Interaction Study of a Secondary Metabolite Quercetin with Metal ions by Conductometry and Fluorescence Spectroscopy

In this work, interaction study of metal ions with quercetin, the secondary metabolite of plants was investigated by conductometric method and fluorescence spectroscopy. The conductometric study was done in acetonitrile solution. The conductance of the solution is measured after each addition of the quercetin to the cation solution. The fluorescence spectrum of quercetin was recorded in presence and absence of metal ions at maximum wave length (481 nm) upon excitation at 425 nm. Among the many cations titrated with quercetin, Mg2+, Al3+, Pb2+ and Zn2+ enhanced the intrinsic fluorescence of the quercetin while Cu2+, Ni2+ and Co2+ ions quench the intrinsic fluorescence emission of the quercetin solution. These different phenomena are observed due to the different release of absorbed energy in formed complex. The ability of quercetin molecule to form a complex with metal ions may be has an effect in quercetin anti-oxidative properties.