Biotransformation of lantadenes, the pentacyclic triterpenoid hepatotoxinsof lantana plant, in guinea pig

Oral administration of lantana (Lantana camara var, aculeata) leaf powder t o guinea pigs at a dose of 6 g/kg body weight elicited cholestasis. The ani mals were euthanized 48 h after dosing. Liver homogenates, bile, gall bladd er, blood, urine, contents of gastrointestinal tract (GIT) and faeces were analysed for the principal hepatotoxin in lantana leaves viz. lantadene A ( LA), its congeners and biotransformation products, using high performance l iquid chromatographic technique. Lantadenes could not be detected in liver, bile, gall bladder, blood and urine samples. LA and lantadene B (LB), thei r derivatives reduced lantadene A (RLA), reduced lantadene B (RLB) and two unidentified metabolites could be detected in the contents of lower GIT and faeces. In vitro incubation of lantana leaf powder with guinea pig caecal contents under anaerobic conditions elicited biotransformation of LA and LB to RLA and RLB, respectively. On the other hand, incubation of lantana lea f powder with cattle rumen liquor under anaerobic conditions did not elicit biotransformation of lantadenes. (C) 2000 Elsevier Science Ltd. All rights reserved.