Molecular docking studies and GC-MS analysis of the antimicrobial compounds isolated from leaves of Moringa oleifera

Medicinal plants based on the indigenous knowledge represent a rich source of antimicrobial agents. They possess several compounds having antimicrobial properties for protection against aggressive pathogens. Moringa oleifera, known as “miracle tree” is a highly nutritious plant with great medicinal values. Various antimicrobial constituents present in extracts prepared in different solvents with different polarity (ethanol, hexane, dichloro methane, butanol, and methanol) were analyzed using gas chromatography-mass spectroscopy (GC-MS). Their antibacterial activity was evaluated against eight human pathogens. Maximum antimicrobial activity was observed in dichloro methane extract of M. oleifera leaf against 5 bacterial [E. coli, B. subtilis, S. aureus, P. vulgaris and P. aeruginosa) and 3 fungi (A. niger, T. rubrum and Fusarium sp) using agar well diffusion assay. Out of ninety six compounds were identified as gas chromatogram of the dichloro methane extract of M. oleifera two major and prominent compounds, were identified as n-hexadecanoic acid (28.35%) and cis-uaccenic acid (10.68%). Further, sixteen selected compounds were then analyzed through docking studies to evaluate their affinity to target bacterial proteins viz. penicillin binding protein 1a, enoyl-ACP reductase III (FabL) and Ampc beta-lactamase (hydrolase) with PDB ID 3UDI, 3OID, 1FSY respectively. Out of the 16, the three compounds viz. 4H-Pyran-4-one, 2, 3-dihydro-3, 5-dihydroxy-6-methyl (C6), 1, 2, 3-Cyclopentanetriol (C8) and 3-Chloro-N-isochroman-1-ylmethyl-propionamide (C15) showed the maximum interaction with the antimicrobial protein and highest docking score, -9.097 Kcal/mol, -7.263 Kcal/mol and-7.950 Kcal/mol, respectively. They were found to be the most potential antimicrobial compounds for treatment or prevention of pathogenic diseases.