Phenolic compounds and antioxidant and antibacterial activities of Algerian honeys

Twenty-six samples of Algerian honeys were analyzed to determine their color intensity, content of bioactive compounds using colorimetric methods and phenolic profile using a high-performance liquid chromatography-ultraviolet (HPLC-UV) analysis. The antioxidant activities of the samples were estimated using 6 methods (1,1-diphenyl-2-picrilhydrazyl and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid free radicals scavenging, reducing power, chelating ferrous activity, nitric oxide radical scavenging assay and β-carotene bleaching) and the antibacterial power was determined in vitro using agar diffusion tests and measuring minimal inhibitory concentration. The color of honeys ranged from light yellow to dark amber with an intensity ranging from 350 to 1510 mAU. The highest content of total polyphenols, flavonoids, carotenoids and vitamin C and the best antioxidant activity was obtained from dark honeys. Sixteen phenolic compounds (8 phenolic acids and 8 flavonoids) were quantified. The antibacterial tests showed that Staphylococcus aureus was the most sensitive strain compared to Salmonella typhi. The results allowed establishing a quantitative phenolic profile of Algerian honeys. The bioactive compounds, the antioxidant and antibacterial activities, of honey did not depend on its monofloral or polyfloral nature, but rather on the type of flowers foraged by the bees and its geographical origin. The dark color of honey is a good indicator of a higher antioxidant content and the best biological properties.