Antibacterial effect of oral care natural products against oral bacteria

Abstract

Several natural extracts are reported to be an effective antibacterial agent against cariogenic bacteria. These natural extracts can be used as an alternative to replace chlorhexidine mouthrinse. However, the antibacterial activity of the natural extracts in commercial products have never been demonstrated. This study aimed to investigate the antibacterial activity of commercially-available oral spray containing natural extracts; essential oil oral, essential oil with mangosteen extract, propolis extract and guava leaf extract. To determine the antibacterial activity, a direct contact of the oral spray and cariogenic bacteria, including S. mutans and L.casei, was performed in vitro. Chlorhexidine mouthrinse and phosphate buffer saline (PBS) were included as a positive and negative control, respectively. After a direct contact with antibacterial agent, or the oral spray, S. mutans and L.casei growth was observed in culture medium for up to 10 hr. The optical density measurement at 600 nm (OD600) and pH in cultures were recorded every 2 hr to demonstrate bacterial growth and acid production. The result showed that all oral sprays except guava leaf extract oral spray significantly inhibited growth and acid production of S. mutans and L. casei for 10 hr (p=0.001) when compared to PBS group analyzed in each time point by one-way ANOVA test. For guava leaf extract oral spray, the growth and acid production of L. casei were inhibited throughout the experiment, while the result showed partial growth and acid production inhibition when S. mutans exposed to this oral spray.