Hyptis pectinata essential oil: chemical composition and anti-Streptococcus mutans activity.

OBJECTIVES: The aim of the present study was to evaluate the anti-Streptococcus mutans activity of Hyptis pectinata essential oil, and present its promising potential against oral diseases. MATERIALS AND METHODS: The essential oil of H. pectinata was obtained by hydrodistillation from dried leaves and analyzed by GC / MS. The effectiveness of this essential oil regarding the antimicrobial activity against several S. mutans strains was investigated by the agar diffusion and microdilution methods, and chlorohexidine was used as a standard control. RESULTS: The H. pectinata essential oil exhibited considerable inhibitory effect against either all the clinical isolates obtained from patients' saliva or the ATCC strains tested, with minimum inhibitory and bactericidal concentrations of 200 microg ml(-1). The study also compared the efficiency of the emulsifying agents Tween 20, Tween 80, dimethyl sulfoxide and propylene glycol in H. pectinata essential oil when tested against S. mutans. The data obtained confirmed the better inhibitory effect of the oil when using all tested diluents, although Tween 80 seemed to be more suitable for emulsification. CONCLUSION: According to our results, H. pectinata essential oil can be considered a promising alternative to chlorhexidine for the control of oral bacteria-related diseases and hygiene.

Antimicrobial activity of Croton cajucara Benth linalool-rich essential oil on artificial biofilms and planktonic microorganisms.

We have previously demonstrated that a linalool-rich essential oil from Croton cajucara Benth presents leishmanicidal activity. In the present study, we demonstrate that this essential oil inhibits the growth of reference samples of Candida albicans, Lactobacillus casei, Staphylococcus aureus, Streptococcus sobrinus, Porphyromonas gingivalis and Streptococcus mutans cell suspensions, all of them associated with oral cavity disease. The purified linalool fraction was only inhibitory for C. albicans. Microbes of saliva specimens from human individuals with fixed orthodontic appliances, as well as the reference strains, were used to construct an artificial biofilm which was exposed to linalool or to the essential oil. As in microbial suspensions, the essential oil was toxic for all the microorganisms, while the purified linalool fraction mainly inhibited the growth of C. albicans. The compounds of the essential oil were separated by thin layer chromatography and exposed to the above-cited microorganisms. In this analysis, the proliferation of the bacterial cells was inhibited by still uncharacterized molecules, and linalool was confirmed as the antifungal component of the essential oil. The effects of linalool on the cell biology of C. albicans were evaluated by electron microscopy, which showed that linalool induced a reduction in cell size and abnormal germination. Neither the crude essential oil nor the purified linalool fraction is toxic to mammalian cells, which suggests that the essential oil or its purified components may be useful to control the microbial population in patients with fixed orthodontic appliances.