In-vitro anti-inflammatory and antioxidant activities of Leea indica (Burm.f.) Merr.
Sujeewa Krishanthi Hettihewa, Thotawaththage Loshadhi Indunika Srilal

The aim of this study was to evaluate in-vitro anti-inflammatory and antioxidant properties of different solvent extracts obtained from leaves of Leea indica (Burulla/Gurulla) grown in Sri Lanka. Two different defatted crude extracts namely, 70% aqueous acetone and 80% aqueous methanol were prepared by steeping method. The total phenolic (TP) and total flavonoid (TF) contents of the both extracts were evaluated using Folin-Ciocalteu and aluminum chloride colorimetric methods respectively. In-vitro radical scavenging activity of the solvent extracts was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and antioxidant activity was determined by ferric-reducing antioxidant power assay (FRAP assay). In-vitro antiinflammatory activity of extracts was determined using Human Red Blood Cell (HRBC) membrane stabilization assay. The results for the total phenolic content of the extracts were 4891.776 ± 64.965 (70% aqueous acetone) and 3413.859 ± 85.493 (80% aqueous methanol) mg Gallic acid equivalents (GAE)/100 g dry weight (DW) of leaves. Results of the total flavonoid content of the extracts were 1711.220 ± 22.829 (70% aqueous acetone) and 920.867 ± 39.833 (80% aqueous methanol) mg Catechin equivalents (CAE)/100 g dry weight (DW) of leaves. Radical scavenging activity of the extracts was determined as 13.418 ± 0.312 (70% aqueous acetone) and 9.421 ± 0.431 (80% aqueous methanol) mmol Trolox equivalents/100 g DW of leaves. Ferric reducing antioxidant power of the extracts was found as 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. Significantly high values of TP, TF contents, radical scavenging and ferric reducing activities were exhibited by leaf extract obtained into 70% aqueous acetone. Half maximal inhibitory concentration (IC50) values obtained in the 
membrane stabilization assay were 431.500 μg/mL and 442.100 μg/mL for 70% aq. acetone and 80% aq. methanol extracts respectively and their responses were significantly greater than the reference drug aspirin (IC50 1062.000 μg/mL). Hence, it is concluded that the leaf extracts of Sri Lankan grown Leea indica possess marked in vitro anti-inflammatory and antioxidant activities which should be further investigated by in-vivo models.

Keywords: Anti-inflammatory, antioxidant, Leea indica, membrane stabilization assay