Antioxidative Activity of the Leaf of Nelumbo nucifera Gaertn. on Oxidative Stress-Induced Erythrocyte Hemolysis in Hypertensive and Normotensive Rats

Abstract

Hypertension is considered as a state of oxidative stress which contribute to several organ damages. The crude leaf of Nelumbo nucifera Gaertn. (NN extract) is traditionally used as a folk medicine, and it was reported to have antioxidant activity. The present study aimed to test our hypothesis that if there is an increase in erythrocyte lipid peroxidation in hypertensive rats, then there should be increased in eryth- rocyte hemolysis as well. In addition, the NN extract would protect erythrocyte membrane from free radical-induced oxidation. The constriction of left renal artery was used to induce hypertension in male Sprague-Dawley rats. The oxidative hemolysis of erythrocytes was performed by using the azo-compound 2,2'-Azobis (2- amidinoporpane) dihydrochloride (AAPH) as a peroxyl radical initiator. The free radical scavenging activity of NN extract was measured by 1,1-diphenyl-2-picryl-hydrazil (DPPH). The total of NN extract phenolic contents was determined by Folin-Ciocalteu reagent. The time-dependent hemolysis curve of erythrocyte from hypertensive rats was similar to that of normotensive ones. The 50 percent inhibitory concentration hemolytic (IC50) NN extract was 48.2 ± 0.2 and 46.8 ± 1.1 ∝g/ml in hypertensive and normotensive rats respectively. The concentration of the NN extract required to scavenge 50 percent DPPH radical (IC50) was 18.14 ± ±± ±± 3.13. The NN extract was rich in phenolic compounds in that 20 - 160 ∝g of NN extract, and was corresponded to the amount of phenolic compounds 3.98 - 20.38 ∝g gallic acid equivalents. The susceptibility of rat erythrocytes to peroxidation in hypertensive rats was similar to that of nor- motensive ones. NN extract have the ability to protect rat erythrocytes against AAPH-induced hemolysis in hypertensive as well as in normotensive rats. It can be concluded that NN extract possesses antioxidant properties, and may have health promotion activities. The antioxidant activity of NN extract may be due to the presence of phenolic compounds.