Chemical Constituents from Tabernaemontana bufalina Lour.

A new monoterpenoid indole alkaloid, namely (3R,7S,14R,19S,20R)-19-hydroxypseudovincadifformine (1), together with nine known compounds (2-10) were isolated and identified from the branch and leaves of Tabernaemontana bufalina Lour. Their structures were established using extensive spectroscopic methods, and the absolute configuration of compound 1 was confirmed by modified mosher's and calculated electronic circular dichroism (ECD) methods. The cytotoxic activities of these isolated metabolites were evaluated on two cancer cell lines. As the results, cytotoxic activities on B16 and MDA-MB-231 cells showed IC50 values of 0.13 and 8.9 μM for 6, and of 11.7 and 20.3 μM for 9, respectively.