title: Biologically active steroidal glycosides from Tribulus terrestris.
abstract: The steroidal saponin constituents obtained from Tribulus terrestris were tested for their antimicrobial and cytotoxic effects. The spirostanol-based steroidal saponins 1-3 exhibited remarkable activity against fungal organisms (Candida albicans and Cryptococcus neoformans) and cancer cell lines [human malignant melanoma (SK-MEL), human oral epidermoid carcinoma (KB), human breast ductal carcinoma (BT-549), and human ovary carcinoma (SK-OV-3)], while none of the compounds possessing the furostanol framework 4-7 showed activity. The most active spirostanol glycoside, compound 3 exhibited a broad range of anticancer activity against cell lines, SK-MEL, KB, BT-549 and SK-OV-3 at IC50s of 6.0, 7.0, 6.0 and 8.2 micrograms/ml, respectively, while compounds 1 and 2 showed selective cytotoxicity against SK-MEL at 6.7 and 9.1 micrograms/ml, respectively. The minimum inhibitory concentrations (MIC) in antifungal bioassay for compounds 1-3 varied from 1.5 to 6.2 micrograms/ml, which prompted to conclude certain structural features are required for these bioactivities.
authors.affiliation: National Center for Natural Products Research, University of Mississippi, USA.
authors.forename: E
authors.initials: E
authors.lastname: Bedir
authors.forename: I A
authors.initials: IA
authors.lastname: Khan
authors.forename: L A
authors.initials: LA
authors.lastname: Walker
mesh_terms: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000302:isolation & purification / Q000494:pharmacology; D000935:Antifungal Agents / Q000302:isolation & purification / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D005658:Fungi / Q000187:drug effects; D006027:Glycosides / Q000302:isolation & purification* / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D010946:Plants, Medicinal / Q000737:chemistry*; D013256:Steroids / Q000302:isolation & purification* / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D028461:Zygophyllaceae / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D000935:Antifungal Agents; D000972:Antineoplastic Agents, Phytogenic; D006027:Glycosides; D013256:Steroids