Antibacterial and Biofilm Inhibition Activities of Nicotiana tabacum Extracts against Streptococcus mutans Isolated from the Oral Cavity

Aim: To determine the antibacterial activity and biofilm inhibitory activity of Nicotiana tabacum leaf extract against Streptococcus mutans isolated from oral cavity. Place and Duration of Study: Department of Microbiology, Faculty of Science, Imo State University, Owerri, Nigeria, between April and November 2019. Methodology: The study was carried out using the agar diffusion method for antibacterial activity and microtiter assay method for the biofilm inhibition effect. Results: All four extracts of hot water, ethanol, acetone and methanol tested against S. mutans had no antibacterial activity as no zone of inhibition was recorded. Likewise, all the extracts did not inhibit the formation of biofilm by the organism on glass. This is seen in the increase of the optical density (OD) values from 0.572 to 0.804 for water, 0.260 to 1.420 for ethanol, 0.216 to 0.626 for acetone and 0.236 to 0.725 for methanol extracts respectively. Conclusion: This study therefore indicates that N. tabacum does not have antibacterial and biofilm inhibitory against S. mutans. This also explains why a lot of tobacco users still suffer from dental caries and other oral infections caused by S. mutans.