ABSTRACT
Objective: To evaluate the potential therapeutic effect of Sang-Yod rice bran hydrolysates (SRH) and in combination with lisinopril against hypertension, endothelial dysfunction, vascular remodeling, and oxidative stress in rats with nitric oxide deficiency-induced hypertension. Methods: Hypertension was induced in male Sprague-Dawley rats by administration of a nitric oxide synthase inhibitor, Nω- nitro-L-arginine methyl ester (L-NAME) in drinking water for 6 weeks. Hypertensive rats were administered daily with SRH (500 mg/kg/day), lisinopril (1 mg/kg/day), or the combination of SRH and lisinopril by gastric lavage for the last 3 weeks of L-NAME treatment. Hemodynamic status, vascular reactivity to vasoactive agents, and vascular remodeling were assessed. Blood and aortic tissues were collected for measurements of oxidative stress markers, plasma angiotensin-converting enzyme (ACE) activity, plasma angiotensin II, and protein expression. Results: L-NAME induced remarkable hypertension and severe oxidative stress, and altered contents of smooth muscle cells, elastin, and collagen of the aortic wall. SRH or lisinopril alone reduced blood pressure, restored endothelial function, decreased plasma ACEs and angiotensin II levels, alleviated oxidant markers and glutathione redox status, and restored the vascular structure. The effects were associated with increased expression of endothelial nitric oxide synthase and decreased expression of gp91phox and AT1R expression. The combination of SRH and lisinopril was more effective than monotherapy. Conclusions: SRH alone or in combination with lisinopril exert an antihypertensive effect and improve endothelial function and vascular remodeling through reducing oxidative stress and suppressing elevated renin-angiotensin system.
ABSTRACT
Objective: To evaluate the potential therapeutic effect of Sang-Yod rice bran hydrolysates (SRH) and in combination with lisinopril against hypertension, endothelial dysfunction, vascular remodeling, and oxidative stress in rats with nitric oxide deficiency-induced hypertension. Methods: Hypertension was induced in male Sprague-Dawley rats by administration of a nitric oxide synthase inhibitor, Nω- nitro-L-arginine methyl ester (L-NAME) in drinking water for 6 weeks. Hypertensive rats were administered daily with SRH (500 mg/kg/day), lisinopril (1 mg/kg/day), or the combination of SRH and lisinopril by gastric lavage for the last 3 weeks of L-NAME treatment. Hemodynamic status, vascular reactivity to vasoactive agents, and vascular remodeling were assessed. Blood and aortic tissues were collected for measurements of oxidative stress markers, plasma angiotensin-converting enzyme (ACE) activity, plasma angiotensin II, and protein expression. Results: L-NAME induced remarkable hypertension and severe oxidative stress, and altered contents of smooth muscle cells, elastin, and collagen of the aortic wall. SRH or lisinopril alone reduced blood pressure, restored endothelial function, decreased plasma ACEs and angiotensin II levels, alleviated oxidant markers and glutathione redox status, and restored the vascular structure. The effects were associated with increased expression of endothelial nitric oxide synthase and decreased expression of gp91phox and AT1R expression. The combination of SRH and lisinopril was more effective than monotherapy. Conclusions: SRH alone or in combination with lisinopril exert an antihypertensive effect and improve endothelial function and vascular remodeling through reducing oxidative stress and suppressing elevated renin-angiotensin system.
ABSTRACT
Background : Coccinia grandis and Centella asistica are tropical vegetables and acclaimed in Thai folk medicind for treatment of various diseases. The mechanisms responsible for their pharmacological effects remain uncertain. The antioxidant activities. Are proposed to play role in th mechanism of action.Objectives : To investigate the antioxidant activities of C.grandis and C.asiatica.Method : Free radical scavenging activity was assessed by 1, 1 – Diphenyl – 2 picrylhydrazyl (DPPH) assay. Total antioxidant power (FRAP) assay. Intracellular oxygen radicals scavenging effect in rats peritoneal macrophages was evaluated by using fluorescent dichlorofluorescein probe.Results: C.grandis and C.asiatica extracts showed ability to scavenge DPPH radical with EC 50 values of 164.78+5.63 and 172.33+9.13 ug/ml, respectively. It appeared that their potency were about 100 folds less than that of ascorbic acid and trolox. Total antioxidant power of wxtracts, as assayed by FRAP method revealed that 1 mg of C. Grandis extract had reducing power comparable to ascorbic acid 8.23 + 0.64 ug or FeCl2 11.4+0.92 ug. In addition, both plant extracts at the concentration of 100, 300 ug/ma and tiron 10, 30 ug/ml significantly decreased the formation of oxygen radicals generated in rat peritoneal macrophages.Conclusins : Although both extracts had relatively low reducing power in these in vitro assays, however, thir antioxidant effects as shown in peritoneal macrophages may be of significance and worthwhile for further investigation.