Enzymatic Synthesis of α-Tocopherol Derivative Glycoside, Daidzein Glycoside, Daidzein Oligosaccharide, Resveratrol Oligosaccharide, and Curcumin Oligosaccharides and Their Anti-Allergic Activity and Neuroprotective Activity

Enzymatic glycosylations of an α-tocopherol derivative, daidzein, resveratrol, and curcumin were investigated. The plant polyphenol, resveratrol, was incubated with glucosyltransferase from Phytolacca americana. The resveratrol glycoside obtained was then incubated with cyclodextrin glucanotransferase to obtain resveratrol oligosaccharide. Daidzein and curcumin were also converted into daidzein glycoside, daidzein oligosaccharide, and curcumin oligosaccharides. Also, α-tocopherol derivative, that is, 2, 5,7,8-tetramethyl-2-(4,8-dimethylnonyl)chroman-6-ol, was glycosylated. The glycosides and oligosaccharides had strong anti-allergic activity such as suppression of IgE formation, inhibition of histamine release, and inhibition of O 2 - generation. In addition, the glycosides and oligosaccharides showed efficient neuroprotective activity by inhibition of phosphodiesterase.