From the leaves of Elaeocarpus tectorius (Lour.) Poir. four previously undescribed phenethylamine-containing alkaloids were isolated, namely, tectoricine, possessing an unprecedented isoquinuclidinone ring system incorporating a phenethylamine moiety, tectoraline, representing a rare alkamide incorporating two phenethylamine moieties, and tectoramidines A and B, representing the first naturally occurring trimeric and dimeric phenethylamine alkaloids incorporating an amidine function. The structures of these alkaloids were established by detailed spectroscopic analysis. The absolute configuration of tectoricine was determined by comparison of the experimental and calculated ECD spectra. Plausible biosynthetic pathways to the four alkaloids are proposed.
Schwarzinicines A-G (1-7), representing the first examples of 1,4-diarylbutanoid-phenethylamine conjugates, were isolated from the leaves of Ficus schwarzii. The structures of these compounds were determined by detailed analysis of their MS, 1D and 2D NMR data. Compounds 1-4 exhibited pronounced vasorelaxant effects in the rat isolated aorta (Emax 106-120%; EC50 0.96-2.10 μM). However, compounds 1 and 2 showed no cytotoxic effects against A549, MCF-7, and HCT 116 human cancer cells (IC50 > 10 μM).