Alkylperoxyl radical-induced oxidation of bovine serum albumin(BSA) was assayed as described elsewhere (Mayo et al., 2003)with some modifications. We prepared AAPH as a 500 mM stock solution, and heated the solution for 2 min at 37 C before it was added to samples. Specifically, BSA (1.2 mg/mL) was incubated with AAPH (500 mM) in the presence or absence of methanolic sample extracts in a shaking water bath at 37 C for 6 h. A protein sample without AAPH was used as the control. After treatment, protein samples were mixed with loading buffer (100 mM TriseHCl buffer(pH 6.8), 4% sodium dodecyl sulfate (SDS), 0.2% bromophenol blue(BPB), 20% glycerol, 2% b-mercaptoethanol) and heated at 100 C for 5 min. A 15-mL aliquot of each sample was separated by SDS-PAGE on 12% acrylamide gels. The gels were stained overnight with 0.1% Coomassie brilliant blue (CBB) R-250 and then washed extensively.The gels were analyzed using a ChemiDoc XRS gel documentation system (Bio-Rad, Hercules, CA, USA). To determine the extent of protein damage, band intensity was estimated using Quantity One 4.6.2 software (Bio-Rad). The optical density of bands was estimated and standardized against that of the control group. The extent of protection against protein oxidation was calculated as follows