Prospects of isolating new antimicrobial compounds from plants: The case of Azadirachta indica bark extract

Abstract

Objectives: Essential oils and extracts from medicinal plants have been shown to have antimicrobial properties in several investigations carried out in regions with diverse floras. This study intends to evaluate the antimicrobial activity of Azadirachta indica (Neem plant) bark extract on microbial isolates. Materials and Methods: The plant’s bark was cut out of the tree, dried, and pulverized using a mechanical grinder. The crushed barks were split in half, one half macerated in ethanol and the other put through the Soxhlet apparatus. The ethanol extract of plant bark was used to analyze microbial isolates (Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Candida albicans). The active components in the extracts were analyzed using gas chromatography-mass spectrometry. Results: According to the inhibition zone width, mean inhibition concentration, and lowest bactericidal concentration, all organisms were shown to be sensitive to the antibacterial activities of A. indica at varied doses of the extracts utilized. For every isolate examined, the minimum inhibitory concentration (MIC) of the extract was 12.5 mg/mL; however, B. subtilis had a concentration of 25 mg/mL. The extract had bactericidal activity on all the isolates except Bacillus sp. The minimum bactericidal concentration (MBC) for the isolates was 12.5 mg/mL for P. aeruginosa, S. aureus, and C. albicans, and 100 mg/mL for E. coli. Among the principal compounds discovered are pentadecanoic acid, 14-methyl-methyl ester, stigmasterol, 9-octadecanoic acid (z)-methyl ester, methyl stearate, n-hexadecanoic acid, linoelaidic acid, and Vitamin E. Conclusion: Our research showed that the ethanol extract from A. indica bark contains several bioactive compounds with antimicrobial properties.