title: Photosensitivity in South Africa. VIII. Ovine metabolism of Tribulus terrestris saponins during experimentally induced geeldikkop.
abstract: Geeldikkop was induced in a sheep by dosing it orally with a crude extract of the steroidal saponins from Tribulus terrestris. GC-MS analysis of the sheep's ruminal contents, bile, faeces and urine for free and conjugated sapogenins, revealed the general features of the metabolic pathway by which diosgenin and yamogenin glycosides were converted into the glucuronides of epismilagenin and episarsasapogenin, the major constituents of the biliary crystals that usually form during geeldikkop. Other steroidal saponins in the T. terrestris extract, including those derived from tigogenin, neotigogenin, gitogenin and neogitogenin appear to be non-lithogenic. The implications of these findings are discussed.
authors.affiliation: Fungal and Plant Toxin Research Group, New Zealand Pastoral Agriculture Research Institute Ltd. Ruakura Agricultural Research Centre, Hamilton, New Zealand.
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
mesh_terms: D000818:Animals; D010787:Photosensitivity Disorders / Q000662:veterinary*; D010939:Plant Poisoning / Q000662:veterinary; D012503:Saponins / Q000302:isolation & purification / Q000378:metabolism / Q000506:poisoning*; D012756:Sheep; D012757:Sheep Diseases / Q000209:etiology* / Q000378:metabolism; D013019:South Africa
chemical_list: D012503:Saponins