3-Phenyllactic Acid and Polyphenols Are Substances Enhancing the Antibacterial Effect of Methylglyoxal in Manuka Honey

• Published in: Foods Vol. 12; no. 5; p. 1098
• Main Authors: Thierig, Marcus, Raupbach, Jana, Wolf, Diana, Mascher, Thorsten, Subramanian, Kannan, Henle, Thomas
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.03.2023; MDPI
• Subjects: 3-phenyllactic acid; Acids; Antibacterial activity; Antibacterial agents; Bacillus subtilis; Chemical properties; Food science; Glucose; Gram-positive bacteria; Health aspects; Hemodialysis; Honey; Liquid culture; manuka honey; methylglyoxal; Optical density; Polyphenols; Proteins; Pyruvaldehyde; Solvents; synergistic effects; Testing; Germany; Berlin Germany; methylglyoxal; 3-phenyllactic acid; Bacillus subtilis; synergistic effects; manuka honey
• ISSN: 2304-8158; 2304-8158
• DOI: 10.3390/foods12051098

Manuka honey is known for its unique antibacterial activity, which is due to methylglyoxal (MGO). After establishing a suitable assay for measuring the bacteriostatic effect in a liquid culture with a time dependent and continuous measurement of the optical density, we were able to show that honey differs in its growth retardingeffect on despite the same content of MGO, indicating the presence of potentially synergistic compounds. In model studies using artificial honey with varying amounts of MGO and 3-phenyllactic acid (3-PLA), it was shown that 3-PLA in concentrations above 500 mg/kg enhances the bacteriostatic effect of the model honeys containing 250 mg/kg MGO or more. It has been shown that the effect correlates with the contents of 3-PLA and polyphenols in commercial manuka honey samples. Additionally, yet unknown substances further enhance the antibacterial effect of MGO in manuka honey. The results contribute to the understanding of the antibacterial effect of MGO in honey.