Citrus leaf extract reduces blood pressure and vascular damage in repeatedly heated palm oil diet-Induced hypertensive rats

Prolonged consumption of repeatedly heated vegetable oil increases blood pressure. This study aimed to determine the effects of Citrus leaf extract, (CLE) on blood pressure, blood pressure-regulating enzymes and mediators, as well as aortic histomorphometry in heated palm oil induced-hypertension. Male Sprague Dawley rats (n=56) were divided into seven groups; control group was given normal diet and the other groups were fed with palm oil-enriched diet (15% w/w) either fresh (FPO), five-time-heated (5HPO) or ten-time-heated (10HPO) with or without CLE (0.15%, w/w) supplementation. CLE supplementation reduced the heated oil-raising effect of blood pressure, plasma TBARS, thromboxane and angiotensin-1 converting enzyme in 5HPO but not in 10HPO group. CLE increased serum heme oxygenase-1 in both 5HPO and 10HPO groups. CLE supplementation reduced the increase in aortic intima-media thickness, intima-media area and circumferential wall tension in 5HPO group but not in 10HPO group. These findings suggested that CLE supplementation reduces the blood pressure-raising effects of 5HPO and vascular damage, possibly through its antioxidant effect by modulating vasoactive mediators and blood pressure-regulating enzymes.