Preparation of Flavonoids from Loquat Flowers (Eriobotrya japonica (Thunb.) Lindl) and Investigation of Their Antioxidant Activities

This study aimed to investigate the extraction and purification of flavonoids from loquat (Eriobotrya japonica (Thunb.) Lindl) flowers (FLF) and the in vitro antioxidant activities. The FLF were obtained by ethanol aqueous solution heating extraction followed by macroporous resin purification, ethyl acetate extraction and dextran gel purification. The content of FLF was determined by high performance liquid chromatography. Using vitamin C (VC) as control, the capacity of FLF in scavenging 1,1-diphenyl-2-picrylhydrazine (DPPH) radical, hydroxyl radical, superoxide anion radical and hydrogen peroxide and their reducing power were determined. The FLF was successfully obtained, and the content of flavonoids in final product was 98.21%. The in vitro anti-oxidation experiments showed that, the FLF had good scavenging capacity of DPPH radicals, hydroxyl radicals, superoxide anion radicals and hydrogen peroxide, and had good reducing power. The total antioxidant activities of FLF were better than VC. FLF has good application prospect and research value.