Phytochemical Profiling and Antimicrobial Efficacy of Withania somnifera and Allium vineale against Escherichia coli and Staphylococcus aureus

Abstract

The emergence of antimicrobial resistance necessitates the exploration of plant-derived alternatives with therapeutic potential. This study evaluates the antimicrobial efficacy and phytochemical composition of Withania somnifera (Ashwagandha) and Allium vineale (Wild Onion), two ethnomedicinal plants traditionally used for infectious disease management. Methanolic extracts of both plants were tested against Escherichia coli and Staphylococcus aureus using disc diffusion and minimum inhibitory concentration (MIC) assays. Phytochemical profiling was conducted via standardized qualitative methods to identify bioactive constituents.

Ashwagandha exhibited broad-spectrum activity, with inhibition zones of 9.52 ± 0.04 mm (E. coli) and 10.84 ± 0.04 mm (S. aureus) at 1g/ml, while Wild Onion showed preferential potency against S. aureus (MIC: 0.25g/ml vs. 0.5g/ml for E. coli). Phytochemical analysis revealed high concentrations of tannins, flavonoids, and alkaloids in Ashwagandha, correlating with its robust antimicrobial effects. Wild Onion, rich in sulfur compounds and flavonoids, demonstrated targeted efficacy against Gram-positive pathogens, likely due to membrane-disruptive mechanisms. Sterile water controls (5.0 mm inhibition) confirmed solvent neutrality, and positive controls (Erythromycin: 24.16 mm; Gentamicin: 25.34 mm) validated assay reliability.

These findings underscore the potential of Ashwagandha and Wild Onion as sustainable alternatives to synthetic antibiotics, particularly in combating multidrug-resistant S. aureus. The study bridges traditional knowledge and modern pharmacology by linking phytochemical diversity to antimicrobial function. Future research should focus on isolating active compounds, optimizing extraction protocols, and evaluating in vivo efficacy to advance plant-based therapeutics in clinical settings.