Abstract

EVALUATION OF ANTIBACTERIAL ACTIVITY, ANTIOXIDANT POTENTIAL AND PHYTOCHEMICALS OF WITHANIA SOMNIFERA (ASHWAGANDHA)

Sukhvir Kaur*, Harjot Pal Kaur and Surbhi Aggarwal

ABSTRACT

This study evaluates the antibacterial activities, antioxidant potential and phytochemical constituents of Withania somnifera. Antibacterial activity of different parts of W. somnifera viz., stem, leaves, roots and fruits was checked against four bacteria (Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa) using aqueous, methanolic and ethanolic solvent extracts by disc diffusion assay. Results indicate that these extracts of W. somnifera showed good antibacterial activity, though the alcoholic extracts revealed better activity. Methanol and ethanol extract of leaves showed highest antibacterial activity against S. aureus (23.6 and 22.4 mm respectively) while aqueous extract had shown moderate antibacterial activity (20.5 mm). Minimum inhibitory concentration (MIC) of extracts against each sensitive test pathogens was also determined and excellent antibacterial activities were observed by aqueous and alcoholic extracts of leaves against S. aureus because of low MIC values. Methanol leaf extract showed higher antioxidant activity than those of aqueous and ethanol extracts of fruits, stem and root. Phytochemical screening of plant extracts revealed the presence of various types of bioactive components such as alkaloids, tannins, saponins, flavinoids, glycosides, carbohydrates, terpenoids, phenolic compounds, proteins and amino acids, which might be responsible for exhibiting antibacterial activity. It concludes that the ethanol and methanol extracts of W. somnifera hold an excellent potential as an antibacterial agent and ascertains the value of medicinal plants used in ayurveda which could be of considerable interest to the development of new drug.

Keywords: Withania somnifera, Antibacterial, Minimum Inhibitory Concentration, Phytochemical, Antioxidant.