Long-term administration of Ziziphus jujuba extract attenuates cardiovascular responses in hypertensive rats induced by angiotensinii

Objective: The fruit of Ziziphus jujuba (ZJ) traditionally has been used for the treatment of hypertension in Iran. The mechanism of this effect of ZJ is unknown but may be mediated via an effect on the renin-angiotensin system (RAS). This study evaluates the effect of hydroalcoholic ZJ extract on acute hypertension induced by angiotensinII (AngII), a main product of RAS. Materials and Methods: Animals were divided into six groups; 1) saline, 2) AngII that received (50 ng/kg) intravenously (i. v.), 3) Losartan (Los, 10 mg/kg) +AngII group that received Los (i.v.) before AngII and 4-6) three groups of ZJ (100, 200 and 400 mg/kg) that were treated four weeks by gavage and on 28th day of experiment received AngII (i. v.). Cardiovascular responses were recorded by cannulation of the femoral artery and drug injection done via the tail vein. Systolic blood pressure (SBP), Mean arterial pressure (MAP) and heart rate (HR) were recorded continuously by power lab system. Maximal changes (Δ) of SBP,MAP and HR were calculated and compared with those of control and AngII groups. Statistical analysis was performed by one-way ANOVA. Results: In AngII group maximal Δ SBP, ΔMAP significantly increased than in control but ΔHR was not significant. Pretreatment of two lower doses (100 and 200 mg/kg) of ZJ significantly attenuate increased ΔSBP and ΔMAP induced by AngII. In contrast pretreatment with a higher dose (400 mg/kg) significantly increased the ΔSBP and ΔMAP compared to AngII group. The ΔHR only in dose 200 mg/kg was significantly lower than AngII group. Conclusion: Consistent with the traditional view, the results indicate that ZJ extract has an antihypertensive effect, and effect of its lower doses partly mediated by an inhibitory effect on RAS.