Antioxidant Activity in Honeys of Various Floral Origins: Isolation and Identification of Antioxidants in Peppermint Honey

Polyphenol fractions from twenty-three honey samples of various floral origins were extracted with an Amberlite XAD-2 column, and total polyphenol content and antioxidant properties were determined. The Folin-Ciocalteu method was used to determine total polyphenol content, and antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Total polyphenol content per 100 g of honey ranged from 17.5 mg (Japanese prickly-ash) to 132.8 mg (peppermint). Peppermint honey had the highest flavonoid content (48.3 mg/100 g) and exhibited the highest antioxidant activity of all samples. A positive linear correlation was observed between honey color and DPPH radical scavenging activity. p-Coumaric acid and kaempferol were isolated and identified as antioxidants from peppermint honey. Additionally, quantification of these compounds in other honey samples was carried out. Peppermint honey contained a large amount of p-coumaric acid (705 mu g/100 g) and kaempferol (471 mu g/100 g). The potent antioxidant activity of peppermint honey is attributable to the quantities of these compounds, especially kaempferol.