| Autor: |
Gonzalez-Alfonso JL; Institute of Catalysis and Petrochemistry (ICP-CSIC), Marie Curie 2, 28049 Madrid, Spain., Alonso C; Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain., Poveda A; CIC bioGUNE, Basque Research and Technology Alliance (BRTA), 48160 Derio, Spain., Ubiparip Z; Centre for Synthetic Biology (CSB), Ghent University, Coupure Links 653, 9000 Ghent, Belgium., Ballesteros AO; Institute of Catalysis and Petrochemistry (ICP-CSIC), Marie Curie 2, 28049 Madrid, Spain., Desmet T; Centre for Synthetic Biology (CSB), Ghent University, Coupure Links 653, 9000 Ghent, Belgium., Jiménez-Barbero J; CIC bioGUNE, Basque Research and Technology Alliance (BRTA), 48160 Derio, Spain.; Basque Foundation for Science, 48009 Bilbao, Spain., Coderch L; Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain., Plou FJ; Institute of Catalysis and Petrochemistry (ICP-CSIC), Marie Curie 2, 28049 Madrid, Spain. |
| Abstrakt: |
The acylation of flavonoids serves as a means to alter their physicochemical properties, enhance their stability, and improve their bioactivity. Compared with natural flavonoid glycosides, the acylation of nonglycosylated flavonoids presents greater challenges since they contain fewer reactive sites. In this work, we propose an efficient strategy to solve this problem based on a first α-glucosylation step catalyzed by a sucrose phosphorylase, followed by acylation using a lipase. The method was applied to phloretin, a bioactive dihydrochalcone mainly present in apples. Phloretin underwent initial glucosylation at the 4'-OH position, followed by subsequent (and quantitative) acylation with C8, C12, and C16 acyl chains employing an immobilized lipase from Thermomyces lanuginosus . Electrospray ionization-mass spectrometry (ESI-MS) and two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) confirmed that the acylation took place at 6-OH of glucose. The water solubility of C8 acyl glucoside closely resembled that of aglycone, but for C12 and C16 derivatives, it was approximately 3 times lower. Compared with phloretin, the radical scavenging capacity of the new derivatives slightly decreased with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and was similar to 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS •+ ). Interestingly, C12 acyl-α-glucoside displayed an enhanced (3-fold) transdermal absorption (using pig skin biopsies) compared to phloretin and its α-glucoside. |
