Total anthocyanins and cyanidin-3-O-glucoside contents and antioxidant activities of purified extracts from eight different pigmented plants

Abstract

Background: Anthocyanin, a subcategory of flavonoid, is a natural water-soluble pigment. There are many plants rich in anthocyanins, and a high intake of anthocyanin food has been shown to have potential beneficial effects on various chronic diseases. Objective: The objective was to evaluate the contents of total anthocyanin and cyanidin-3-O-glucoside (C-3-G) and their contribution to the antioxidant activities in commonly consumed pigmented plants. Materials and Methods: The total anthocyanin in Lonicera caerulea L., Rubus fruticosus L., Ribes nigrum L., Morus alba L., Zea mays L. seed, Z. mays L. cob, Brassica oleracea L., and Dioscorea alata L. was extracted by tissue-smashing extraction method, and then the contents of total anthocyanin (TAC) and C-3-G contents (C-3-GC) in the purified extracts were determined by pH differential method and high-performance liquid chromatography, respectively. Antioxidant activities were assessed by 2,2-diphenyl-1-picrylhydrazyl, ferric-reducing antioxidant power, and total reducing power (TRP) assays. Results: TAC ranged from 97.11 to 320.27 milligrams cyanidin-3-glucoside equivalents per Gram of dry weight. TAC, C-3-GC, and antioxidant activities in most berry extracts were higher than that in vegetables. Z. mays cob showed the similar TAC, C-3-GC, and antioxidant activities to L. caerulea, and the two vegetables were the lowest. The major anthocyanin in the berries and grains was identified as C-3-G. There was a significant positive correlation between antioxidant activity and TAC. Conclusions: The closer the plant color is to black, the higher TAC is, and the stronger its antioxidant activity is. Z. mays cob will be a promising source of anthocyanin. This study provides a theoretical basis for the use of anthocyanin in functional food and further pharmacological research. Abbreviations used: C-3-G: cyanidin-3-O-glucoside; C3GC: cyanidin-3-O-glucoside contents; DPPH: 2, 2-diphenyl-1-picrylhydrazyl; FRAP: Ferric-reducing antioxidant power; HPLC: High-performance liquid chromatography; TAC: Total anthocyanin content; TAE: Total anthocyanin extract; TE: Trolox equivalent; TRP: Total reducing power; TPTZ: 1,3,5-tri (2-pyridyl)-2,4,6-triazine; TSE: Tissue-smashing extraction.