ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY OF DIFFERENT FLORAL ORIGIN HONEYS FROM TURKIYE

Abstract

The bioactivities of phenolic extracts of nine Turkish honeys from different floral sources were investigated. The antioxidant properties of the extracts were assessed by ferric reducing/antioxidant power (FRAP) assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and cupric reducing antioxidant capacity (CUPRAC) assay. The total phenolic contents measured by Folin–Ciocalteau method varied from 66 to 223 mg/g extract as gallic acid equivalent. The antioxidant activities found with CUPRAC, expressed as trolox equivalent antioxidant capacity, ranged from 124.8 to 532 µmol/g, those determined with DPPH· expressed as IC50 ranged from 84 to 296 µg/mL, and those determined with FRAP expressed as trolox equivalent were in 33–166 µmol/g range. The antioxidant activities showed a marked correlation with total phenolics. In the antimicrobial tests using six bacteria and a yeast, Escherichia coli was moderately sensitive to each extract. There was no correlation between antimicrobial activity and total phenolic contents. PRACTICAL APPLICATIONS Honey has functional properties and promotes human health, and such properties depend largely on the floral source. Although studies on screening the antimicrobial and antioxidant activity of raw honey samples have been done densely, studies on phenolic compounds of honey are very limited. The present study demonstrates that honey phenolic compounds are partially responsible for honey antioxidant activity, displaying the relevance of honey as both healthy foodstuff and source of antioxidant.