英语语法分析

A new method of determining the antioxidant activity of betulin from betula bark is established.

建立了一种测定白桦树皮中白桦脂醇对羟自由基清除率的新方法。

Betulin and Betulinic acid treatment could decrease serum AST, ALT activities and hepatic MDA level significantly, and critically increased hepatic GSH and CAT levels.

预防给予不同剂量的白桦酯醇或白桦酯酸可明显降低小鼠血清中alt、AST和肝脏中MDA活性，提高GSH和CAT水平。