Enzymatic routes for the production of mono- and di-glucosylated derivatives of hydroxytyrosol

In this work, a new eco-friendly procedure for the synthesis of hydroxytyrosol and tyrosol α-glycosidic derivatives was proposed by using the marine α-glucosidase from Aplysia fasciata, and a commercial tyrosinase from mushroom for the bioconversion of tyrosol glycosidic derivatives into the corresponding hydroxytyrosol products. New hydroxytyrosol mono- and di-saccharide derivatives were synthesized at final concentrations of 9.35 and 10.8 g/l of reaction, respectively, and their antioxidant activity was evaluated by DPPH test. The best antioxidant agent resulted the (3,4-dihydroxyphenyl) ethyl-α-d-glucopyranoside; it showed a radical scavenging activity similar to that of the hydroxytyrosol, together with an increased hydrosolubility. This molecule could be a good response to many food industry demands, always in search of cheap antioxidants with nutritional properties to improve the nutritional value and the quality of foods.

► New eco-friendly syntheses of more hydrosoluble biophenols were proposed. ► A marine α-glucosidase and a commercial tyrosinase from mushroom were used. ► Hydroxytyrosol and tyrosol α-glycosidic derivatives were efficiently produced. ► Antioxidant activity of hydroxytyrosol α-glycosylated derivatives was tested. ► The most interesting product is the (3,4-dihydroxyphenyl)ethyl-α-d-glucopyranoside.