Enhanced chemical and biological activities of a newly biosynthesized eugenol glycoconjugate, eugenol α-D-glucopyranoside.

Eugenol, the essential component (over 90 %) of clove oil from Eugenia caryophyllata Thunb. (Myrtaceae), is a phenolic compound well known for its versatile pharmacological actions, including analgesic, local anesthetic, anti-inflammatory, antimicrobial, antitumor, and hair-growing effects. However, the application of eugenol is greatly limited mainly because of its unwanted physicochemical properties, such as low solubility, liability to sublimation, and pungent odor. Since glycosylation has been suggested to improve the physicochemical and biological properties of the parental compound, we have previously developed a novel and efficient way to biosynthesize highly purified eugenol α-D-glucopyranoside (α-EG). In light of the widely acknowledged importance of pure eugenol and the potential superiority of the glycosylation, it is crucial to further explore and compare the physicochemical and biological properties of these two phenolic compounds. In this study, we demonstrate that glucosylation is a promising method for modification of phenolic compound, and that α-EG is superior over its parent eugenol, in all of the tested aspects, including physicochemical properties, antioxidation activity, and antimicrobial and antitumor activities. These results strongly suggest that α-EG, as a novel prodrug, may serve as a useful probe and potential therapeutic drug in both fundamental research and clinical application in the coming future.