Glucosylation of pterostilbene published in Molecules

In this paper was performed the synthesis of a novel α-glucosylated derivative of pterostilbene by a transglycosylation reaction using starch as glucosyl donor, catalyzed by cyclodextrin glucanotransferase (CGTase) from Thermoanaerobacter sp.

Due to the formation of several polyglucosylated products with CGTase, the yield of monoglucoside was increased by the treatment with a recombinant amyloglucosidase (STA1) from Saccharomyces cerevisiae (var. diastaticus).

The glucosylation of pterostilbene enhanced its solubility in water to approximately 0.1 g/L. The α-glucosylation caused a slight loss of antioxidant activity towards ABTS˙⁺ radicals. Pterostilbene α-D-glucopyranoside was less toxic than pterostilbene for human SH-S5Y5 neurons, MRC5 fibroblasts and HT-29 colon cancer cells, and similar for RAW 264.7 macrophages.

''Enzymatic synthesis of a novel pterostilbene α-glucoside by the combination of cyclodextrin glucanotransferase and amyloglucosidase''. J.L. González-Alfonso, D. Rodrigo-Frutos, E. Belmonte-Reche, P. Peñalver, A. Poveda, J. Jimenez-Barbero, A.O. Ballesteros, Y. Hirose, J. Polaina, J.C. Morales, M. Fernández-Lobato and F. J. Plou. Molecules 25;23(6) (2018). doi:10.3390/molecules23061271 

Our group visited CPhI Worldwide in Madrid

The ABG group visited the pharmaceutical exhibition CPhI Worldwide in Madrid on October 10th 2018. It was an opportunity to connect with pharma professionals and meet companies from around the world.

Glycosylation of hydroxytyrosol published in ChemCatChem

We have investigated the ability of the β-fructofuranosidase pXd-INV from the yeast Xanthophyllomyces dendrorhous to glycosylate the olive biophenol hydroxytyrosol (HT). Two fructosylated derivatives (Fru-HT1 and Fru-HT2) were synthesized.MS and 2D-NMR analyses showed that the major product (Fru-HT1) was fructosylated at the primary OH of HT. The structure of the complexes with the substrates and the product analyzed by crystallography led to the understanding of the molecular determinants regulating the enzymatic mechanism. Product-soaked crystals revealed that the minor derivative (Fru-HT2) was fructosylated at the phenolic p-OH group.  One of the studied mutants (N342Q) was notably more specific for the fructosylation at the phenolic OH than the wild-type.

Reference:“Fructosylation of hydroxytyrosol by the β-fructofuranosidase from Xanthophyllomyces dendrorhous: Insights into the molecular basis of the enzyme specificity”. N. Míguez, M. Ramírez-Escudero, M. Gimeno-Pérez, A. Poveda, J. Jiménez-Barbero, A. O. Ballesteros, M. Fernández-Lobato, J. Sanz-Aparicio* and F. J. Plou* ChemCatChem, http://dx.doi.org/10.1002/cctc.201801171(2018)