In vitro antioxidant activity of different solvent extracts obtained from Leea indica (Burm.f.) Merr (Burulla) leaves grown in Sri Lanka

Abstract

The importance of natural antioxidants has been arisen due to the carcinogenic nature of the synthetic antioxidants. Leea indica (Burm.f.) Merr. is a medicinal plant used in traditional Ayurvedic medicine in Sri Lanka to treat various diseases. The present study was aimed to evaluate in vitro antioxidant activity of Leea indica (Burm.f.) Merr. (Burulla) leaves grown in Sri Lanka. 70% aqueous acetone and 80% aqueous methanol extracts were prepared by steeping method and subjected to the determination of total phenolic and total flavonoid contents by Folin-Ciocalteu assay and aluminiumchloride colorimetric method, respectively. In vitro radical scavenging activity and antioxidant activity of the extracts were evaluated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay and ferric-reducing antioxidant power (FRAP) assay. Total phenolic contents were 4891.776 ± 64.965 (70% aqueous acetone) and 3413.859 ± 85.493 (80% aqueous methanol) mg Gallic acid equivalent /100 g dry weight of leaves. Total flavonoid contents were 1711.220 ± 22.829 (70% aqueous acetone) and 920.867 ± 39.833 (80% aqueous methanol) mg Catechin equivalents /100 g dry weight of leaves. The results of DPPH assay showed significantly high antioxidant capacity (13.418 ± 0.312 mMol Trolox equivalents/100 g DW of leaves) for 70% aqueous acetone extract compared to the value (9.421 ± 0.431 mMol Trolox equivalents/100 g DW of leaves) obtained for the 80% aqueous methanol extract. Antioxidant activity by FRAP assay was 17.796 ± 0.343 (70% aqueous acetone) and 12.422 ± 0.490 (80% aqueous methanol) mMol Fe (II) equivalents/100 g DW of the leaves. It can be concluded that the leaf extracts of Leea indica (Burulla) possess promising in vitro antioxidant activity which should be further investigated.