Antibacterial, Antibiofilm, Anti-adherence Activity, and Cytotoxicity Assay of Different Green Tea (Camellia sinensis) Extract Concentrations on Dental Pathogens: Aggregatibacter Actinomycetemcomitans and Streptococcus Mutans: An In Vitro study

This in vitro study aimed to assess the antibacterial, cytotoxicity, and anti-adherence properties of Camellia sinensis extracts (Green tea extract) against two dental pathogens associated with periodontal disease and dental caries, Aggregatibacter actinomycetemcomitans and Streptococcus mutans, respectively.

The minimal inhibitory concentration and anti-biofilm (anti-adherence) activity of different concentrations of green tea were determined using standard microbiological methods. The standard well diffusion was used to test for antibacterial activity. The biocompatible property of the selected concentrations on L₉₂₉ fibroblast cells was tested using the MTT assay method.

Among the different test concentrations of green tea, the growth of both test organisms was significantly inhibited at 500 µg/ml. Anti-biofilm concentrations of green tea extracts against both test organisms were found to be 300µg/ml. Antibacterial activity of selected concentrations showed significant inhibitory zones against Aggregatibacter actinomycetemcomitans and Streptococcus mutans when compared to standard antibiotics. During the MTT assay, no cytotoxicity was observed at any of the three test concentrations of green tea extracts. The concentration of 10µg/ml showed a maximum cell viability of 94.6 ± 0.57%, which was closest to control cell numbers. The test concentrations also had an antiadhesion effect on the tested bacteria.

The study shows the positive antimicrobial activity of Green Tea (GT) extracts against Streptococcus mutans and Aggregatibacter actinomycetemcomitans, which correlates with earlier studies. Furthermore, it shows that GT extract has antiadhesion potential and further has no cytotoxic effects on normal fibroblast cells, indicating GT's potential for oral health applications.

The results show that green tea has a positive deterrent effect on biofilm formation and can be used as an additive in herbal formulations; however, further research is necessary.