Abstract
Fluoride is present in almost all oral hygiene products with an average concentration range of 250 to 1000 ppm. Fluoride anions have unique biochemical properties and can inhibit a wide variety of metabolic processes. Here we report fluoride toxicity in Enterococcus faecalis which is commonly found in oral infections in humans. We grew E. faecalis in Luria Bertani medium at different concentrations of NaF (0, 250, 500, 750, and 1000 ppm). The results showed that E. faecalis growth was slightly decreased with increases in the concentration of NaF. The total protein level in the treated bacterial cells was slightly changed with 250, 500, and 750 ppm of NaF while with 1000 ppm of NaF there was a significant decrease (p<0.05). The glutathione Stransferase (GST) level showed some decrease with 250, 500, and 750 ppm and was significantly decreased (p<0.05) with 1000 ppm of NaF. The glutathione (GSH) level fluctuated with increasing concentrations of NaF and was significantly decreased (p<0.05) with 250 and 1000 ppm of NaF. Our observations suggest that fluoride can control the growth of pathogenic bacteria in the mouth and can induce oxidative stress in bacterial cells via GSH metabolism.