Synthesis of 2-hydroxynicotinaldehyde grafted isonicotinic acid hydrazide compounds and their antimicrobial evaluation

Abstract

Bacterial infection is one of the main causes of disease and death, and most drugs show resistance during treatment. It is necessary to develop novel, efficient, and less toxic drugs to handle drug resistance. This study synthesized isoniazid/2-hydroxy nicotinoid Schiff base compounds using isoniazid and 2-hydroxy nicotinoid compounds as raw materials in a 40℃ water bath and further evaluated their antibacterial properties. The structure of isoniazid/2-hydroxynicotinal Schiff base compound was confirmed by FT-IR, 1H NMR, DSC, XRD and XPS. MIC against S.aureus and E.coli was determined by liquid method and plate method. The results showed that the new infrared absorption peak of isoniazid/2-hydroxynicotinal Schiff base compound at 1662cm-1 was formed by ligand imine group ν (C=N), and the melting peak decreased to 159℃. There was also a new diffraction peak at 2θ=10.74° on XRD spectra and chemical shift signal peak on 1H NMR spectrum. The characteristic peaks of XPS shift towards higher fields. MIC of isoniazid, 2-hydroxynicotinoid, and isoniazid/2-hydroxynicotinoid compounds against S.aureus and E.coli are 402.50μg/mL, 402.50μg/mL, 201.25μg/mL, and 402.50μg/mL, 402.50μg/mL, and 100.63μg /mL, respectively. SEM images reveal that isoniazid/2-hydroxynicotinoid compounds kill bacteria by disrupting cell membranes, and have better antibacterial effects compared to raw materials.