The ethanolic extract of Kaempferia parviflora reduces ischaemic injury in rat isolated hearts

Aims of the study: The ethanolic extract of Kaempferia parviflora (KPE) has been reported to contain a range of flavonoids and to enhance endothelial synthesis of NO. We investigated the vascular relaxant, antioxidant and cardioprotective activities of KPE. Materials and methods: Vascular function was assessed in rat aortic rings and superoxide generation determined using lucigenin enhanced chemiluminescence. Ischaemia and reperfusion were induced in rat isolated, perfused hearts. Results: KPE caused vasorelaxation (R(max) 102 +/- 2%), which was partly inhibited by removal of the endothelium (R(max) 91 +/- 1%) or by N(G)-nitro-L-arginine (L-NNA, R(max) 83 +/- 3%) or 1H-[1,2,4] oxadiazolo[4,3-a]quinoxaline-1-one (ODQ, R(max) 80 +/- 2%). In addition KPE caused concentration-dependent inhibition of the contractile response to exogenous Ca(2+). KPE (10(-3) M) also significantly inhibited superoxide radical generation induced by of xanthine/xanthine oxidase (2.3 +/- 0.4% of control) to a similar extent to the xanthine oxidase inhibitor allopurinol (10(-4) M, 1.6 +/- 0.5%) or by rat isolated aorta in the presence of NADPH (30.0 +/- 6.3% of control) similarly to the NADPH oxidase inhibitor diphenyliodonium (5 x 10(-6) M, 23.1 +/- 5.6%). In the presence of oxidant stress generated by pyrogallol endothelium-dependent relaxation of rat aortic rings was impaired (ACh R(max) control 99 +/- 1%; pyrogallol 44 +/- 5%), an effect that was significantly reduced by KPE (10(-4) M, ACh R(max) 82 +/- 4%). In addition, KPE was found to attenuate the ventricular dysfunction caused by 20 min global ischaemia and 30 min reperfusion (I/R) in rat isolated hearts (dP/dt IR 1016 +/- 242, IR + KPE 2238 +/- 233 mmHg/s). Conclusion: KPE is an effective vasodilator and antioxidant that is able to prevent myocardial ischaemia-reperfusion injury. We suggest that KPE may be useful as an adjunct to thrombolytic therapy in the management of reperfusion injury. (C) 2011 Elsevier Ireland Ltd. All rights reserved.