柿叶黄酮的降血压作用及其作用机制研究

用一氧化氮合酶抑制剂N^G-硝基-L-精氨酸甲酯（N^G-nitro-L-arginine-methlester，L-NAME）复制高血压大鼠模型研究柿叶黄酮对高血压大鼠的降血压作用。试验分为正常对照组、模型对照组，柿叶黄酮低、中、高剂量组（20mg·kg^-1·d^-1，40mg·kg^-1·d^-1，80mg·kg^-1·d^-1）、卡托普利组（10mg·kg^-1·d^-1）。每周测大鼠尾动脉压，给药4周后处死大鼠，测定血清中一氧化氮（N0）、血浆内皮素（ET）和血管紧张素（Ang）Ⅱ的含量。结果显示，柿叶黄酮能明显降低L—NAME诱导的高血压大鼠的血压（P〈0．05），并在剂量范围内呈剂量依赖性；与模型对照组相比，血清N0含量上升（77．15±15．14）μmol·L^-1vs（30．77±10．62）μmol·L^-1，P〈0．01]，血浆ET含量降低（56．21±9．23）pg·ml^-1vs（87．28±11．75）pg·ml^-1，P〈0．01]，血浆AngⅡ含量降低（503．4±33．40）pg·ml^-1vs（666．62±33．45）pg·ml^-1，P〈0．01]。柿叶黄酮可能是通过增加内源性舒血管活性物质的释放和减少内源性收缩血管活性物质的释放来调节两者之间的平衡而发挥其抗高血压作用。

Antihypertensive Effect and Its Mechanism of Persimmon Leaf Flavonoid

In order to study hypotensive effects and its mechanism of persimmon leaf flavonoid, hypertensive in rats was indused by L-NAME. Hypertensive rats were induced by NG-vitro-L- arginine-methlester （L-NAME）, and were devided into six groups. The normal control group was treated by normal saline, model group was treated by L-NAME alone, Low-, mid-, and high-dose of flavone groups were treated by flavone at the doses of 20, 40 and 80mg·kg^-1·d^-1 respectively,and captopril group was treated by captopril at dose of 10 mg·kg^-1·d^-1. Tail blood pressure was measured every week. Rats were sacrificed to determine serum nitric oxide （NO）, plasma endothelin （ET） and angiotension Ⅱ （Ang Ⅱ ） after four weeks of treatment. Persimmon leaf flavonoid could decrease the tail blood pressure of rats in a dose dependant manner （P 〈 0. 05）. Persimmon leaf flavonoid could increase the serum NO （77.15±15.14 vs 30. 774±10.62 μmol· L^-1, P 〈0.01）,and decrease the plasma ET （56.21±9.23 vs 87. 28±11.75 pg· L^-1, P 〈0.01） and Ang Ⅱ （503.4±33.40 vs 666.62±33.45 pg· L^-1, p 〈0.01） as compared with model group. It is suggested that persimmon leaf flavonoid may adjust the imbalance of cardiovascular active substances by increasing the release of endogenous vasodilators and reducing the release of endogenous vasoconstrictors,resulting in antihypertention.