Antibacterial activity of flavonoids of Withania somnifera L.

Geeta Singh, Padma Kumar


Context: Flavonoids from different parts (leaf, stem, root and fruits) of Withania somnifera have been screened for antibacterial activity against Enterobacter aerogens, Bacillus subtilis, Klebsiella pneumoniae, Raoultella planticola and Agrobacterium tumefaciens. Materials and Methods: Disc diffusion assay (DDA) was performed for antimicrobial screening. Minimum inhibitory concentration (MIC), minimum bactericidal (MBC) and total activity (TA) of extracts found sensitive against test pathogens have also been evaluated. Results and Conclusions: Most susceptible microorganisms in the present study were R. planticola and A. tumefaciens,
which had shown susceptibility for almost all the extracts tested. Thereafter sensitive was shown by K. pneumoniae, B. subtilis,
E. aerogens. However, highest inhibition zone was observed for E. aerogens (IZ 25.5 mm; AI 1.159 ± 0.023) followed by R. planticola (IZ 22 mm; AI 0.733 ± 0.133). Antimicrobial activity of flavonoids extracts of W. somnifera were carried out to validate the use of traditional medicinal herb and the results of this study tend to give credence to the common use of W. sominfera plant. The study provide platform for further studies in plant, so as to pinpoint specific alkaloids and/or flavonoids responsible for antimicrobial activity and might open new vistas in the therapeutic use of the plant in allopathy medicine too.
Key words: Antibacterial activity, flavonoids, minimum bactericidal, minimum inhibitory concentration, W. somnifera

Full Text:



Thomson WA (ed.). Medicines from the Earth. Maidenhead:

McGraw‑Hill Book Co; 1978.

Stockwell C. Nature’s pharmacy. London: Century Hutchinson

Ltd; 1988.

Olowosulu AK, Ibrahim YK. Studies on the antimicrobial screening

of aqueousextracts of five plants used in Folk medicine in Nigeria.

West Afr J Boil Sci 2006;3:21‑6.

Ibekwe VI, Ubochi KC, Anyanwu BN. Prevalence of penicillia

resistance in organisms that cause sexually transmitted diseases

in port Harcourt, Nigeria. Int J Environ Health Res 2000;10:251‑5.

Chopra RN, Chopra IC, Honda KL, Kapur LD. In: Indigenous

Drugs of India. Vol. 12. Calcutta: U. M. Dhu and Sons Pvt. Ltd;

p. 436.

Anbalagan K, Sadique J. Influence of an Indian medicine

(Ashwagandha) on acute‑phase reactants in inflammation. Indian

J Exp Biol 1981;19:245‑9.

Dadkar VN, Ranadive NU, Dhar HL. Evaluation of antistress

(adaptogen) activity of Withania somnifera (Ashwagandha). Ind J

Clin Bio Chem. 1987;2:101‑8.

Archana R, Namasivayan A. Antistressor effect of Withania

somnifera. J Ethnopharmacol 1999;64:91‑3.

Dhuley JN. Effect of ashwagandha on lipid peroxidation in

stress‑induced animals. J Ethnopharmacol 1998;60:173‑8.

Singh N, Nath R, Lata A. Withania somnifera (ashwagandha),

a rejuvenating herbal drug which enhances survival during

stress (an adaptogen). Int J Crude Drug Res 1982;20:29‑35.

Singh N, Singh SP, Nath R. Prevention of urethane‑induced lung

adenomas by Withania somnifera (L.) Dunal in albino mice. Int J

Crude Drug Res 1986;24:90‑100.

Devi PU, Sharada AC, Solomon FE, Kamath MS. In vivo growth

inhibitory effect of Withania somnifera (Ashwagandha) on a

transplantable mouse tumor, Sarcoma 180. Indian J Exp Biol


Devi PU. Withania somnifera Dunal (ashwagandha): Potential

plant source of a promising drug for cancer chemotherapy and

radiosensitization. Indian J Exp Biol 1996;34:927‑32.

Subramanian SS, Nagarjan S. Flavonoids of the seeds of

Crotolariaretusa and Crotolariastriata. Current Sci 1969;38:65.

Gould JC. The determination of bacterial of sensitivity of

antibiotics. Edinb Med J 1952;59:178‑99.

Andrews JM. BSAC Working Party On Susceptibility Testing

ft. BSAC standardized disc susceptibility testing method.

J Antimicrob Chemother 2001;4:43‑57.

Barsi DF, Fan SH. The potential of aqueous and acetone extracts

of galls of Quercus infectoria as antibacterial agents. Indian J

Pharmacol 2005;37:26‑9.

Eloff JN. Quantifying the bioactivity of the plant extracts during

screening and bioassay guided fractionation. Phytomedicine


Rajendra NK, Ramakrishan J. In vitro evaluation of antimicrobial

activity of crude extracts of medicinal plants against multi

drug resistant pathogens. Biyoloji Bilimleri Araptyrma Dergisi


Mirjalili MH, Moyano E, Bonfill M, Cusido RM, Palazon J.

Steroidal lactones from Withania somnifera an ancient plant for

novel medicine. Molecules 2009;14:2373‑93.

Arora S, Dhillon S, Rani G, Nagpal A. The in vitro antibacterial

synergistic activities of Withania somnifera extracts. Fitoterapia


Kambizi L, Afolayan AJ. Extracts from Aloe ferox and Withania

somnifera inhibit Candida albicans and Neisseria gonorrhea. Afr J

Biotechnol 2008;7:12‑5.

Mahesh B, Satish, S. Antimicrobial activity of some important

medicinal plant against plant and human pathogens. World J

Agric Sci 2008;4:839‑43.



  • There are currently no refbacks.