The Alkaloid-Enriched Fraction of Pachysandra terminalis (Buxaceae) Shows Prominent Activity against Trypanosoma brucei rhodesiense

In the course of our studies on antiprotozoal natural products and following recent discovery that certain aminosteroids aminocycloartanoid compounds from Holarrhena africana A. DC. (Apocynaceae) Buxus sempervirens L. (Buxaceae), respectively, are strong selective antitrypanosomal agents, we have extended these to another plant, related latter—namely, Pachysandra terminalis Sieb. Zucc. (Buxaceae). This species is known contain similar those structurally aminocycloartanoids Buxus. The dicholoromethane extract obtained aerial parts P. and, in particular, its alkaloid fraction by acid–base partitioning showed prominent activity against Trypanosoma brucei rhodesiense (Tbr). Activity-guided fractionation along with UHPLC-(+)ESI QTOF MS analyses coupled partial least squares (PLS) regression modelling relating analytical profiles various fractions their bioactivity Tbr highlighted eighteen constituents likely responsible for activity. Detailed analysis (+)ESI mass spectral fragmentation allowed identification four as well structural characterization ten further amino-/amidosteroids not previously reported this plant.