The structural difference of flavonoids strongly affects the binding process with plasma proteins. This work in here mainly concerns about the molecular property-binding affinity relationship of dietary flavonoids for common rat plasma proteins (CRPP). The magnitudes of binding constants between flavonoids and CRPP were within the range of 10(4)-10(5) L/mol and the number of binding sites (n) was determined as 1.02 ± 0.19. These data were much smaller than the affinities between flavonoids and purified bovine and human serum albumins. The hydroxylation on rings A, B and C of flavonoids significantly affected the binding affinity. The glycosylation of dietary flavonoids decreased the binding affinity and the C2=C3 double bond hardly affected it. The galloylated catechins have higher binding affinities for CRPP than non-galloylated catechins. Flavonoids played as a hydrogen bond acceptor when bound to CRPP. The flavonoids with high topological polar surface areas (TPSA) are bound tightly while those with low TPSA are not.
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