Leonardo Cespedes
Universidad del Bio-bio, Basic Sciences Dpt, Faculty Member
- Biochemistry, Teacher Education, Higher Education, Instructional Design, Chile, Biological Activity Of Natural Products, and 21 moreNatural Products Chemistry, Molecular biology of oxidative stress in seed-ROS and Antioxidant enzymes, Enzyme Inhibitors, Biopesticides, Educación superior, Education, Chemistry, Organic Chemistry, Pharmacology, Functional or nutraceutical foods, Pharmacy, Alkaloids, Indole Alkaloids, Phytochemistry, Phytoecdysteroids, Chemoprotection, Toxicology, Antioxidants, Antimicrobials, Medicinal plants for cancer diabetes hypertensive and nutraceutical developments, and Allelopathyedit
- The scopes of investigation are the natural products (extracts, fractions, and secondary metabolites SM) and their ap... moreThe scopes of investigation are the natural products (extracts, fractions, and secondary metabolites SM) and their applications, and the interactions of SM with enzymes, insects, microbes, plants and with different biological systems, such as insect pests and weeds.edit
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ABSTRACT
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Secondary metabolites from fungi have become a major source of chemical innovation in programs searching for lead molecules with bioactivities, especially over the last 50 years. In this review, we discuss the fundamental considerations... more
Secondary metabolites from fungi have become a major source of chemical innovation in programs searching for lead molecules with bioactivities, especially over the last 50 years. In this review, we discuss the fundamental considerations in the discovery of molecules for agricultural and medicinal uses. This group of organisms possesses a strong potential for scientific and industrial communities. Recently, the incorporation of new technologies for the artificial cultivation of fungi and the use of better equipment to isolate and identify active metabolites has allowed the discovery of leading molecules for the design of new and safer drugs and pesticides. The geographical region including the Patagonian Andes mountains harbors a wide diversity of fungi, many of them still unknown and so far associated with Chilean-Argentinian Andean endemic forests. There have been very few chemical studies of the fungi located in this region. However, those few studies have allowed the discovery of...
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The effects of phytochemicals occurred in fractions and extracts of fruits of "Maqui-berry" (Aristotelia chilensis), on the expression of cyclooxygenase-2 (COX-2), inducible-nitric oxide synthases (iNOS) and the production of... more
The effects of phytochemicals occurred in fractions and extracts of fruits of "Maqui-berry" (Aristotelia chilensis), on the expression of cyclooxygenase-2 (COX-2), inducible-nitric oxide synthases (iNOS) and the production of proinflammatory mediators were investigated in lipopolysaccharide (LPS)-activated murine macrophage RAW-264 cells, as well as their antioxidant activities. The MeOH extract (A), acetone/methanol extract (B), fractions F3, F4, subfractions (SF4-SF6, SF7, SF8-SF10, SF11-SF15, SF16-SF20), quercetin, gallic acid, luteolin, myricetin, mixtures M1, M2 and M3 exhibited potent anti-inflammatory and antioxidant activities. The results indicated that anthocyanins, flavonoids and its mixtures suppressed the LPS induced production of nitric oxide (NO), through the down-regulation of iNOS and COX-2 protein expressions and showed a potent antioxidant activity against SOD, ABTS, TBARS, ORAC, FRAP and DCFH. The inhibition of enzymes and NO production by selected frac...
Research Interests: Chemistry, Inflammation, Medicine, Brain, Polyphenols, and 15 moreMice, Animals, Iron, Fruit, Lipid peroxidation, Antioxidant Activity, Plant extracts, Rats, Food Sciences, Antiinflammatory Natural Products, Food and Chemical Toxicology, Total Phenolics, Antiinflammatory Activity, Oxidation-Reduction, and Aristotelia Chilensis
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As a defense mechanism of the aerial parts of Calceolaria talcana (Calceolariaceae; formerly Scrophulariaceae) against herbivore offenses and insect pest attack, diterpenoids, triterpenoids, phenylethanoids, flavonoids, and iridoids are... more
As a defense mechanism of the aerial parts of Calceolaria talcana (Calceolariaceae; formerly Scrophulariaceae) against herbivore offenses and insect pest attack, diterpenoids, triterpenoids, phenylethanoids, flavonoids, and iridoids are rapidly accumulated along the aerial parts, resulting in a unique natural biopesticide complex from this plant. In addition to verbascoside a series of known compounds were screened for their inhibitory activity against mushroom tyrosinase and protease enzymes. Ethyl acetate and n-hexane extracts, together with cyclopropyl-7,15-ent-pimaradiene (1), abietatriene (2), ursolic acid (3), α-lupeol (4), β-sitosterol (5), 2-hydroxy-3-(1,1-dimethylallyl)-1,4-naphthoquinone (6), α-dunnione (7), verbascoside (8), martynoside (9), and some known model compounds proved to be inhibitors of oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) catalyzed by tyrosinase (EC 1.14.18.1) with an IC50 between 10.0 and 200 ppm or μM, respectively, suggesting that phenolic mo...
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The aim of this work was to isolate and identify the antifungal compounds present in the hexanic extract of the aerial parts of Gymnosperma glutinosum. The antifungal activity against six pathogenic fungi was determined in accordance with... more
The aim of this work was to isolate and identify the antifungal compounds present in the hexanic extract of the aerial parts of Gymnosperma glutinosum. The antifungal activity against six pathogenic fungi was determined in accordance with the inhibition of radial growth method. Four of those fungi Aspergillus niger, Candida albicans, Fusarium sporotrichum and Trichophyton mentagrophytes are of clinical importance
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The effects of 9β-benzoyloxy-la, 2α, 6β, 8α, 15-pentaacetoxy-dihydro-β-agarofuran and 9β furoyloxy-1α, 6β, 8α-triacetoxy-dihydro-β-agarofuran, major phytogrowth inhibitors isolated from the aerial parts of Maytenus disticha (Celastraceae)... more
The effects of 9β-benzoyloxy-la, 2α, 6β, 8α, 15-pentaacetoxy-dihydro-β-agarofuran and 9β furoyloxy-1α, 6β, 8α-triacetoxy-dihydro-β-agarofuran, major phytogrowth inhibitors isolated from the aerial parts of Maytenus disticha (Celastraceae) and seeds of Maytenus boaria (Celastaraceae), respectively, on different photosynthetic activities of isolated spinach chloroplasts have been investigated. Photophosphorylation and electron transport (basal, phosphorylating and uncoupled) were inhibited in a concentration dependent manner by both compounds, therefore acting as Hill reaction inhibitors. The site of action of these natural compounds was located in the span from P680 to QA. 9β-benzoyloxy-1,2,6,8,15-pentaacetoxydihydro-β-agarofuran was one order of magnitude more potent (I50 = 2.6 μм) than 9β-furoyloxy-1,6,8,-triacetoxydihydro-β-agarofuran, suggesting that the substitution at C-9 and the acetoxy groups at carbons 2 and 15 are important structural requirements for the displayed inhibito...
ABSTRACT OF THE MEETING
Research Interests:
ABSTRACTS
Research Interests:
The effects of phytochemicals occurred in fractions and extracts of fruits of “Maqui-berry” (Aristotelia chilensis), on the expression of cyclooxygenase-2 (COX-2), inducible-nitric oxide synthases (iNOS) and the production of... more
The effects of phytochemicals occurred in fractions and extracts of fruits of “Maqui-berry” (Aristotelia
chilensis), on the expression of cyclooxygenase-2 (COX-2), inducible-nitric oxide synthases (iNOS) and
the production of proinflammatory mediators were investigated in lipopolysaccharide (LPS)-activated
murine macrophage RAW-264 cells, as well as their antioxidant activities. The MeOH extract (A),
acetone/methanol extract (B), fractions F3, F4, subfractions (SF4-SF6, SF7, SF8-SF10, SF11-SF15, SF16-
SF20), quercetin, gallic acid, luteolin, myricetin, mixtures M1, M2 and M3 exhibited potent antiinflammatory
and antioxidant activities. The results indicated that anthocyanins, flavonoids and its
mixtures suppressed the LPS induced production of nitric oxide (NO), through the down-regulation of
iNOS and COX-2 protein expressions and showed a potent antioxidant activity against SOD, ABTS, TBARS,
ORAC, FRAP and DCFH. The inhibition of enzymes and NO production by selected fractions and compounds
was dose-dependent with significant effects seen at concentration as low as 1.0e50.0 (ppm) and
5.0e10.0 mM, for samples (extracts, fractions, subfractions and mixtures) and pure compounds, respectively.
Thus, the phenolics (anthocyanins, flavonoids, and organic acids) as the fractions and mixtures
may provide a potential therapeutic approach for inflammation associated disorders and therefore might
be used as antagonizing agents to ameliorate the effects of oxidative stress.
© 2016 Elsevier Ltd. All rights reserved.
chilensis), on the expression of cyclooxygenase-2 (COX-2), inducible-nitric oxide synthases (iNOS) and
the production of proinflammatory mediators were investigated in lipopolysaccharide (LPS)-activated
murine macrophage RAW-264 cells, as well as their antioxidant activities. The MeOH extract (A),
acetone/methanol extract (B), fractions F3, F4, subfractions (SF4-SF6, SF7, SF8-SF10, SF11-SF15, SF16-
SF20), quercetin, gallic acid, luteolin, myricetin, mixtures M1, M2 and M3 exhibited potent antiinflammatory
and antioxidant activities. The results indicated that anthocyanins, flavonoids and its
mixtures suppressed the LPS induced production of nitric oxide (NO), through the down-regulation of
iNOS and COX-2 protein expressions and showed a potent antioxidant activity against SOD, ABTS, TBARS,
ORAC, FRAP and DCFH. The inhibition of enzymes and NO production by selected fractions and compounds
was dose-dependent with significant effects seen at concentration as low as 1.0e50.0 (ppm) and
5.0e10.0 mM, for samples (extracts, fractions, subfractions and mixtures) and pure compounds, respectively.
Thus, the phenolics (anthocyanins, flavonoids, and organic acids) as the fractions and mixtures
may provide a potential therapeutic approach for inflammation associated disorders and therefore might
be used as antagonizing agents to ameliorate the effects of oxidative stress.
© 2016 Elsevier Ltd. All rights reserved.
Research Interests:
On behalf The Chilean Society of Chemistry, through the Division of Natural Products Chemistry invite you to participate in the VIII International Symposium on Natural Products Chemistry and Applications to be held at the Gran Hotel... more
On behalf The Chilean Society of Chemistry, through the Division of Natural Products Chemistry invite you to participate in the VIII International Symposium on Natural Products Chemistry and Applications to be held at the Gran Hotel Termas de Chillan, Chillan, Chile, 22 - 25 November, 2016.
The organizers are the University of Bio Bio, University of Talca, Federico Santa María Technical University and the Division of Chemistry of Natural Products of the Chilean Society of Chemistry.
The organizers are the University of Bio Bio, University of Talca, Federico Santa María Technical University and the Division of Chemistry of Natural Products of the Chilean Society of Chemistry.
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Aims: Bring together national and international researchers in the area of natural products, from universities and research organizations, in order to disseminate the results of research in the area. The Symposium includes the... more
Aims: Bring together national and international researchers in the area of natural products, from universities and research organizations, in order to disseminate the results of research in the area.
The Symposium includes the presentation of plenary lectures on the modalities of invited-lecture, short lecture and plenary conference, with national and international speakers.
In addition there will be poster session in the following subjects:
- Chemistry of Natural Products.
- (Ethno) botany (ethno) pharmacology.
- Medicinal Chemistry
- Industrial applications
- Ecological Chemistry
- Biological Activities
- Biotechnology
- Metabolomics
- Toxicology (ecotoxicology, genotoxicity, etc)
Target audiences:
- Researchers / academics from universities and public and private entities.
- Researchers at research institutes (public and private)
- Postdoctoral Students - Graduate Students (PhD and Master) - Undergraduates
- Entrepreneurs - General public
The Symposium includes the presentation of plenary lectures on the modalities of invited-lecture, short lecture and plenary conference, with national and international speakers.
In addition there will be poster session in the following subjects:
- Chemistry of Natural Products.
- (Ethno) botany (ethno) pharmacology.
- Medicinal Chemistry
- Industrial applications
- Ecological Chemistry
- Biological Activities
- Biotechnology
- Metabolomics
- Toxicology (ecotoxicology, genotoxicity, etc)
Target audiences:
- Researchers / academics from universities and public and private entities.
- Researchers at research institutes (public and private)
- Postdoctoral Students - Graduate Students (PhD and Master) - Undergraduates
- Entrepreneurs - General public
Research Interests:
Aims: Bring together national and international researchers in the area of natural products, from universities and research organizations, in order to disseminate the results of research in the area. The Symposium includes the... more
Aims: Bring together national and international researchers in the area of natural products, from universities and research organizations, in order to disseminate the results of research in the area.
The Symposium includes the presentation of plenary lectures on the modalities of invited-lecture, short lecture and plenary conference, with national and international speakers.
In addition there will be poster session in the following subjects:
- Chemistry of Natural Products.
- (Ethno) botany (ethno) pharmacology.
- Medicinal Chemistry
- Industrial applications
- Ecological Chemistry
- Biological Activities
- Biotechnology
- Metabolomics
- Toxicology (ecotoxicology, genotoxicity, etc)
Target audiences:
- Researchers / academics from universities and public and private entities.
- Researchers at research institutes (public and private)
- Postdoctoral Students - Graduate Students (PhD and Master) - Undergraduates
- Entrepreneurs - General public
The Symposium includes the presentation of plenary lectures on the modalities of invited-lecture, short lecture and plenary conference, with national and international speakers.
In addition there will be poster session in the following subjects:
- Chemistry of Natural Products.
- (Ethno) botany (ethno) pharmacology.
- Medicinal Chemistry
- Industrial applications
- Ecological Chemistry
- Biological Activities
- Biotechnology
- Metabolomics
- Toxicology (ecotoxicology, genotoxicity, etc)
Target audiences:
- Researchers / academics from universities and public and private entities.
- Researchers at research institutes (public and private)
- Postdoctoral Students - Graduate Students (PhD and Master) - Undergraduates
- Entrepreneurs - General public