Synthesis and Antimicrobial Evaluation of Some Schiff Base Derivatives

Schiff bases are the nitrogen analogs of ketones or aldehydes, with the carbonyl functional group replaced by an imine or azomethine group. They are formed by the condensation reaction of a primary amine and a carbonyl group, and they are widely employed in industry and have a variety of biological activities. Four Schiff base derivatives were successfully synthesized from benzaldehyde (PC1), anisaldehyde (PC2), 4-nitrobenzaldehyde (PC 2), and cinnamaldehyde (PC4) and tested for their antibacterial capabilities were evaluated against bacteria and fungi. The Schiff base had a high percentage yield of 98.28% (PC1), 95.7% (PC2), 91.6% (PC3), and 98% (PC4), with melting points ranging from 178 -187°C, 183-191°C, 160-164°C, and 195-205°C respectively. All Schiff bases showed activity against Escherichia coli with a Minimum Inhibitory Concentration (MIC) of 62.5ug/ml (PC1, PC4) and 250ug/ml (PC2, PC3). The Minimum Bactericidal Concentrations (MBC) were 125ug/ml, 500ug/ml, and 250ug/ml for PC1, PC2 and PC4 respectively. PC3 showed no bactericidal activity against Escherichia coli. Schiff bases PC1, PC2, and PC3 showed activity against Staphylococcus aureus with MIC of 62.5ug/ml. The MBC obtained was 125ug/ml for PC1 and PC2, while 125ug/ml, and 250ug/ml for PC3. PC4 showed no bacteriostatic and bactericidal activity against Staphylococcus aureus. Schiff bases showed fungistatic activity against Candida albican with MIC of 250ug/ml, 62.5ug/ml, and 125ug/ml for PC1, PC2/PC3, and PC4 respectively. However, none showed fungicidal activity.