Comparative study of the chemical composition and biological potential of honey from different regions of Serbia

Abstract

A chemical characterization and biological activity of 7 honey types (multifloral, linden, rapeseed, sunflower, phacelia, acacia and honeydew honey) from different regions of Serbia were presented. The physicochemical characteristics, mineral content, antioxidant and antimicrobial activity were estimated and discussed. All honeys showed good nutritional characteristics, according to the adopted criteria of the standard codex for honey. The concentrations of 15 elements in honey samples were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Limits of quantification were in the range from 0.003 mg/kg (Cd, Cr, Cu, Mn, and Pb) to 1.50 mg/kg for sodium. Precision was expressed as relative standard deviation and its values were lower than 1.50%. Accuracy was evaluated with certified reference material (fish protein, DORM 4, NRC and cooking chocolate, SRM 2384, NIST) and obtained recovery percentages were 71-127%. The content of the most abundant elements (K, Mg, and Na) and microelements (Al, Cu, Fe, Mn, Ni, Se, Si, and Zn) showed a significant variability in accordance of their botanical and geographical origin, but also the influence of harvest conditions. The levels of toxic metals (As, Cd, Cr, and Pb) are much lower than the maximal allowed for these metals according to European Commission Regulation. The antioxidant activity was evaluated by DPPH (Diphenylpicrylhydrazyl) assay while antimicrobial activity against Gram positive and Gram negative bacteria (E. coli and S. aureus) and fungi Candidi albicans was estimated by microdilution assay. The free radical scavenging assay (%RSA) varies significantly among the honey samples. The highest antioxidant activity was observed with honeydew honeys (over 75% RSA) and the lowest was observed in the acacia, ranging from 22.96 to 24.57% RSA. All honeys tested in this study exhibited antibacterial activity, with inhibition of bacterial growth, generally the higher against E. coli (80% for linden honeys) than against S. aureus (mostly much lower than 50%). Activity against Candidi albicans was almost negligible. The dataset composed of all experimental results was subjected to a chemometric evaluation and cluster analysis as hierarchical nonsupervised method was applied. According to the obtained outcome of applied algorithms, both botanical and geographical origin have important role in the elemental composition, antioxidant and antimicrobial activities.