IADR Abstract Archives
Effects of Black Cumin Seed Oil on Streptococcus mutans Biofilm
Objectives: Methyl mercaptan (CH3SH) produced by oral bacteria is one of the principal components of oral malodor. We have presented deodorizing effects on CH3SH and antibacterial activities of essential oil from black cumin seed (Nigella sativa L.: BCS) in IADR 2016. However, the effects of BCS oil on oral bacteria contained within biofilms located on the tooth surfaces or tongue dorsum were unclear. In this study, we examined antibacterial effect of BCS oil on Streptococcus mutans contained within single-species biofilms.
Methods: S. mutans UA159 was cultivated in tryptic soy broth supplemented with 0.25% (w/v) sucrose in 96 well microtiter plate for 16 hours to form biofilms. After incubation, bacterial suspensions were removed and the biofilms were washed with PBS. The biofilms were then incubated with BCS oil, its active components (thymoquinone and thymohydroquinone etc.), or antibacterial agent (cetylpyridinium chloride: CPC) at room temperature. Following incubation, the biofilms were washed, stained ( Live/Dead staining kit), and observed by confocal laser microscope.
Results: Incubation of 0.1% BCS oil or 0.1% thymoquinone for 30 min significantly induced membrane-damage and increased the number of dead cells within the biofilms. The degree of cell surface damage was lower in biofilms treated with BCS oil or thymoquinone compared with that in CPC-treated biofilms. However, CPC did not completely kill bacteria in biofilms. Lower concentrations of BCS oil and thymoquinone had no significant effect on membrane integrity or cell death.
Conclusions: Both BCS oil and thymoquinone have antibacterial effects on S. mutans within a biofilms, and may therefore also have a deodorizing effect on CH3SH produced by malodorous microbes. BCS oil could be used in the future for the prevention of oral malodor.
Methods: S. mutans UA159 was cultivated in tryptic soy broth supplemented with 0.25% (w/v) sucrose in 96 well microtiter plate for 16 hours to form biofilms. After incubation, bacterial suspensions were removed and the biofilms were washed with PBS. The biofilms were then incubated with BCS oil, its active components (thymoquinone and thymohydroquinone etc.), or antibacterial agent (cetylpyridinium chloride: CPC) at room temperature. Following incubation, the biofilms were washed, stained ( Live/Dead staining kit), and observed by confocal laser microscope.
Results: Incubation of 0.1% BCS oil or 0.1% thymoquinone for 30 min significantly induced membrane-damage and increased the number of dead cells within the biofilms. The degree of cell surface damage was lower in biofilms treated with BCS oil or thymoquinone compared with that in CPC-treated biofilms. However, CPC did not completely kill bacteria in biofilms. Lower concentrations of BCS oil and thymoquinone had no significant effect on membrane integrity or cell death.
Conclusions: Both BCS oil and thymoquinone have antibacterial effects on S. mutans within a biofilms, and may therefore also have a deodorizing effect on CH3SH produced by malodorous microbes. BCS oil could be used in the future for the prevention of oral malodor.