Acylated flavone glucosides: Synthesis, conformational investigation, and complexation properties

Acylated flavonoid glycosides are ubiquitous in plants; however, the possible influence of the acyl groups on the typical properties of flavonoids is rather poorly documented. In this work, a series of chrysin (= 5,7 dihydroxyflavone) glucosides acylated with aromatic and aliphatic acid residues has been synthesized in a simple three-step procedure. Aromatic acyl groups are shown to impose folded conformations on the chrysin glucosides owing to their ability to stack on the polyphenolic nucleus. The acyl groups may also cause significant changes in the ability of the flavonoid glucosides to bind hard metal ions and proteins, as demonstrated in this work in the case of Al³⁺ and bovine serum albumin.