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Nature-Inspired Antibacterial Agents: Derivatization of Eugenol toward promising anti-H. pylori agents
* 1 , 2 , 2 , 3 , 2 , 2 , 3 , 4
1  Department of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy
2  Department of Pharmacy, “G. d’Annunzio” University of Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy
3  Department of Chemistry ‘‘Ugo Schiff'', University of Florence, Via della Lastruccia 3–13, 50019 Sesto Fiorentino, Italy
4  Department of Biomedical, Surgical and Dental Sciences, University of Milan, Via Pascal 36, 20133 Milan, Italy
Academic Editor: Marc Maresca

Published: 30 November 2023 by MDPI in The 3rd International Electronic Conference on Antibiotics session Poster Session

Bacterial resistance dramatically affects the effectiveness of current antibiotics, being considered a big concern for Public Health. Also, some bacterial survival capabilities in harsh conditions and invasiveness can cause infection recrudescence and failure in its eradication, as often occurs with Helicobacter pylori, recognized as an important risk factor for the development of gastric adenocarcinoma. The search for new antibacterial agents led us to explore the activity of Eugenol (Figure 1), an essential oil component known for its polypharmacology and, in particular, broad-spectrum antimicrobial1,2 and anti-H. pylori activity in vitro.3

In this study, we investigated three chemical modifications on Eugenol scaffold, generating three different series of derivatives: in series A, a diazo function was added in the ortho position; in B, the phenolic group was alkylated or incorporated into a carbamate or ester moiety; in C, the allylic portion was replaced by a differently substituted tail, including an epoxide ring, alcohol or chalcogen-bearing chains (Figure 1). The antibacterial susceptibility of H. pylori strains for these compounds was evaluated on the reference NCTC 11637 strain and three drug-resistant clinical isolates. Interestingly, some of the derivatives showed lower minimal inhibitory concentration (MIC) values on H. pylori NCTC 11637 (MICs ranging from 8 to 16 µg/mL) than the parent compound (Eugenol, MIC = 32 µg/mL). They also maintained their antibacterial activity on the resistant strains, exerting a bactericidal effect.

  1. Kamatou, G. P.; Vermaak, I.; Viljoen, A. M. Molecules. 2012, 17, 6953-6981.
  2. Marchese, A.; Barbieri, R.; Coppo, E.; Orhan, I. E.; Daglia, M.; Nabavi, S. F.; Izadi, M.; Abdollahi, M.; Nabavi, S. M.; Ajami, M. Crit. Rev. Microbiol. 2017, 43, 668-689.
  3. Ali, S.M.; Khan, A. A.; Ahmed, I.; Musaddiq, M.; Ahmed, K. S.; Polasa, H.; Rao, L. V.; Habibullah, C. M.; Sechi, L. A.; Ahmed, N. Ann. Clin. Microbiol. Antimicrob. 2005, 4-20.
Keywords: eugenol, antibacterial, Helicobacter pylori, bactericidal, diazo