Physicochemical properties, antioxidant and antimicrobial activities of Nigerian Polyfloral honeys

Abstract

Natural honey is widely applied as food sweetener, food preservative and in folk medicine for treatment of varying degree of human affliction and diseases. This study evaluates the antimicrobial activities, physicochemical, phytochemical and antioxidant properties of four Nigerian honey samples collected from Ekiti, Kogi, Osun and Ondo (coded as A, B, C and D respectively). Physicochemical determination of honey samples include: pH, free acidity, electrical conductivity and density. Determination of phytochemical was carried out quantitatively using phenolics and flavonoid; while the total antioxidant capacities was measured in an in-vitro system using inhibition of lipid peroxidation, thiobarbituric acid reactions and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Agar diffusion method was used to measure the antimicrobial activities of the honey samples against some selected microorganisms (Staphylococcus aureus, Bacillus subtilis, Psuedomonas aeruginosa and Escherichia coli). The results of the physicochemical characterization showed that the honey samples were polyflorals characterized by low pH (3.76 ± 0.02, 4.17 ± 0.15, 3.94 ± 0.10 and 3.77 ± 0.01 for A, B, C and D respectively) capable of inhibiting the growth of most microorganisms and density ranging between 1.38 and 1.45 g/ml. All the honey samples showed antimicrobial activity against the selected microorganisms at concentration greater than 60 % v/v. The antioxidant investigation also demonstrated ability to inhibit lipid peroxidation and thiobarbituric acid reactions and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity possibly due to the reasonable amount of flavonoids and phenolics therein.