Phaeanthuslucidines A-D, dimeric aporphine alkaloid derivatives from Phaeanthus lucidus Oliv.

Abstract

The first phytochemical investigation of the twigs of Phaeanthus lucidus Oliv. resulted in the isolation and identification of four undescribed alkaloids, including two aporphine dimers, phaeanthuslucidines A and B, a hybrid of aristolactam-aporphine, phaeanthuslucidine C, and a C–N linked aporphine dimer, phaeanthuslucidine D, together with two known compounds. Their structures were determined by extensive analysis of spectroscopic data, and by comparison of their spectroscopic and physical data with previous reports. Phaeanthuslucidines A–C and bidebiline E were analysed and resolved by chiral HPLC to yield the (Ra) and (Sa) atropisomers, whose absolute configurations were respectively determined by ECD calculations. Phaeanthuslucidines A and B, bidebiline E, and lanuginosine showed α-glucosidase inhibitory activities with IC50 values in the range of 6.7–29.2 μM. Moreover, molecular docking simulations of α-glucosidase inhibition of active compounds were studied.