Two novel norquassinoids possessing a unique ketal skeleton, designated quassilactones A (1) and B (2), were isolated from the fruits of Brucea javanica (Simaroubaceae). Their structures were established by extensive NMR and HR-ESI-MS spectroscopic analysis. The absolute configuration of 1 was determined through single-crystal X-ray crystallography, and that of 2 was assigned by comparing the calculated electronic and experimental circular dichroism with compound 1. In addition, their cytotoxic activities against three human cancer cell lines and their antimicrobial activities were evaluated.
Keywords: Brucea javanica; Norquassinoid; Quassilactone; X-ray crystallography.