title: Cytotoxic cholestane and pregnane glycosides from Tribulus macropterus.
abstract: The methanol extract of the whole parts of Tribulus macropterus Boiss. (family Zygophyllaceae) showed cytotoxic activity against a human tumour cell line (hepatocyte generation 2, HepG2) (IC50 = 2.9 microg/ml). The n-butanolic fraction obtained from successive fractionation of the methanolic extract exhibited activity against HepG2 (IC50 = 2.6 microg/ml). Therefore, this fraction was subjected to separation using different chromatographic techniques. Five compounds, 1-5, were isolated and identified as: (22S,25S)-16beta,22,26-trihydroxy-cholest-4-en-3-one-16-O-beta-D-glucopyranosyl-(1-->3)-beta-D-xylopyranoside (1), (22S,25S)-16beta,22,26-trihydroxy-cholest-4-en-3-one-16-O-beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranoside (2), sucrose (3), D-pinitol (4) and 3beta-hydroxy-5a-pregn-16(17)en-20-one-3-O-beta-D-xylopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-ga-lactopyranoside (5) on the basis of spectroscopic and chemical data. The three steroidal compounds 1, 2 and 5 were also tested against the same cell line HepG2 and their IC50 values were 2.4, 2.2 and 1.1 microg/ml, respectively.
authors: Laboratory of Medicinal Chemistry, Theodor Bilharz Research Institute, Warrak El-Hader, Egypt. Shzssayed@yahoo.com
authors: El-Sayed S
authors: el-SS
authors: Abdel-Hameed
authors: Hanan A
authors: HA
authors: El-Nahas
authors: Eman A
authors: EA
authors: El-Wakil
authors: Wafaa S
authors: WS
authors: Ahmed
mesh_terms: D006528:Carcinoma, Hepatocellular; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects*; D002776:Cholestanes / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity; D006801:Humans; D008113:Liver Neoplasms; D008958:Models, Molecular; D010936:Plant Extracts / Q000737:chemistry; D011278:Pregnanes / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D032444:Tribulus / Q000737:chemistry*
chemical_list: D002776:Cholestanes; D006027:Glycosides; D010936:Plant Extracts; D011278:Pregnanes