Cardioprotective effects of silver fir (Abies alba) extract in ischemic-reperfused isolated rat hearts

Background: Silver fir trunk extract (SFTE) is a complex mixture of antioxidative polyphenols (lignans and phenolic acids) from the trunks of silver fir trees (Abies alba, lignum). In our previous study, we have shown that SFTE exerts strong antioxidative and protective effects against atherogenic, diet-induced arterial wall damage. Objective: The aim of the present study was to test the potential protective effects of SFTE and its compounds, two phenolic acids (p-coumaric and protocatechuic acids) in ischemia-reperfusion injury of isolated rat hearts. Design: Isolated hearts of Wistar rats aged 4-8 weeks were exposed to perfusion, ischemia, and reperfusion periods. The experiments were performed using the following five groups: control, SFTE (10 mu g/L), SFTE (100 mu g/L), protocatechuic acid, and p-coumaric. Aortas were isolated to measure vascular responses in the presence of N-omega-Nitro-L-arginine. Results: SFTE dose-dependently reduced ischemic-reperfusion heart damage, which was indicated as the decrease in the lactate dehydrogenase (LDH) release rate and arrhythmias duration by 80% and an increase in coronary flow rate during the reperfusion period. Two tested compounds (p-coumaric and protocatechuic acids) acted less cardioprotective, since they decreased the duration of arrhythmias only by 40 and 45%, respectively, and did not decrease LDH release rates during the reperfusion period. Only p-coumaric acid increased coronary flow rates, whereas protocatechuic acid did not. Conclusions: We conclude that the SFTE exerted the strongest cardioprotective effect, whereas its constituents (the p-coumaric and protocatechuic acids) were less effective in inducing cardioprotection.