title: Free radical scavengers and antioxidants from Tagetes mendocina.
abstract: Tagetes mendocina (Asteraceae) is a medicinal plant widely used in the Andean provinces of Argentina. Preliminary assays showed free radical scavenging activity in the methanol extract of the aerial parts, measured by the decoloration of a methanolic solution of the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and scavenging of the superoxide anion. Assay-guided isolation led to 4'-hydroxyacetophenone (1), protocatechuic acid (2), syringic acid (3), patuletin (4), quercetagetin 7-O-beta-D-glucoside (5), patuletin 7-O-beta-D-glucoside (6) and axillarin 7-O-beta-D-glucoside (7) as the free radical scavengers and antioxidant compounds from Tagetes mendocina. On the basis of dry starting material, the total phenolic content of the crude drug was 3.00% with 0.372% of flavonoids. The content of compounds 1-7 in the crude drug was 0.008, 0.015, 0.010, 0.029, 0.238, 0.058 and 0.017%, respectively. Quercetagetin 7-O-beta-D-glucoside proved to be the main free radical scavenger of the extracts measured by the DPPH decoloration test as well as for quenching the superoxide anion and inhibition of lipoperoxidation in erythrocytes. In the lipid peroxidation assay the percentual inhibition was related with the number of methoxy groups in the molecule, ranging from 86% for the quercetagetin glucoside to 67% for the monomethoxylated and 31% for the dimethoxylated derivative. The compounds showed low cytotoxicity towards human lung fibroblasts with IC50 > 1 mM for compounds 1-3 and 0.24 to 0.52 mM for the flavonoids 4-7.
authors.affiliation: Universidad de Talca, Instituto de Química de Recursos Naturales, Laboratorio de Productos Naturales, Talca, Chile. schmeda@utalca.cl
authors.forename: Guillermo
authors.initials: G
authors.lastname: Schmeda-Hirschmann
authors.forename: Alejandro
authors.initials: A
authors.lastname: Tapia
authors.forename: Cristina
authors.initials: C
authors.lastname: Theoduloz
authors.forename: Jaime
authors.initials: J
authors.lastname: Rodríguez
authors.forename: Susana
authors.initials: S
authors.lastname: López
authors.forename: Gabriela Egly
authors.initials: GE
authors.lastname: Feresin
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000302:isolation & purification* / Q000494:pharmacology*; D002417:Cattle; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002855:Chromatography, Thin Layer; D004912:Erythrocytes / Q000187:drug effects / Q000502:physiology; D000431:Ethanol; D005260:Female; D016166:Free Radical Scavengers / Q000302:isolation & purification* / Q000494:pharmacology*; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects / Q000502:physiology; D008168:Lung / Q000166:cytology / Q000187:drug effects; D008892:Milk / Q000201:enzymology; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D018514:Plant Structures; D013481:Superoxides / Q000378:metabolism; D031686:Tagetes; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D013481:Superoxides; D000431:Ethanol; D014969:Xanthine Oxidase