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 (Rmax 91 ± 1%) or by NG-nitro-l- arginine (L-NNA, Rmax 83 ± 3%) or 1H-[1,2,4] oxadiazolo[4,3-a]quinoxaline-1-one (ODQ, Rmax 80 ± 2%). In addition KPE caused concentration-dependent inhibition of the contractile response to exogenous Ca2+. 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 × 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 Rmax control 99 ± 1%; pyrogallol 44 ± 5%), an effect that was significantly reduced by KPE (10-4 M, ACh Rmax 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).