*2.3. Antimicrobial Evaluation*

Different organisms were selected to cover the Gram-positive and Gram-negative bacteria; namely Staphylococcus aureus ATCC 29213 and *Bacillus subtilis* ATCC 3366 as Gram-positive, *Escherichia coli* ATCC 25922, *Klebsiella pneumoniae* ATCC 13883, *Salmonella typhi* ATCC 25566 and *Pseudomonas aeruginosa* ATCC 27853 as Gram-negative microorganisms. Antifungal effect was investigated using *Candida albicans* NRRL Y-477. Disc diffusion method was used as the method of the microbiological study, where the standard antibiotic discs were Ampicillin 10 μg/disc, erythromycin 10 μg/disc and anti-fungal fluconazole. The negative control was DMSO (100%). The result was collected to estimate the existence of antibacterial efficiencies of the prepared compounds depending on the criterion procedure by Bauer et al [34]. Bacterial culture, at first, which is adjusted to 0.5 McFarland standards, was applied to Mueller Hinton agar plates in-house. After that, the plates were dried for 15 min. and then applied for the sensitivity test. The discs were impregnated with the tested compounds on the MH agar surface together with the control antibiotic and the negative control and incubated at 37 ◦C for 24 h. After incubation, the plates were examined for any inhibition zone. To ensure reliability of the result, the test was repeated three times.
