Two new sesquiterpene pyridine alkaloids from root barks of Celastrus angulatus

Abstract

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.

Graphical Abstract

Keywords:

• Celastraceae
• Celastrus angulatus
• sesquiterpene pyridine alkaloids
• Chinese bittersweet alkaloid A
• Chinese bittersweet alkaloid B
• NMR

Acknowledgements

We are grateful to Mr. W. G. Zhu, G. S. Zhao, Y. X. Xie, and Ms S. M. Wang for the NMR, IR and MS measurements. This work was financially supported by grants from National Science and Technology Major Project of China (2018ZX09711001-008-004).

Disclosure statement

No potential conflict of interest was reported by the authors.