Phytochemical Investigation and Antimicrobial Activity of Root Extracts of Withania Somnifera (L.) Dunal. against Drug-Resistant Bacterial Pathogens Umaarasu Thirunavukkarasu1,2, Padmavathy Kesavaram3,*, Thirunavukkarasu Dharmalingam4, Govindaraj Jayamathi5, Rajesh SV.6, Shanmugam Gnanendra7 1Reserach Scholar, Department of Microbiology, Research Laboratory for Oral & Systemic Health, Sree Balaji Dental College & Hospital, Bharath Institute of Higher Education & Research, Chennai, Tamil Nadu, India 2Professor, Department of Microbiology, Vivekanandha Dental College, Thiruchengode, Tamil Nadu, India 3Professor, Department of Microbiology, Research Laboratory for Oral & Systemic Health, Sree Balaji Dental College & Hospital, Bharath Institute of Higher Education & Research, Chennai, Tamil Nadu, India 4Assistant Professor, Department of Microbiology, Government Mohan Kumaramangalam Medical College, Salem, Tamil Nadu, India 5Assistant Professor, Department of Botany, Ramakrishna Mission Vivekanandha College, Mylapore, Chennai, Tamilnadu, India 6Professor, Department of Biochemistry, Sree Balaji Dental College & Hospital, Bharath Institute of Higher Education & Research, Chennai, Tamil Nadu, India 7Scientist, Department of Biotechnology, Yeungnam University, Gyeongsan, South Korea *Corresponding Author: Kesavaram Padmavathy, Department of Microbiology, Research Laboratory for Oral and Systemic Health, Sree Balaji Dental College and Hospital, Bharath Institute of Higher Education and Research, Chennai, Tamil Nadu, India, Email: padmabakianath@gmail.com
Online published on 4 April, 2020. Abstract With the emergence of multidrug resistance among clinical bacterial pathogens there is a growing need for the development of herbal alternatives for the effective therapeutic management of bacterial infections. Plants and plants products have long been used in traditional folk medicine worldwide. Hence this study was designed to test the antimicrobial efficacy of Withania somnifera L. Dunal. (root) against drug resistant bacterial pathogens. Extracts of W. somnifera (L.) Dunal (root) was prepared by cold percolation method. Antimicrobial activity of different solvent extracts of W. somnifera (L.) Dunal. (root) was studied against drug-resistant clinical isolates of Gram-positive cocci (vancomycin resistant Enterococcus faecalis and Methicillin resistant Staphylococcus aureus) and Gram-negative bacilli (ESBL Escherichia coli and Pseudomonas aeruginosa). The standard strains of ATCC 25922 E. coli, ATCC 25923 S. aureus, ATCC 27853 P. aeruginosa, and ATCC 29212 E. faecalis were used as controls. Antibacterial activities of extracts were evaluated using agar well diffusion method. Minimum inhibitory concentration was determined by microbroth dilution method. All the extracts (methanol, ethanol, acetone and chloroform) were inhibitory to gram positive bacteria tested. Nevertheless, inhibitory effect waspronounced in the methanol and ethanol extract, against gram negative bacteria (Both ATCC and clinical strains).Further based on the phytochemical and GC-MS analysis, it could be speculated that the antibacterial activity exhibited by the methanol extract of W. somnifera root could be attributed to the presence of phenolic compounds, flavonoids, steroids and terpenes. Top Keywords Antibacterial efficacy, ESBL, E. coli, Withania somnifera, MRSA, VRE, Pseudomonas aeruginosa. Top |