Stability Comparison of Quercetin and its Metal Complexes and their Biological Activity

Quercetin being an essential flavonoid, controls the metal flow in our body, and is an important dietary component in many daily foodstuffs. In this study, quercetin (QCT) metal complexes are synthesized, and their stability has been investigated in different pH conditions. Further, the oxidized forms of quercetin in the processed food products (garlic pickle) and in non-processed food (garlic) are examined. The quercetin metal complexes (M-QCT) and their oxidized derivatives are characterized by using UV-vis, FT-IR, UPLC-DAD, GC-MS, and AAS. The disintegration of QCT and M-QCT complexes is monitored by RP-UPLC with diode array (RP-UPLC-PDA) detection in detecting the loss of major components. Moreover, the present project has checked the exposure of M-QCT (M = Mg, Zn) on the development/growth of zebrafish embryos. This study reveals that the Zn-QCT complex is more stable compare to std. QCT and Mg-QCT complex. Also, Zn-QCT is toxic to zebrafish embryos compared to std. QCT and Mg-QCT complex. The results of this study suggest the usage of M-QCT complexes in the processed foodstuffs instead of pure QCT.