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Structure–affinity relationship of flavones on binding to serum albumins: Effect of hydroxyl groups on ring A

2010; Wiley; Volume: 54; Issue: S2 Linguagem: Inglês

10.1002/mnfr.200900454

1613-4133

Jianbo Xiao, Hui Cao, Yuanfeng Wang, Koichiro Yamamoto, Xinlin Wei,

Natural Antidiabetic Agents Studies

Four flavones (flavone, 7-hydroxyflavone, chrysin, and baicalein) sharing the same B- and C-ring structure but a different numbers of hydroxyl groups on the A-ring were studied for their affinities for BSA and HSA. The hydroxylation on ring A of flavones increased the binding constants (K(a)) and the number of binding sites (n) between flavones and serum albumins. The affinities of 7-hydroxyflavone for BSA and HSA were about 800 times and 40 times higher than that of flavone, respectively. It appears that the optimal number of hydroxyl groups introduced to the ring A of flavones is one. As more hydroxyl groups were introduced to positions at C-5, C-6, and/or C-7 of flavones, the affinities for serum albumins decrease. The critical energy transfer distances (R(0)) between the hydroxylated flavones (1-3 OH on the ring A) and serum albumins decreased with the increasing affinities for serum albumins.