Nwanekwu K.E.N, C.E. Obiukwu and C. Anumudu
Department of Microbiology, Faculty of Science, Imo state University, Owerri, Nigeria
The present study investigates antimicrobial activity of tobacco leaf and local snuff extracts from Nicotiana tabacum at different concentrations in methanol and water solvents. Four different concentrations (12.5, 25, 50, 100 and 200 mg/mL) of each extract were subjected for preliminary antimicrobial screening against Streptococcus pyogenes and Candida albicans using agar diffusion method. The result of in vitro antimicrobial screening showed that the extracts revealed different ranges of antimicrobial activities. Methanol extracted samples were more effective than the water extracted samples against the test organisms. Both methanol and water snuff extracts demonstrated antibacterial activity against S. pyogenes at concentrations of 200 and 100 mg/mL only with varying diameter zones of inhibition. Below 100 mg/mL, no activity was recorded. However against C. albicans, both snuffs extracts demonstrated antifungal activities from 200 to 25 mg/mL concentrations with varying diameters of inhibition. The MICs recorded for both snuff extracts against the test organisms ranged from 50 mg/mL to 200 mg/mL while that recorded for both extracts of tobacco leaves against the test organisms ranged from 25 to 200mg/mL, respectively. The MBC/MFC values recorded for both samples against the test organisms ranged from 100mg/mL to 200 mg/mL. In comparing both samples, tobacco leaves were more active than the snuff extracts.
Keywords: Antimicrobial activity, methanol, water, MIC, MBC/MFC, Zone of Inhibition..