Protein Technologies, CSIR Biosciences, P.O. Box 395, Pretoria, 0001, South Africa.
J Ind Microbiol Biotechnol. 2012 Jul;39(7):1091-7. doi: 10.1007/s10295-012-1101-5. Epub 2012 Feb 29.
Leaf exudates from Aloe species, such as the Southern African Aloe ferox, are used in traditional medicines for both humans and livestock. This includes aloesin, a skin bleaching product that inhibits the synthesis of melanin. Aloesin, (a C-glycoside-5-methylchromone) can be released from aloeresin A, an ester of aloesin, through hydrolysis. The objective of the current study was to identify an enzymatic hydrolysis method for converting aloeresin A to aloesin, resulting in increased concentrations of aloesin in the aloe bitters extract. More than 70 commercially available hydrolytic enzymes were screened for the conversion of aloeresin A. An esterase (ESL001-02) from Diversa, a lipase (Novozym 388) and a protease (Aspergillus oryzae) preparation were identified during screening as being capable of providing conversion of pure aloeresin A, with the protease giving the best conversion (~100%). It was found that a contaminating enzyme in Novo 388 was responsible for the conversion of aloeresin A to aloesin. This contaminating enzyme, possibly a protease, was able to give almost complete conversion using crude aloe bitters extract, doubling the concentration of aloesin in aloe bitters extract via the hydrolysis of aloeresin A.
叶片分泌物从物种，如南非芦荟 ferox，用于传统医药为人类和牲畜。这包括芦荟素，一种皮肤漂白产品，抑制黑色素的合成。芦荟素，（一 C-糖苷-5-methylchromone）可以从 aloeresin 答，芦荟素的酯，通过水解释放。目前研究的目的是确定一种酶促水解法转化 aloeresin 答芦荟素，导致增加芦荟 bitters 提取物中芦荟素的浓度。超过 70 种市售的水解酶进行了筛选，以转化 aloeresin 答。酯酶（ESL001-02）来自 Diversa，脂肪酶（诺维信 388）和蛋白酶（米曲霉）制剂被鉴定为能够提供纯 aloeresin 答的转化，其中蛋白酶的转化率最高（~100%）。结果发现，Novozym 388 中的一种污染酶负责 aloeresin 答转化为芦荟素。这种污染酶，可能是一种蛋白酶，能够使用粗芦荟 bitters 提取物进行几乎完全的转化，通过 aloeresin 答的水解将芦荟 bitters 提取物中芦荟素的浓度提高一倍。
