Enterolosaponins A and B, novel triterpene bisdesmosides from Enterolobium contortisiliquum, and evaluation for their macrophage-oriented cytotoxic activity

Two novel triterpene bisdesmosides, designated as enterolosaponin A (1) and B (2), were isolated from Enterolobium contortisiliquum. The chemical structures of 1 and 2 were determined by analysis of their extensive spectroscopic data, as well as hydrolysis followed by chromatographic study. Enterolosaponins have a 2-amino-2-deoxy- -glucosyl unit ( -glucosamine) as one of the monosaccharides constituting their oligosaccharide moieties, which have been rarely found in natural product research. Enterolosaponin A (1) exhibited a highly selective cytotoxicity against BAC1.2F5 mouse macrophages, and it should be notable that the macrophage death caused by 1 was shown to be neither necrotic nor due to induction of apoptosis from morphology of the died cells, whose cytosol occurred in vacuolation.