title: Canthin-6-one alkaloids and a tirucallanoid from Eurycoma longifolia and their cytotoxic activity against a human HT-1080 fibrosarcoma cell line.
abstract: Phytochemical investigation of the stems of Eurycoma longifolia Jack led to the isolation of two new canthin-6-one alkaloids, 4,9-dimethoxycanthin-6-one (1) and 10-hydroxy-11-methoxycanthin-6-one (2), and a new tirucallane-type triterpenoid, 23,24,25-trihydroxytirucall-7-en-3,6-dione (3), along with 37 known compounds. Among these, an oxasqualenoid (4) was isolated as a natural product for the first time. The structures of the isolates were elucidated by spectroscopic and mass spectrometric means. All the isolates were evaluated for their cytotoxic activity against a HT-1080 human fibrosarcoma cell line. Among them, 9,10-dimethoxycanthin-6-one (14, IC50 = 5.0 microM), 10-hydroxy-9-methoxycanthin-6-one (15, IC50 = 7.2 microM), dihydroniloticin (18, IC50 = 8.2 microM), and 14-deacetyleurylene (34, IC50 = 3.2 microM) displayed stronger activity than the positive control 5-FU (IC50 = 9.2 microM).
authors.affiliation: Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Miyake
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tezuka
authors.forename: Suresh
authors.initials: S
authors.lastname: Awale
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Kadota
mesh_terms: D000470:Alkaloids / Q000302:isolation & purification*; D000972:Antineoplastic Agents, Phytogenic / Q000032:analysis; D002243:Carbolines / Q000302:isolation & purification*; D045744:Cell Line, Tumor; D035701:Eurycoma / Q000737:chemistry*; D006801:Humans; D015394:Molecular Structure; D018547:Plant Stems / Q000737:chemistry; D014315:Triterpenes / Q000302:isolation & purification*
chemical_list: C548385:10-hydroxy-11-methoxycanthin-6-one; C548386:23,24,25-trihydroxytirucall-7-en-3,6-dione; C548384:4,9-dimethoxycanthin-6-one; D000470:Alkaloids; D000972:Antineoplastic Agents, Phytogenic; D002243:Carbolines; D014315:Triterpenes