Cardioprotective effects of Ilex paraguariensis extract:: evidence for a nitric oxide-dependent mechanism

Aim: To examine the effects of an Ilex paraguariensis (Ip) extract on postischemic alterations derived from 20 min of global ischemia and 30 min of reperfusion. Methods: Isolated rat hearts were treated 10 min before ischemia and the first 10 min of reperfusion with Ip 30 mu g/ml. In other hearts, chelerythrine (1 PM), a protein kinase C blocker, or L-G-nitro L-arginine methyl ester ((L)-NAME), a nitric oxide synthase inhibitor, were administered prior to Ip infusion. Left ventricular developed pressure (LVDP), +dP/dt(max), -dP/dt(max), and left ventricular end diastolic pressure (LVEDP) were used to assess myocardial function. Thiobarbituric acid reactive substances (TBARS) were measured. Results: Ip treatment produced an improvement of postichemic recovery (LVDP = 96 +/- 8%; +dP/dt(max) = 95 +/- 10%; -dP/dt(max) = 90 +/- 12% vs. 57 +/- 6%, 53 +/- 6% and 57 +/- 8%, respectively, in untreated hearts) and an attenuation of the increase of LVEDP and TBARS content. Chelerythrine did not modify and L-NAME abolished the protection induced by Ip. Conclusions: These data are the first demonstration that Ip extract attenuates the myocardial dysfunction provoked by ischemia and reperfusion and that this cardioprotection involves a diminution of oxidative damage through a nitric oxide-dependent mechanism. (c) 2004 Elsevier Ltd. All rights reserved.