During the course of a study of leguminous plants, cytotoxicity was demonstrated by the crude saponin fraction of Albizia julibrissin. Following chromatographic purification, the structures of three novel saponins, julibrosides I-III (1-3), inclusive of a cytotoxic principle, were elucidated. A comparison of the cytotoxicity of julibrosides (1-3) and their prosapogenins (4-15) prepared by alkaline hydrolysis clearly indicated that both an α-L-arabinofuranosyl-(1→4)-[β-D-glucopyranosyl--(1→3)]-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl ester unit and a monoterpene-quinovopyranosyl moiety are crucial substituents for cytotoxicity among this class of compounds. The hydroxy group at C-16 of aglycon may play an important role in mediating cytotoxicity, and the N-acetyl-glucosamine moiety at C-3 seems to enhance activity because 3 showed the strongest cytotoxicity.
NCBI PubMed ID: 9051910Publication DOI: 10.1021/np960556tJournal NLM ID: 7906882Publisher: American Society of Pharmacognosy
Correspondence: none@kumamoto-u.ac.jp
Institutions: Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-Honmachi, Kumamoto 862, Japan,
Methods: 13C NMR, 1H NMR, IR, FAB-MS, sugar analysis, TLC, GC, chemical methods, biological assays, alkaline hydrolysis, extraction, CC
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