In vitro antibacterial effect of Withania somnifera root extract on Escherichia coli

AIM: The aim was to investigate antibacterial activity of Withania somnifera (Ashwagandha), an Indian traditional medicinal plant against Escherichia coli O78, a pathogenic strain. MATERIALS AND METHODS: Two-fold serial dilutions of 20% aqueous W. somnifera root (WSR) extract were inoculated with E. coli O78 @ 1*10(7) colony forming units grown in nutrient broth. Following inoculation, turbidity optical density was measured by spectrophotometer at 600 nm in all the tubes at 0, 2, 4, 6 and 8 h of incubation at 37°C. RESULT: The results revealed that the maximum inhibition of bacterial growth was observed at 1:8 dilution of WSR extract. The highest dilution of the extract that showed inhibited growth of the test organism when compared with control was 1:16. Therefore, the minimum inhibitory concentration of aqueous extract of WSR is 1:16. CONCLUSION: It is concluded that WSR possessed good antibacterial activity, confirming the great potential of bioactive compounds and its rationalizing use in health care.