Modifications of hepatic drug metabolizing enzyme activities in rats fed baobab seed oil containing cyclopropenoid fatty acids

The effects on drug metabolizing enzymes of cyclopropenoid fatty acids present in baobab seed oil were evaluated in rats fed either a diet with baobab seed oil (1.27% cyclopropenoid fatty acids in the diet) or a diet with heated baobab seed oil (0.046% cyclopropenoid fatty acids in the diet). Comparison was made with rats fed a mixture of oils that contained no cyclopropenoid fatty acid. Rats fed baobab oil showed retarded growth. In comparison with the other groups, the relative liver weights were markedly increased whereas cytochrome P-450 content and NADPH cytochrome c reductase and NADH cytochrome c reductase activities were decreased. In rats fed the heated baobab oil the relative liver weight was decreased and the cytochrome P-450 level and reductase activities were increased relative to levels in rats fed the unheated oil. Ethoxycoumarin deethylase, ethoxyresorufin deethylase and pentoxyresorufin depentylase activities, expressed on the basis of cytochrome P-450, were greater in the group fed unheated baobab seed oil. Cytosolic glutathione transferase activity was markedly decreased in rats fed fresh baobab seed oil and heating the oil, which reduced the content of cyclopropenoid fatty acids, led to a considerable increase of this activity. UDP-glucuronyl transferase activities were not modified by the type of oil included in the diet. It is possible that the mechanisms of action of cyclopropenoid fatty acids are related to alterations of membrane lipid composition or microsomal proteins.