In Vitro Synergistic Antibacterial Activity of Natural Honey Combined with Curcuma Starch and their Correlation with Diastase Number, Flavonoid and Polyphenol Content

Abstract

Honey has been acknowledged worldwide as a good source of natural carbohydrates and sweetner. Six honey samples of Apis mellifera forged on plants from western Algeria were analyzed to determine Total Phenolic Content (TPC), Total Flavonoid Content (TFC), Diastase Number (DN), Hydroxy Methyl Furfural (HMF) content and antibacterial activity alone and in combination with Curcuma Starch. The total phenol content was determined by using the Folin-Ciocalteu method, and the flavonoid content was analyzed using by the aluminum chloride method. The HMF and DN were determined by harmonized methods. An agar incorporation technique was used to assess the Minimum Inhibition Concentration (MICs) and Minimum Inhibition Additive Concentration (MIACs) of honey against two strains of Gram-Negative bacteria (Escherchia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 2154). Total phenolic content of honeys ranged from 63.93 to 95.36 mg GAE/100 g honey, while Total Flavonoid Content (TFC) ranged from 5.41 to 9.94 mg CE/100 g. Hydroxy Methyl Furfural (HMF) content shows values between 3.8 and 78.4 mg kg-1; diastase values were between 7.3 and 26. The MAIC for the six varieties of honeys tested ranged between 12 and 18% (vol/vol) and 11 and 15% (vol/vol) against E. coli and P. aeruginosa, respectively. The MIC range for honey alone was 5-70% (vol/vol) and 5-40 % (vol/vol) against E. coli and S. aureus, respectively. A positive correlation was observed between total phenolic content and diastase activity (r=0.248) and between diastase activity and total flavonoid content (r=0.240). No clear correlation has been established between the MIC drop and the Diastase Number. The use of curcuma starch allows honey benefit and would constitute a synergetic effect to the antibacterial activity of honey.