Antibacterial Activity of Green Tea and Black Tea on Streptococcus mutans: An in Vitro Study

Abstract

Background: Camellia sinensis (green tea & black tea) has been shown to possess antimicrobial properties and also, its consumption is associated to lower incidences of various pathological conditions, including cardiovascular disease, strokes, obesity, diabetes, inflammatory conditions and aging process. However there is paucity of literature regarding its inhibitory effect on Streptococcus mutans. Materials and methods: An in-vitro experimental study was conducted using ethanolic extract of Green and Black tea. The extract of each was then diluted with an inert solvent, Dimethyl Formamide, to obtain 4 different concentrations (100mg/ml, 200mg/ml, 300mg/ml, and 400mg/ml) of each at 10,20,30,50 & 75 microlitres. 0.2% chlorhexidine mouthwash was used as a positive control and dimethyl formamide was used as negative control. The different extracts, along with controls, were then subjected to microbiological investigation. Results: Green and Black tea extracts presented the largest zone of inhibition 14.4 and 20.4mm respectively at the concentration of 400mg/ml. Conclusion: The comparison between Green tea and Black tea extracts with Chlorhexidine showed significant results while the mean zone of inhibition of Black tea extract was found to be highly significant than that for Green tea suggesting higher anti microbial activity of Black tea (p = 0.008) than Green tea (p = 0.017).