Phytomedicine 12 (2005) 229–235 Antibacterial efficacy of Withania somnifera (ashwagandha) an indigenous medicinal plant against experimental murine salmonellosis M. Owais à , K.S. Sharad, A. Shehbaz, M. Saleemuddin Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India Received 13 March 2003; accepted 8 July 2003 Abstract In the present study, we evaluated the antibacterial activity of ashwagandha [Withania somnifera L. Dunal (Solanaceae; root and leaves)], an Indian traditional medicinal plant against pathogenic bacteria. Both aqueous as well as alcoholic extracts of the plant (root as well as leaves) were found to possess strong antibacterial activity against a range of bacteria, as revealed by in vitro Agar Well Diffusion Method. The methanolic extract was further sub- fractionated using various solvents and the butanolic sub-fraction was found to possess maximum inhibitory activity against a spectrum of bacteria including Salmonella typhimurium. Moreover, in contrast to the synthetic antibiotic (viz. chloramphenicol), these extracts did not induce lysis on incubation with human erythrocytes, advocating their safety to the living cells. Finally, the antibacterial efficacy of the extracts isolated from plant (both root and leaves) was determined against experimental salmonellosis in Balb/C mice. Oral administration of the aqueous extracts successfully obliterated salmonella infection in Balb/C mice as revealed by increased survival rate as well as less bacterial load in various vital organs of the treated animals. r 2004 Published by Elsevier GmbH. Keywords: Withania somnifera (ashwagandha); Antibacterial activity; Salmonella typhimurium Introduction Ashwagandha [Withania somnifera L. Dunal (Sola- naceae)] is an important medicinal plant, widely used as a home remedy for several diseases in India as well as other parts of the world (Patwardhan et al., 1998; Sharma and Dandiya, 1991). It is described as an herbal tonic and health food in Vedas and considered as ‘Indian Ginseng’ in traditional Indian system of medicine. In fact, it is mentioned as an official drug in the Indian Pharmacopoeia as well (Indian Pharmaco- poeia, 1985). Beside its use as general tonic (Agarwal et al., 1999; Dhuley, 2000; Ziauddin et al., 1996), several recent reports have demonstrated immunomodulator and antitumor effect of ashwagandha as well (Agarwal et al., 1999; Devi, 1999; Sharad et al., 1996; Budhiraja and Sudhir, 1987; Ziauddin et al., 1996). Moreover, various parts of the plant have been reported to possess antiserotogenic, anticancer and anabolic properties and has beneficial effects in the treatment of arthritis, stress and geriatric problems (Asthana and Raina, 1989; Grandhi et al., 1994; Davis and Kuttan, 2000; Singh et al., 2001; Prakash et al., 2001). Recently, the plant was demonstrated to possess strong antifungal activity and was found effective ARTICLE IN PRESS www.elsevier.de/phymed 0944-7113/$-see front matter r 2004 Published by Elsevier GmbH. doi:10.1016/j.phymed.2003.07.012 Abbreviations: PBS, Phosphate Buffer Saline; MIC, Minimum Inhibition concentration; CFU, colony forming units; NS, Normal Saline; NB, Nutrient Broth; NA, Nutrient Agar. à Corresponding author. Tel.: +91-0571-2701718; fax: +91-0571- 2701081. E-mail address: owais_lakhnawi@yahoomail.com (M. Owais).