In the present study, acetone extract and sub-fractions of Albizia amara stem bark were evaluated for their free radical potential. The results showed that the crude extract and all the fractions exhibited antioxidant and free radical scavenging activities under different in vitro assays. Among the different fractions, the ethyl acetate fraction exhibited higher DPPH and ABTS radical scavenging activities than the standard quercetin. A. amara stem bark might be valuable source of natural antioxidants that could be used for medicinal and food applications.

In this study, we investigated antioxidant capacity and determined the phenolic and flavonoid contents using each of various solvent conditions from fermented Rhus verniciflua stem bark (F-RVS). Each extracts displayed markedly similar content of extraction yield. However, M80 extract showed a significantly higher antioxidant activity in comparison to other extract investigated. M80 exhibited strong DPPH radical scavenging activity with RC50 value of 10.5±1.4μg/ml, reducing power value 1.04 Abs (concentration of 1 mg/ml), and anti-lipid peroxidation activity value of 94.6% (concentration of 10 mg/ml). M80 extract showed the high content of total phenolic (319.7 mg GAE/ml extract) and total flavonoid (111.6 mg QE/ml extract). Phenolic and flavonoid compounds showed significant relationship in DPPH radical scavenging (R2=0.911 and 0.912, each extract) and reducing power (R2=0.903 and 0.837, each extract) from fermented R. verniciflua stem bark. However, antilipid peroxidation activity (R2=0.589 and 0.441, each extract) was not significant like DPPH radical scavenging and reducing power. Therefor the result indicated that the potential antioxidant activities and functional values were ovserved significantly at M80 solvent condition from the fermented R. verniciflua stem bark.