Synthesis of Alpha-Linked Glucosides from Soybean Isoflavone Aglycones Using Amylosucrase from Deinococcus geothermalis

Soybean isoflavone aglycones (SIAs) have many biological activities but are poorly water-soluble in the human body. Glycosylation provides structural diversity to SIAs and can alter their physicochemical properties, including water solubility. An alpha-linked glucosylation of SIA was achieved using amylosucrase from Deinococcus geothermalis. A total of 13 alpha-linked glucosyl SIAs were obtained, and their colors in solution were confirmed. The structures of the isolated compounds were identified by mass spectrometry and multidimensional nuclear magnetic resonance spectroscopy. The amylosucrase transglycosylation formed new isoflavone glycosides with alpha glycosidic bonds at C-7 and/or C-4 ' of SIAs, followed by the production of isoflavone glycosides with alpha (1 -> 6) glycosidic bonds. The products with a glucosyl moiety attached to the C-4 ' of SIAs were found to be more water-soluble than their counterparts attached to the C-7 and/or beta -linkages. This study suggests a strategy for the synthesis of bioactive compounds with enhanced water solubility through alpha-linked glucosylation.

Automated summary

Using amylosucrase from Deinococcus geothermalis, alpha-linked glucosylation of Soybean isoflavone aglycones (SIAs) was achieved, resulting in 13 alpha-linked glucosyl SIAs with confirmed colors in solution. The structures of the compounds were identified using mass spectrometry and multidimensional nuclear magnetic resonance spectroscopy. The study suggests a strategy for the synthesis of bioactive compounds with enhanced water solubility through alpha-linked glucosylation, with the products attached to the C-4 ' of SIAs found to be more water-soluble than those attached to the C-7 and/or beta-linkages.