The MeOH extract of the twig of Morus alba L. (Moraceae) inhibited strong lipid peroxidation activity. In order to find out active principle from the plant, acivity-guided fractionation was performed and five antioxidant compounds were isolated. Their chemical structures were identified as 6-geranylapigenin (1), 6-geranylnorartocarpetin (2), resveratrol (3), oxyresveratrol (4) and quercetin (5) by physicochemical and spectrometric methods. Compounds 1-5 significantly inhibited lipid peroxidation in rat brain homogenate $(IC_{50};values;of;3.37,;3.74,;0.23,;0.29;and;0.06; {mu}M,;respectively)$.