ABSTRACT
In an oral cavity, dental caries, periodontal disease, and endodontic lesions are caused by well-known bacterial and fungal pathogens. Essential oils (EOs) have demonstrated antimicrobial activity suggesting their use for oral hygiene. The goal of this study was to evaluate the interaction of bitter orange flower (Citrus aurantium L.) essential oil with cariogenic bacteria Streptococcus mutans and human gingival epithelial cells. After extraction, the chemical composition of the essential oil was analyzed by gas chromatography, and its antimicrobial activity was evaluated against the growth and the expression of virulent genes in S. mutans. Finally, the effects of this essential oil on human gingival epithelial cell adhesion and growth were assessed using cell adhesion and proliferation assays. We showed that the major constituents of the tested essential oil were limonene, linalool, and ß-ocimene. The essential oil reduced the growth of S. mutans, and decreased expression of comC, comD, comE, gtfB, gtfC, and gbpB genes. It should, however, be noted that essential oil at high concentration was toxic to gingival epithelial cells. Overall, this study suggests that C. aurantium L. essential oil could be used to prevent/control oral infections.
ABSTRACT
The rise in resistance and changes in the spectrum of Candida infections have generated enormous interest in developing new antifungal drugs using natural molecules such as plant essential oils (EOs). Antimicrobial activity against foodborne pathogenic and spoilage microorganisms has been reported for EOs. The goal of this study was to assess the effect of Mentha × piperita essential oil (EO) on C. albicans growth, transition (change from blastospore to hyphae forms), and biofilm formation as well as on the expression of certain virulent genes. We show that whole EO and its vapor attenuated the yeast's growth, compared to that in the control. The effect of the EO was comparable to that of amphotericin-B (AmB). The EO and its vapor significantly decreased the morphological changes of C. albicans, reduced biofilm formation, and disrupted mature C. albicans biofilms. The effect produced by whole EO on biofilm formation/disruption was notably comparable to that observed with AmB. Exposure of C. albicans to EO and its vapor downregulated the expression of various genes, such as secreted aspartyl proteinases (SAP 1, 2, 3, 9, 10) and hyphal wall protein 1 (HWP1). Altogether, these results provide new insight into the efficacy of Mentha × piperita EO against C. albicans and suggest the potential of Mentha × piperita EO for use as an antifungal therapy in multiple applications.
