Antioxidant activities of different solvent extracts of leaves and root of Flabellaria paniculata Cav. (Malpighiaceae)

The antioxidant activities of different solvent extracts of the leaves (ethanol (FLE), aqueous (FLH), chloroform (FLC)) and root (ethanol (FRE), aqueous (FRH) and chloroform (FRC)) of Flabellaria paniculata  were screened by different methods using free radical scavenging against DPPH and hydroxyl radicals, ex vivo lipid peroxidation, ferrous ion chelating activity, reducing power and total antioxidant capacity in phosphomolybedum assay. The extracts (10 to 100 µg/ml) showed varying degrees of antioxidant activity in different test systems. The leaves and root extracts showed significant inhibition of lipid peroxidation and scavenging of hydroxyl radicals. The extracts also showed moderate chelating property which could explain the affinity of the extracts for iron (Fe), hence their antioxidant capability. However, in DPPH radical scavenging and reducing power assays, FRE extract had higher activity than all the extracts, and the activity is comparable to that of quercetin and tocopherol at higher concentrations (80 to 100 µg/ml) of the extract used in this study. Flavonoid content of different extracts of F. paniculata is in the order FLE>FLC>FRE>FRC>FRH>FLH. Ethanol extracted the highest root amount of condensed tannin (216.42 ± 0.018 mg equivalent of catechin/g of extract), while proanthocyanidin contents of leaf extracts varied from 12.7 to 47.9 mg of gallic acid equivalence (GAE)/g extract. No correlation was observed between DPPH, Fe chelating, lipid peroxidation, reducing power, and total phenolic contents of the extracts. However, proanthocyanidin content was moderately correlated with chelating (R² = 0.43) and DPPH radical scavenging (R² = 0.7811) activities. Hence, these extracts could be considered as natural antioxidants and may be useful for curing diseases arising from oxidative deterioration.   Key words: Flabellaria paniculata, antioxidant, polyphenolic content, solvent extraction, leaves, root.