Department of Cosmetic Science, Providence University, 200 Chung-Chi Road, Shalu, Taichung, 43301, Taiwan; E-Mails:
Int J Mol Sci. 2010 Oct 15;11(10):3977-87. doi: 10.3390/ijms11103977.
Tyrosinase is the key and rate-limiting enzyme responsible for the conversion of tyrosine into melanin. Competitive inhibition of tyrosinase enzymatic activity results in decreased or absent melanin synthesis by melanocytes in human skin. DeoxyArbutin (4-[(tetrahydro-2H-pyran-2-yl)oxy]phenol), a novel skin whitening agent, was synthesized through the removal of hydroxyl groups from the glucose side-chain of arbutin. DeoxyArbutin not only shows greater inhibition of tyrosinase activity but is also safer than hydroquinone and arbutin. Hence, deoxyArbutin is a potential skin whitening agent for cosmetics and depigmenting drugs; however, stability of this compound under some conditions remains a problem. The lack of stability poses developmental and practical difficulties for the use of deoxyArbutin in cosmetics and medicines. Improving the thermostability of deoxyArbutin is an important issue for its development. In this research, we established an analytical procedure to verify the amount of deoxyArbutin in solutions using a high performance liquid chromatographic (HPLC) method. The results indicate that this novel skin whitening agent is a thermolabile compound in aqueous solutions. Additionally, the rate constant for thermodegradation (k) and the half-life (t(1/2)) of deoxyArbutin were determined and can be used to understand the thermodegradation kinetics of deoxyArbutin. This information can aid in the application of deoxyArbutin for many future uses.
酪氨酸酶是将酪氨酸转化为黑色素的关键限速酶。竞争性抑制酪氨酸酶的酶活性会导致人皮肤中的黑色素细胞减少或停止黑色素的合成。脱氧熊果苷（4-[(四氢-2H-吡喃-2-基)氧基]苯酚）是一种新型的皮肤美白剂，它是通过去除熊果苷葡萄糖侧链上的羟基合成的。脱氧熊果苷不仅对酪氨酸酶活性的抑制作用更强，而且比氢醌和熊果苷更安全。因此，脱氧熊果苷是化妆品和脱色药物中一种有潜力的皮肤美白剂；然而，这种化合物在某些条件下的稳定性仍然是一个问题。缺乏稳定性给脱氧熊果苷在化妆品和药物中的应用带来了发展和实际困难。提高脱氧熊果苷的热稳定性是其发展的一个重要问题。在这项研究中，我们建立了一种分析程序，使用高效液相色谱（HPLC）方法验证溶液中脱氧熊果苷的含量。结果表明，这种新型皮肤美白剂在水溶液中是一种热不稳定的化合物。此外，还确定了脱氧熊果苷的热降解速率常数（k）和半衰期（t(1/2)），可用于了解脱氧熊果苷的热降解动力学。这些信息可以帮助将脱氧熊果苷应用于未来的许多用途。
