RESUMO
AIM To observe the effects of Taxilli Herba from six different hosts (Morus alba L.,Salix babylonica L.,Camellia oleifera Abel.,Castanea mollissima B1.,Liquidambar formosana Hance and Nerium indicum Mill.) on lowering blood pressure of spontaneously hypertensive rats (SHR).METHODS SHR were randomly divided into 14 groups,captopril positive group (20 mg/kg),model group,and Taxilli Herba groups of 6 different hosts,and each Taxilli Herba group was further divided into high-dose group (5.9 g/kg) and low-dose group (1.48 g/kg);WKY,in addition,was the blank control.And the 20-day consective correspondence medication was applied to the groups,each with eight rats.The caudal arterial systolic blood pressure (SBP) was measured by tail-cuff method before the administration,and on the 10th day and 20th day of the administration.Anaesthesia was performed at the blood collection 12 h after the last administration;and thus final serum contents of nitric oxide (NO) and changes of superoxide dismutase (SOD) activity,plasmatic contents of angiotensin Ⅱ (Ang Ⅱ) and endothelin-1 (ET-1) were determined.RESULTS From the data before and after administration,an SBP drop among all SHR groups was observed on the 10th day of administration,among which the blood pressure lowering effect by high-dose Taxilli Herba from Morus alba L.was very obvious (P ＜ 0.01);remarkable SBP decrease on the 20th day of administration induced by Taxilli Herba from Salix babylonica L,Liquidambarformosana Hance and Camellia oleifera Abel,and high-dose Taxilli Herba from Morus alba L,low-dose Taxilli Herba from Castanea mollissima B1 were detected (P ＜ 0.01).No significant SBP variation was available between the model group and Taxilli Herba groups after10-day administration;all the Taxilli Herba groups exhibited obvious effect in lowering SBP except Taxilli Herba from Nerium indicum Mill,low-dose Taxilli Herba from Morus alba L.and high-dose Taxilli Herba from Castanea mollissimaBl.after 20-day administration,compared to the model group (P ＜ 0.05).Highdose Taxilli Herba from Morus alba L.and Salix babylonica L significantly decreased plasmatic Ang Ⅱ and ET-1 contents of SHR groups in comparison with the model group (P ＜0.01).High-dose Taxilli Herba from Morus alba L.,Salix babylonica L.and Liquidambarformosana Hance significantly increased serum NO release and superoxide dismutase (SOD) activity (P ＜ 0.01).CONCLUSION Taxilli Herba from the five different hosts,except Nerium indicum Mill,can lower blood pressure,and there exists an effect difference due to the host variation.