The Effects of Robusta Coffee Bean (Coffee canephora) Polyphenols Extract on Growth and Morphological Alteration Streptococcus mutans

Abstract

Background. Coffee polyphenols are antibacterial because they can inhibit growth and damage the cell wall. S mutans is a bacterium that plays a role in the caries process. Purpose. This study aimed to analyze the effect of polyphenols extract of robusta coffee beans on the growth and morphological changes of S mutans bacteria. Method. This research was conducted with two stages of observation. The first step is to observe the growth of S. mutans in treatment with polyphenolic extract of robusta coffee beans using the minimum inhibitory concentration (MIC) growth test and minimum bactericidal concentration (MBC). The second stage is to observe the morphology of S. mutans bacteria by analyzing changes in the shape and size of the cell membrane of S. mutans using Scanning Electron Microscope (SEM). Data were observed by a non-parametric test. Result. The results showed that in the MIC test, 0.2 ml concentration of robusta coffee polyphenol extract significantly (p <0.05) caused inhibition of growth of S. mutans while in the MBC test at the same concentration detected S. mutans existence. This indicates that the coffee bean polyphenol extract is not bactericidal. Analysis of SEM showed 12.5% concentration of polyphenol extract resulted in larger cell size and cell morphology changes with blebs on the cell wall and ghost cell formation. Conclusion. It was concluded that polyphenolic extract of robusta coffee beans caused inhibition of bacterial growth of S. mutans by influencing morphological changes of the bacterial cell wall. However, the extract did not show bactericidal properties at the same concentration.