Atividade antioxidante de xantonas isoladas de espécies de Leiothrix (Eriocaulaceae)

Abstract

RESUMO:Leiothrix (Eriocaulaceae) é um gênero exclusivo da América do Sul, com 37 espécies restritas ao Brasil. Leiothrix flavescens (Bong.) Ruhland e Leiothrix curvifolia (Bong.) Ruhland, são espécies endêmicas em áreas dos Estados de Minas Gerais e Bahia. Existem na literatura poucos estudos químicos e biológicos realizados com espécies desse gênero. Neste trabalho, foi estudada a atividade antioxidante pelo ensaio TEAC (Trolox Equivalent Antioxidant Capacity) e de autoxidação, utilizando ácido linoléico, de xantonas isoladas dos extratos etanólicos de L. curvifolia e L. flavescens. As substâncias apresentaram moderada atividade antioxidante, quando comparadas com padrões de quercetina e de BHT (2, 6 -ditercbutil -4 -metóxifenil).Unitermos: Ação antioxidante; TEAC; Autoxidação; ácido linoléico; Eriocaulaceae; Leiotrhrix spp.; xantonas.ABSTRACT: Antioxidant effects of xanthones isolated from Leiothrix species (Eriocaulaceae). Leiothrix (Eriocaulaceae) is an exclusively South American genus of which 37 species are restricted to Brazil. Leiothrix flavescens (Bong.) Ruhland and Leiothrix curvifolia (Bong.) Ruhland, are species endemic to areas of Minas Gerais and Bahia States. Chemical and biological investigations of this genus are scarse. The objective of this work was to investigate the antioxidant effect using TEAC and linoleic acid assays of the xanthones isolated from the ethanolic extract of these species. These substances showed a moderate antioxidant activity when compared to quercetin and to BHT.

High-Performance Liquid Chromatographic Quantification of Flavonoids in Eriocaulaceae Species and Their Antimicrobial Activity

“…Studies aiming to describe the diverse biological activities of the Eriocaulaceae species have shown promising results. Some studies have described the antioxidant [ 9 ], cytotoxic and mutagenic activities [ 10 , 11 ], and some extracts of the assayed plants presented antiulcerogenic activity [ 12 ].…”

High-Performance Liquid Chromatographic Quantification of Flavonoids in Eriocaulaceae Species and Their Antimicrobial Activity

“…Some studies have described the antioxidant [9], cytotoxic and mutagenic activities [10,11], and some extracts of the assayed plants presented antiulcerogenic activity [12].…”

Flavonoids and a Naphthopyranone from Eriocaulon ligulatum and Their Mutagenic Activity

“…When revealed with Natural Product/Polyethylenoglycol Reagent (NP/PEG Reagent), compounds 1-3 showed yellow spots, characteristic of flavonoids. 9) Compounds 1-4 were determined to be 6-methoxyapigenin (3) and eriocauline (4). Compounds 3 and 4 were identified using spectroscopic methods (IR, UV, HR-ESI-MS and NMR 1-D and 2-D).…”

“…3) Taxonomic studies to delimit the genus, about which there is still some confusion, and the biological investigation into the isolated molecules of Eriocaulaceae are of great importance because several molecules possess antioxidant, 4) cytotoxic, mutagenic, 5,6) and antiulcerogenic activity. 7,8) We report here the isolation of taxonomically relevant flavonoids and a naphthopyranone dimer isolated from methanol and dichloromethane extracts from capitulae of E. ligulatum, respectively, and also the mutagenic activity of methanol and dichloromethane extracts assayed using the Ames test.…”