Suppressive Effect of Components in Lemon Juice on Blood Pressure in Spontaneously Hypertensive Rats

The effects of lemon juice and its crude flavonoids on blood pressure were examined using spontaneously hypertensive rats (SHR). The 5% diluted lemon juice was orally administered in the diet to SHR, and they tended to have a lower systolic blood pressure than the control rats after 90 days. The systolic blood pressure of SHR fed a diet containing crude flavonoids from the juice for 16 weeks was significantly lower than that of the control group (p<0.05). The systolic blood pressure with administration of fraction B, which was fractionated from the crude flavonoids, was significantly lower (p<0.05) after 4 weeks. The crude flavonoids and fraction B contained abundant flavonoid glycosides of eriocitrin, hesperidin, and 6,8-di-C-β-glucosyldiosmin as determined by high performance liquid chromatography (HPLC) analysis. The crude flavonoids and the flavonoid glycosides had an inhibitory effect on angiotensin I converting enzyme (ACE).