Methylation of genistein and kaempferol improves their affinities for proteins.

摘要

Methylation of flavonoids appears to be a simple and effective way to improve metabolic resistance and transport of flavonoids. Serum albumins are major soluble proteins serving as transport proteins for many exogenous compounds. This study examined the effect of methylation of flavonoids on the affinity for human serum albumin (HSA) and ovalbumin. 1 isoflavone (genistein) and 1 flavonol (kaempferol) and their monomethylated derivatives at position 4' (biochanin A and kaempferide, respectively) were studied for their affinities for ovalbumin and HSA. Methylation significantly affected the binding process. In general, methylation of the flavonoids improved the affinities for proteins by 2-16 times. This result suggested that methylation of genistein and kaempferol enhanced transporting ability, which led to facilitated absorption and greatly increased bioavailability. Methylation increased the hydrophobicity of genistein and kaempferol, and the hydrophobic interaction played an important role in binding flavonoids to HSA and ovoalbumin.