Identification and antioxidative properties of transglycosylated puerarins synthesised by an archaeal maltogenic amylase

Puerarin is helpful for the prevention and treatment of various cardiovascular diseases. However, its insolubility often limits its uses. Transglycosylation reaction between 1% puerarin and 10% β-CD was catalysed by maltogenic amylase from archaeon Thermofilum pendens (TfMA) at 0.2 U/mg β-CD, 90 °C and pH 5.5, for 1 h in order to obtain puerarin glucosides of high water solubility. Seven puerarin derivatives with different number of additional α-glucosyl in the reaction solution were identified by HPLC–UV–MS analysis. Although less than puerarin, the transglycosylated puerarins still fully maintained their antioxidant activities, assessed by a radical scavenging test and a reducing power assay. Therefore, the transglycosylated puerarins exhibit a greater potential to be developed into new medicines and foods. This is the first report on the flavonoids glycosylation using the transglycosylation activity of archaeal maltogenic amylase.