Synthesis and evaluation of antioxidant and β-glucuronidase inhibitory activity of hesperidin glycosides
Keywords:β-Cyclodextrin (β-CD), Cyclodextrin glycosyltransferase (CGTase), Functional glycoside, Hesperidin glycoside, Transglycosylation
Cyclodextrin glycosyltransferase (CGTase) catalyzes an intermolecular transglycosylation reaction to produce functional oligosaccharides or glycosides. Such products are used in the food and drug industry to improve bioavailability. Previous work purified recombinant CGTase and identified hesperidin as a flavonoid acceptor. The current study optimized the conditions for recombinant CGTase to convert β-cyclodextrin (β-CD) and hesperidin to three major products identified using mass spectrometry: hesperidin glucoside (HG1), hesperidin maltoside (HG2) and hesperidin maltotrioside (HG3), whose molecular weights were 754 Da, 916 Da and 1,078 Da, respectively. They were hesperidin glycosides with 1, 2 and 3 monosaccharide units. The solubility and free-radical scavenging properties of HG1 and HG2 were increased compared to original hesperidin but they had lower anti-inflammatory activity by inhibiting less β-glucuronidase and all properties were dependent on the number of glucose or maltose molecules attached to the -OH groups of hesperidin. The results suggested hesperidin glycosides could replace hesperidin in food and drugs and more work is needed to see whether their antioxidant properties can be exploited.