Cyclopeptide alkaloids of Zizyphus oenoplia

Abstract The known alkaloids zizyphine-A ( 1 ) and -B ( 2 ), abyssinine-A ( 4 ) and -B ( 5 ), and the previously undescribed zizyphine-C ( 3 ), -D ( 6 ) and -E ( 7 ) have been isolated from the stem bark of Zizyphus oenoplia . The structures of the new compounds were elucidated by spectroscopic methods applied to the alkaloids and to some of their transformation products, and by chemical degradation reactions.