Antihypertensive Effect of Pomegranate Polyphenols in Spontaneously Hypertensive Rats

Zhu WANG; Ying CHEN

ABSTRACT

Objective:

To observe the anti-hypertensive effect of pomegranate polyphenols in spontaneously hypertensive rats ( SHR) and explore the underlying mechanism.

Methods:

Totally 40 male SHR rats at the age of 12 weeks were randomly divided into five groupsSHR control group, pomegranate polyphenols groups respectively at the dose of 120 mg·kg-1 , 240 mg·kg-1 and 480 mg ·kg-1 , and captopril group at the dose of 15 mg·kg-1 . The age-matched Wistar-Kyoto ( WKY) rats were randomly divided into two groupsWKY control group and pomegranate polyphenols group at the dose of 480 mg·kg-1 . All the rats were given corresponding drug or water by intragastric administration for four weeks. The systolic blood pressure ( SBP) and diastolic blood pressure ( DBP) were measured weekly. After the 4-week administration, the rats were fasted 12 hours and anaesthetized with 25% urethane solution. The blood samples were collected from abdominal aorta. The serum concentrations of angiotensin II ( Ang II) and endothelin ( ET) were de-termined by euzymelinked immunosorbent assay. The concentration of nitric oxide ( NO) in serum was determined by nitrate reduction test.

Results:

Pomegranate polyphenols could significantly lower the SBP and DBP, decrease the serum concentrations of Ang II and ET, and increase the serum concentration of NO(P<0.05 or P<0.01). In addition, pomegranate polyphenols had no effects on blood pressure and vasoactive substances in WKY rats.

Conclusion:

Pomegranate polyphenols has anti-hypertensive effect in SHR rats. The mechanism may be related to regulating the expression of vasoactive substances, such as Ang II, ET and NO.