Menthol has a considerable cooling effect, but the use range of menthol is limited because of its extremely low solubility in water and inherent flavor. (−)-Menthol β-glucoside was determined to be more soluble in water (>27 times) than (−)-menthol α-glucoside; hence, β-anomer-selective glucosylation of menthol is necessary. The in vitro glycosylation of (−)-menthol by uridine diphosphate glycosyltransferase (BLC) from Bacillus licheniformis generated (−)-menthol β-glucoside and new (−)-menthol β-galactoside and (−)-menthol N-acetylglucosamine. The maximum conversion rate of menthol to (−)-menthol β-d-glucoside by BLC was found to be 58.9%. Importantly, (−)-menthol β-d-glucoside had a higher cooling effect and no flavor compared with menthol. In addition, (−)-menthol β-d-glucoside was determined to be a non-sensitizer in a skin allergy test in the human cell line activation test, whereas menthol was a sensitizer.
薄荷醇具有显著的降温效果,但由于其在
水中的溶解度极低和固有的味道,薄荷醇的使用范围受到了限制。(经测定,
(-)-薄荷醇β-
葡萄糖苷比
(-)-薄荷醇α-
葡萄糖苷更易溶于
水(>27 倍);因此,有必要对薄荷醇进行β-异构体选择性糖基化。地衣芽孢杆菌的二
磷酸尿苷糖基转移酶(BLC)对
(-)-薄荷醇进行体外糖基化,生成了
(-)-薄荷醇β-
葡萄糖苷以及新的
(-)-薄荷醇β-半
乳糖苷和
(-)-薄荷醇N-乙酰
葡萄糖胺。发现 BLC 将薄荷醇转化为
(-)-薄荷醇 β-d-
葡萄糖苷的最大转化率为 58.9%。重要的是,与薄荷醇相比,
(-)-薄荷醇 β-d-
葡萄糖苷具有更高的冷却效果,而且没有味道。此外,
(-)-薄荷醇 β-d-
葡萄糖苷在人体
细胞系活化试验的皮肤过敏测试中被确定为非致敏物,而薄荷醇则是致敏物。