Preparation of Zn²⁺ Complex of Total Flavonoids from Fruit of Rosa davurica Pall and Its Antioxidant Activity in Vitro

The preparation process of Zn²⁺ complex of total flavonoids from fruit of Rosa davurica Pall.(FRDP)and its antioxidant activity in vitro were explored in this work. Taking the conversion rate of total flavonoids as index,the preparation procedures of Zn²⁺ complex of total flavonoids from FRDP were investigated by using single factor combined with orthogonal experiments. The scavenging ability for ·OH,O₂^-·,anti-liposome peroxidation capability and ABTS⁺· of total flavonoids and its Zn²⁺ complexes were tested to evaluate the antioxidant activity in vitro. Results showed the optimal preparation process of Zn²⁺ complex of total flavonoids were as follows:14 mg/mL of zinc chloride solution,8 mg/mL of total flavonoids solution,the pH was adjusted to 9,followed by the shaking at 50℃ for 3.0 h,the resulting mixture was centrifuged,and total flavonoids Zn²⁺ complex of FRDP was obtained by collecting the precipitation,in which the conversion rate reached 96.94% with a yield of 35.76%.Compared with total flavonoids of FRDP and V_C solution,Zn²⁺ complex had superior scavenging ability for ·OH,O₂^-· and excellent anti-liposome peroxidation capability,and it also had good ABTS⁺· clearing ability. Therefore,Zn²⁺ complex of total flavonoids from FRDP prepared in this work showed a certain antioxidant capacity.