NMR metabolomics analysis of Escherichia coli cells treated with Turkish propolis water extract reveals nucleic acid metabolism as the major target.

AIMS: Propolis is a resinous bee product containing several hundred biologically active compounds. Although the antibacterial activity of propolis has been demonstrated in many in vitro studies, less is known about its mode of action. In this study, we aimed to shed some light on the antibacterial mechanism of action of propolis against Escherichia coli BW25113 using a nuclear magnetic resonance (NMR) based metabolomics approach. METHODS: E. coli BW25113 cells were subjected to different sub-lethal concentrations (0, 2, 4, and 6 mg/mL) of Turkish propolis water extract (PWE). The 500-MHz 1H NMR spectroscopy was then employed to ascertain the metabolic profiles of E. coli extracts. RESULTS: A total of 52 metabolites were identified from the NMR spectra, belonging to 17 main classes, such as amino acids and peptides, purines, and fatty acids. Twelve out of these 52 metabolites displayed remarkable changes at all tested PWE concentrations when compared to control conditions (P < .05). Levels of 28 more metabolites were significantly altered in at least one of the three PWE treatments. The results of partial least squares discriminant analysis showed that there was a clear separation between control and propolis-treated cells and that putrescine, adenine, adenosine, guanosine, glucose, N6-acetyllysine, and acetamide had the highest effect on group differentiation. Finally, quantitative pathway analysis revealed that purine metabolism was significantly affected by PWE treatments. CONCLUSIONS: Our results suggest that PWE inhibits the growth of E. coli BW25113 by affecting nucleic acid metabolism to a great extent. To the best of our knowledge, this is the first study to evaluate the global metabolic response of a bacterium to propolis.

Peritonsillar infiltration with levobupivacaine for posttonsillectomy pain relief: does concentration have any effect? A double-blind randomized controlled clinical study.

OBJECTIVE: Post-tonsillectomy pain is believed to be mediated by noxious stimulation of C-fiber afferents located in the peritonsillary space, and local anesthetic infiltration to this area may decrease pain by blocking the sensory pathways and thus preventing the nociceptive impulses. We aimed to compare the effects of different concentrations of preincisional peritonsillar levobupivacaine (0.25% and 0.5%) infiltration on postoperative pain and bleeding in a placebo-controlled design. PATIENTS AND METHODS: After obtaining Institutional Ethics Committee approval, 72 ASA I-II patients between 3 and 12 years of age, scheduled to undergo tonsillectomy were enrolled and randomly assigned to one of the three groups using the sealed envelope technique, as Group I (Control group), Group II, and Group III receiving preincisional bilateral peritonsillar infiltration with saline, 0.25% levobupivacaine and 0.5% levobupivacaine, respectively (3 mL to each tonsil). Pain, fever, dysphagia; nausea-vomiting and hemorrhage were evaluated at postoperative 0, 30, and 60 minutes and 2, 6, 12, and 24 hours. Oral paracetamol was administered at a dose of 15 mg/kg when FLACC score was > 4. The number of paracetamol administrations within the first 24 hours were recorded. RESULTS: The patients in Groups I, II and III defined pain (FLACC > 4) at a rate of 87%, 60.9%, and 54.2% within the postoperative first 24 hours, respectively. The total number of additional analgesic requirements was significantly low in Group II and III when compared with Group I. There was no difference between groups in terms of fever, dysphagia, nausea-vomiting, hemorrhage. CONCLUSIONS: Both concentrations (0.50% and 0.25%) of levobupivacaine were found to be equally safe and effective during preincisional peritonsillar infiltration in children. NCT number: 02322346.