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

Oral administration of lantana (Lantana camara var, aculeata) leaf powder to guinea pigs at a dose of 6 g/kg body weight elicited cholestasis. The animals were euthanized 48 h after dosing. Liver homogenates, bile, gall bladder, 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 liquid chromatographic technique. Lantadenes could not be detected in liver, bile, gall bladder, blood and urine samples. LA and lantadene B (LB), their 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 leaf powder with cattle rumen liquor under anaerobic conditions did not elicit biotransformation of lantadenes. (C) 2000 Elsevier Science Ltd. All rights reserved.