Two new sesquiterpene pyridine alkaloids from root barks of Celastrus angulatus

Two new sesquiterpene pyridine alkaloids, Chinese bittersweet alkaloid A (1) and Chinese bittersweet alkaloid B (2), together with five known compounds 3β- hydroxyolean-9(11),12-diene, β-sitosterol, 1β,2β,6α,15β-tetraacetoxy-8β,9α- dibenzoyloxy-β-dihydroagarofuran, angulatin A and angulatin J, were isolated from the root barks of Celastrus angulatus. The structures of 1 and 2 were elucidated as 1β,6α,8β,9β-tetraacetoxy-2β,4α-dihydroxy-15β-isobutanoyloxy-(3,12)-evoninoyloxy-β-dihydroagarofuran and 1β,2β,6α,8β,9β-pentaacetoxy-4α-hydroxy-15β- isobutanoyloxy- (3,12)- evoninoyloxy-β-dihydroagarofuran mainly by NMR spectroscopic means.