Icariside II Preparation from Icariin Separated from Epimedium Herbal Extract Powder by a Special Icariin Glycosidase

In this study, icariside II was prepared from icariin by a special enzyme. The yield of the substrate icariin from a powdered extract of the popular herb Epimedium was 16.9%. The enzyme, which was produced from Aspergillus sp.y48 fermentation, hydrolyzes icariin to icariside II and was characterized. The molecular weight was 75 kDa, while the optimum temperature and pH were 45°C and 5.0. The purified enzyme hydrolyzed the 7-O-glucoside of icariin or epimedin A, B, and C to icariside II, or sagittatoside A, B, and C, respectively, and further hydrolyzed the terminal 3-O-xyloside of sagittatoside B to icariside II. The enzyme is a special icariin glycosidase that hydrolyzed icariin to icariside II at low cost. Based on the crude enzyme's reaction dynamics, the optimal conditions for icariside II preparation showed that 2% icariin reacted at 45°C for 6 to 9 h. Here, we obtained 13.3 g icariside II and 0.45 g of the by-product icaritin from 20 g icariin. The icariside II molar yield was 87.4%, the by-product icaritin yield was 4.1%, and the total molar yield was 91.5%. Therefore, icariside II was resoundingly prepared from an icariin glycosidase of an Epimedium extract using a non-GMO, crude enzyme from Aspergillus sp.y48. The obtained icariside II and the by-product icaritin can be directly applied in the production of cosmetics and pharmaceuticals.