Antimicrobial and antioxidant activity of proteins isolated from honey.

Proteins from honey were purified by concanavalin A (conA) affinity chromatography and eluted with a stepwise glucose gradient into fractions named F2-F5. The conA-unbound fraction (F1) was further separated by molecular exclusion into fractions named MbF1-1,2 and MbF1-3. All fractions were evaluated for antibacterial activity against foodborne pathogens and antioxidant capacity. F1 fraction possessed highest antimicrobial activity against , , Typhimurium, and with MIC's 1.4 ± 0.2, 15 ± 1, 39 ± 2, 1 ± 0.1, and 75 ± 2 µg/mL, respectively. F1, MbF1-1,2 and MbF1-3 had bactericidal effect except against . When the antioxidant capacity of the fractions was determined, F2 had the highest antioxidant activity measured by DPPH radical scavenging activity (IC = 2.4 ± 0.4 µg/µL) and reducing power of Fe(III) (IC = 1.8 ± 0.2 µg/µL). We provide evidence that honey proteins possess broad spectrum antibacterial and antioxidant activity, the latter probably through their reducing agent and free radical scavenger properties.