Antimicrobial activity of Cymbopogon citratus (Poaceae) on Streptococcus mutans biofilm and its cytotoxic effects

Abstract

Antimicrobial activity of Cymbopogon citratus (Poaceae) on Streptococcus mutans biofilm and its cytotoxic effectsDental caries is a pathology of multifactorial origin and currently natural products are an efficientalternative treatment. The work sought to evaluate the antimicrobial activity of the three substances(Cymbopogon citratus essential oil and the citral and myrcene components) against Streptococcus mutans ATCCUA159, as well as their cytotoxicity on keratinocytes and human fibroblasts. Through Scanning electron microscopy,the typical morphology of S. mutans was observed and, a characteristic formation of polysaccharides, withmore structured arrangement at 48 h. The bacterial viability effect against S. mutans on biofilms was evaluatedthrough exposure to the three substances by using the MBEC technique-high-throughput at concentrations of 1,0.1, and 0.01 μg/mL and chlorhexidine as positive control. The cytotoxicity of the compounds was evaluated onkeratinocytes and fibroblasts through the MTT reduction technique, using 0.5 mM H2O2 as cell-death control(negative control) and ethanol 1 % as vehicle control (positive control). The three substances evaluated hadeffects on the bacterial viability of S. mutans with mortality between 74 and 96 %, without significant differenceamong them (P > 0.393); additionally, no cytotoxicity was evident on keratinocytes and fibroblasts in a 24h treatment. The substances evaluated showed significant antimicrobial effects; hence, these should be studiedfurther as potential co-adjuvants to prevent dental caries that cause minor adverse effects.