title: Urinary metabolites of cinobufagin in rats and their antiproliferative activities.
abstract: Cinobufagin was one of the important cardenolidal steroids and a major component of Chan'Su, a famous traditional Chinese medicine. The urinary metabolites of cinobufagin after single oral doses of 25 mg kg⁻¹ in rats were investigated. Eleven metabolites were isolated and purified by liquid-liquid extraction, open-column chromatography, medium-pressure liquid chromatography, as well as semi-preparative high-performance liquid chromatography. Their structures were elucidated by chemical and various spectroscopic methods, which were identified as desacetylcinobufagin (M-1), 3-oxo-desacetylcinobufagin (M-2), 3-oxo-cinobufagin (M-3), 3-epi-desacetylcinobufagin (M-4), 3-epi-12β-hydroxyl desacetylcinobufagin (M-5), 5β-hydroxyl cinobufagin (M-6), 5β-hydroxyl desacetylcinobufagin (M-7), 12β-hydroxyl cinobufagin (M-8), 1β,12β-dihydroxyl cinobufagin (M-9), 12β-hydroxyl desacetylcinobufagin (M-10) and 1β,12β-dihydroxyl desacetylcinobufagin (M-11), respectively. Among them, M-1 was the main urinary metabolite of cinobufagin with a yield of 17.7%. Most metabolites were hydroxylated products of cinobufagin at C-1β, 5β and 12β positions, as well as deacetylated products at C-16. Except M-1, M-4 and M-7, the other eight metabolites were novel in vivo metabolites of cinobufagin. Some metabolites showed potential cytotoxicity against human hepatoma cells (HepG2) and human leukaemia (K562, HL-60) cells; however, their cytotoxicities generally decreased after metabolic conversion.
authors.affiliation: College of Pharmacy, Wuhan University, 185 Donghu Road, Wuhan 430071, China. hexiangjiu@whu.edu.cn
authors.forename: Xiangjiu
authors.initials: X
authors.lastname: He
authors.forename: Hui
authors.initials: H
authors.lastname: Hu
authors.forename: Yixuan
authors.initials: Y
authors.lastname: Wu
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Zeng
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000032:analysis* / Q000494:pharmacology; D002018:Bufanolides / Q000737:chemistry / Q000494:pharmacology / Q000652:urine*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000970:Antineoplastic Agents; D002018:Bufanolides; C002471:cinobufagin