title: Photosensitivity in South Africa. VII. Chemical composition of biliary crystals from a sheep with experimentally induced geeldikkop.
abstract: Geeldikkop was induced in a sheep by oral administration of crude saponins from Tribulus terrestris. Centrifugation of the bile from this sheep gave a pale green sediment of crystalloid material which was insoluble in common organic solvents, but soluble in acetic acid. Analysis of the crystalloid material by 1H and 13C NMR, EDXA, TLC, LSIMS, and by acidic hydrolysis followed by TLC and GC-MS, revealed it to be composed principally of a 6:1 mixture of the calcium salts of the beta-D-glucuronides of the steroidal sapogenins epismilagenin and episarsasapogenin. The administered saponin was found to contain glycosides of the steroidal sapogenins diosgenin, yamogenin, epismilagenin, tigogenin, neotigogenin, gitogenin and neogitogenin in the ratio 10:7:1:11:7:35:25. A metabolic pathway for the conversion of diosgenin and yamogenin saponins to the biliary glucuronides is proposed.
authors.affiliation: Fungal and Plant Toxin Research Group, New Zealand Pastoral Agriculture Research Institute Ltd., Ruakura Agricultural Research Centre, Hamilton.
authors.forename: C O
authors.initials: CO
authors.lastname: Miles
authors.forename: A L
authors.initials: AL
authors.lastname: Wilkins
authors.forename: G L
authors.initials: GL
authors.lastname: Erasmus
authors.forename: T S
authors.initials: TS
authors.lastname: Kellerman
authors.forename: J A
authors.initials: JA
authors.lastname: Coetzer
mesh_terms: D000818:Animals; D001646:Bile / Q000737:chemistry*; D001660:Biliary Tract Diseases / Q000209:etiology / Q000662:veterinary; D003460:Crystallization; D004144:Diosgenin; D010787:Photosensitivity Disorders / Q000209:etiology / Q000662:veterinary*; D010939:Plant Poisoning / Q000662:veterinary*; D012502:Sapogenins / Q000032:analysis / Q000506:poisoning; D012756:Sheep; D012757:Sheep Diseases / Q000209:etiology
chemical_list: D012502:Sapogenins; D004144:Diosgenin; C514916:yamogenin