The Influence of Glycosylation of Natural and Synthetic Prenylated Flavonoids on Binding to Human Serum Albumin and Inhibition of Cyclooxygenases COX-1 and COX-2.

The synthesis of different classes of prenylated aglycones (α,β-dihydroxanthohumol () and ()-6,4'-dihydroxy-4-methoxy-7-prenylaurone ()) was performed in one step reactions from xanthohumol ()-major prenylated chalcone naturally occurring in hops. Obtained flavonoids (-) and xanthohumol () were used as substrates for regioselective fungal glycosylation catalyzed by two species and . As a result six glycosides (-) were formed, of which four glycosides (-) have not been published so far. The influence of flavonoid skeleton and the presence of glucopyranose and 4--methylglucopyranose moiety in flavonoid molecule on binding to main protein in plasma, human serum albumin (HSA), and inhibition of cyclooxygenases COX-1 and COX-2 were investigated. Results showed that chalcone () had the highest binding affinity to HSA (8.624 × 10⁴ M) of all tested compounds. It has also exhibited the highest inhibition of cyclooxygenases activity, and it was a two-fold stronger inhibitor than α,β-dihydrochalcone () and aurone (). The presence of sugar moiety in flavonoid molecule caused the loss of HSA binding activity as well as the decrease in inhibition of cyclooxygenases activity.