Active constituents of Zanthoxylum nitidum from Yunnan Province against leukemia cells in vitro

Zanthoxylum nitidium (Roxb.) DC (Rutaceae) is well known for inhibiting the proliferation of human gastric, liver, kidney and lung cancer cells, though research on its potential use in treating leukaemia is relatively rare. Twenty-six compounds were isolated from the chloroform and petroleum ether extracts of the roots and leaves of Z. nitidium (Zanthoxylum nitidium). They were (+)-9′-O-transferuloyl-5, 5′-dimethoxylaricriresinol (1), 8-(3′-oxobut-1′-en-1′-yl)-5, 7-dimethoxy-coumarin (2), 5, 7, 8-trimethoxy-coumarin (3), 5-(3′, 3′-dimethyl-2′-butenyloxy)-7, 8-dimethoxy-coumarin (4), 2-(5-methoxy-2-methyl-1H-indol-3-yl) methyl acetate (5), 2′-(5, 6-dihydrochleletrythrine-6-yl) ethyl acetate (6), 6-acetonyldi-hydrochelerythrine (7), 6β-hydroxymethyldihydronitidine (8), bocconoline (9), zanthoxyline (10), O-methylzanthoxyline (11), rhoifoline B (12), N-nornitidine (13), nitidine (14), chelerythrine (15), 4-hydroxyl-7,8-dimethoxy-furoquinoline (16), dictamnine (17), γ-fagarine (18), skimmianine (19), robustine (20), R-(+)-platydesmine (21), 4-methoxyl-1-methyl-2-quinoline (22), 4-methoxy-2-quinolone (23), liriodenine (24), aurantiamide acetate (25), 10-O-demethyl-12-O-methylarnottianamide (26). Four among them, compounds 4-6 and 16, were first confirmed in this study by UV, IR, 1D, 2D NMR and HR-ESI-MS spectra. Compounds 1-2 and 11 were isolated from Z. nitidium for the first time. Of the assayed compounds, 1, 2, 9, 10, 14, 15 and 24, exhibited good inhibitory activities in the leukaemia cell line HEL, whereas compound 14 (IC50: 3.59 µM) and compound 24 (IC50: 15.95 µM) exhibited potent inhibitory activities. So, to further investigate the possible mechanisms, cell cycle and apoptosis assays were performed, which indicated that compound 14 causes obvious S-phase arrest in HEL cells and induced apoptosis, whereas compound 24 only induced apoptosis. The present results suggested both compounds 14 and 24 are promising potential anti-leukaemia drug candidates.