Glycosylation of polyphenols may increase their aqueous solubility, stability, bioavailability and pharmacological activity. Herein, we used a mutant of sucrose phosphorylase engineered to accept large polyphenols (variant TtSPP_R134A) to produce phloretin glucosides. The selective formation of a monoglucoside or a diglucoside can be kinetically controlled. MS and 2D-NMR determined that the monoglucoside was phloretin 4’-O-α-D-glucopyranoside and the diglucoside phloretin-4’-O-[α-D-glucopyranosyl-(1→3)-O-α-D-glucopyranoside], a novel compound. The mono- and diglucoside were, respectively, 71- and 1200-fold more soluble in water than phloretin at room temperature. The α-glucosylation decreased the antioxidant capacity of phloretin, measured by DPPH and ABTS assays; however, this loss was moderate and the activity could be recovered upon deglycosylation in vivo. Since phloretin attracts a great interest in dermocosmetic applications, we analyzed the percutaneous absorption of glucosides and the aglycon employing a pig skin model.
Ref.:" Enzymatic Synthesis of Phloretin α‐Glucosides using a Sucrose Phosphorylase Mutant and its Effect on Solubility, Antioxidant Properties and Skin Absorption." J.L. Gonzalez-Alfonso, Z. Ubiparip, E. Jimenez-Ortega, A. Poveda, C. Alonso, L. Coderch, J. Jimenez-Barbero, J. Sanz-Aparicio, A. Ballesteros, T. Desmet, F.J. Plou. Advanced Synthesis & Catalysis (2021). Volume 363, 3079-3089, doi: 10.1002/adsc.202100201