%0 Journal Article
%T Free Radical Scavenging Activity of Kielmeyera variabilis (Clusiaceae)
%A Aline Coqueiro
%A Luis Oct¨¢vio Regasini
%A Scheila Cristina Gutkoski Skrzek
%A Marcos Mar£¿al Ferreira Queiroz
%A Dulce Helena Siqueira Silva
%A Vanderlan da Silva Bolzani
%J Molecules
%D 2013
%I MDPI AG
%R 10.3390/molecules18022376
%X 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 ¡À 0.3 and 4.4 ¡À 0.2 ¦Ìg mL £¿1 for DPPH ¡¤ and 6.6 ¡À 0.4 and 3.1 ¡À 0.1 ¦Ìg 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-b-glucoside ( 3), and quercetin-3- O-b-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.
%K Kielmeyera variabilis
%K Clusiaceae
%K antioxidant
%K free radical scavenging activity
%K DPPH¡¤
%K ABTS¡¤+
%K flavonoid
%K flavonol
%U http://www.mdpi.com/1420-3049/18/2/2376