砂仁提取物对蘑菇酪氨酸酶活力的抑制效应

酪氨酸酶(EC 1.14.18.1)是生物体合成色素的主要酶.以地道阳春砂仁(Amomum)果实为材料,经过超声提取、萃取、树脂AB-8分离纯化,得到对蘑菇酪氨酸酶活力有显著抑制作用的砂仁30％(体积分数)乙醇提取物.研究该提取物对蘑菇酪氨酸酶的效应,结果表明,砂仁果实乙醇提取物对蘑菇酪氨酸酶的单酚酶活力和二酚酶活力都有明显的抑制作用.对单酚酶的作用,当质量浓度达到10.5 μg/mL时,可使单酚酶的稳定态活性酶活力下降40％,迟滞时间延长了3.12倍;对二酚酶活力的抑制作用也呈现浓度依赖性关系,其半抑制率浓度(IC50)为64 μg/mL,抑制作用属于可逆效应,抑制类型为混合型,抑制常数KI和KIS分别为41.85和98.51 μg/mL.这些数据为新型的酪氨酸酶的开发和寻找新型的食品保鲜剂和杀虫剂提供基础.

Inhibition Effects of the Extract of Amomum on Mushroom Tyrosinase Activity

Tyrosinase(EC 1.14.18.1) is a key enzyme in pigment biosynthesis of organisms.The 30% ethanol extract from Amomum which has significant inhibition on mushroom tyrosinase activity was purified by ultrasonic extracting,organic solution extracting,resin AB-8 chromatography.In the present paper,the effects of extract on the activity of mushroom tyrosinase were studied.The results showed that the extract could inhibit both monophenolase activity and diphenolase activity of the enzyme.For the monophenolase activity,the extract lengthened the lag time and decreased the steady-state activity.When the inhibitor concentration reached 10.5 μg/mL,the steady-state activity decreased 40%,the lag time lengthened 3.12 times.For the diphenolase activity,it also showed that concentration-dependent relationship.The IC50 value was estimated to be 64 μg/mL.The kinetic analysis showed that the inhibition of the extract on the diphenolase activity of the enzyme was reversible and belonged to mix-type,and the inhibition constants(KI and KIS) were determined to be 41.85 and 98.51 μg/mL.All of these data may provide the basis for developing novel tyrosinase activity inhibitors and searching for new potent food preservatives or insecticides.