In vitro antioxidative activities and polyphenol content of Eugenia polyantha Wight grown in Indonesia.

Antioxidative activities of three bark extracts (methanol, methanol-water and water) from Eugenia polyantha Wight grown in Indonesia were evaluated using various in vitro assays; 2, 2-diphenyl-1-picrylhydrazyl radical-scavenging, hydrogen peroxide-scavenging and beta-carotene bleaching assays. From the assays, Eugenia polyantha bark extracts were found to be potential antioxidative activities. The methanol-water extract showed the highest level of free radical-scavenging activity (Effective dose (ED50) = 0.18 mg mL-1) and protection from beta-carotene bleaching (85.7% at 100 microg mL-1). The methanol-water extracts showed the highest total phenolic content (856 mg gallic acid equivalent (GAE)/g and 161 mg catechin equivalent (CE)/g) and total antioxidative capacity (449 mg ascorbic acid equivalent (AAE)/g). Furthermore, it exhibited dose-dependent antioxidative activities. A relationship between total antioxidative capacity and total phenolic content was recognized in the three extracts from Eugenia polyantha bark.