Free Radical Scavenging Activity of Kielmeyera variabilis (Clusiaceae)

Aline Coqueiro, Luis Regasini, Scheila Skrzek, Marcos Queiroz, Dulce Silva, Vanderlan da Silva Bolzani
2013 Molecules  
As part of our ongoing research on antioxidant agents from Brazilian flora, we screened the free radical scavenging activity of two extracts and eight fractions of Kielmeyera variabilis (Clusiaceae) using DPPH  (2,2-diphenyl-1-picrylhydrazyl-hydrate) and ABTS  [2,2'-azinobis(3-ethylenebenzothiazoline-6-sulfonic acid)] colorimetric assays. The ethyl acetate and n-butanol fractions of the leaves of K. variabilis displayed the strongest activity (IC 50 of 3.5 ± 0.3 and 4.4 ± 0.2 μg mL −1 for
more » ... 0.2 μg mL −1 for DPPH  and 6.6 ± 0.4 and 3.1 ± 0.1 μg mL −1 for ABTS  , respectively). Chromatographic fractionation of the most potent fractions led to identification of three flavonols with previously described antioxidant activity, quercitrin (1), quercetin-3-O--glucoside (3), and quercetin-3-O--galactoside (4), and of one biflavone, podocarpusflavone A (2). This is the first time that the presence of these flavonoids in Kielmeyera variabilis has been reported.
doi:10.3390/molecules18022376 pmid:23429348 fatcat:sm3e7she4ffs7aibsjagg2qaby