Biosynthesis Of Aryl Alcoholic Glucosides Under Two Non-aqueous Phases And The Application Of Benzyl β-glucoside

Glycosides are secondary metabolites in plants during growth and serve as the potential aroma source of fruit,flowers,and some economic crops such as tea and tobacco.Volatile compounds in plants are often synthesized and accumulated as glycosidically bound components.The aglycones will released from their respective glycosides by enzymatic hydrolysis when the plants are suffering water deficit stress, plucking,tissue damage,malady infection and so on,and served as aroma components and antifungal substance.Researches on the synthesis and application of glycosides are getting more and more attraction in broad fields,such as chemical industry,food industry,agriculture and medicine.The technology of chemical synthesis is remarkably developed,but the application is greatly restricted because a series of steps such as protection and de-protection are needed during the synthesis process,and the problem of chemical residue is also one of the disadvantages of chemical synthesis.Recently,study on enzymatic synthesis is getting popular because of its mild reaction conditions and high selectivity.Besides,unprotected and free glucose can be treated as substrate directly in the process of enzymatic synthesis.Aryl alcoholic glucosides of benzyl alcohol,2-phenylethanol and(Z)-3-hexenol were biosynthesized using almondβ-glucosidase in non-aqueous media.The resulting products were preliminarily purified and identified by LC-MS.As a result,the yields ofβ-D-glucosides between water-organic two phases system and non-organic media are compared.Both the two kinds of organic solvents and the water content in reaction system have effects on enzymatic synthesis in non-aqueous media.Using silk protein as the matrix,almondβ-glucosidase was immobilized for the synthesis ofβ-D-glycosides,and the enzyme activity was detected.The resultingβ-D-glucosides were applied to evaluate the possibilities of its inhibition against colletorichum camelliae Masse.It demonstrated that the yields of glucosides in micro-aqueous media were notably higher than that in water-organic two phases system.The yields were close in those two non-aqueous systems which content 80%dioxane and 90%acetonitrile.Yields in system with10%DMSO were relatively lower and the enzymatic synthesis can not be realized in the two reaction systems which include 90%DMSO and 50%DMSO. After almondβ-glucosidase was immobilized on the silk protein matrix,the hydrolysis activity of almondβ-glucosidase remained but the synthetic activity disappeared.Benzyl alcohol and 2-phenylethanol exhibited antifungal activities against Colletotrichum Camelliae Massee obviously.2-Phenylethanol showed stronger antifungal activity than benzyl alcohol with the EC₅₀of 0.71μL/mL and a minimum inhibitory concentration(MIC)of 1.8μL/mL.As for benzyl alcohol,the EC₅₀and MIC were 0.72μL/mL and 0.5μL/mL respectively.Benzylβ-glucoside also exhibited antifungal activities obviously in concentrations between 5mg/mL to 40mg/mL in PDA culture medium.