White Pepper Extract (Piper nigrum L.) as Antibacterial Agent for Streptococcus mutans In Vitro

Abstract

Streptococcus mutans is a gram-positive bacterium in oral cavity which metabolism produces acid as the common cause of dental caries (tooth decay). In order to prevent the growth or kill Streptococcus mutans, antibacterial agent is required. White pepper (Piper nigrum L.) is suspected to contain antibacterial substances such as alkaloid, phenol, tannin and coumarine. This research is conducted to prove the antibacterial effect of white pepper on growth activity of Streptococcus mutans in vitro. An experimental study using post test only control group design is carried out to Streptococcus mutans with tube dilution method and streaking on the Brain Heart agar plate. The treated groups are groups treated with white pepper extract with a range of concentration from 5%; 7,5%; 10%; 12,5%; 15%; 17,5%; and 20%. The control groups consist of bacteria control and white pepper extract control. Result of the research indicates that Minimum Inhibitory Concentration (MIC) is found at concentration 10% of the white pepper extract, where as the Minimum Bactericidal Concentration (MBC) is found at concentration 12,5% of the extract. Data analysis is conducted with non parametric test of Kruskal Wallis. Kruskal Wallis test shows at least there is a difference of the number of colonies as the given concentration (p < 0,05). The correlation test of Spearman reveals a very strong reciprocal correlation between concentration of white pepper extract and the number of Streptococcus mutans colonies growth (Correlation, r = -0,986; p < 0,05). The conclusion is white pepper extract has effect on the growth also as antibacterial agent for Streptococcus mutans in vitro, with MIC at concentration 10% and MBC at concentration 12,5%. The higher concentration of white pepper extract, the lower growth rate of Streptococcus mutans.