桑叶提取物对酪氨酸酶活性的抑制作用

Inhibition of extract from mulberry leaves on tyrosinase activity

目的:研究桑叶提取物对酪氨酸酶活性的抑制作用,为预防和治疗色素沉着疾病提供实验依据。方法:实验采用桑叶、酪氨酸酶、L-酪氨酸、曲酸,测定不同浓度曲酸对酪氨酸酶活性的抑制作用,以抑制率(抑制率=1-酪氨酸酶活性%)结果选择阳性对照组,测定不同浓度的桑叶提取物对酪氨酸酶活性的抑制作用,并以桑叶提取物浓度为自变量,以桑叶提取物对酪氨酸酶活性抑制率为应变量,建立回归方程,确定桑叶提取物浓度与其对酪氨酸酶活性抑制率之间的相关关系。结果:13,14,15mg/L的曲酸对酪氨酸酶活性的抑制率分别为24.7%,71.89%,85.74%,酪氨酸酶活性率为50%时曲酸质量浓度为13.65mg/L;2.3,4.7,7,9.3,11.7g/L的桑叶提取物对酪氨酸酶活性的抑制率分别为24.49%,38.22%,51.95%,74.83%,79.41%,酪氨酸酶活性率为50%时桑叶提取物质量浓度为6.4g/L。桑叶提取物浓度与其对酪氨酸酶活性抑制率呈正相关(r=0.9855,P<0.05)。结论:桑叶提取物对酪氨酸酶活性起到了与曲酸相似的抑制作用。

AIM: To investigate inhibition of extract from mulberry leaves on tyrosinase activity so as to provide experimental evidence for preventing and treating the disease of pigmentation. METHODS: Inhibition of kojic acid with different concentration on tyrosinase activity was measured. The control group was selected according to the positive results of inhibition rate (IR%= tyrosinase activity%)Regression equation was based using concentration of extract from mulberry leaves as independent variable and inhibition rate of independent variable on tyrosinase activity as dependent variable. The correlation between the extract from mulberry leaves and the inhibition rate was determined. RESULTS: The inhibition rates of kojic acid at 13, 14 and 15 mg/L on tyrosinase activity were 24.7%, 71.89%, 85.74%respectively, and the concentration of kojic acid was 13.65 mg/L when the inhibition rate was 50%. The inhibition rates of extract from mulberry leaves at 2.3, 4.7, 7, 9.3 and 11.7 g/L on tyrosinase activity were 24.49%,38.22%, 51.95%, 74.83%, 79.41%respectively, and the concentration of kojic acid was 6.4 g/L when the inhibition rate was 50%. Positive correlation was found between the concentration of extract from mulberry leaves and its inhibition for tyrosinase activity (r=0.985 5,P< 0.05). CONCLUSION: The inhibition of extract from mulberry leaves on tyrosinase activity is similar to that of kojic acid.