Growth Curve Analysis and the Influence of the Chemopreventive Agent Curcumin on the Bacteria Prevotella Melaninogenica and Capnocytophaga Gingivalis from the Oral Cavity
Drake, Daniel R.
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Metabolites of Helicobacter pylori, Salmonella typhi and Neisseria spp. have been implicated in gastric, gall bladder, and colon cancer through specific metabolic interactions. Preliminary results from a recent study showed that Capnocytophaga gingivalis and Prevotella melaninogenica were associated with oral cancer lesions, acting as diagnostic indicators for Oral Squamous Cell Carcinoma (OSCC). The aim of this project was to elucidate the growth curve for P. melaninogenica and C. gingivalis for reference in future studies analyzing their characteristic metabolisms. C. gingivalis cultures were inoculated into an enriched liquid broth supplemented with L-cystein and glucose and the absorbence was taken of the concentration over a time of 72 hours. P. melaninogenica was inoculated into trytpic-soy broth supplemented with vitamin-K and the absorbence was measured over 48 hours. The exponential phase for P. melaninogenica and C. gingivalis was achieved approximately 6 and 12 hours, respectively, following inoculation. In order elucidate the effects of anti-cancer treatment on the two bacteria, curcumin, a polyphenol with antimicrobial properties, was tested against the bacteria to find the Minimum Bactericidal Concentration (MBC). Curcumin was dissolved in dimethylsulfoxide and inoculated into enriched agar media for testing against the bacteria. Separate cultures of P. melaninogenica and C. gingivalis were plated on agar containing the curcumin dilution standards. In vitro, P. melaninogenica remained resistant to all concentrations of curcumin tested. Curcumin effectively . inhibited C. gingivalis at a MBC of 64µg/ml. Oral species may play a major role in the development of oral cancer, specifically OSCC, by metabolizing certain carcinogens and these studies may shed light on the uses of chemopreventative agents.