Study on composition of flavonoids and antioxidant capacity of citrus peels

Six major flavonoids in 15 citrus varieties' peels were determined by HPLC(High Performance Liquid Chromatography),as well as their antioxidant capacity by 4 antioxidant methods(DPPH assay,FRAP assay,metal chelating capacity assay,and TBARS assay). The results showed that PMFs(Polymethoxylated Flavones)were richest in Ponkan(nobiletin was 9.01 mg/g DW,and tangeretin 5.10 mg/g DW),and Satsuma mandarin had the highest content of narirutin(10.83 mg/g DW),hesperidin(56.74 mg/g DW),and total flavonoids(sum of the 6 flavonoids:68.26 mg/g DW). Meanwhile,most citrus peel extract exhibited high antioxidant capacity determined by 4 different antioxidant assays. The result of FRAP assay and DPPH assay had significant correlation( p <0.05), and no significant correlation were observed with metal chelating capacity assay and TBARS assay(p>0.05).