Cardioprotective Effects of Cocoa Extract Polyphenols against Ischemia/Reperfusion Injury in Rats.

Background: Consumption of flavonoid-rich nutraceuticals has been associated with a reduction in coronary events. The present study analyzed the effects of cocoa extract flavonols on myocardial injury following acute coronary ischemia/reperfusion. Materials and methods: A commercially available cocoa extract was identified by chromatographic mass spectra. Nineteen different phenolic compounds were identified and 250 mg of flavan-3-ols (procyanidin) were isolated in 1 gram of extract. Oral administration of cocoa extract in incremental doses from 5mg/kg up to 25 mg/kg were given to five group of Sprague-Dawley rats (5 each group) daily for 15 days and additional 5 rats were used as control. This produced a corresponding increase in blood serum polyphenols and became constant after 15 mg/kg dose. Thirty rats were divided into treated and control groups. Treated group (n=15) received the optimal selected dose (i.e. 15 mg/kg) of cocoa extract daily for 15 days orally and the control group (n=15) was remained untreated. Both groups underwent surgical occlusion of the left anterior descending coronary artery for 30 minutes and 24 hours of reperfusion. Finally, hearts were excised and processed for biomolecular analysis. Results: Cocoa extract reversed (p < 0.001) membrane peroxidation, nitrosative stress and superoxide dismutase and catalase activity caused by myocardial I/R injury. Treatment with cocoa extract, diminished inflammatory markers (CCL5/RANTES, IL-6 and NFkB) and myocardial apoptosis (TUNEL, p < 0.01). Cocoa treatment also showed activation of both p-Akt and p-ERK1/2. The diminished inflammatory marker and apoptosis in cocoa extract treated rat heart could be modulated by the activity p-Akt and p-ERK1/2. Conclusion: The augmentation of cocoa extract once a day for 15days in rats attenuates myocardial I/R injury and limits oxidative and nitrosative stress and inflammation with reduction of myocardial apoptosis.