Antibacterial, Antioxidant Activities and GC-MS Analysis of Methanol Extracts of Andrographis paniculata, Indigofera tinctoria, Moringa oleifera, and Justicia adhatoda: An In-vitro Study

Introduction: Medicinal plants possess different groups of phytocompounds such as flavonoids, alkaloids, phenols, and tannins and saponins and offer protection against various infectious diseases. It has been proved that medicinal plants have antimicrobial, antispasmodic, emetic, and anticancer properties. The conventional synthetic drugs often lead to undesirable side effects and contribute to resistance, highlighting the need for alternative therapeutic agents. Medicinal plants have traditionally been used as effective remedies for a wide range of ailments in traditional medicine systems. Aim: To evaluate the antioxidant and antibacterial properties of Andrographis paniculata, Indigofera tinctoria, Moringa oliefera, and Justicia adhatoda methanol extracts, in in-vitro. Materials and Methods: The present in-vitro study was conducted at the Department of Microbiology, Dr ALM PGIBMS, University of Madras (January-December 2017). Methanol extracts of powdered A paniculata, I tinctoria, M oleifera, and J adhatoda were prepared via 48-hour maceration with methanol, followed by Seitz filtration and lyophilisation. Antibacterial activity was evaluated using the agar-well diffusion method against six gram-negative and two gram-positive bacterial pathogens. Antioxidant potential was assessed using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. Major phytochemical constituents were identified through Gas ChromatographyMass Spectrometry (GC-MS) analysis. Data were analysed using Excel and two-way Analysis of Variance (ANOVA); graphs were made in GraphPad Prism 5. and p<0.05 was considered significant. Results: A. paniculata showed higher zone of inhibition against Shigella, S. aureus and Enterococcus. I. tinctoria showed higher zone of inhibition against P. aeruginosa. S. aureus and Shigella. and showed moderate inhibition against K. pneumoniae. M. oleifera had higher zone of inhibition against P. aeruginosa and moderate activity against Enterococcus and P. vulgaris. J. adhatoda had moderate inhibition against Enterococcus and K. pneumoniae. A. paniculata and I. tinctoria had shown the highest antioxidant activity. The 1-Hexene, 1-butoxy-2-ethyl, cyclopentaneundecanoic acid methyl ester, 17 Alpha-ethyl-6beta-methooxy-3alpha, 5cyclo5alpha androstane-17 beta diol and Methyl Z-tetradecnoate were the major phytochemicals identified in A. paniculata, I. tinctoria, M. oleifera and J. adhatoda, respectively. Conclusion: Combinations of these four extracts might have broad-spectrum antibacterial properties. The extracts of A. paniculata, I. tinctoria, and J. adhatoda have significant antioxidant properties. Using these medicinal plants could support recovery from bacterial infections and oxidative stress of chronic diseases, along with additional healthcare benefits