Effects of long chain fatty acids oleic and linoleic, on the growth of the cariogenic bacterium streptococcus mutans

Abstract

Objective- This study evaluated the efficacy of long-chain fatty acids, Oleic (C18:1) and Linoleic (C18:2) acid on the growth of Streptococcus mutans. S. mutans is one of the primary etiological agents associated with the onset of dental caries which is considered to be an oral health epidemic in industrialized countries. Assays were carried out to assess the viability of the oral pathogen in the presence of these long chain fatty acids (FAs). Design- The FA’s were prepared in 2% ethanol (EtOH) to ensure bacterial viability was not affected by the solvent. Concentrations of 0.1mM ranging up to 50mM were prepared for analysis. S. mutans was cultured at 37°C for 18 h in Brain Heart Infusion Broth (BHI) and assays were performed in sterile 96 well plates over a period of 24 h. Growth inhibition was recorded using optical density (OD) readings, from which they were evaluated and tabulated. Results- Linoleic acid showed significantly higher antimicrobial activity in contrast to Oleic acid. Linoleic displayed up to 97% inhibition of S. mutans growth during early stationary phase, whereas the highest inhibition by oleic acid at this point was 38%. Conclusions- Linoleic acid exhibited a higher level of antibacterial activity towards the cariogenic bacterium than its monounsaturated counterpart oleic acid. It is questionable whether the presence of a second double bond enhances the antimicrobial activity of linoleic acid. Antimicrobial FA’s such as these have worthy potential for applications within the oral healthcare industry in the reduction and prevention of carious lesions.