Antihypertensive and cardioprotective effects of the Lagenaria siceraria fruit in NG-nitro-L-arginine methyl ester (L-NAME) induced hypertensive rats.

Lagenaria siceraria (Molina) Standl. (Cucurbitacae) (LS) has been reported to possess cardioprotective, antihyperlipidemic, and diuretic activities. To evaluate antihypertensive and cardioprotective effects of the Lagenaria siceraria fruit powder in N(G)-nitro-L-arginine methyl ester (L-NAME) induced hypertension in rats. Male Wistar rats were divided in four groups. Control 2% gum acacia p.o., L-NAME (40 mg/kg p.o.), LS (500 mg/kg p.o.) + L-NAME (40 mg/kg p.o.), L-arginine (100 mg/kg p.o.) + L-NAME (40 mg/kg p.o.). Treatment period was 4 weeks. On day 29 serum marker enzymes, cholesterol and heamodynamic parameters were measured. Histology of heart was performed. LS powder was characterized by HPLC. Systolic blood pressures were increased by L-NAME (p < 0.001). In both drug treated groups systolic and diastolic blood pressures were reduced significantly (p < 0.001) compared to L-NAME. In L-NAME group significantly (p < 0.01) elevated cholesterol which was reduced (p < 0.05) by LS treatment. In L-NAME group inflammation and necrosis (0-35%) was present in heart whereas there was no change in myocardium of LS and L-arginine treated rats. Vitexin, orientin and isoorientin were detected in methanol extract of LS powder. L-NAME induced hypertension in rats was reduced by treatment with LS. The absence of necrosis, inflammation in the heart and significant reduction in serum cholesterol in LS and L-arginine treated rats indicated cardioprotective activity. Antioxidant activity of orientin and isoorientin appears to reduce the L-NAME induced damage. It is concluded that LS fruit possess antihypertensive and cardioprotective activity.