Phytochemical analysis and in vitro antioxidant activity of Uncaria gambir

Abstract

The present research work was carried out to evaluate the antioxidant potential and antiradical property of methanolic extract of Uncaria gambir. Antioxidant and radical scavenging activity were determined by using different in vitro assays including reducing power assay, superoxide anion scavenging activity assay, hydroxyl radical scavenging activity assay, nitric oxide scavenging activity assay, DPPH free radical scavenging assay and hydrogen peroxide method. Preliminary phytochemical screening revealed that the extract of U. gambir possesses flavonoids, alkaloids and phenolic materials. In the present investigation, quantitative estimation of flavonoids content and phenolic content was also carried out by colorimetric methods, using aluminium chloride and Folin–Ciocalteu reagent method, respectively, to establish relationship between antioxidant activity and total phenolics and flavonoid contents. The total phenolic and flavonoid contents were found to be 18.37±2.79 mg gallic acid equivalents (GAE)/g dry weight and 5.82±2.23 mg rutin equivalents (RE)/g dry weight, respectively. The extract showed significant antioxidant activity in a dose-dependent manner in all the assays. The IC50 values of all parameters were determined. Ascorbic acid was used as standard. The results obtained in the present study indicated that U. gambir extract could be a potential source of natural antioxidant. Key words: Antioxidant, ascorbic acid, DPPH, hydroxyl radical, Uncaria gambir