Original Research Article
Flavone attenuates nicotine-induced lung
injury in rats exposed to gamma radiation
via modulating PI3K/Nrf2 and FoxO1/
NLRP3 inflammasome
International Journal of
Immunopathology and Pharmacology
Volume 38: 1–15
© The Author(s) 2024
Article reuse guidelines:
sagepub.com/journals-permissions
DOI: 10.1177/03946320241272642
journals.sagepub.com/home/iji
Nora A Elsayed1, Mohammed A Marzouk1, Fatma SM Moawed2 , Esraa SA Ahmed3
and Omayma AR Abo-Zaid1
Abstract
Prolonged exposure to different occupational or environmental toxicants triggered oxidative stress and inflammatory
reactions mediated lung damage. This study was designed to explore the influence and protective impact of flavone on lung
injury in rats intoxicated with nicotine (NIC) and exposed to radiation (IR). Forty rats were divided into four groups; group
I control, group II flavone; rats were administered with flavone (25 mg/kg/day), group III NIC + IR; rats were injected
intraperitoneally with NIC (1 mg/kg/day) and exposed to γ-IR (3.5 Gy once/week for 2 weeks) while group IV NIC + IR +
flavone; rats were injected with NIC, exposed to IR and administered with flavone. Redox status parameters and histopathological changes in lung tissue were evaluated. Nuclear factor-kappa B (NF-κB), forkhead box O-class1 (FoxO1) and
nucleotide-binding domain- (NOD-) like receptor pyrin domain-containing-3 (NLRP3) gene expression were measured in
lung tissues. Moreover, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and phosphatidylinositol three kinase (PI3K) were
measured using ELISA kits. Our data demonstrates, for the first time, that flavone protects the lung from NIC/IR-associated
cytotoxicity, by attenuating the disrupted redox status and aggravating the antioxidant defence mechanism via activation of
the PI3K/Nrf2. Moreover, flavone alleviates pulmonary inflammation by inhibiting the inflammatory signaling pathway
FOXO1/NF-κB/NLRP3- Inflammasome. Collectively, the obtained results exhibited a notable efficiency of flavone in
alleviating lung injury induced by NIC and IR via modulating PI3K/Nrf2 and FoxO1/NLRP3 Inflammasome.
Keywords
Nicotine, radiation, lung, PI3K/Nrf2, FoxO1/NLRP3, flavone
Date received: 22 February 2024; accepted: 15 July 2024
1
Biochemistry and Molecular Biology Department, Faculty of Veterinary Medicine, Benha University, Egypt
Health Radiation Research, National Center for Radiation Research and Technology, Egyptian Atomic Energy Authority, Cairo, Egypt
3
Radiation Biology Research, National Center for Radiation Research and Technology, Egyptian Atomic Energy Authority, Cairo, Egypt
2
Corresponding author:
Esraa SA Ahmed, Radiation Biology Research, National Center for Radiation Research and Technology, Egyptian Atomic Energy Authority, Nasr City,
Cairo 11787, Egypt.
Emails: esraa.tamim@yahoo.com; esraa.tamim@eaea.org.eg
Creative Commons Non Commercial CC BY-NC: This article is distributed under the terms of the Creative Commons
Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use,
reproduction and distribution of the work without further permission provided the original work is attributed as specified on the
SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).
2
International Journal of Immunopathology and Pharmacology
Introduction
pathway.11 Nrf2 is a cytoprotective transcription factor that
maintains the cellular antioxidant defence mechanism,
interacts with several signaling pathways, affects the activity of many oxidases associated with inflammation, and
has an antioxidant.12 The activated Nrf2 attenuates the
oxidative stress and inflammation induced by FoxO1NLRP3 beside suppressing the NF-κB which eventually
alleviates lung injury.13
Owing to their potential efficacy and absence of side
effects, together with little or no toxicity, medicinal plants
are preferable to conventional drugs in treating various
diseases that are considered difficult to cure. From these
medicinal plants, flavonoids are natural phytochemical
compounds that have been used in herbal complementary
medicines for a long time now.14,15 Flavonoids are considered derivatives of the parent compound flavone and are
classified into flavones, flavonols, isoflavones, and anthocyanidins based on their oxidation state and the degree
of conjugation of the central heterocyclic ring.16,17 Flavones (from Latin flavus, “yellow”) are a vital subclass of
the flavonoid’s family, which are natural polyphenolic
products with the backbone of 2-phenylchromen-4-one (2phenyl-1-benzopyran-4-one) (as shown in Figure 1). Flavones are usually found in large amounts in a glycosylated
form in various common foods such as yellow or orange
fruits, celery, parsley, red peppers, chamomile, mint, as
well as spices. This class commonly includes flavone,
apigenin, luteolin, and chrysin.18 Based on their role in
supporting health, flavones have a valuable effect in many
applicable fields (pharmacy, nutrition cosmetic, and therapy) owing to their low toxicity, anti-inflammatory, antimicrobial, anticancer activities, antioxidant, antiallergic,
neuroprotective, antidiabetic, cardioprotective, and metal
chelating properties, in addition to their immune-regulatory
activities in various diseases either prophylaxis or
therapeutic.19
Prolonged exposure to different occupational or environmental toxicants either from chemical (asbestos, formaldehyde and polycyclic aromatic hydrocarbons) or physical
(ionizing and non-ionizing radiations) as well as cigarette
smoke and air pollutants negatively affect lung functions
promoting lung diseases and eventually lung cancer.1
These toxicants elicit oxidative stress and inflammatory
reactions which deteriorate the lung architecture via the
destruction and fibrosis of the lung parenchyma impairing
the repair mechanism and consequently increasing morbidity and mortality globally due to pulmonary dysfunction
and diseases.2
Nicotine (NIC) is one of the widely spread and known
environmental biohazards. It is the most abundant alkaloid
of tobacco, which is responsible for the addiction and
toxicity of cigarettes on lung health and immunity.3 Regarding the excessive nicotine receptors, solubility and
transfer across cellular membranes are rapidly absorbed
into the blood circulation and deposited in the lung tissue
due to the large surface area of the alveoli.4 Additionally, its
metabolism to nitrosamine compounds results in the production of free radical species like reactive oxygen species
(ROS) that promote toxicity and oxidative damage of the
lung epithelial cells as well as inflammatory response,
pulmonary dysfunction and other diseases.5
Exposure of humans to radiation regarding its source
natural environment (background, radon or ultraviolet
(UV) medical (diagnostic X-rays or γ-rays radiotherapy),
occupational or accidental seriously implies the life quality
owing to its adverse effects such as toxicity, organ dysfunction and injury besides body immunosuppression.1
Collectively, radiation boosts lung injury and toxicity
owing to their high radiosensitivity leading to radiationinduced lung injury (RILI).6,7 The detrimental and toxic
effect of radiation was attributed to its interaction with
biological organs and systems triggering the excessive
generation of ROS and oxidative stress that eventually
augments cellular oxidative damage and impairs diverse
signaling pathways.8
The excessive production of ROS from both nicotine
and γ-IR markedly promotes acute lung injury (ALI) by
sustaining oxidative stress and aggravating pulmonary
inflammation by activation of many inflammatory pathways such as nuclear factor-kappa B (NF-κB), Forkhead
box protein O1 (FoxO1)- nucleotide-binding domain(NOD-) like receptor pyrin domain-containing-3 (NLRP3)
and other inflammatory cytokines.9 Moreover, the inflammatory signaling pathway FOXO1/NF-κB/NLRP3 is
negatively regulated by the PI3k/Akt signaling pathway10
which regulates cell proliferation, survival, apoptosis and
cytoprotective defence via activation of its downstream
Nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling
Figure 1. Flavone backbone structure adopted from Catarino
et al. study.20
3
Elsayed et al.
Therefore, the current study was conducted to examine
the efficiency of flavone in mitigating lung injury induced
by Nicotine and γ -IR and its modulatory effects on disrupted redox status as well as FoxO1-NLRP3 Inflammasome and PI3K/Nrf2 signaling pathway.
Materials and methods
using urethane. Lung tissues were dissected out and
washed with saline, dried on filter paper, and then divided into two parts. The first part from each lung was
stored at 80°C for the biochemical analysis. Moreover,
the other part of the lung was immediately preserved in a
10% buffered formalin-saline solution for histopathological examination.
Materials
Nicotine, synthesis grade Product Code: NI00200100,
CAS No. 54-11-5 was obtained from Scharlau, Scharlab
S.L Barcelona, Spain. Flavone was purchased from Sigma–
Aldrich® (St Louis, Missouri, United States).
Irradiation process
Rats were subjected to whole-body γ-irradiation at the
National Centre for Radiation Research and Technology
(NCRRT), Egyptian Atomic Energy Authority, using Canadian gamma cell-40 (137Cesium) at a dose of 3.5 Gy
once/week for 2 weeks (cumulative dose 7 Gy), at a dose
rate of 0.333 Gy•min-1.
Animals. The handling of the experimental animals involved in this study followed the approved ethical
guidelines of the Institutional Animal Care and Use
Committee Research Ethic Board of Benha University,
Faculty of Veterinary Medicine (BUFVTM12-11-22).
Male rats weighing between 100 and 120 g were procured
from the Nile Company for Pharmaceuticals & Chemical
Industries S.A.E. (Egypt) and were housed in hygienic
cages at a temperature of 22 ± 2°C, with a consistent 12-h
light/dark cycle, and unrestricted access to a commercial
pellet diet and potable water.
Experimental design. Experimental rats were divided into
the following groups (10 rats each).
(1) Control Group: Normal rats served as control.
(2) Flavone Group: where rats were treated orally with
flavone (25 mg/kg/day) for 2 weeks.
(3) Nicotine + IR Group: its rats were daily injected with
Nicotine intraperitoneally at a dose of 1 mg/kg body
weight with modification3 for 3 weeks and exposed
to whole body γ-IR at a dose of 3.5 Gy once/week for
2 weeks (total dose 7 Gy).
(4) Nicotine + IR + Flavone Group: Its rats were daily
injected with Nicotine and exposed to IR and at the
beginning of the second week, rats were treated
with flavone (25 mg/kg/day) for 2 weeks.
At the end of the experimental period, the animals
were fasted overnight and sacrificed under anaesthesia
Bioinformatic analysis
Data source and processing. The corresponding Gene
Expression Omnibus (GEO) datasets contain mRNA
expression profiles of rats exposed to cigarette smoking
(CS) and control rats were selected. The target microarray dataset, including GSE178513, was extracted
from the GEO database (https://www.ncbi.nlm.nih.
gov/geo/). The GSE178513 dataset based on the
GPL26961 platform (Agilent-085,985 Arraystar Rat
lncRNA V3 microarray) contained 3 CS rats and three
control rats.
Screening of differentially expressed genes (DEGs). The
GEO2R web tool was applied to identify the DEGs of
GSE178513 with the criteria of adjusted p-value (Adj.p) <
0.05 and | log2 fold-change (FC) | > 2.0.
Functional enrichment analysis of DEGs. KOBAS server21
was used to perform functional annotation analyses including Kyoto Encyclopedia of Genes and Genomes
pathways (KEGG) and Gene ontology (GO terms). This
program can provide a functional interpretation of gene
lists derived from genomic studies. A p-value <0.05 was
applied to get a significant pathway. However, the bar
charts for GO terms and KEGG pathways were performed
via the R package statistical software.22
Biochemical measurements
Evaluation of oxidative stress parameters. The levels of
Malondialdehyde (MDA: Cat. No. MD 25 29) as an indicator for lipid peroxidation, as well as the antioxidant
parameters glutathione (GSH: Cat. No. GR 25 11) and
glutathione peroxidase (GPx: Cat. No. GP 25 24) activity
were measured by commercial kits obtained from BioDiagnostic Company in Cairo, Egypt.
ELISA estimations. The concentrations of tumor necrosis
factor-α (TNF-α: Cat #MBS924824), nuclear factor (erythroid-derived 2)-like 2 (Nrf2: Cat # MBS012148),
phosphatidylinositol three kinase (PI3K: Cat #
MBS26.381)and Caspase-1 (CASP1: Cat# MBS2019421)
were measured in the homogenates of lung tissues by
commercially ELISA kits from My BioSource, San Diego,
USA according to the manufacturer’s guidelines.
4
International Journal of Immunopathology and Pharmacology
Quantitative real-time PCR (RT-PCR) analysis
Results
To determine mRNA expression for nuclear factor-kappa B
(NF-κB), FoxO1 and nucleotide-binding domain- (NOD-)
like receptor pyrin domain-containing-3 (NLRP3), the
RNA was extracted from lung tissues using the RNA
Purification Kit (Thermo Scientific, Fermentas, #K0731)
and the complementary DNA (cDNA) was obtained by
Reverse Transcription Kits (Thermo Scientific, Fermentas,
#EP0451). Real-time PCR was performed using a Step
OnePlus thermal cycler (Applied Biosystems, Life Technology, USA) and SYBR Green PCR Master Mix (Thermo
Scientific, USA, #K0221). The internal reference β-actin
was used to normalize the expression of the target genes.
The relative mRNA expression of the target genes was
calculated using the Livak and Schmittgen23 2 ΔΔCt
method. The used primer sequences are listed in Table 1.
Differential expression analysis between rats
exposed to cigarette smoking and control rats
Histopathological examination of lung
Lung tissues were initially preserved in a solution of 10%
neutral buffered formalin solution, subsequently excised,
cleansed, and dehydrated using a series of ascending alcohol concentrations. After that, the dehydrated specimens
were embedded in paraffin blocks and sliced into 4-6 µm
sections. Finally, the resulting tissue sections were stained
with hematoxylin and eosin (H&E) for evaluating the
histopathological changes in the lung by electric light
microscope.24 Each lung section was scored from 0 to
4 depending on the area exposed to interstitial inflammation, alveolar wall thickening, peribronchial inflammation and interstitial edema (0 ≤ 10%, 1 = up to 30%, 2 =
up to 50%, 3 = up to 70%, 4 ≥ 70%).25
Statistical analysis
The Statistical Program for Social Science (SPSS 20, SPSS
Inc, USA), and a one-way ANOVA test were used to
analyze the results. For the comparisons between groups,
Duncan’s test at p ≤ 0.05 was used. The results were
presented as means ± standard error of the mean (SEM).
Moreover, GraphPad Prism 8 Software (GraphPad Software, Inc., San Diego, CA, United States) was used to
display the charts.
The transcriptomic analyses of gene expression data of
GSE178513 to identify DEGs between rats exposed to
cigarette smoking and control rats (Figure 2); the results
showed 354 genes were differentially expressed with Adj.
p < 0.05 and | log2 fold-change (FC) | > 2.0 (Figure 3).
Functional enrichment analysis of DEGs
The Differentially expressed genes analysis exhibited that
there were 540 DEGs between CS and control. Additionally, functional enrichment analyses were applied for
DEGs to explore the molecular functions and signaling
regulated by smoking. GO analysis via KOBAS servers
showed that DEGs were markedly enriched in molecular
functions related to the oxidation-reduction process, inflammatory response, and immune response. Similarly,
KEGG pathways were enriched in Inflammatory mediator
regulation of TRP channels, NF-kappa B signaling pathway, TNF signaling pathway, Cytokine-cytokine receptor
interaction, IL-17 signaling pathway, Toll-like receptor
signaling pathway, and Nicotine addiction via KOBAS
servers (Figure 4).
Influence of flavone on pulmonary oxidative
stress parameters
The effect of nicotine and IR on oxidative stress is shown in
Figure 5. Both nicotine and gamma irradiation significantly
elevated ROS levels in the lung leading to impaired redox
status. A notable reduction in the pulmonary levels of GSH
and GPx associated with marked elevation of MDA level
was demonstrated in rats intoxicated with nicotine and
exposed to IR as compared to the control group. This
indicates pulmonary toxicity and abolished antioxidant
capacity. Conversely, there was a significant improvement
in the oxidative stress parameters with flavone treatment
relative to the Nicotine + IR group as indicated by the
significant increase in antioxidant parameters (GSH and
GPx) along with the reduction of MDA level.
Table 1. Primer sequences.
Gene
Forward primer (/5 ------ /3)
Reverse primer (/5 ------ /3)
NF-κB
FoxO1
NLRP3
B-actin
CCTAGCTTTCTCTGAACTGCAAA
CAGCAAATCAAGTTATGGAGGA
GTCCAGTGTGTTTTCCCAGAC
AAGTCCCTCACCCTCCCAAAAG
GGGTCAGAGGCCAATAGAGA
TATCATTGTGGGGAGGAGAGTC
TTGAGAAGAGACCTCGGCAG
AAGCAATGCTGTCACCTTCCC
Elsayed et al.
5
Figure 2. Box plots show the mean expression level for each sample in the dataset. Box plots generated from normalized microarray
measurements. X-axis: individual samples grouped into green color (CS) and violet color (control); Y-axis: the expression intensity
values.
Figure 3. Differentially Expressed Genes. (A) The Venn diagram shows the number of DEGs. B) Volcano plot shows the magnitude of
differential expression between CS and control samples, each dot represents one gene that had detectable expression in both groups.
The blue dots represent down-regulated genes with Fold change <-2.0 and p value <0.05 while the reds represent up-regulated ones
with Fold change >2.0 and p value <0.05.
6
International Journal of Immunopathology and Pharmacology
Figure 4. Functional enrichment analyses. (A) Bar charts show the GO terms for DEGs in this study. (B) Bar charts show the KEGG
pathways for DEGs.
7
Elsayed et al.
Figure 5. Effect of flavone on oxidative stress status in lung tissues. (A) Lipid peroxidation (MDA), (B) glutathione (GSH), and (C)
glutathione peroxidase (GPx). Data is presented as Means ± SE. Columns with different letters are significant (p < 0.05) while those
with similar letters are non-significant.
Influence of flavone on the levels of Nrf2, and PI3K
in lung tissue
Interestingly, the PI3K/Akt signaling pathway promotes
antioxidant, cytoprotective and cell survival mechanisms by activating the Nrf2 signaling pathway against
oxidative stress-induced injury. Collectively, in response to the impaired redox balance and blunted antioxidant capacity, the current results revealed a
significant decrease in the Nrf2 and its upstream PI3K in
the lung tissue of rats injected with nicotine and exposed to IR relative to their control (Figure 6). Whereas,
rats that received flavone exhibited a significant upregulation in the pulmonary levels of Nrf2 and PI3K.
Thus, suggesting the antioxidant and cytoprotective
effect of Flavone by the upregulation of the PI3K/
Nrf2 signaling pathway against nicotine and IR-induced
lung toxicity.
Impact of flavone on the inflammatory mediators
(TNF-α and NF-κB) in pulmonary tissues
Regarding the crosstalk of Nrf2 with NF-kB signaling
pathway, the interaction between them regulates cellular redox homeostasis and inflammatory response.
The marked elevation in the ROS production derived
from nicotine and IR coupled with suppression of the
PI3K/Nrf2 signaling pathway is associated with inflammatory response and subsequently release of proinflammatory mediators as well as further generation of
ROS in lung tissues. Herein, this was evident by the
remarkable upregulated mRNA expression of the NF κB
which in turn increased the levels of the TNF-α in the
lung tissues of the nicotine + IR group. Conversely,
treatment with flavone hindered this inflammatory response by suppressing the NF κB mRNA expression and
consequently reducing the levels of the TNF-α as well
(Figure 7).
Impact of flavone on FoxO1, caspase-1 and
NLRP3 expression in lung tissue
Additionally, the PI3K/AKT signal pathway is the regulator
of FoxO1 which has a key role in the inflammatory reaction. The interaction between the activated NF-κB and
FOXO1 provoked the production of the pro-inflammatory
mediators such as NLRP3, which in turn stimulate caspase1 activation and eventually mediate pulmonary injury. As
shown in Figure 8, our data exhibited that intoxication with
nicotine and exposure to IR remarkably upregulated the
gene expression of FoxO1, Caspase-1 and NLRP3 in the
lung tissue as compared to the control group. However, rats
supplemented with flavone showed a significant suppression in the expression of these genes.
Histopathological changes. The photomicrographs of the
lung tissues of the control group and Flavone group
showed normal lung architecture, the airspaces were
separated by fine delicate inter-alveolar septa and clear
alveolar sacs with regular air sacs, normal vasculature with
scant perivascular connective tissue, folded columnar epithelial cells of bronchi and bronchiole, and normal fibrous
tissues distribution score 0 (Figure 9(a) and (b)). Conversely, rats intoxicated with nicotine and exposed to IR
showed disruption of the normal lung architecture manifested by multiple focal areas of collapsed lung alveoli
8
International Journal of Immunopathology and Pharmacology
Figure 6. Effect of flavone on the lung levels of PI3K and Nrf2. Data is presented as Means ± SE. (A): PI3K and (B): Nrf2. Columns with
different letters are significant (p < 0.05) while those with similar letters are non-significant.
Figure 7. Effect of flavone on inflammatory markers in lung tissues. (A): NF-κB and (B): TNF-α. Columns with different letters are
significant (p < 0.05) while those with similar letters are non-significant.
with marked thickening of the inter-alveolar septa and
hyperplasia of the bronchial epithelial lining. Numerous
numbers of mononuclear and inflammatory cell infiltration
of the alveolar wall and peribronchial areas were seen score
4 (Figure 9(c)). On the other hand, lung sections of rats
treated with nicotine + IR + Flavone showed marked
improvement in comparison with the previous group
evidenced by mild damage of lung tissues, few inflammatory cell infiltrations of the alveolar wall along with
reducing thickening
(Figure 9(d)).
of
the
alveolar
wall
score1
Discussion
Oxidative stress associated with excessive environmental
pollutants alters many signaling pathways which is involved in the pathomechanisms of various disorders.17
Herein the Gene Expression Omnibus (GEO) datasets
Elsayed et al.
9
Figure 8. Effect of flavone on the mRNA expression of FoxO1, Caspase-1 and NLRP3 in the lung tissue. (A): FoxO1, (B): Caspase-1 and
(C): NLRP3. Columns with different letters are significant (p < 0.05) while those with similar letters are non-significant.
Figure 9. Photomicrograph of lung tissue section (A and B) showing normal lung architecture with regular air sacs and airspaces, thin
inter-alveolar septa and clear alveolar sacs, normal vasculature with scant perivascular peribronchiolar cells of the lung representing
the control and Flavone group respectively. In the Nicotine + IR group (C): a marked disruption of the normal lung architecture,
collapsed lung alveoli, thickening of the inter-alveolar septa, hyperplasia of bronchial epithelial lining and inflammatory cells infiltration of
the alveolar wall and peribronchial were observed. (D): rats treated with nicotine + IR + Flavone showed marked improvement of the
lung tissues with mild thickening of the alveolar wall and lower numbers of inflammatory cells.
10
International Journal of Immunopathology and Pharmacology
contain mRNA expression profiles of rats exposed to
cigarette smoking (CS) in addition to DEGs analysis were
applied to explore the molecular functions and signaling
regulated by smoking. GO analysis via KOBAS servers21
showed that DEGs were markedly enriched in molecular
functions related to the oxidation-reduction process, inflammatory response, and immune response. Accordingly,
the novelty of our study is to elucidate the influence and
protective effect of flavone on PI3K/Nrf2 and FoxO1/NFκB/NLRP3 signaling pathway-mediated inflammation and
injury in the lung of rats intoxicated with nicotine and
exposed to radiation.
Herein, nicotine coupled with exposure to γ-IR
markedly triggered oxidative stress in the lung leading to
impaired redox status, injury and disrupted signaling
pathways. Hanania et al.26 indicated that the cytotoxic
effect of radiation on lung tissue was attributed to their
high radiosensitivity as well as the generation of ROS
triggering oxidative stress, vascular damage, and inflammation which consequently results in alveolar walls
edema, vascular permeability and thickening of interalveolar septa.27 Moreover, the histopathological examination showed that ROS derived from nicotine and
IR was associated with disruption of the normal lung
architecture manifested by multiple collapsed lung alveoli with marked thickening of the inter-alveolar septa
and hyperplasia of bronchial epithelial lining besides
fibrosis of the lung parenchyma and inflammatory cells
infiltration of the alveolar wall.28,29 In line with our
results, Cha et al.30 indicated that ROS generated from
nicotine modified the cellular membrane permeability
besides disrupting the antioxidant defence system which
was evidenced by the elevation of lipid peroxidation
(MDA) accompanied with the depletion of the antioxidant components (GSH content and GPx activity) reflecting lung tissues damage.
Based on the aforementioned results, it was found that
the sustained oxidative stress was associated with the
depletion of the antioxidant defence system and diminished response to excessive ROS leading to suppression of Nrf2 which is a major redox cellular
homeostasis transcription factor maintaining cellular
antioxidant defence mechanism,31 detoxifying xenobiotics and pollutants32 and protecting many organs such
as the lungs against impaired redox status and oxidative
damage.33 our results agree with many previous results
which showed that lung injury was associated with inhibition of the Nrf2.34,35
In addition to its role in cell proliferation, differentiation
and apoptosis, PI3K/Akt signaling pathway promotes
antioxidant, cytoprotective and cell survival mechanisms
via activation of the Nrf2 signaling pathway against oxidative stress-induced injury.36 Considerably, in response to
the impaired redox balance and blunted antioxidant
capacity, a significant decrease in the protein levels of the
PI3K alongside that of its downstream Nrf2 was observed.
The current results coincide with many studies indicating
the suppressive potential of cigarette smoke and nicotine on
Nrf2 or its upstream regulator PI3K in lung tissues.37–39
Previous data indicated that the PI3K/Akt and
Nrf2 signaling pathways regulate cellular homeostasis and
defence system versus inflammatory and oxidative damage40 due to the crosstalk with NF-kB signaling pathway.41
Cha et al.30 indicated that the deactivation of Nrf2 with
respect to impaired redox status and an insufficient response to oxidative stress promote redox-sensitive proinflammatory signaling in lung tissues. This was attributed to
the competition between both transcription factors for the
binding DNA site of cAMP- response-element-bindingprotein (CREB)-binding protein (CBP), leading to the
upregulation of NF-κB.35
Collectively, the excessive ROS resulting from exposure to both toxin nicotine and γ-IR act synergistically as
inflammatory signaling molecules in the lung to stimulate
alveolar macrophages and neutrophils42,43 as well as many
pro-inflammatory transcription factors (NF-κB due to the
proteasomal degradation of IκBα35 and protein (NLRP3)
leading to upregulation of the pro-inflammatory cytokine
TNF-α coupled with infiltration of many inflammatory
cells and edema which ultimately induced lung tissue
damage and injury.9,44 Accordingly, our results are in line
with previous data indicating that nicotine activated NF-κB
which aggravates the release of the pro-inflammatory cytokines TNF-α in lung tissues.45,46 Additionally, exposure
to radiation (X-ray) promoted pulmonary inflammation via
the excessive production of ROS causing the recruitment of
inflammatory cells, activation of the NF-kB pathway and
eventually the release of pro-inflammatory cytokines such
as TNF-α.47,48 Lu et al.40 and Wang et al.49 exhibited the
involvement of NLRP3 inflammasome in the pathogenesis
and progression of the inflammatory diseases of the lung
whereas it was upregulated subsequent to the activation of
the NF-κB. The activation of the NLRP3 was associated
with another inflammasome component caspase-1 which in
turn aggravates the inflammatory response mediating diverse lung damage.50,51
The existing inflammation boosted the activity of
FoxO1 which is a transcription factor involved in the
regulation of the inflammatory response via transcriptional
regulation, and signal transduction besides its role in
maintaining tissue homeostasis and regulation of many
cellular processes (proliferation, differentiation apoptosis
and oxidative stress.52,53 The increased activity of
FOXO1 along with the activated NF-κB synergistically
enhances the expression of pro-inflammatory mediators
NLRP3 and IL-1β. Meanwhile, the inflammatory signaling
pathway FOXO1/NF-κB/NLRP3 is negatively regulated
by the PI3k/Akt signaling pathway.10 Moreover, both
Elsayed et al.
FOXO and Nrf2, downstream factors of the PI3K/Akt
signaling pathway,54 are two major conflicting pathways
against cellular oxidative stress.55
Conversely, Alsemeh and Abdullah56 indicated that the
activation of the PI3K/Akt signaling pathway has a crucial
role in alleviating lung tissue toxicity and injury. This was
attributed to boosting the function of alveolar sodium
channels and Na+-K+-ATP, consequently eliminating excess edema fluid in the alveoli.40 Furthermore, the activation of the Nrf2 signaling subsequent to the activation of
the PI3K/Akt signaling pathway activation resulted in
stimulation of Nrf2-mediated antioxidant/phase-II detoxification enzymes thus, restoring the cellular homeostasis by
the attenuation of the impaired redox status and enhancement of the antioxidants system.57,58 Notably, Li
et al.59 and Zhao et al.60 reported that Nrf2 activation
clearly suppressed the inflammatory response and hampered the release of the pro-inflammatory mediators by
suppressing many inflammatory signaling pathways such
as NF-κB suggesting the anti-inflammatory effect of Nrf2.
Additionally, the inhibition of the NF-κB transcriptional
activity hindered the inflammasome components (NLRP3,
caspase-1), therefore alleviating lung injury.61 Moreover,
Fu et al.34 and Cui & Zhang62 indicated that activation of
the PI3K/Akt/Nrf2 signaling pathway alleviated the pulmonary oxidative damage and inflammation via the
downregulation and inhibition of the FoxO1 as well as
NLRP3-Caspase1 inflammasome in LPS induced lung
injury.
Consistent with the aforementioned results, our study
revealed that treating rats intoxicated with nicotine and
γ-IR with the natural product flavone significantly attenuated the impaired redox status by minimizing the
lipid peroxidation contents and aggravating the antioxidant defence system (Nrf2, GSH and GPx). The
powerful antioxidant effect of the flavone as one of the
flavones was appointed to its chemical structure whereas
the presence of Chromone (1-benzopyran-4-one) backbone (2,3-double bond in conjugation with 4-keto
functional group provides electron delocalization from
the ring B and the electron-donating groups on the ring B
reduce the O–H bond dissociation energy) provoking
scavenging of the various free radicals either reactive
oxidative or nitrosative species owing to the rapid hydrogen transfer, hindering lipid peroxidation63 alongside
with chelating metals ions and impeding various redox
reactions.64 Moreover, it modulates the Nrf2 pathway
which in turn alleviates oxidative stress65 together with
modulating various oxidative stress-related processes by
hampering the activity of central free radical-producing
enzymes as well as enhancing the intracellular levels of
antioxidant enzymes thus preventing the subsequent
damage to the cellular biomolecules such as lipids,
proteins, and DNA.66 Interestingly, the hydrophilic and
11
lipophilic fragments in flavone potentiated its antioxidant activity and maintained the cellular membrane’s
structure and functions along with abolishing the effects
of the harmful molecules through its partitioning in the
hydrophobic core of the cellular membrane lipid bilayers
and formation of hydrogen bonds between the polar
groups of the lipids and the hydrophilic fragments of
flavones.67 Another prominent role of flavone is radioprotection whereas Singh et al.68 showed that flavones
have a photo-protective activity by which they can
protect normal living cells from the deleterious effects of
radiation through quenching the free radicals and absorption of UV radiation.
Several studies have indicated that the antiinflammatory effect of flavone as one of the flavonoids
was attributed to the activation of the Keap1-Nrf2 signaling
pathway, repression of several inflammatory enzymes
activities (cyclooxygenase and lipoxygenase activities)69
in addition to blockage of various signaling pathways such
as Toll-like receptor (TLR)/NF κB axis and NLRP3,
consequently blunting the excessive release of the proinflammatory mediators (TNFα and IL-1β) and inflammatory metabolites. Thus, diminishing the cell damage and
mitigating the inflammatory response.19,70 Additionally,
Geraets et al.71 reported that flavone alleviated NF-κBderived inflammatory response in a Chronic Obstructive
Pulmonary Disease (COPD) model. This was confirmed by
Rudrapal et al.72,73 who exhibited the protective roles of
dietary polyphenols against CS-induced inflammationmediated chronic disorders such as COPD and other
lung diseases indirectly by activating endogenous defense
systems and modulating cellular signaling pathways, such
as NF-κB activation, glutathione biosynthesis, the PI3kinase/Akt pathway, and Nrf2 translocation into the
nucleus.
Furthermore, Tianzhu et al.74 and Lim et al.75 exhibited
the suppression of the NLRP3 inflammasome and its
components (caspase-1 and inhibition of IL-1β) by flavonoid (apigenin) which belong to the flavone class
therefore alleviating inflammatory diseases related to the
NLRP3 inflammasomes and the supplementation with
flavones minimized the treatment period in inflammatory
diseases.76 This was attributed to their potential for free
radical scavenging, signaling pathways modulation, and
inhibiting the inflammatory enzymes.77
Our study has some limitations. First, the sample size
was not calculated. Second, BALF samples were not aspirated for further analysis in addition to the lack of using a
siRNA or an inhibitor of PI3K/Nrf2. Therefore, further
studies are required as an extensive in-depth analysis regarding the molecular proteins PI3K/Nrf2 and FoxO1/
NLRP3 inflammasome to elucidate the mechanism of
protective effect of flavone in the future along with this
study.
12
International Journal of Immunopathology and Pharmacology
Conclusion
Data availability statement
The current results manifested that flavone mitigates lung
injury by attenuating the disrupted redox balance and
aggravating the antioxidant content via activation of the
PI3K/Nrf2. Moreover, flavone alleviates lung inflammation by inhibiting the inflammatory signaling pathway
FOXO1/NF-κB/NLRP3. Consequently, flavone may be
used to alleviate oxidative stress and inflammationmediated lung injury in rats.
All data obtained from this study are included in the current
manuscript.
Acknowledgements
The authors are grateful to Prof. Dr Ahmed Osman (Prof. Of
Pathology, Faculty of Veterinary Medicine, Cairo University) for
his help in histopathology. We also thank Dr Ahmed Hammad
(Radiation Biology Research Department, National Centre for
Radiation Research and Technology, Egyptian Atomic Energy
Authority) for his help in the bioinformatic analysis.
Authors’ contributions
The authors participated in the study’s design, conception, and
implementation as well as the experimental component, investigations and findings analysis, and manuscript writing. All authors read and approved the manuscript for publication.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research,
authorship, and/or publication of this article.
Ethical statement
Ethical approval
The handling of the experimental animals involved in this
study followed the approved ethical guidelines of the Institutional Animal Care and Use Committee Research Ethic
Board of Benha University, Faculty of Veterinary Medicine
(BUFVTM12-11-22).
Animal welfare
The present study followed international, national, and/or institutional guidelines for humane animal treatment and complied
with relevant legislation.
ORCID iDs
Fatma SM Moawed https://orcid.org/0000-0002-5792-0815
Esraa SA Ahmed https://orcid.org/0000-0001-5358-4394
References
1. Shehata SA, Toraih EA, Ismail EA, et al. (2023) Vaping,
environmental toxicants exposure, and lung cancer risk.
Cancers (Basel) 15(18): 4525. DOI: 10.3390/
cancers15184525
2. Eckhardt CM and Wu H (2021) Environmental exposures
and lung aging: molecular mechanisms and implications
for improving respiratory health. Current environmental
health reports 8(4): 281–293. DOI: 10.1007/s40572-02100328-2
3. Okada K and Matsuo K (2023) Nicotine exerts a stronger
immunosuppressive effect than its structural analogs and
regulates experimental colitis in rats. Biomedicines 11(3):
922. DOI: 10.3390/biomedicines11030922
4. Wawryk-Gawda E, Chylińska-Wrzos P, Zarobkiewicz M,
et al. (2020) Lung histomorphological alterations in rats
exposed to cigarette smoke and electronic cigarette vapour.
Experimental and therapeutic medicine 19(4): 2826–2832.
DOI: 10.3892/etm.2020.8530
5. Avino P, Scungio M, Stabile L, et al. (2018) Second-hand
aerosol from tobacco and electronic cigarettes: Evaluation of
the smoker emission rates and doses and lung cancer risk of
passive smokers and vapers. The Science of the total environment 642: 137–147. DOI: 10.1016/j.scitotenv.2018.06.
059
6. Eroglu C, Soyuer S, Saraymen R, et al. (2018) Protective
effects of erdosteine against radiation-induced lung injury in
rats. Int J Clin Exp Med 11(10): 11155–11160.
7. Abd El-Hady A and AlJalaud N (2018) Therapeutic effects
of olive leaf extract or bone marrow mesenchymal stem cells
against lung damage induced in male albino rats exposed to
gamma radiation. The Egyptian Journal of Hospital Medicine 61(1): 685–699. DOI: 10.12816/0018770
8. Abo-Zaid OA, Moawed FS, Ismail ES, et al. (2023)
β-Sitosterol mitigates hepatocyte apoptosis by inhibiting
endoplasmic reticulum stress in thioacetamide-induced hepatic injury in γ-irradiated rats. Food and chemical toxicology: an international journal published for the British
Industrial Biological Research Association 172: 113602.
DOI: 10.1016/j.fct.2023.113602
9. Liu Y, Li H, Ouyang Y, et al. (2023) Exploration of the role
of oxidative stress-related genes in LPS-induced acute lung
injury via bioinformatics and experimental studies. Scientific reports 13: 21804. DOI: 10.1038/s41598-02349165-3
10. Wang Q, Hu J, Liu Y, et al. (2019) Aerobic Exercise Improves Synaptic-Related Proteins of Diabetic Rats by Inhibiting FOXO1/NF-κB/NLRP3 Inflammatory Signaling
Pathway and Ameliorating PI3K/Akt Insulin Signaling
Elsayed et al.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
Pathway. Journal of molecular neuroscience: MN 69: 28–38
DOI: 10.1007/s12031-019-01302-2
Lin M, Xie W, Xiong D, et al. (2023) Cyasterone ameliorates
sepsis-related acute lung injury via AKT (Ser473)/GSK3β
(Ser9)/Nrf2 pathway. Chinese medicine 18: 136 DOI: 10.
1186/s13020-023-00837-2
Luan R, Ding D and Yang J (2022) The protective effect of
natural medicines against excessive inflammation and oxidative stress in acute lung injury by regulating the
Nrf2 signaling pathway. Frontiers in pharmacology 13:
1039022. DOI: 10.3389/fphar.2022.1039022
Lim EY, Lee S-Y, Shin HS, et al. (2023) Reactive Oxygen
Species and Strategies for Antioxidant Intervention in Acute
Respiratory Distress Syndrome. Antioxidants 12(11): 2016
DOI: 10.3390/antiox12112016
Roy A, Khan A, Ahmad I, et al. (2022) Flavonoids a Bioactive Compound from Medicinal Plants and Its Therapeutic
Applications. BioMed research international 2022:
5445291. DOI: 10.1155/2022/5445291
Melrose J (2023) The Potential of Flavonoids and Flavonoid
Metabolites in the Treatment of Neurodegenerative Pathology in Disorders of Cognitive Decline. Antioxidants 12(3):
663 DOI: 10.3390/antiox12030663
Mancarz GFF, Prado MRM and de Santi Pazzim M (2023)
Flavonoids: an alternative therapy for oxidative stress-related
diseases. Studies in Natural Products Chemistry 77: 37–64
DOI: 10.1016/B978-0-323-91294-5.00002-6
Sokan-Adeaga AA, Sokan-Adeaga MA, Sokan-Adeaga ED,
et al. (2023) Environmental toxicants and health adversities:
A review on interventions of phytochemicals. Journal of
Public Health Research 12(2): 22799036231181226. DOI:
10.1177/22799036231181226
Motghare AP, P Katolkar P, Chacherkar PA and Baheti JR
(2022) Flavones and their derivatives: synthetic and pharmacological importance. Asian Journal of Pharmaceutical
and Clinical Research 15(7): 25–34.
Lu Q, Xie Y, Luo J, et al. (2023) Natural flavones from edible
and medicinal plants exhibit enormous potential to treat
ulcerative colitis. Frontiers in pharmacology 14: 1168990.
DOI: 10.3389/fphar.2023.1168990
Catarino MD, Alves-Silva JM, Pereira OR, et al. (2015)
Antioxidant capacities of flavones and benefits in oxidativestress related diseases. Current topics in medicinal chemistry
15(2): 105–119.
Wu J, Mao X, Cai T, et al. (2006) KOBAS server: a webbased platform for automated annotation and pathway
identification. Nucleic acids research 34(Web Server issue):
W720–W724. DOI: 10.1093/nar/gkl167
R Team (2018) The R project for statistical computing.
Available at: https://www.r-project.org
Livak KJ and Schmittgen TD (2001) Analysis of relative
gene expression data using real-time quantitative PCR and
the 2(-Delta Delta C(T)) method. Methods (San Diego, Calif)
25(4): 402–408. DOI: 10.1006/meth.2001.1262
13
24. Bancroft JD, Stevens A and Turner DR (2013) Theory
and practice of histological techniques. 4th edn. Edinburgh, London, Melbourne, New York: Churchill
Livingstone.
25. Eldh T, Heinzelmann F, Velalakan A, et al. (2012) Radiationinduced changes in breathing frequency and lung histology
of C57BL/6 J mice are time- and dose-dependent. Strahlenther Onkol 188(3): 274–281.
26. Hanania AN, Mainwaring W, Ghebre YT, et al. (2019)
Radiation-induced lung injury: assessment and management.
chest 156(1): 150–162. DOI: 10.1016/j.chest.2019.03.033
27. Yan Y, Fu J, Kowalchuk RO, Wright CM, et al. (2022)
Exploration of radiation-induced lung injury, from mechanism to treatment: a narrative review. Translational lung
cancer research 11(2): 307–322. DOI: 10.21037/tlcr-22-108
28. Gao Y, Li X, Gao J, et al. (2019) Metabolomic analysis of
radiation-induced lung injury in rats: the potential radioprotective role of taurine. Dose-response: a publication of
International Hormesis Society 17(4): 1559325819883479.
DOI: 10.1177/1559325819883479
29. Wang X, Zhao Y, Li D, et al. (2021) Intrapulmonary distal
airway stem cell transplantation repairs lung injury in chronic
obstructive pulmonary disease. Cell proliferation 54(6):
e13046.
30. Cha SR, Jang J, Park SM, et al. (2023) Cigarette smokeinduced respiratory response: insights into cellular processes
and biomarkers. Antioxidants 12: 1210 DOI: 10.3390/
antiox12061210
31. Kawara RS, Moawed FS, Elsenosi Y, et al. (2024) Melissa
officinalis extract palliates redox imbalance and inflammation associated with hyperthyroidism-induced liver damage
by regulating Nrf-2/ Keap-1 gene expression in γ-irradiated
rats. BMC complementary medicine and therapies 24(1): 71.
DOI: 10.1186/s12906-024-04370-z
32. Brasil FB, Bertolini Gobbo RC, Souza de Almeida FJ, et al.
(2021) The signaling pathway PI3K/Akt/Nrf2/HO-1 plays a
role in the mitochondrial protection promoted by astaxanthin
in the SH-SY5Y cells exposed to hydrogen peroxide.
Neurochemistry international 146: 105024. DOI: 10.1016/j.
neuint.2021.105024
33. Xu W, Zheng H, Fu Y, et al. (2022) Role of PI3K/AktMediated Nrf2/HO-1 Signaling Pathway in Resveratrol
Alleviation of Zearalenone-Induced Oxidative Stress and
Apoptosis in TM4 Cells. Toxins (Basel) 14(11): 733. DOI:
10.3390/toxins14110733
34. Fu Z, Jiang Z, Guo G, et al. (2021) rhKGF-2 Attenuates
Smoke Inhalation Lung Injury of Rats via Activating PI3K/
Akt/Nrf2 and Repressing FoxO1-NLRP3 Inflammasome.
Frontiers in pharmacology 12: 641308. DOI: 10.3389/fphar.
2021.641308
35. Aranda-Rivera AK, Cruz-Gregorio A, Pedraza-Chaverri J,
et al. (2022) Nrf2 Activation in Chronic Kidney Disease:
Promises and Pitfalls. Antioxidants (Basel) 11(6): 1112. DOI:
10.3390/antiox11061112
14
36. Lekshmi VS, Asha K, Sanicas M, et al. (2023) PI3K/Akt/
Nrf2 mediated cellular signaling and virus-host interactions:
latest updates on the potential therapeutic management of
SARS-CoV-2 infection. Frontiers in molecular biosciences
10: 1158133. DOI: 10.3389/fmolb.2023.1158133
37. Dianat M, Radan M, Badavi M, et al. (2018) Crocin attenuates cigarette smoke-induced lung injury and cardiac
dysfunction by anti-oxidative effects: the role of
Nrf2 antioxidant system in preventing oxidative stress.
Respiratory research 19: 58 DOI: 10.1186/s12931-0180766-3
38. Kubo H, Asai K, Kojima K, et al. (2019) Astaxanthin
Suppresses Cigarette Smoke-Induced Emphysema through
Nrf2 Activation in Mice. Marine drugs 17: 673. DOI: 10.
3390/md17120673
39. Li Z, Xu W, Su Y, et al. (2019). Nicotine induces insulin
resistance via downregulation of Nrf2 in cardiomyocyte.
Molecular and Cellular Endocrinology 110507. DOI: 10.
1016/j.mce.2019.110507
40. Lu Q, Yu S, Meng X, et al. (2022) MicroRNAs: Important Regulatory Molecules in Acute Lung Injury/
Acute Respiratory Distress Syndrome. International
journal of molecular sciences 23: 5545. DOI: 10.3390/
ijms23105545
41. Tu W, Wang H, Li S, et al. (2019) The anti-inflammatory and
anti-oxidant mechanisms of the keap1/nrf2/ARE signaling
pathway in chronic diseases. Aging and disease 10(3):
637–651. DOI: 10.14336/AD.2018.0513
42. Hendawy AK, El-Toukhey NES, AbdEl-Rahman SS, et al.
(2021) Ameliorating effect of melatonin against nicotine
induced lung and heart toxicity in rats. Environmental science and pollution research international 28: 35628–35641.
DOI: 10.1007/s11356-021-12949-z
43. Chen Z, Wang B, Wu Z, et al. (2023) The occurrence and
development of radiation-induced lung injury after interstitial brachytherapy and stereotactic radiotherapy in SD rats.
Journal of inflammation (London, England) 20: 23. DOI: 10.
1186/s12950-023-00348-9
44. Miklós Z and Horváth I (2023) The Role of Oxidative
Stress and Antioxidants in Cardiovascular Comorbidities in COPD. Antioxidants 12(6): 1196. DOI: 10.3390/
antiox12061196
45. Hamza RZ and El-Shenawy NS (2017) Anti-inflammatory
and antioxidant role of resveratrol on nicotine-induced lung
changes in male rats. Toxicology reports 4: 399–407, Published 2017 Jul 17. DOI: 10.1016/j.toxrep.2017.07.003.
46. Aslan M, Gürel E, Üremiş N, et al. (2023) Anti-inflammatory
and antioxidative effects of dexpanthenol on nicotineinduced lung injury in rats. Toxicology and Environmental
Health Sciences 15: 303–313.
47. Hong ZY, Song KH, Yoon JH, et al. (2015) An experimental model-based exploration of cytokines in ablative
radiation-induced lung injury in vivo and in vitro. Lung
193: 409–419.
International Journal of Immunopathology and Pharmacology
48. Zhang T, Ma S, Liu C, et al. (2020) Rosmarinic Acid
Prevents Radiation-Induced Pulmonary Fibrosis Through
Attenuation of ROS/MYPT1/TGFβ1 Signaling Via miR19b-3p. Dose-response: a publication of International
Hormesis Society 18(4): 1559325820968413. DOI: 10.
1177/1559325820968413
49. Wang K, Zhang Y, Cao Y, et al. (2020) Glycyrrhetinic acid
alleviates acute lung injury by PI3K/AKT suppressing
macrophagic Nlrp3 inflammasome activation. Biochemical
and biophysical research communications 532(4): 555–562.
DOI: 10.1016/j.bbrc.2020.08.044
50. Lu H, Yao H, Zou R, et al. (2019) Galangin Suppresses Renal
Inflammation via the Inhibition of NF-κB, PI3K/AKT and
NLRP3 in Uric Acid Treated NRK-52E Tubular Epithelial
Cells. BioMed research international 2019: 3018357. DOI:
10.1155/2019/3018357
51. Freeman TL and Swartz TH (2020) Targeting the
NLRP3 Inflammasome in Severe COVID-19. Frontiers in
immunology 11: 1518. DOI: 10.3389/fimmu.2020.01518
52. Arcidiacono B, Chiefari E, Messineo S, et al. (2018)
HMGA1 Is a Novel Transcriptional Regulator of the
FoxO1 Gene. Endocrine 60(1): 56–64. DOI: 10.1007/
s12020-017-1445-8
53. Zhang L, Li N, Zhang X, et al. (2023) Hexavalent chromium
caused DNA damage repair and apoptosis via the PI3K/
AKT/FOXO1 pathway triggered by oxidative stress in the
lung of rat. Ecotoxicology and environmental safety 267:
115622. DOI: 10.1016/j.ecoenv.2023.115622
54. Sun X, Chen L and He Z (2019) PI3K/Akt-Nrf2 and AntiInflammation Effect of Macrolides in Chronic Obstructive
Pulmonary Disease. Current drug metabolism 20(4):
301–304. DOI: 10.2174/1389200220666190227224748
55. Ghareghomi S, Moosavi-Movahedi F, Saso L, et al. (2023)
Modulation of Nrf2/HO-1 by Natural Compounds in Lung
Cancer. Antioxidants 12: 735.
56. Alsemeh AE and Abdullah DM (2022) Protective effect of
alogliptin against cyclophosphamide-induced lung toxicity
in rats: Impact on PI3K/Akt/FoxO1 pathway and downstream inflammatory cascades. Cell and tissue research
388(2): 417–438. DOI: 10.1007/s00441-022-03593-1
57. Yang H, Lv H, Li H, et al. (2019) Oridonin protects LPSinduced acute lung injury by modulating Nrf2-mediated
oxidative stress and Nrf2-independent NLRP3 and NF-κB
pathways. Cell communication and signaling: CCS 17: 62.
58. Zeng J, Zhao H and Chen B (2019) DJ-1/PARK7 inhibits
high glucose-induced oxidative stress to prevent retinal
pericyte apoptosis via the PI3K/AKT/mTOR signaling
pathway. Experimental eye research 189: 107830. DOI: 10.
1016/j.exer.2019.107830
59. Li Q, Wang G, Xiong SH, et al. (2020) Bu-Shen-Fang-Chuan
formula attenuates cigarette smoke-induced inflammation by
modulating the PI3K/Akt-Nrf2 and NF-κB signalling
pathways. Journal of ethnopharmacology 261: 113095.
DOI: 10.1016/j.jep.2020.113095
15
Elsayed et al.
60. Zhao X, Tian Z, Sun M, et al. (2023) Nrf2: a dark horse in
doxorubicin-induced cardiotoxicity. Cell death discovery 9:
261.
61. Zhang Y, Ma X, Jiang D, et al. (2020) Glycine Attenuates
Lipopolysaccharide-Induced Acute Lung Injury by Regulating NLRP3 Inflammasome and NRF2 Signaling. Nutrients 12(3): 611. DOI: 10.3390/nu12030611
62. Cui H and Zhang Q (2021) Dexmedetomidine ameliorates
lipopolysaccharide-induced acute lung injury by inhibiting
the PI3K/Akt/FoxO1 signaling pathway. Journal of anesthesia 35(3): 394–404. DOI: 10.1007/s00540-021-02909-9
63. Lewandowski W, Lewandowska H, Golonko A, et al. (2020)
Correlations between molecular structure and biological
activity in “logical series” of dietary chromone derivatives.
PLoS ONE 15(8): e0229477.
64. Das M, Manna K, Banik U, et al. (2014) Biologically potential flavones: a subgroup of flavonoids. Int J Pharm Sci &
Res 5(9): 3840–3848. DOI: 10.13040/IJPSR.0975-8232.
5(9).3840-48
65. Kariagina A and Doseff AI (2022) Anti-Inflammatory
Mechanisms of Dietary Flavones: Tapping into Nature to
Control Chronic Inflammation in Obesity and Cancer. International journal of molecular sciences 23: 15753.
66. Saadullah M, Rashad M, Asif M, et al. (2023) Chapter 4 Biosynthesis of phytonutrients. In: Phytonutrients and
Neurological Disorders. Academic Press, 57–105.
67. Oteiza PI, Erlejman AG, Verstraeten SV, et al. (2005) Flavonoidmembrane interactions: a protective role of flavonoids at the
membrane surface? Clinical & developmental immunology 12(1):
19–25. DOI: 10.1080/10446670410001722168
68. Singh M, Kaur M and Silakari O (2014) Flavones: an important scaffold for medicinal chemistry. European journal
of medicinal chemistry 84: 206–239. DOI: 10.1016/j.ejmech.
2014.07.013
69. Rudrapal M, Eltayeb WA, Rakshit G, et al. (2023) Dual
synergistic inhibition of COX and LOX by potential
chemicals from Indian daily spices investigated through
70.
71.
72.
73.
74.
75.
76.
77.
detailed computational studies. Scientific reports 13:
8656.
Chagas MDSS, Behrens MD, Moragas-Tellis CJ, et al.
(2022) Flavonols and Flavones as Potential antiInflammatory, Antioxidant, and Antibacterial Compounds.
Oxidative medicine and cellular longevity 2022: 9966750.
Geraets L, Moonen HJ, Brauers K, et al. (2007) Flavone as
PARP-1 inhibitor: its effect on lipopolysaccharide induced
gene-expression. European journal of pharmacology 573(13): 241–248. DOI: 10.1016/j.ejphar.2007.07.013.
Rudrapal M, Khairnar SJ, Khan J, et al. (2022) Dietary
polyphenols and their role in oxidative stress-induced human
diseases: insights into protective effects, antioxidant potentials and mechanism(s) of action. Frontiers in pharmacology 13: 806470, Published 2022 Feb 14. DOI: 10.3389/
fphar.2022.806470
Rudrapal M, Maji S, Prajapati SK, et al. (2022) Protective
effects of diets rich in polyphenols in cigarette smoke (cs)induced oxidative damages and associated health implications. Antioxidants (Basel) 11(7): 1217, Published 2022 Jun
21. DOI: 10.3390/antiox11071217
Tianzhu Z, Shihai Y and Juan D (2014) The effects of morin
on lipopolysaccharide-induced acute lung injury by suppressing the lung NLRP3 inflammasome. Inflammation 37:
1976–1983.
Lim H, Min DS, Park H, et al. (2018) Flavonoids interfere
with NLRP3 inflammasome activation. Toxicology and
applied pharmacology 355: 93–102. DOI: 10.1016/j.taap.
2018.06.022
Özcan FÖ, Aldemir O and Karademir B (2020) Flavones
(Apigenin, Luteolin, Crhysin) and their importance for
health. Mellifera 20(1): 16–27.
Rudrapal M, Rakshit G, Singh RP, et al. (2024) Dietary
polyphenols: review on chemistry/sources, bioavailability/
metabolism, antioxidant effects, and their role in disease
management. Antioxidants (Basel) 13(4): 429. DOI: 10.
3390/antiox13040429