Prophylactic Effects of Plant Flavonoids on Hypertensive Organ Injury in Female SHRSP

Abstract

We investigated the effects of plant flavonoids on hypertensive vascular changes. Female stroke-prone SHR (SHRSP) underwent ovariectomy at 21 weeks of age, and were allowed free access to 1% NaCl for 10 weeks. From 30 weeks of age, the rats were fed Funabashi SP diet with added lemon peel flavonoid (0.2%) (FL group) or isoflavone aglycone (0.15%) (iso group) for 6 weeks. Control rats received the SP diet alone. Although no differences were found in blood pressure among the three groups, stroke lesion incidence was low in the FL group. Vascular dysfunction in the control group, such as downregulation of aquaporin-4 expression in the cerebral cortex, decreased distensibility of the thoracic aorta and upregulation of bFGF expression in the aortic media, were improved by the treatment with isoflavone aglycone. In the FL group, the serum 8-OHdG level (a marker of oxidative DNA damage) was significantly lower than in the control group. An in vitro experiment using human brain endothelial cells revealed that the level of soluble ICAM-1 in the culture medium induced by angiotensin II was decreased by treatment with eriocitrin, being identical to that after treatment with NADH/NADPH oxidase inhibitor. These results indicate that plant flavonoids have beneficial effects for prevention of hypertensive organ injury as radical scavengers in addition to their estrogen-like properties.