[Show abstract][Hide abstract] ABSTRACT: Seven new bisdesmosidic triterpene saponins, with up to eight monosaccharides, which were given the trivial names contortisiliosides A–G (1–7), were isolated from Enterolobium contortisiliquum. The structures of the new saponins were determined on the basis of extensive spectroscopic and chromatographic analyses of both intact and acid-hydrolyzed compounds. The isolated saponins were evaluated for their cytotoxic activities against BAC1.2F5 mouse macrophages, EL-4 mouse lymphoma cells, and L-929 mouse fibroblasts. Whereas contortisiliosides A (1) and C (3) were moderately cytotoxic to both BAC1.2F5 macrophages and EL-4 cells, and contortisiliosides D–G (4–7) did not show any apparent cytotoxic activities against the three cell lines, contortisilioside B (2) exhibited selective cytotoxic activity against BAC1.2F5 mouse macrophages, with an IC50 value of 3.4 μM. The macrophage death caused by 2 was shown to be neither necrotic nor apoptosis-inducing based on the unique morphological change of the killed cells, whose cytosols were transformed into large vacuoles, and according to the TUNEL assay.
[Show abstract][Hide abstract] ABSTRACT: To characterize the stems of Akebia trifoliata chemically, a detailed phytochemical examination was carried out on A. trifoliata stems, with particular attention to the triterpene and triterpene saponin constituents, and resulted in the isolation of three new triterpenes (1-3) and three new triterpene saponins (11-13), together with seven known triterpenes (4-10) and 12 known triterpene saponins (14-25). The structures of the new compounds were determined on the basis of spectroscopic analysis, including two-dimensional NMR spectroscopic data, and the results of hydrolysis. Four saponins (22-25), which were obtained in good yields and were not isolated from Akebia quinata stems, are concluded to be applicable as marker compounds in chemically distinguishing between A. trifoliata and A. quinata by conventional TLC examination. To the best our knowledge, the current work is the first chemical investigation of A. trifoliata.
No preview · Article · Sep 2003 · CHEMICAL & PHARMACEUTICAL BULLETIN
[Show abstract][Hide abstract] ABSTRACT: 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-D-glucosyl unit (D-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.
No preview · Article · Mar 2003 · Bioorganic & Medicinal Chemistry Letters