GC-MS Analysis of Bioactive Compounds in Azadirachta indica Extracts and their Antibacterial Effect against Fish Pathogen Aeromonas hydrophila

The bioactive chemicals found in herbal plants are responsible for their antibacterial properties against many infections. In this present study, Azadirachta indica extracts of isopropyl alcohol, ethanol, ethyl acetate, and hexane were tested for antibacterial activity against Aeromonas hydrophila at concentrations of 0.25 µl, 0.5 µl, 0.75 µl, and 1.0 µl, respectively. In antibacterial activity tests, isopropyl alcohol and ethanol extracts of A. indica leaves showed maximum zones of inhibition of 14.2 ± 0.2 mm, 14.7 ± 0.5 mm, 15.4 ± 0.3 mm, and 15.9 ± 0.2 mm; 14.0 ± 0.2 mm, 14.6 ± 0.5 mm, 15.2 ± 0.3 mm, and 15.6 ± 0.2 mm at 0.25 µl, 0.5 µl, 0.75 µl, and 1.0 µl concentrations, respectively, against the fresh water fish pathogen A. hydrophila. The phytochemical study of isopropyl alcohol and ethanol extracts of A. indica leaves revealed the existence of bioactive substances. The bioactive components of A. indica leaf isopropyl alcohol and ethanol extracts were analysed using a Perkin Elmer Gas Chromatography-Mass Spectrometer. The chemicals found in these extracts were matched to those of the National Institute of Standards and Technology (NIST-2008). The findings of the GC-MS analysis revealed that the isopropyl alcohol extract of Azadirachta indica had one major (Diethyl phthalate) and two minor (Methoxy acetic acid, pentyl ester and 2-hexanol, 3-methyl-) compounds, while the ethanol extract contained one major (Diethyl phthalate) and one minor (2-hexanol, 3-methyl-) compound. The findings of this study indicate that bioactive chemicals found in isopropyl alcohol and ethanol extracts of A. indica leaves may have anti-inflammatory and anti-bacterial properties.