Disposition of lantadene A, the pentacyclic triterpenoid hepatotoxin, orally administered to guinea pigs.

Lantadene A (LA) administered orally to guinea pigs elicited cholestasis. LA could not be detected in liver, bile, gall bladder, blood and urine. LA and its biotransformation product reduced lantadene A (RLA) could be detected in caecum, large intestine, and faeces. In vitro incubation of LA with liver homogenates under aerobic and anaerobic conditions did not elicit its biotransformation to RLA. On the other hand, in vitro incubation of LA with guinea pig caecal and large intestinal contents under anaerobic conditions elicited conversion of LA to RLA. This is the first report of the biotransformation of LA in the animal system.