研究茶多酚对大鼠血管紧张素Ⅰ转换酶（angiotensinⅠ converting enzyme,ACE）活性的影响。血管紧张素Ⅰ在ACE的作用下,通过脱去C端His-Leu二肽,转化为有生物活性的血管紧张素Ⅱ,从而产生强升压作用。通过体外试验和体内试验研究茶多酚对大鼠ACE活性的影响效应。试验结果表明,随着茶多酚摄入量的增加（45βmg/kg,90βmg/kg,180βmg/kg）,ACE活性显著降低（84.43±4.59βu/μl,75.17±6.85βu/μl,60.19±8.62βu/μl,P<0.05）说明茶多酚对大鼠ACE有抑制作用,从而有可能起到降低血压的作用。

Effects of tea plyphenols on angiotensinⅠconverting enzyme（ACE） activity were studied in this paper. Activity of ACE were determined by in vivo and in vitro on rats. The concentrationof polyphenols were 0, 0.31, 0.62, 1.24, 2.48, 4.96βmmol/L in vitro and polyphenols concentrations were 0, 45, 90, 180βmg/kg in vivo. ACE activity decreased markedly with the increase of tea polyphenols level in vivo and in vitro test. Results showed that activity of ACE is inhibited by tea polyphenols in vivo and in vitro test and these results showed that tea polyphenols possess the function of reducing blood pressure possibly.