Effect of Aqueous and Ethyl Acetate Fractions of Ziziphus jujuba   Mill Extract on Cardiovascular Responses in Hypertensive Rats

Background: Ziziphus jujuba Mill (ZJ) is a plant with anti-hypertensive property. In this regard, the present study investigated the effect of aqueous and ethyl acetate fractions of ZJ extract on acute hypertension (HTN) induced by nitro-L-arginine methyl ester (L-NAME).
Methods: The current study was carried on 49 hypertensive rats divided into seven groups, including i) control; ii) L-NAME (10 mg/kg); iii) sodium nitroprusside (SNP) (50 μg/kg) plus L-NAME; iv and v) aqueous fraction of ZJ (150 mg/kg and 300 mg/kg) plus L-NAME; vi) and vii) ethyl acetate fractions of ZJ (150 mg/kg and 300 mg/kg) plus L-NAME. The rats were orally treated with both fractions for four weeks and received intravenous L-NAME on the 28th day. The mean arterial pressure (MAP), systolic blood pressure (SBP) and heart rate (HR) of the rats were recorded then maximal changes (∆) of MAP, SBP and HR were calculated and compared with changes of control and L-NAME.
Results: According to the obtained results of the present study, it was shown that the administration of L-NAME significantly increased ∆MAP, ∆SBP and ∆HR, and these effects were significantly attenuated by administration of SNP. The pre-treatment with both doses (150 mg/kg and 300 mg/kg) of aqueous and ethyl acetate fractions could significantly reduce cardiovascular responses induced by L-NAME that comparable with SNP. However, a lower dose of aqueous fractions and higher dose of ethyl acetate fractions were reported with stronger effects.
Conclusion: The results of the current study showed that both the aqueous and ethyl acetate fractions of ZJ through the effect on nitric oxide system can prevent the development of HTN induced by L-NAME.

Keywords
Ziziphus jujuba Mill; hypertension; aqueous fraction; ethyl acetate fraction; blood pressure