Synthesis of Eugenol-Derived Coumarins as Broad-Spectrum Biosafe Antimicrobial Agents

Objective: Eugenol (EG) is a significant ingredient in clove oil that is commonly used as a tooth pain reliever. However, topical application of this phenol has been linked to a number of serious negative consequences. Methods: The goal of this study was to position EG into the coumarin nucleus, yielding a precursor and ten variants labeled (EGCOU1–EGCOU10). To validate their molecular structures, the FT-IR, ¹H, ¹³C NMR, and mass spectra were analyzed. The microbiological study was conducted against many pathogens using a growth medium-dilution approach. These include four aerobic bacteria, four anaerobic bacteria, and two fungi. On the other hand, the biosafety study explored the effect of the experimental coumarins on two non-pathogenic aerobic bacteria, three normal cellular populations, and lab-treated human blood. Results and Discussion: The results of the former study indicated that the experimental coumarins demonstrated outstanding antimicrobial activity compared with the standards used, with minor variances. The most efficacy was discovered against the test fungi, followed by aerobic bacteria, and lastly anaerobic ones, with (EGCOU7) having a preferential impact. The biosafety investigation found that the experimental coumarins were extremely biocompatible with the test nonpathogenic bacteria, normal cells, and human blood erythrocytes. Conclusions: Given the above findings, the author concluded that EG transferred into biosafe wide-spectrum antimicrobial agents through its incorporation within coumarin backbones. Among them, the ones with three substituted groups on the off-side aromatic ring showed higher activity than those with one or two groups. Furthermore, among the prior compounds, the one containing di-meta chlorides and mono-para methoxy exhibited the best benefits. These results and conclusions may light the path to covering the negative biological impacts of harmful phenols by housing them in a coumarin framework.