Effects of Medicinal Plant Extracts on Volatile Sulphur Compounds Production

Objectives: The aim of this study was to evaluate the effects of Melaleuca alternifolia and Malva sylvestris extracts on the growth and VSC production of oral bacteria, comparing to chlorhexidine. Methods: Porphyromonas gingivalis and Porphyromonas endodontalis cultures were incubated for 48 hours to determine the Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) of M. alternifolia and M. sylvestris extracts. In addition, the gas chromatography (Oral Chroma®) was carried out to analyze the VSC production after 16 h of bacterial exposure to sub-MIC concentrations of the extracts. Gas samples were collected from the tubes and were taken into the Oral Chroma® to measure the VSC concentrations: hydrogen sulfide – H2S, methyl mercaptan – CH3SH and dimethyl sulfide – (CH3)2S. Results: MIC and MBC values were found: Melaleuca – P. gingivalis (MIC and MBC = 0,007%), Melaleuca – P. endodontalis (MIC = 0,007% and MBC = 0,05%); Clorexidina – P. gingivalis and P. endodontalis (MIC and MBC = 1,5µg/mL); Malva = no antimicrobial activity. Regarding to the VSC production, Malva promoted a significant reduction in the concentration of H2S in both bacterial cultures (p<0,05, ANOVA- Dunnet), while the Melaleuca reduced the production of H2S by P. gingivalis (p<0,05) and H2S/CH3SH by P. endodontalis (p<0,05). The extracts and chlorhexidine showed similar effects on VSC levels. Conclusion: In conclusion, M. alternifolia and M. sylvestris were able to reduce VSC extracts, while only M. alternifolia presented antimicrobial activity against the species studied. Financial support (FAPESP 09/14736-3 and 09/06037-8).