In Vitro Evaluation of Antibacterial and Antifungal Properties of Some New 1, 3, 4-Oxadiazole Derivatives Containing Phenyl Group

Antibiotic resistance is recognized as one of the most challenging public health problems in the world. The need for new antibacterial and antifungal drugs is justified because many pathogens are currently resistant to available drugs. Several components of 1, 3, 4‑oxadiazoles have been shown to pose a wide range of antibacterial activities.

The new derivatives of 1, 3, 4-oxadiazole were synthesized using a single-stage method. The structure of derivatives was evaluated by IR, H-NMR, C-NMR, and GC-Mass methods. Then to measure the antibacterial and antifungal activities of the prepared derivatives at a concentration of 0.5 mg/mL, agar well diffusion method was employed, and the minimum inhibitory concentration (MIC) and the minimum bactericidal/fungicidal concentration (MBC/MFC) were determined with three replications.

The study of antibacterial properties of the prepared derivatives showed the highest activity of the compounds 4b-g against Enterococcus faecalis strains, among which the compound 4g with IZ= 55.66 ± 0.5 mm and MIC=31.25 mg/mL had the greatest effect compared to the others. Also, the compound 4f with MIC= 125 mg/mL had a powerful effect against E. faecalis strains. In the case of fungal samples, the highest activity of the compound 4b was with IZ=12.33±0.5 mm against Candida glabrata and with IZ=13.33±0.5 mm against C. krusei strains.

The new 1, 3, 4‑oxadiazole derivatives (4b, 4d, and 4g) with tolyl, dimetylphenyl, and methoxyphenyl groups were shown to be a promising compounds for pharmaceutical applications so that by adding other functional groups to their structure, it is possible to increase the destructive power of these compounds.