Diels-Alder Type Adducts from Morus wittiorum

Nine Diels-Alder type adducts have been isolated from the stem bark of Morus wittiorum for the first time.And on the basis of spectral analysis such as NMR,MS etc.,structures of the compounds were identified as mulberrofuran K(1),mulberrofuran G(2),guangsangon L(3),kuwanon J(4),kuwanon X(5),guangsangon G(6),guangsangon B(7),guangsangon D(8),kuwanon P(9).The anti-oxidative activity of compounds 1-9 were assayed. As a result,compounds 1,2,5-7,9 showed inhibition to malondialdehyde(MDA)produced during microsomal lipid peroxidation induced by ferrous-cysteine(the inhibitory ratios were more than 50%)at a concentration of 10-5 M.