Antimicrobial and phytochemical profiling of nicotiana tabacum leaf extract: a potential source of bioactive compounds

Tobacco (Nicotiana tabacum) leaves are traditionally valued as therapeutic agents in various Asian countries, including Bangladesh, due to their diverse bioactivities, including antimicrobial, antifungal, anthelmintic, and anti-Alzheimer’s properties. The aim of this study was to evaluate the antimicrobial and phytochemical properties of Nicotiana tabacum leaf extracts. Alcoholic extracts were prepared using 95% ethanol, 95% methanol, and water in a 1:3 ratio for comparative analysis. Antimicrobial activity was assessed using the agar cup diffusion method against a range of bacterial and fungal strains, and phytochemical screening for alcoholic extracts was carried out following some standard methods. The methanol extract demonstrated significant antimicrobial activity, producing inhibition zones of 20.0 mm, 25.0 mm, and 32.0 mm against Streptococcus agalactiae at extract concentrations of 50 µL, 100 µL, and 150 µL, respectively. Additionally, it showed inhibition against Candida albicans, with inhibition zones of 15 mm, 25 mm, and 30 mm, alongside other Candida species. The water extract exhibited a high inhibition zone of 47.0 mm against Escherichia coli at 150 µL, along with substantial antifungal activity. Ethanol extracts demonstrated similar efficacy, with inhibition zones up to 39.0 mm against Escherichia coli and Candida species. The results highlight the potential of Nicotiana tabacum leaves as a source of bioactive compounds with antimicrobial properties, warranting further exploration for therapeutic applications.