Effect of Garlic on Streptococcus mutans Collagen Binding

Objectives: To evaluate the ability of garlic to inhibit Streptococcus mutans from binding to collagen in the presence of nicotine. The long-term goal of this research aims to assess the ability of garlic as a therapeutic agent in the treatment of atherosclerosis.
Methods: Garlic cloves were pressed through a garlic press into 47.5% ethanol to extract antimicrobial phytochemicals. The garlic was strained through a cheese cloth to remove large plant material. Trypticase Soy Broth (TSB) containing 1% sucrose (TSBS) was used to culture S. mutans with various concentrations of nicotine (0-32 mg/ml). Garlic was added at 720, 360, 180, 90, 45, 22.5, 11.2, and 5.6 mg/ml. 190 μL of nicotine/garlic/TSBS and 10 μL of a 24 h bacterial culture was added and incubated for 24 h. Collagen was added to every well, followed by primary rabbit anti-collagen antibody and secondary alkaline phosphatase labeled anti-rabbit IgG antibody. Binding of collagen to the S. mutans biofilm cells was measured using a spectrophotometer.


Results: S. mutans treated with garlic alone without nicotine failed to bind collagen at 720, 360, 180, and 90 mg/mL of garlic compared to the 0 garlic control (p<0.05). Collagen binding to S. mutans in the presence of 45 mg/mL garlic and varying levels of nicotine was significantly reduced (p<0.05) in the 16 mg/mL and 32 mg/mL of nicotine groups.

Conclusions: In conclusion, the results of this study identified garlic as a potential therapeutic agent in preventing atherosclerosis by preventing S. mutans from binding to collagen even in the presence of nicotine.