Antihypertensive effect and eNOS expressions in naclinduced hypertensive rats treated with purple sweet potato

Anthocyanins can improve vascular endothelial function by increasing the bioavailability of nitric oxide (NO), a powerful vasodilator. Purple sweet potato (Ipomoea batatas L.) contains anthocyanins that act as antioxidants and are expected to preserve endothelial function by increasing endothelial nitric oxide synthase (eNOS) expression. To prove this hypothesis, a study was done on 24 adult male Wistar rats that were divided into 4 groups which consist of 6 rats for each group, with randomized control group pre- and post-test design. Hypertension in those rats was induced by the administration of high doses of NaCl. Rats of the control group were treated with NaCl for 14 days. Treatment groups were treated with NaCl and aqueous extract, ethanolic extract and syrup of purple sweet potato tuber, respectively, with a dose of 4 ml per day for 14 days. Blood pressure was measured every day with special sphygmomanometer, before treatment and during treatment. The eNOS expression of aortic endothelium was evaluated immunohistochemically using eNOS antibody. This study showed that there was a significant difference in blood pressure between the control group with treatment groups (p<0,05), in which the blood pressures of treatment groups were significantly lower than the control group. The increase of eNOS expression in rats treated with aqueous extract or ethanolic extract of purple sweet potato was significantly higher than that of the control group (p<0,05). These results suggested that the administration of aqueous or ethanolic extract of purple sweet potato tuber may lower blood pressure and increase the expression of eNOS in rats with NaCl-induced hypertension