Two new monoterpenoid indole alkaloids from the leaves and twigs of Ochrosia borbonica

Abstract

Two new monoterpenoid indole alkaloids, ochrobonines A (1) and B (2), together with five known compounds (3–7), were isolated from the leaves and twigs of Ochrosia borbonica. Their structures were determined by spectroscopic method, and the absolute configuration of compound 3 was first established by single-crystal X-ray diffraction. Compounds 1 and 2 represent a rare class of monoterpenoid indole alkaloids that with a 2-[1-(3-ethylpiperidin-4-yl)vinyl]-3-methyl-1H-indole skeleton.

Keywords:

• Ochrosia borbonica
• monoterpenoid indole alkaloids
• single-crystal X-ray diffraction

Acknowledgments

We cordially thank Dr W. Li at School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China, for his help with the isolation and structure elucidation.