Triterpene trimers from Maytenus scutioides: cycloaddition compounds?

Two novel trimers, triscutins A and B (1 and 2), based on pristimerin triterpene units, were isolated and characterized from Maytenus scutioides. Their structures were determined on the basis of spectroscopic evidence, including 1H-13C heteronuclear correlation (HMQC), long-range correlation with inverse detection (HMBC), and ROESY NMR experiments; and their absolute configurations, by means of CD studies. Compounds 1 and 2 were assayed for antimicrobial and cytotoxic activities, and their possible biosynthetic route is proposed.