Purification and characterization of phenolic compounds from the leaves of Cnestis ferruginea (De Candolle): Investigation of antioxidant property

Abstract

The presence of yet to be explored radical scavengers in the leaf extracts of Cnestis ferruginea (De Candolle) have been reported. Thus, the present study is focused on isolating and characterizing these radical scavengers for possible therapeutic use as lead drug candidates against oxidatively induced pathological conditions. The defatted methanol extracts (MECF) of the leaves of Cnestis ferruginea was fractionated into Chloroform (CF), Ethylacetate (EF), Butanol (BF) and Water (WF) fractions. Total antioxidant property, superoxide anion, l,l-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities and inhibition of xanthine oxidase activity by the fractions were determined. The extent of inhibition of Fe 2+/ascorbate stimulated lipid peroxidation in mitochondrial membranes was also evaluated. All fractions and crude extracts exhibited antioxidant properties at different degrees. The pattern of DPPH radical scavenging activity and inhibition of mitochondrial membrane lipid peroxidation by MECF and EF were similar, β-sitosterol, para-hydroxyphenol and six other sub-fractions were isolated from EF. The DPPH radical scavenging activities of the sub-fractions were not significantly (p>0.05) different from one another. Robustaside B or 6'-(3", 4"-dihydroxycinnamoyl) arbutin was also isolated from sub-fraction III from EF using sephadex LH 20. Structural elucidation of all compounds was determined by spectroscopy (IR, UV, ID and 2D 1H and 13C NMR). The present study reported for the first time the isolation and radical scavenging activity of Robustaside B-an arbutin derivative and para-hydroxyphenol from leaves of Cnestis ferruginea. Leaf extracts of Cnestis ferruginea was demonstrated to be a rich source of antioxidants. © 2011 Academic Journals Inc.