Catinella Giorgia, Donzella Silvia, Borgonovo Gigliola, Dallavalle Sabrina, Contente Martina Letizia, Pinto Andrea
Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Via Celoria 2, 20133 Milan, Italy.
Antioxidants (Basel). 2022 Jan 28;11(2):260. doi: 10.3390/antiox11020260.
Among the plant bioactive components, oleuropein (OLE) is the most abundant phenolic compound in all parts of olive trees ( L.), particularly concentrated in olive leaves. It has been shown to present various remarkable biological actions, such as antimicrobial, antioxidant, anticancer and anti-inflammatory ones. On the other hand, hydroxytyrosol (HT), the main degradation product of OLE, is considered one of the most powerful antioxidant agents, with higher beneficial properties than the OLE parent compound. In this work, oleuropein was efficiently transformed into hydroxytyrosol using a 2-step biotransformation involving a thermo-halophilic β-glucosidase from (Ahe), which gave the corresponding aglycone with complete conversion (>99%) and rapid reaction times (30 min), and an acyltransferase from (MsAcT), here employed for the first time for its hydrolytic activity. After cascade completion, hydroxytyrosol was obtained in excellent yield (>99% m.c., 96% isolated yield) in 24 h. Starting from a natural substrate and employing enzymatic approaches, the final hydroxytyrosol can be claimed and commercialized as natural too, thus increasing its market value.
在植物生物活性成分中，橄榄苦苷（OLE）是橄榄树（Olea europaea L.）所有部位中含量最丰富的酚类化合物，尤其集中在橄榄叶中。它已被证明具有多种显著的生物学作用，如抗菌、抗氧化、抗癌和抗炎作用。另一方面，橄榄苦苷的主要降解产物羟基酪醇（HT）被认为是最强大的抗氧化剂之一，其有益特性比橄榄苦苷母体化合物更高。在这项工作中，使用两步生物转化法将橄榄苦苷高效转化为羟基酪醇，该方法涉及来自嗜热嗜盐栖热袍菌（Thermotoga maritima）的嗜热嗜盐β-葡萄糖苷酶（Ahe），它能以完全转化（>99%）和快速反应时间（30分钟）得到相应的苷元，以及来自马氏栖热放线菌（Actinotoga missouriensis）的酰基转移酶（MsAcT），这里首次利用其水解活性。级联反应完成后，在24小时内以优异的产率（>99%质量浓度，96%分离产率）获得了羟基酪醇。从天然底物出发并采用酶法，最终得到的羟基酪醇也可被认定为天然产物并商业化，从而提高其市场价值。
