The effect of Ginkgo biloba extract on mitochondrial oxidative phosphorylation in the normal and ischemic rat heart.
Free radical-induced myocardial damage and impairment of vascular endothelium-dependent relaxation are amongst the most important mechanisms responsible for ischemic heart injury. Ginkgo biloba leaf extract (GE) has been reported to improve blood circulation in the brain and have a beneficial impact on the cardiovascular system but its cardioprotective effects have not been elucidated yet. Therefore, this study investigated the influence of GE in 70% ethanol (1:5) administered orally to rats on the functions of isolated heart mitochondria under normal and ischemic conditions. Wistar rats were given GE or ethanol (solvent control) at a dosage of 0.32 mL/kg in drinking water for 10 and 18 days, while the control animals received untreated drinking water. Mitochondrial respiration rates were determined oxygraphically. Pyruvate and malate, succinate or palmitoyl-L-carnitine and malate were used as substrates. The GE treatment partially uncoupled mitochondrial oxidation from phosphorylation, reduced the generation of free radicals in the mitochondria, diminished the ischemia-induced V₃ decrease and the degree of respiration stimulation by exogenous cytochrome c. Thus, these results indicate that GE exerts cardioprotective effects reducing ischemia-caused impairment of the functions of heart mitochondria.
Department of Drug Technology and Social Pharmacy, Kaunas University of Medicine, A. Mickeviciaus Str. 9, LT-44307 Kaunas, Lithuania. jurgabernatoniene@yahoo.com
Jurga
J
Bernatoniene
Daiva
D
Majiene
Rimantas
R
Peciura
Ale
A
Laukeviciene
Ruta
R
Bernatoniene
Tauras
T
Mekas
Arturas
A
Kasauskas
Dalia
D
Kopustinskiene
D000818:Animals; D020441:Ginkgo biloba / Q000737:chemistry*; D007511:Ischemia / Q000188:drug therapy*; D008297:Male; D008929:Mitochondria, Heart / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction; D010085:Oxidative Phosphorylation; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism
D010936:Plant Extracts; D017382:Reactive Oxygen Species