Complexation of resveratrol with cyclodextrins: Solubility and antioxidant activity

The slightly water-soluble cancer chemopreventive polyphenol resveratrol (Res) and its inclusions with β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-CD) have been investigated. The stoichiometric ratios and stability constants have been determined by phase-solubility measurements. In all cases 1:1 complexes are formed. The inclusion ability of HP-CD is larger than that of β-CD. The antioxidant activity of the Res complexes has been determined by the scavenging of the stable radical DPPH. The scavenging capacity of the two complexes increases with increasing concentration of cyclodextrins. Res/HP-CD complex shows a higher scavenging capacity than Res/β-CD complex. The antioxidant activity of Res in free form has little difference with Res in complexed form at the same concentration.