Influence of glucose on the human serum albumin-flavone interaction and their antioxidant activity.

High levels of glucose in diabetics can react with plasma proteins through a non-enzymatic process. Herein, the influence of glucose on the interaction between flavones and human serum albumin (HSA) was investigated, as well as the effect of glucose on the antioxidant potential of a flavone-HSA system. It looks like the interactions of HSA and flavones with more hydroxyl groups on ring A are more easily affected by glucose. Flavones act as hydrogen bond donors with HSA by means of interacting with glucose. With increased incubation time in air (from 1 to 23 days), the affinities of HSA for multi-hydroxyl flavones on ring A were obviously higher than for non- or mono-hydroxyl flavones on ring A. HSA significantly masked the DPPH radical scavenging potential of 7,8-dihydroxyflavone and baicalein. However, glucose obviously enhances the DPPH scavenging potential of a baicalein-HSA system. Moreover, glucose slightly weakens the DPPH scavenging potential of a 7,8-dihydroxyflavone-HSA system.