title: Effects of the Kielmeyera coriacea extract on energy metabolism in the rat liver.
abstract: Kielmeyera coriacea Mart is a medicinal plant of the Clusiacea (Guttiferae) family used by the native population of Brazil in the treatment of several tropical diseases such as malaria, schistosomiasis, leishmaniasis, and fungal or bacterial infections. Kielmeyera coriacea is also effective as an antidepressant drug. Extracts of the plant are rich in xanthones. Compounds of this class have been reported to inhibit mitochondrial energy metabolism. For this reason the action of the Kielmeyera coriacea extract on hepatic energy metabolism was investigated in the present work, using isolated rat liver mitochondria and the perfused rat liver. In perfused livers the extract (20-80 microg/ml) caused stimulation of oxygen consumption, inhibition of gluconeogenesis and stimulation of glycogenolysis and glycolysis. In isolated mitochondria the Kielmeyera coriacea extract (5-20 microg/ml) stimulated state IV respiration, reduced the ADP/O ratio and decreased the respiratory coefficient. The activities of succinate-oxidase, NADH-oxidase, NADH dehydrogenase and succinate dehydrogenase were inhibited. The ATPase of intact mitochondria was stimulated and the ATPase of uncoupled mitochondria was inhibited. The results of this investigation suggest that the Kielmeyera coriacea extract impairs the hepatic energy metabolism by acting as mitochondrial uncoupler and inhibitor of enzymatic activities linked to the respiratory chain. The impairment of mitochondrial energy metabolism could lead to adverse metabolic effects by the use of the crude extract, but it could equally be the basis of its antiprotozoan and antifungal effects.
authors.affiliation: Laboratory of Liver Metabolism, Department of Biochemistry, University of Maringá, Avenida Colombo, 5790, 87020900 Maringá, Brazil.
authors.forename: Janaína Naldi
authors.initials: JN
authors.lastname: Zagoto
authors.forename: Adelar
authors.initials: A
authors.lastname: Bracht
authors.forename: Clairce Luzia Salgueiro
authors.initials: CL
authors.lastname: Pagadigorria
authors.forename: Emy Luiza
authors.initials: EL
authors.lastname: Ishii-Iwamoto
authors.forename: Diógenes Aparício Garcia
authors.initials: DA
authors.lastname: Cortez
authors.forename: Nair Seiko
authors.initials: NS
authors.lastname: Yamamoto
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D028084:Clusiaceae / Q000737:chemistry*; D004734:Energy Metabolism / Q000187:drug effects*; D006003:Glycogen / Q000378:metabolism; D006019:Glycolysis; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism; D010101:Oxygen Consumption; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats
chemical_list: D010936:Plant Extracts; D006003:Glycogen; D000251:Adenosine Triphosphatases