The inhibitory effects of flavonoids on α-amylase and α-glucosidase

AbstractThe objective of this review is to summarize knowledge on the inhibitory effects (IEs) of flavonoids on α-amylase (αA) and α-glucosidase (αG) relevant to the search of substitutes of acarbose (Aca). Flavonoids reported to be more effective at inhibiting αG than Aca have been summarized. The concept of “relative coefficient to Aca (RCAca)” has been proposed to integrate data from various reports. Correlations between hydrogen bond donors (H-donors), hydrogen bond acceptors (H-acceptors), partition coefficient values (XLog P3), and RCAca are discussed. Two kinds of binding modes between flavonoids and enzymes have been observed: (i) flavonoids directly bind to amino acid residues (AARs) in the active sites of enzymes and exclude the binding of substrate; (ii) flavonoids interact with AARs near the active site and close the channel to the active center. Some groups are correlated with stronger IEs: (i) substitutions of caffeoyl, galloyl, and prenyl groups in flavonoids enhance IEs; (ii) steric hindra...