Optimization of Preparation Procedures of Phlorizin-Zn (Ⅱ) Complex and Its Antioxidant Activity Study in vitro

Flavonoid metal complexes possess more effective antioxidant properties than flavonoids. However, the preparation of the phlorizin-Zn (Ⅱ) complex and its antioxidant activity has not been reported. In this research, the preparation procedures of the phlorizin-Zn (Ⅱ) complex were enhanced using by single factor test and Response Surface Methodology (RSM). The optimal preparation procedures of the phlorizin-Zn (II) complex were as follows: The time of 4.1 h, the pH of 5.9, the temperature of 48.7°C and the molar ratio (phlorizin: Zn²⁺) of 1:1. Under these conditions, the predicted preparation yield of phlorizin-Zn (Ⅱ) complex was 79.052%. Additionally, the antioxidant activity of the phlorizin-Zn (Ⅱ) complex was analyzed in this research. 1, 1-Diphenyl-2-Picrylhydrazyl (DPPH), 2, 2'-Azino-bis (3-Ethylbenzothiazoline-6-Sulfonic acid) (ABTS), hydroxyl free radical and Ferric ion Reducing Antioxidant Power (FRAP) experiments revealed that phlorizin-Zn (Ⅱ) complex had significant DPPH, ABTS and hydroxyl free radical scavenging abilities and exhibited substantial reducing power in a dose-dependent manner. Moreover, the phlorizin-Zn (Ⅱ) complex displayed stronger in vitro antioxidant capacity compared with phlorizin. The findings demonstrated that the phlorizin-Zn (Ⅱ) complex had great potential in antioxidant applications in the future.