The absolute configuration and cytotoxic properties of roehybridine β-N-oxide

Abstract

Roehybridine β-N-oxide (RNO) is a proaporphine-tryptamine dimer alkaloid from Roemeria hybrida. RNO possesses five stereogenic centers and so far its absolute configuration has not been determined. In this study, the absolute configuration of RNO was established as 6aS,7aR,6R,9S,10R by comparing experimental and TDDFT calculated electronic circular dichroism (ECD) spectra. In addition, we have reported an amendment indicating exact 1H and 13C chemical shifts of RNO. RNO exhibited cytotoxic activity when tested in vitro against prostate cancer cell lines including PC3 and DU145. The IC50 values of RNO against PC3 and DU145 were 13.3 and 15.1 μg/mL, respectively.