Department of Marine Food Science and Technology, Medical and Bio-Materials Research Center, Gangneung-Wonju National University, Gangneung, Republic of Korea.
J Sci Food Agric. 2011 Jul;91(9):1541-7. doi: 10.1002/jsfa.4335. Epub 2011 Mar 7.
Tyrosinase plays a key role in hyperpigmentaion and enzymatic browning. The present study was aimed at investigating the inhibitory effects of water and 70% aqueous ethanol extracts of Stichopus japonicus, a sea cucumber long consumed as a tonic food and traditional medicine, on the diphenolase activity of tyrosinase.
In the tyrosinase inhibition study, high-performance liquid chromatography completely separated L-3,4-dihydroxyphenylalanine and dopachrome from other compounds present in the extracts, and provided more reliable results than the commonly used spectrophotometry. The ethanol extract (IC(50)=0.49-0.61 mg mL(-1)) showed higher inhibitory activity than the water extract (IC(50)=1.80-1.99 mg mL(-1)). Enzyme inhibition by the extracts was reversible and of mixed type. For both extracts, the dissociation constants for binding to free enzyme were significantly smaller than those for binding to enzyme-substrate complex. Ethyl-α-D-glucopyranoside (IC(50)=0.19 mg mL(-1)), isolated for the first time from sea cucumber, and adenosine (IC(50)=0.13 mg mL(-1)), were identified as key tyrosinase inhibitors.
The sea cucumber extracts were demonstrated to possess considerable inhibitory potency against the diphenolase activity of tyrosinase, suggesting that the sea cucumber may be a good source of safe and effective tyrosinase inhibitors.
酪氨酸酶在皮肤色素沉着和酶促褐变中起着关键作用。本研究旨在探讨海参水提物和 70%乙醇提取物对酪氨酸酶二酚酶活性的抑制作用。
在酪氨酸酶抑制研究中，高效液相色谱法能将提取物中存在的 L-3,4-二羟基苯丙氨酸和多巴色素与其他化合物完全分离，比常用的分光光度法提供更可靠的结果。乙醇提取物（IC（50）=0.49-0.61mg/ml）的抑制活性高于水提取物（IC（50）=1.80-1.99mg/ml）。提取物对酶的抑制作用是可逆的和混合型的。对于两种提取物，与游离酶结合的解离常数明显小于与酶-底物复合物结合的解离常数。首次从海参中分离出的乙基-α-D-吡喃葡萄糖苷（IC（50）=0.19mg/ml）和腺苷（IC（50）=0.13mg/ml）被鉴定为关键的酪氨酸酶抑制剂。
海参提取物对酪氨酸酶的二酚酶活性具有相当大的抑制作用，这表明海参可能是安全有效的酪氨酸酶抑制剂的良好来源。
