamate-glutamine cycle and impaired cystine/cysteine uptake, which would inhibit GSH biosynthesis. Therefore, we suggest that the targeting of P2X7R, which would exert nitrosative stress with iNOS in a positive feedback manner, may be one of the important therapeutic strategies of nitrosative stress under pathophysiological conditions. Full article

(This article belongs to the Special Issue Molecular Targets of Oxidative Stress: Focus on the Nrf2 Signaling Pathway in Health and Disease)

► Show Figures

Graphical abstract

18 pages, 1766 KiB

Open AccessArticle

Nutraceutical Profile of “Carosello” (Cucumis melo L.) Grown in an Out-of-Season Cycle under LEDs

by Onofrio Davide Palmitessa, Miriana Durante, Annalisa Somma, Giovanni Mita, Massimiliano D’Imperio, Francesco Serio and Pietro Santamaria

Antioxidants 2022, 11(4), 777; https://doi.org/10.3390/antiox11040777 - 13 Apr 2022

Cited by 2 | Viewed by 2626

Abstract

The world population is projected to increase to 9.9 billion by 2050 and, to ensure food security and quality, agriculture must sustainably multiply production, increase the nutritional value of fruit and vegetables, and preserve genetic variability. In this work, an Apulian landrace of [...] Read more.

The world population is projected to increase to 9.9 billion by 2050 and, to ensure food security and quality, agriculture must sustainably multiply production, increase the nutritional value of fruit and vegetables, and preserve genetic variability. In this work, an Apulian landrace of Cucumis melo L. called “Carosello leccese” was grown in a greenhouse with a soilless technique under light-emitting diodes (LEDs) used as supplementary light system. The obtained results showed that “Carosello leccese” contains up to 71.0 mg·g⁻¹ dried weight (DW) of potassium and several bioactive compounds important for human health such as methyl gallate (35.58 µg·g⁻¹ DW), α-tocopherol (10.12 µg·g⁻¹ DW), and β-carotene (up to 9.29 µg·g⁻¹ DW under LEDs). In fact, methyl gallate has antioxidative and antiviral effects in vitro and in vivo, tocopherols are well recognized for their effective inhibition of lipid oxidation in foods and biological systems and carotenoids are known to be very efficient physical and chemical quenchers of singlet oxygen. Finally, it was demonstrated that the LEDs’ supplementary light did not negatively influence the biochemical profile of the peponids, confirming that it can be considered a valid technique to enhance horticultural production without reducing the content of the bioactive compounds of the fruits. Full article

(This article belongs to the Special Issue Plant Antioxidants and other Bioactive Compounds for Food Quality and Safety)

► Show Figures

Figure 1

Figure 1
Relative spectral power of LEDs fixtures R + B (A) and R + B + FR (B). Light spectra were measured with spectrophotometer LI-180 (LI-COR, Lincoln, NE, USA). Full article ">Figure 2
Bar charts showing the average daily light integral supplied by sun (DLI NL) and from LEDs (DLI SL) in 9-day intervals. Line graph represents the average daily light integral supplied from sun and LEDs DLI NL + SL in 9-day intervals. Full article ">Figure 3
Gallic acid content of “Carosello leccese” (Cucumis melo L.) fruits grown under solar light (NL, no supplementary lighting) and two light spectra (see <a href="#antioxidants-11-00777-f001" class="html-fig">Figure 1</a>). Values are the average of three replications. Vertical bars represent mean values ± standard error. R + B represents supplementary light with red + blue spectra; R + B + FR represents supplementary light with red + blue + far red spectra; NL represents solar light (control) treatment. Full article ">Figure 4
β-carotene content of “Carosello leccese” (Cucumis melo L.) fruits from plants grown under solar light (NL, no supplementary lighting) and two light spectra (see <a href="#antioxidants-11-00777-f001" class="html-fig">Figure 1</a>). Values are an average of three replications. Bars represent mean values ± standard error. R + B represents supplementary light with red + blue spectra; R + B + FR represents supplementary light with red + blue + far red spectra; NL represents solar light (control) treatment. Full article ">Figure 5
Sweetness index of “Carosello leccese” (Cucumis melo L.) fruits grown under solar light (NL, no supplementary lighting) and two light spectra (see <a href="#antioxidants-11-00777-f001" class="html-fig">Figure 1</a>) 32 and 50 DAT. Values are an average of three replications. Vertical bars represent mean values ± standard error. R + B represents supplementary light with red + blue spectra; R + B + FR represents supplementary light with red + blue + far red spectra; NL represents solar light (control) treatment. Full article ">Figure 6
Iron (Fe) content, expressed as mg·kg−1 D.W. of “Carosello leccese” (Cucumis melo L.) fruits grown under solar light (NL, no supplementary lighting) and two light spectra (see <a href="#antioxidants-11-00777-f001" class="html-fig">Figure 1</a>). Values are an average of three replications. Vertical bars represent mean values ± standard error. R + B represents supplementary light with red + blue spectra; R + B + FR represents supplementary light with red + blue + far red spectra; NL represents solar light (control) treatment. Full article ">

20 pages, 2626 KiB

Open AccessArticle

Effect of Exogenous Melatonin Application on the Grain Yield and Antioxidant Capacity in Aromatic Rice under Combined Lead–Cadmium Stress

by Ye Jiang, Suihua Huang, Lin Ma, Leilei Kong, Shenggang Pan, Xiangru Tang, Hua Tian, Meiyang Duan and Zhaowen Mo

Antioxidants 2022, 11(4), 776; https://doi.org/10.3390/antiox11040776 - 13 Apr 2022

Cited by 23 | Viewed by 4229

Abstract

This study aimed to determine the mechanism of exogenous melatonin application in alleviating the combined Pb and Cd (Pb-Cd) toxicity on aromatic rice (Oryza sativa L.). In this study, a pot experiment was conducted; two aromatic rice varieties, Yuxiangyouzhan and Xiangyaxiangzhan, were [...] Read more.

This study aimed to determine the mechanism of exogenous melatonin application in alleviating the combined Pb and Cd (Pb-Cd) toxicity on aromatic rice (Oryza sativa L.). In this study, a pot experiment was conducted; two aromatic rice varieties, Yuxiangyouzhan and Xiangyaxiangzhan, were selected, and sprays using 50, 100, 200, and 400 μmol L⁻¹ melatonin (denoted as S50, S100, S200, and S400) and irrigation using 100, 300, and 500 μmol L⁻¹ melatonin (denoted as R100, R300, and R500) were also selected. The results showed that, under the S50, S100, and S200 treatments, the Pb content of aromatic rice grain decreased, and the grain yield increased significantly. Moreover, the application of exogenous melatonin significantly reduced the accumulation of H₂O₂ in rice leaves at maturity under Cd–Pb stress and reduced the MDA content in Xiangyaxiangzhan leaves. In addition, the microbial community structure changed significantly under S50 and R300 treatments. Some pathways, such as the synthesis of various amino acids and alanine, aspartate, and glutamate metabolism, were regulated by S50 treatment. Overall, melatonin application improved aromatic rice grain yield while reducing heavy metal accumulation by regulating the antioxidant capacity and metabolites in aromatic rice plants and altering the physicochemical properties and microbial community structures of the soil. Full article

(This article belongs to the Topic Antioxidant Activity in Plants, Plant-Derived Bioactive Compounds and Foods)

► Show Figures

Graphical abstract

17 pages, 2734 KiB

Open AccessArticle

Protective Effects against the Development of Alzheimer’s Disease in an Animal Model through Active Immunization with Methionine-Sulfoxide Rich Protein Antigen

by Adam S. Smith, Kyle R. Gossman, Benjamin Dykstra, Fei Philip Gao and Jackob Moskovitz

Antioxidants 2022, 11(4), 775; https://doi.org/10.3390/antiox11040775 - 13 Apr 2022

Cited by 1 | Viewed by 6137

Abstract

The brain during Alzheimer’s disease (AD) is under severe oxidative attack by reactive oxygen species that may lead to methionine oxidation. Oxidation of the sole methionine (Met35) of beta-amyloid (Aβ), and possibly methionine residues of other extracellular proteins, may be one [...] Read more.

The brain during Alzheimer’s disease (AD) is under severe oxidative attack by reactive oxygen species that may lead to methionine oxidation. Oxidation of the sole methionine (Met35) of beta-amyloid (Aβ), and possibly methionine residues of other extracellular proteins, may be one of the earliest events contributing to the toxicity of Aβ and other proteins in vivo. In the current study, we immunized transgenic AD (APP/PS1) mice at 4 months of age with a recombinant methionine sulfoxide (MetO)-rich protein from Zea mays (antigen). This treatment induced the production of anti-MetO antibody in blood-plasma that exhibits a significant titer up to at least 10 months of age. Compared to the control mice, the antigen-injected mice exhibited the following significant phenotypes at 10 months of age: better short and long memory capabilities; reduced Aβ levels in both blood-plasma and brain; reduced Aβ burden and MetO accumulations in astrocytes in hippocampal and cortical regions; reduced levels of activated microglia; and elevated antioxidant capabilities (through enhanced nuclear localization of the transcription factor Nrf2) in the same brain regions. These data collected in a preclinical AD model are likely translational, showing that active immunization could give a possibility of delaying or preventing AD onset. This study represents a first step toward the complex way of starting clinical trials in humans and conducting the further confirmations that are needed to go in this direction. Full article

(This article belongs to the Topic Redox Metabolism)

► Show Figures

Graphical abstract

Graphical abstract
Full article ">Figure 1
A graphical summary of the proposed events leading to MetO-Aβ and MetO-protein mediated toxicity in Alzheimer’s disease brain. Full article ">Figure 2
Antigen-injected mice produce antibody against MetO-rich protein in blood-plasma. (A). The MetO-rich protein (Antigen) was produced and purified according to the procedures described under the “Materials and Methods” section. The purified antigen was separated on SDS-gel-electrophoresis that was stained with Coomassie brilliant blue (the limited protein staining level is due to the relatively low presence of basic amino acids in the Met-rich protein sequence). M, molecular mass markers; kDa, molecular mass numbers. (B). A dot-blot analysis using the MetO-rich protein as the loaded protein (Antigen) and rabbit anti-MetO antibody (1:1000 dilution) as the primary antibody. (C). A dot-blot analysis using the MetO-rich protein, as the loaded protein (Antigen), probed with plasma moiety (used as the primary antibody, 1:100 dilution, 1 h incubation time) from 10-month-old mice. Only the antigen-injected mice showed positive reactions with the antigen (a round black reaction in the middle of the blot), while the controls were all negative. Numbers 5 and 9 of the control blots had almost no background reactions. Full article ">Figure 3
Vaccinated APP/PS1 mice have improved short- and long-term spatial memory. (A) Antigen-immunized APP/PS1 mice have a novel arm preference in a forced Y-maze test but control APP/PS1 do not, displaying improved short-term memory after vaccination. The details of the experimental procedures are listed under “Materials and Methods”. (B) Arm crossing is not affected by vaccination, indicating age-typical locomotion. (C) Morris Water Maze (MWM) analyses (the details of the experimental procedures are listed under the <a href="#sec2-antioxidants-11-00775" class="html-sec">Section 2</a>). These are representative schematics of swimming patterns performed by mice over the 5-day training period of the MWM. These swimming patterns illustrate that antigen-immunized APP/PS1 mice improve their escape latency after a single day of training, while control mice require repeated training days to improve in this task (as reflected in Day 2). (D) This is a statistical presentation of the significant effect on the antigen-immunized mice’s reduced escape latency during the second day of training, while the control mice do not improve in this task until day 3. This demonstrates an improved learning for this long-term spatial memory task in antigen-immunized mice (E) Antigen-immunized mice also spend more time swimming in the target quadrant (after the platform is removed from the pool) compared to controls, who are only performing at chance. Standard deviation is shown for each group of mice. Data were acquired from all tested mice (n = 9 per each group of mice). Statistical significances were assessed for the acquired data using one-way analysis of variance (ANOVA) with post hoc Tukey’s test: # p < 0.05 familiar vs. novel arm within condition; * p < 0.05, ** p < 0.01 vs. control; vvvv p < 0.0001 vs. day 1 training for antigen-immunized mice; ++++ p < 0.0001 vs. day 1 training for control mice. Full article ">Figure 4
Reduction of Aβ42 in blood-plasma and brain, and reduction of amyloid plaque burden in brains of antigen-injected mice. (A). Hemisphere brains of post-mortem mice (control and antigen-immunized) were dissected, and immunohistochemistry analyses were performed to detect Aβ42, according to the procedure described under the <a href="#sec2-antioxidants-11-00775" class="html-sec">Section 2</a>. The data shows a decline in the levels of Aβ42 in the three brain regions (HPC, hippocampus; RSC, retrosplenial cortex, and EC, entorhinal cortex) of the antigen-immunized as compared with the control mice. (B). Quantification of the data presented in Panel A using NIH-Image J program. Quantification of Aβ42 in blood-plasma (C) and post-mortem brain extracts (D) of antigen-injected and control mice using ELISA kit according to the procedure described under the <a href="#sec2-antioxidants-11-00775" class="html-sec">Section 2</a>. (E). Thioflavin-S staining of the post-mortem mouse brains according to the procedure described under the “Materials and Methods” section. Lower plaque-burden was observed in the antigen-injected versus control mice. (F). Quantification of the data depicted in panel E using NIH Image-J program. In all of the graphs, black and white bars represent control and antigen-injected mice, respectively. Standard deviation is shown for each averaged bar. Data were acquired from all tested mice for panels C and D (n = 9 per each group of mice) and five mice per each tested group of mice for panels B and F. Statistical analyses were performed using two-tailed student t-test with the following p values: *, p < 0.05; **, p < 0.01, and ***, p < 0.001. Full article ">Figure 5
Reduction of MetO-protein levels in brain astrocytes in antigen-injected mice (A). Hemisphere brains of post-mortem mice (control and antigen-immunized) were dissected, and immunohistochemistry analyses were performed to detect MetO-proteins according to the procedure described under the <a href="#sec2-antioxidants-11-00775" class="html-sec">Section 2</a>. The data shows a decline in the levels of MetO-proteins in the three brain regions (HPC, hippocampus; RSC, retrosplenial cortex, and EC, entorhinal cortex) of the antigen-immunized compared with control mice. (B). Quantification of the data presented in Panel A using NIH-Image J program. Black and white bars represent control and antigen-injected mice, respectively. Standard deviation is shown for each averaged bar. Data were acquired for five mice per tested group of mice. Statistical analyses were performed using two-tailed student t-test with the following p values: *, p < 0.05, and **, p < 0.01. Full article ">Figure 6
Reduced activation of microglia in antigen-injected mice. (A). Hemisphere brains of post-mortem mice (control and antigen-immunized) were dissected, and immunohistochemistry analyses were performed to detect Iba1 according to the procedure described under the <a href="#sec2-antioxidants-11-00775" class="html-sec">Section 2</a>. The data show a decline in the levels of Iba1 of neuronal cells in the three brain regions (HPC, hippocampus; RSC, retrosplenial cortex, and EC, entorhinal cortex) of the antigen-immunized compared with control mice. (B). Quantification of the data presented in Panel A using NIH-Image J program. Black and white bars represent control and antigen-injected mice, respectively. Standard deviation is shown for each averaged bar. Data were acquired from five mice per tested group of mice. Statistical analyses were performed using two-tailed student t-test with the following p values: *, p < 0.05; ***, p < 0.001. Full article ">Figure 7
Increased nuclear localization of Nrf2 in antigen-injected mice. (A). Hemisphere brains of post-mortem mice (control and antigen-immunized) were dissected, and immunohistochemistry analyses were performed to detect Nrf2 according to the procedure described under the <a href="#sec2-antioxidants-11-00775" class="html-sec">Section 2</a>. The data shows an increased nuclear localization within astrocytes of Nrf2 in a representative image of the EC region of the antigen-immunized compared to the control mice. A similar pattern of Nrf2 localization ratio between the two mouse groups was observed for the HPC and RSC regions (images are not shown). The white triangle symbols point to cells harboring nuclear Nrf2 and the black-filled triangle symbols point to cells harboring cytosolic Nrf2 (B). Quantification of the data presented in Panel (A) by manually counting the nuclear Nrf2 signal per same-size area in the three selected brain regions. Black and white bars represent control and antigen-injected mice, respectively. Standard deviation is shown for each averaged bar. Data were acquired from five mice per tested group of mice. Statistical analyses were performed using two-tailed student t-test with the following p values: ***, p < 0.001 and **, p < 0.01. Full article ">

13 pages, 300 KiB

Open AccessArticle

Pre-Operative Assessment of Micronutrients, Amino Acids, Phospholipids and Oxidative Stress in Bariatric Surgery Candidates

by Thorsten Henning, Bastian Kochlik, Paula Kusch, Matthias Strauss, Viktorija Jurić, Marc Pignitter, Frank Marusch, Tilman Grune and Daniela Weber

Antioxidants 2022, 11(4), 774; https://doi.org/10.3390/antiox11040774 - 13 Apr 2022

Cited by 3 | Viewed by 2709

Abstract

Obesity has been linked to lower concentrations of fat-soluble micronutrients and higher concentrations of oxidative stress markers as well as an altered metabolism of branched chain amino acids and phospholipids. In the context of morbid obesity, the aim of this study was to [...] Read more.

Obesity has been linked to lower concentrations of fat-soluble micronutrients and higher concentrations of oxidative stress markers as well as an altered metabolism of branched chain amino acids and phospholipids. In the context of morbid obesity, the aim of this study was to investigate whether and to which extent plasma status of micronutrients, amino acids, phospholipids and oxidative stress differs between morbidly obese (n = 23) and non-obese patients (n = 13). In addition to plasma, malondialdehyde, retinol, cholesterol and triglycerides were assessed in visceral and subcutaneous adipose tissue in both groups. Plasma γ-tocopherol was significantly lower (p < 0.011) in the obese group while other fat-soluble micronutrients showed no statistically significant differences between both groups. Branched-chain amino acids (all p < 0.008) and lysine (p < 0.006) were significantly higher in morbidly obese patients compared to the control group. Malondialdehyde concentrations in both visceral (p < 0.016) and subcutaneous (p < 0.002) adipose tissue were significantly higher in the morbidly obese group while plasma markers of oxidative stress showed no significant differences between both groups. Significantly lower plasma concentrations of phosphatidylcholine, phosphatidylethanolamine, lyso-phosphatidylethanolamine (all p < 0.05) and their corresponding ether-linked analogs were observed, which were all reduced in obese participants compared to the control group. Pre-operative assessment of micronutrients in patients undergoing bariatric surgery is recommended for early identification of patients who might be at higher risk to develop a severe micronutrient deficiency post-surgery. Assessment of plasma BCAAs and phospholipids in obese patients might help to differentiate between metabolic healthy patients and those with metabolic disorders. Full article

(This article belongs to the Special Issue The 10th Anniversary of Antioxidants: Past, Present and Future)

8 pages, 1349 KiB

Open AccessCommunication

Verification of the Relationship between Redox Regulation of Thioredoxin Target Proteins and Their Proximity to Thylakoid Membranes

by Yuka Fukushi, Yuichi Yokochi, Ken-ichi Wakabayashi, Keisuke Yoshida and Toru Hisabori

Antioxidants 2022, 11(4), 773; https://doi.org/10.3390/antiox11040773 - 13 Apr 2022

Cited by 1 | Viewed by 1804

Abstract

Thioredoxin (Trx) is a key protein of the redox regulation system in chloroplasts, where it modulates various enzyme activities. Upon light irradiation, Trx reduces the disulfide bonds of Trx target proteins (thereby turning on their activities) using reducing equivalents obtained from the photosynthetic [...] Read more.

Thioredoxin (Trx) is a key protein of the redox regulation system in chloroplasts, where it modulates various enzyme activities. Upon light irradiation, Trx reduces the disulfide bonds of Trx target proteins (thereby turning on their activities) using reducing equivalents obtained from the photosynthetic electron transport chain. This reduction process involves a differential response, i.e., some Trx target proteins in the stroma respond slowly to the change in redox condition caused by light/dark changes, while the ATP synthase γ subunit (CF₁-γ) located on the surface of thylakoid membrane responds with high sensitivity. The factors that determine this difference in redox kinetics are not yet known, although here, we hypothesize that it is due to each protein’s localization in the chloroplast, i.e., the reducing equivalents generated under light conditions can be transferred more efficiently to the proteins on thylakoid membrane than to stromal proteins. To explore this possibility, we anchored SBPase, one of the stromal Trx target proteins, to the thylakoid membrane in Arabidopsis thaliana. Analyses of the redox behaviors of the anchored and unanchored proteins showed no significant difference in their reduction kinetics, implying that protein sensitivity to redox regulation is determined by other factors. Full article

(This article belongs to the Special Issue Thioredoxin and Glutaredoxin Systems II)

► Show Figures

Figure 1

Figure 1
Generation of A. thaliana mutants expressing membrane-anchored SBPase. (A) Construction of SBPase-TMAPX. The blue ovals represent SBPase and the magenta cylinder represents TMAPX. The gray chain represents the Hexa-His-tag linker connecting SBPase to TMAPX. (B) SBPase-TMAPX expression in two independent lines was confirmed by Western blotting. (C) The relative expression level of SBPase-TMAPX in OE-SBPase-TMAPX plant was calculated from the signal intensities shown in (B). The expression level of endogenous SBPase in an OE-SBPase-TMAPX plant was defined to 100%. Each value represents the mean ± SD (n = 3). Full article ">Figure 2
Phenotypes of mutant plants expressing membrane-anchored SBPase. (A) Four-week-old OE-SBPase-TMAPX plants. (B) Fresh weight (FW) and chlorophyll content of OE-SBPase-TMAPX plant. Each value represents the mean ± SD (n = 4). Different letters indicate significant differences among plant lines (p < 0.05; one-way ANOVA and Tukey’s honestly significant difference). Full article ">Figure 3
Localization of the membrane-anchored SBPase in chloroplasts. Proteins from stroma and thylakoid membrane fractions of leaves in OE-SBPase-TMAPX plants were prepared for immunoblot analysis. The same amounts of proteins were loaded into each lane as shown in an SDS-PAGE gel in the right panel (silver-stained). Antibodies against SBPase was used to detect the endogenous SBPase and SBPase-TMAPX. FBPase and light-harvesting complex protein LHCA1 were detected as markers of stroma and thylakoid membrane fractions, respectively, using their specific antibodies. Full article ">Figure 4
In vivo redox responses of membrane-anchored SBPase. Dark-adapted plants were placed under light conditions (650–750 µmol photons m−2 s−1) for the specified time period and then leaves were frozen in liquid nitrogen. The redox states of endogenous SBPase, SBPase-TMAPX and CF1-γ were determined by the method previously described in [<a href="#B12-antioxidants-11-00773" class="html-bibr">12</a>]. Antibodies against SBPase and CF1-γ were used to detect the endogenous proteins, while the Penta·His-tag antibody was used to detect SBPase-TMAPX, thus providing a clear distinction between the reduced band of endogenous SBPase and the oxidized band of SBPase-TMAPX in OE-SBPase-TMAPX plants. (A) The redox state of endogenous SBPase and CF1-γ in WT plants. (B) The redox state of SBPase-TMAPX and CF1-γ in OE-SBPase-TMAPX plants. (C) The reduction level of SBPase and CF1-γ is based on the signal intensities shown in (A,B). The reduction level was calculated as the ratio of the reduced form to the total amount of reduced and oxidized forms. Each value represents the mean ± SD (n = 3). Red, reduced form; Ox, oxidized form. Full article ">

15 pages, 2382 KiB

Open AccessArticle

Hop Tannins as Multifunctional Tyrosinase Inhibitor: Structure Characterization, Inhibition Activity, and Mechanism

by Jiaman Liu, Yanbiao Chen, Xinxin Zhang, Jie Zheng, Weiying Hu and Bo Teng

Antioxidants 2022, 11(4), 772; https://doi.org/10.3390/antiox11040772 - 13 Apr 2022

Cited by 7 | Viewed by 2699

Abstract

The application of hops could be extended to obtain higher commercial values. Tannins from hops were assessed for their tyrosinase inhibition ability, and the associated mechanisms were explored. Nuclear magnetic resonance (NMR) and high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC–ESI–MS/MS) revealed that the [...] Read more.

The application of hops could be extended to obtain higher commercial values. Tannins from hops were assessed for their tyrosinase inhibition ability, and the associated mechanisms were explored. Nuclear magnetic resonance (NMR) and high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC–ESI–MS/MS) revealed that the hop tannins were characterized as condensed tannins with (epi)catechin and (epi)gallocatechin as subunits and an average polymerization degree of 10.32. Tyrosinase inhibition assay indicated that hop tannins had an IC₅₀ = 76.52 ± 6.56 μM. Kinetic studies of the inhibition processes indicated the tannins provided inhibition through competitive–uncompetitive mixed reactions. In silico molecule docking showed that tannins were bound to the active site of tyrosinase via hydrogen and electrovalent bonds. Circular dichroism (CD) observed the structural variation in the tyrosinase after reacting with the tannins. Fluorescence quenching analysis and free radical scavenging assays indicated that the tannins had copper ion chelating and antioxidant activities, which may also contribute to inhibition. The intracellular inhibition assay revealed that the melanin was reduced by 34.50% in B16F10 cells. These results indicate that these tannins can be applied as whitening agents in the cosmetics industry. Full article

(This article belongs to the Special Issue Antioxidants in Food and Cosmetics)

► Show Figures

Figure 1

Figure 1
Schematic diagram of sample preparation and analyses in the study. Full article ">Figure 2
Structure and numbering scheme of the flavanol-3-ol subunit. Full article ">Figure 3
The proposed structure of the (epi)catechin (A), (epi)catechin–cysteamine (B), and (epi)gallocatechin (C) released from hop tannins (D) after acid–cleavage reaction. The fragmentation pathways are illustrated: blue lines = RDA reaction; brick-red lines = rearrangement of B-ring; yellow lines = HRF reaction; green lines = loss of water; black lines = loss of cysteamine adduct. Full article ">Figure 4
Tyrosinase concentration–reaction rate plots (A) and Lineweaver–Burk plots (B) of hop tannins of different concentrations (from 1 to 5, tannin concentration: 0, 0.041, 0.027, 0.041, and 0.068 mM); the plot of slope (C) or intercept (D) versus hop tannin concentration for determining inhibition constants KI and KIS. Full article ">Figure 5
Molecular docking of catechin (A), gallocatechin (B), epicatechin (C), and epigallocatechin (D) on active site of tyrosinase. Full article ">Figure 6
Fluorescence emission spectra of hop tannin solutions with different Cu2+ concentrations. Full article ">Figure 7
Intracellular tyrosinase inhibition rate (A) and intracellular melanin inhibition rate (B) of hop tannins. Full article ">

10 pages, 15584 KiB

Open AccessArticle

Apoptotic p53 Gene Expression in the Regulation of Persistent Organic Pollutant (POP)-Induced Oxidative Stress in the Intertidal Crab Macrophthalmusjaponicus

by Kiyun Park and Ihn-Sil Kwak

Antioxidants 2022, 11(4), 771; https://doi.org/10.3390/antiox11040771 - 13 Apr 2022

Cited by 6 | Viewed by 1801

Abstract

Persistent organic pollutants (POPs), some of the most dangerous chemicals released into the aquatic environment, are distributed worldwide due to their environmental persistence and bioaccumulation. In the study, we investigated p53-related apoptotic responses to POPs such as hexabromocyclododecanes (HBCDs) or 2,2′,4,4′-tetrabromodiphenyl ether [...] Read more.

Persistent organic pollutants (POPs), some of the most dangerous chemicals released into the aquatic environment, are distributed worldwide due to their environmental persistence and bioaccumulation. In the study, we investigated p53-related apoptotic responses to POPs such as hexabromocyclododecanes (HBCDs) or 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) in the mud crab Macrophthalmus japonicus. To do so, we characterized M. japonicus p53 and evaluated basal levels of p53 expression in different tissues. M. japonicus p53 has conserved amino acid residues involving sites for protein dimerization and DNA and zinc binding. In phylogenetic analysis, the homology of the deduced p53 amino acid sequence was not high (67–70%) among crabs, although M. japonicus p53 formed a cluster with one clade with p53 homologs from other crabs. Tissue distribution patterns revealed that the highest expression of p53 mRNA transcripts was in the hepatopancreas of M. japonicus crabs. Exposure to POPs induced antioxidant defenses to modulate oxidative stress through the upregulation of catalase expression. Furthermore, p53 expression was generally upregulated in the hepatopancreas and gills of M. japonicus after exposure to most concentrations of HBCD or BDE-47 for all exposure periods. In hepatopancreas tissue, significant increases in p53 transcript levels were observed as long-lasting apoptotic responses involving cellular defenses until day 7 of relative long-term exposure. The findings in this study suggest that exposure to POPs such as HBCD or BDE-47 may trigger the induction of cellular defense processes against oxidative stress, including DNA repair, cell cycle arrest, and apoptosis through the transcriptional upregulation of p53 expression in M. japonicus. Full article

(This article belongs to the Special Issue Environmental Stress and Antioxidant Defences)

► Show Figures

Figure 1

Figure 1
Characterization of Macrophthalmus japonicus p53 gene. (A) ClustalW multiple-sequence alignment of the deduced Mjp53 gene sequence with homologous p53 genes of various crabs. Shaded marks in black indicated completely conserved residues in all species. Dimerization site (polypeptide-binding site) and zinc-binding site (ion-binding site) are indicated by black asterisk mark and blue asterisk mark, respectively. DNA-binding site (nucleic-acid-binding site) is presented as a red rectangular box. (B) Phylogenetic circle tree of Mjp53 gene with other p53s. Neighbor-joining analysis showed a circle tree for phylogenetic relationships in p53 amino acid sequences using the MEGA v.4.0 software. Bootstrap values represent 1000 replicates. Full article ">Figure 2
Basal transcriptional levels of M. japonicus p53 genes in various tissues (Gi, gills; Hp, hepatopancreas; Ht, heart; Gn, gonad; Ms, muscle; and St, stomach). All data are indicated as means ± standard deviation. Expression level of GAPDH transcripts was used for normalization of the relative transcriptional levels in each tissue from 10 crabs. The experiment was repeated three times. Full article ">Figure 3
Relative transcriptional levels of catalase gene in M. japonicus gills (A,C) and hepatopancreas (B,D) after exposures to 1, 10, and 100 μg L−1 HBCD (A,B) and 0.1, 1, and 10 μg L−1 BDE-47 (C,D). Exposure periods were days 1, 4, and 7. GAPDH levels were used for normalization of the values. All values are indicated as mean ± SD. Statistically significant differences are presented by an asterisk mark (* p < 0.05 and ** p < 0.01) compared with the relative control value (catalase = 1). Full article ">Figure 4
Relative transcriptional levels of p53 gene in M. japonicus gills (A,C) and hepatopancreas (B,D) after exposures to 1, 10, and 100 μg L−1 HBCD (A,B) and 0.1, 1, and 10 μg L−1 BDE-47 (C,D). Exposure periods were days 1, 4, and 7. GAPDH levels were used for normalization of the values. All values are indicated as mean ± SD. Statistically significant differences are presented by an asterisk mark (* p < 0.05 and ** p < 0.01) compared with the relative control value (p53 = 1). Full article ">Figure 5
Schematic summary of the suggested molecular process involving antioxidation and p53-mediated apoptosis in M. japonicus animals exposed to POPs (HBCD and BDE-47). SOD: Superoxide dismutase, ROS: Reactive oxygen species. Full article ">

12 pages, 18548 KiB

Open AccessArticle

Marker-Free Rice (Oryza sativa L. cv. IR 64) Overexpressing PDH45 Gene Confers Salinity Tolerance by Maintaining Photosynthesis and Antioxidant Machinery

by Ranjan Kumar Sahoo, Renu Tuteja, Ritu Gill, Juan Francisco Jiménez Bremont, Sarvajeet Singh Gill and Narendra Tuteja

Antioxidants 2022, 11(4), 770; https://doi.org/10.3390/antiox11040770 - 12 Apr 2022

Cited by 3 | Viewed by 2422

Abstract

Helicases function as key enzymes in salinity stress tolerance, and the role and function of PDH45 (pea DNA helicase 45) in stress tolerance have been reported in different crops with selectable markers, raising public and regulatory concerns. In the present study, we developed [...] Read more.

Helicases function as key enzymes in salinity stress tolerance, and the role and function of PDH45 (pea DNA helicase 45) in stress tolerance have been reported in different crops with selectable markers, raising public and regulatory concerns. In the present study, we developed five lines of marker-free PDH45-overexpressing transgenic lines of rice (Oryza sativa L. cv. IR64). The overexpression of PDH45 driven by CaMV35S promoter in transgenic rice conferred high salinity (200 mM NaCl) tolerance in the T₁ generation. Molecular attributes such as PCR, RT-PCR, and Southern and Western blot analyses confirmed stable integration and expression of the PDH45 gene in the PDH45-overexpressing lines. We observed higher endogenous levels of sugars (glucose and fructose) and hormones (GA, zeatin, and IAA) in the transgenic lines in comparison to control plants (empty vector (VC) and wild type (WT)) under salt treatments. Furthermore, photosynthetic characteristics such as net photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO₂ (Ci), and chlorophyll (Chl) content were significantly higher in transgenic lines under salinity stress as compared to control plants. However, the maximum primary photochemical efficiency of PSII, as an estimated from variable to maximum chlorophyll a fluorescence (Fv/Fm), was identical in the transgenics to that in the control plants. The activities of antioxidant enzymes, such as catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), and guaiacol peroxidase (GPX), were significantly higher in transgenic lines in comparison to control plants, which helped in keeping the oxidative stress burden (MDA and H₂O₂) lesser on transgenic lines, thus protecting the growth and photosynthetic efficiency of the plants. Overall, the present research reports the development of marker-free PDH45-overexpressing transgenic lines for salt tolerance that can potentially avoid public and biosafety concerns and facilitate the commercialization of genetically engineered crop plants. Full article

(This article belongs to the Special Issue Plant Response and Tolerance to Abiotic Oxidative Stress: Antioxidant Machinery as a Paradigm of Defense)

► Show Figures

Figure 1

Figure 1
Screening and analysis of PDH45 marker-free transgenic lines. (a) T-DNA construct of pCAMBIA 1300-PDH45. (b) Transgenic lines (L4, L7, L8, L11, L13, VC, and WT). (c) PCR conformation of the PDH45-overexpressing transgenic (T1) lines showed the amplification of 1.2 Kb fragment. (d) Southern blot analysis showing the integration and copy number of the PDH45 gene. (e) Relative gene expression of PDH45 transgenic lines. (f) Western blot analysis showing the PDH45 protein (≈45 kDa). Full article ">Figure 2
Salinity tolerance of PDH45-overexpressing transgenic T1 IR64 rice lines. (a) Leaf disk senescence assay under 100 and 200 mM NaCl treatment. (b) Chlorophyll content (mg/g fw) in PDH45 transgenic lines after salt treatment. (c) Third day in 200 mM NaCl treatment. (d) After 15 days of NaCl treatment. Full article ">Figure 3
Measurement of photosynthetic characteristics and chlorophyll a fluorescence of WT, VC, and PDH45 marker-free transgenic lines (L4, L7, L8, L11, and L13) under 200 mM NaCl treatment. (a) Photosynthetic rate. (b) Stomatal conductance. (c) Intracellular CO2. (d) CO2 release. (e) Transpiration rate. (f) Photosynthetic yield (Fv/Fm). Values are mean ± SE (n = 3). Different letters on the top of bars indicate significant differences at p ≤ 0.05 level as determined by Duncan’s multiple range test (DMRT). Full article ">Figure 4
Biochemical analysis of PDH45-overexpressing T1 transgenic lines (L4, L7, L8, L11, L13, VC) and WT plants exposed to 24 h at 200 mM NaCl treatment. (a) Ion leakage. (b) Hydrogen peroxide (H2O2) content. (c) Lipid peroxidation expressed in terms of MDA content. (d) Level of proline accumulation. (e) Catalase (CAT) activity; one unit of enzyme activity defined as 1 μmol H2O2 oxidized min−1. (f) Ascorbate peroxidase (APX) activity; one unit of enzyme activity defined as 1 μmol of ascorbate oxidized min−1. (g) Guaiacol peroxidase (GPX) activity. (h) Glutathione reductase (GR) activity; one unit of enzyme activity is defined as 1 μmol of GS-TNB formed min−1 due to reduction of DTNB. (i) Percent relative water content (RWC). Values are mean ± SE (n = 3). Different letters on the top of bars indicate significant differences at p ≤ 0.05 level as determined by Duncan’s multiple range test (DMRT). Full article ">Figure 5
Soluble sugar, hormones, and K+ and Na+ content in the roots and shoots of PDH45-overexpressing marker-free transgenic lines (L4, L7, L8, L11, L13) as compared to WT and VC plants exposed to 24 h at 200 mM NaCl treatment. (a) Glucose content. (b) Fructose content. (c) Endogenous GA content. (d) Endogenous zeatin content. (e) Endogenous IAA content. (f) Endogenous potassium and sodium content. Values are mean ± SE (n = 3). Different letters on the top of bars indicate significant differences at p ≤ 0.05 level as determined by Duncan’s multiple range test (DMRT). Full article ">

17 pages, 1383 KiB

Open AccessReview

Oxidative Stress and Ischemia/Reperfusion Injury in Kidney Transplantation: Focus on Ferroptosis, Mitophagy and New Antioxidants

by Simona Granata, Valentina Votrico, Federica Spadaccino, Valeria Catalano, Giuseppe Stefano Netti, Elena Ranieri, Giovanni Stallone and Gianluigi Zaza

Antioxidants 2022, 11(4), 769; https://doi.org/10.3390/antiox11040769 - 12 Apr 2022

Cited by 60 | Viewed by 6519

Abstract

Although there has been technical and pharmacological progress in kidney transplant medicine, some patients may experience acute post-transplant complications. Among the mechanisms involved in these conditions, ischemia/reperfusion (I/R) injury may have a primary pathophysiological role since it is one of the leading causes [...] Read more.

Although there has been technical and pharmacological progress in kidney transplant medicine, some patients may experience acute post-transplant complications. Among the mechanisms involved in these conditions, ischemia/reperfusion (I/R) injury may have a primary pathophysiological role since it is one of the leading causes of delayed graft function (DGF), a slow recovery of the renal function with the need for dialysis (generally during the first week after transplantation). DGF has a significant social and economic impact as it is associated with prolonged hospitalization and the development of severe complications (including acute rejection). During I/R injury, oxidative stress plays a major role activating several pathways including ferroptosis, an iron-driven cell death characterized by iron accumulation and excessive lipid peroxidation, and mitophagy, a selective degradation of damaged mitochondria by autophagy. Ferroptosis may contribute to the renal damage, while mitophagy can have a protective role by reducing the release of reactive oxygen species from dysfunctional mitochondria. Deep comprehension of both pathways may offer the possibility of identifying new early diagnostic noninvasive biomarkers of DGF and introducing new clinically employable pharmacological strategies. In this review we summarize all relevant knowledge in this field and discuss current antioxidant pharmacological strategies that could represent, in the next future, potential treatments for I/R injury. Full article

(This article belongs to the Special Issue Antioxidants and their Role in the Prevention and Treatment of Chronic Kidney Disease-II)

► Show Figures

Figure 1

Figure 1
Schematic representation of the mechanisms of ferroptosis and mitophagy in renal ischemia/reperfusion (I/R) injury. During I/R several pathways contribute to ferroptosis: (i) the overproduction of ROS by NADPH oxidase (NOX), nitric oxide synthase (NOS), xanthine oxidoreductase (XOR) and mitochondria promotes lipid peroxidation and plasmatic membrane rupture; (ii) the reduction in glutathione (GSH) content inhibits glutathione peroxidase 4 (GPX4) activity and its protective action against membrane lipid peroxidation; (iii) I/R can indirectly induce ferritinophagy which causes the degradation of intracellular ferritin, and the increment of intracellular labile iron pool. Mitophagy is activated in I/R through both ubiquitin-dependent and ubiquitin-independent mechanisms and seems to have a protective role in I/R injury by reducing the release of reactive oxygen species from dysfunctional mitochondria. In physiological conditions, PINK1 is imported into mitochondria where it is cleaved by the intramembrane serine protease presenilin associated rhomboid-like (PARL) and ultimately degraded. When mitochondria are damaged, and lose their membrane potential, PINK1 accumulates on the mitochondrial outer membrane (MOM) and recruits Parkin. Parkin ubiquitinates several mitochondrial substrates such as voltage-dependent anion-selective channel protein (VDAC) and dynamin-1-like protein (DRP1). These ubiquitinated proteins can recruit mitophagy receptors (such as optineurin, p62) that link mitochondria to autophagosomes through interacting with LC3. This causes an autophagic engulfment of the organelle necessary for its degradation. The ubiquitin-independent mechanism is regulated by mitophagy receptors that localize on MOM, such as BCL2 interacting protein 3 (BNIP3), BNIP3-like (BNIP3L/NIX), and FUN14 domain containing 1 (FUNDC1). These proteins bridge mitochondria to autophagosome by directly interacting with LC3. Full article ">Figure 2
Mechanism of Nrf2 regulation in the treatment of renal I/R. In physiological condition Nrf2 binds to Kelch-like ECH-associated protein-1 (Keap1) in the cytoplasm and is degraded by ubiquitin-proteasome pathway. During renal I/R the hyperactivation of Nrf2 by CDDO, H2S, water-soluble H2S donor (such as GYY4137) leads to nuclear traslocation of Nrf2 that binds to antioxidant response elements and activates transcription of the genes encoding proteins involved in antioxidants mechanisms and iron metabolism thereby preventing the ROS-mediated tubular damage and the ferroptotic cascade. Full article ">

18 pages, 1209 KiB

Open AccessArticle

Chemical, Antioxidant, and Antimicrobial Properties of the Peel and Male Flower By-Products of Four Varieties of Punica granatum L. Cultivated in the Marche Region for Their Use in Cosmetic Products

by Maria Rosa Gigliobianco, Manuela Cortese, Samanta Nannini, Lucrezia Di Nicolantonio, Dolores Vargas Peregrina, Giulio Lupidi, Luca Agostino Vitali, Elena Bocchietto, Piera Di Martino and Roberta Censi

Antioxidants 2022, 11(4), 768; https://doi.org/10.3390/antiox11040768 - 12 Apr 2022

Cited by 15 | Viewed by 3259

Abstract

We are now seeing an increase in the production of agri-food waste, which is an essential resource for the recovery of bioactive compounds that may be employed as innovative natural ingredients in cosmetics. To date, the approach to cosmetics preservation has seen a [...] Read more.

We are now seeing an increase in the production of agri-food waste, which is an essential resource for the recovery of bioactive compounds that may be employed as innovative natural ingredients in cosmetics. To date, the approach to cosmetics preservation has seen a significant shift in the search for biological components that give healthier alternatives for customers and help businesses operate in an environmentally friendly manner. To achieve this goal, we studied pomegranate extracts using the peel and, for the first time, extracts from the male flowers of a wide pomegranate variety cultivated in the Marche region, specifically, the Wonderful, Mollar de Elche, Parfianka, and less-studied G1 varieties. We studied the phenol compounds profile, antioxidant capacity, antimicrobial activity, and cell viability of the obtained pomegranate extracts. The identification and quantification of phenol compounds belonging to different classes, such as hydrolysable tannins, hydroxybenzoic acid, hydroxycinnamic acid, dihydroflavonol, gallocatechin, and anthocyanins, were performed using UPLC-ESI-MS/MS. Punicalagin isomers and punicalin resulted in the most abundant polyphenols found in the peel and male flower extracts. Mollar de Elche 2020 peel extract revealed a high concentration of punicalagin A and B (7206.4 mg/kg and 5812.9), while the content of gallic acid revealed high results in the G1 and Parfianka varieties. All extracts were spectrophotometrically analysed to determine their total phenol content (TPC) using the Folin–Ciocalteu method and their antioxidant capacity (AC). In terms of the total phenol obtained by the Folin–Ciocalteu colorimetric method, Mollar de Elche 2020 extracts reported the highest TPC content of 12.341 µmol GAE/g. Results revealed that the Mollar de Elche and Wonderful 2020 peel extracts demonstrated the highest TPC and AC. Furthermore, AC results indicated that the peel extracts displayed higher AC than the male flower extract due to the high punicalagin content detected by UPLC analysis. The antimicrobial activity testing revealed that the Wonderful and G1 2020 peel extracts resulted active against Escherichia coli, while all extracts exhibited promising anticandidal activity. Additionally, the cytocompatibility was evaluated in keratinocytes HaCaT cells by testing concentrations of pomegranate extracts ranging from 0.15 to 5.00 mg/mL. Extracts were non-toxic for the cells in the tested concentration range. The acquired results may help exploit pomegranate agri-food waste products provided by the Marche region’s short supply chain for their use as an antimicrobial and antioxidant booster in the formulation of cosmetic products. Full article

(This article belongs to the Special Issue Dietary Antioxidants and Cosmetics)

► Show Figures

Figure 1

17 pages, 4976 KiB

Open AccessArticle

TLR4 Signaling and Heme Oxygenase-1/Carbon Monoxide Pathway Crosstalk Induces Resiliency of Myeloma Plasma Cells to Bortezomib Treatment

by Grazia Scandura, Cesarina Giallongo, Fabrizio Puglisi, Alessandra Romano, Nunziatina Laura Parrinello, Tatiana Zuppelli, Lucia Longhitano, Sebastiano Giallongo, Michelino Di Rosa, Giuseppe Musumeci, Roberto Motterlini, Roberta Foresti, Giuseppe Alberto Palumbo, Giovanni Li Volti, Francesco Di Raimondo and Daniele Tibullo

Antioxidants 2022, 11(4), 767; https://doi.org/10.3390/antiox11040767 - 12 Apr 2022

Cited by 11 | Viewed by 2678

Abstract

Relapse in multiple myeloma (MM) decreases therapy efficiency through unclear mechanisms of chemoresistance. Since our group previously demonstrated that heme oxygenase-1 (HO-1) and Toll-like receptor 4 (TLR4) are two signaling pathways protecting MM cells from the proteasome inhibitor bortezomib (BTZ), we here evaluated [...] Read more.

Relapse in multiple myeloma (MM) decreases therapy efficiency through unclear mechanisms of chemoresistance. Since our group previously demonstrated that heme oxygenase-1 (HO-1) and Toll-like receptor 4 (TLR4) are two signaling pathways protecting MM cells from the proteasome inhibitor bortezomib (BTZ), we here evaluated their cross-regulation by a pharmacological approach. We found that cell toxicity and mitochondrial depolarization by BTZ were increased upon inhibition of HO-1 and TLR4 by using tin protoporphyrin IX (SnPP) and TAK-242, respectively. Furthermore, the combination of TAK-242 and BTZ activated mitophagy and decreased the unfolded protein response (UPR) survival pathway in association with a downregulation in HO-1 expression. Notably, BTZ in combination with SnPP induced effects mirroring the treatment with TAK-242/BTZ, resulting in a blockade of TLR4 upregulation. Interestingly, treatment of cells with either hemin, an HO-1 inducer, or supplementation with carbon monoxide (CO), a by-product of HO-1 enzymatic activity, increased TLR4 expression. In conclusion, we showed that treatment of MM cells with BTZ triggers the TLR4/HO-1/CO axis, serving as a stress-responsive signal that leads to increased cell survival while protecting mitochondria against BTZ and ultimately promoting drug resistance. Full article

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Antioxidants, Volume 11, Issue 4 (April 2022) – 194 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI