Evaluation of in vitro antioxidant and sunscreening activities of different solvent extracts obtained from Drypetes sepiaria (Weera) leaves

Abstract

In this study in vitro antioxidant and sunscreening activities of extracts obtained from Drypetes sepiaria (Weera) leaves grown in Sri Lanka were evaluated. The two different solvent systems, 70% aqueous acetone and 80% aqueous ethanol were used to prepare crude extracts from oven dried leaves of the plant. The defatted crude extracts prepared were subjected to preliminary phytochemical screening. The total phenolic and flavonoid contents were evaluated by using Folin-Ciocalteu assay and aluminiumchloride colorimetric methods. The in vitro antioxidant and in vitro sunscreening activities were evaluated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and UV-vis spectroscopic measurements followed by Mansur equation for the calculations of SPF values respectively. The results of phytochemical screening tests indicated the presence of phenolic compounds, flavonoids, saponins, carbohydrates and absence of alkaloids in both leaf extracts. The total phenolic content determined for the two extracts were 2.539±0.215 (70% acetone extract) and 3.478±0.299 (80% methanol extract) g Gallic acid equivalents (GAE)/100 g dry weight (DW) of the leaves. Total flavonoid content for the two extracts were 1.454±0.109 (70% acetone extract) and 2.285±0.243 (80% methanol extract) g Catechin equivalents (CAE)/100 g DW of the leaves. Antioxidant capacity for the two extracts were 1.932±0.142 (70% acetone extract) and 2.468±0.204 (80% methanol extract) mmol Trolox equivalents/100 g DW of the leaves. The 80% methanol leaf extract of Drypetes sepiaria showed significant sun protective factor of (SPF) 31 at the concentration of 1 mg/mL. The results indicated that Drypetes sepiaria leaves which contain high total phe nolic, flavonoid contents, have promising antioxidant and sunscreening activities.