Antibacterial activity of organic crude extract of Camellia sinensis on bi-species cariogenic biofilm.

Abstract

Objective: The study aimed to determine the antibacterial inhibitory activity and anti-biofilm effect of the ethanolic crude extract of Camellia sinensis leaves on bi-species oral bacterial biofilms.

Materials and methods: An ethanolic crude extract of Camellia sinensis leaves was used. Streptococcus mutans ATCC 25175 and Streptococcus gordonii ATCC 51656 were cultivated and used under anaerobic conditions for biofilm formation. Three groups were formed: Camellia sinensis extract, 0.12% chlorhexidine, and dimethyl sulfoxide. The inhibitory effect was determined by using the Kirby-Bauer Disk Diffusion Agar method, measuring the zone of inhibition formed around each of them. Additionally, the minimum inhibitory concentration was identified, considering the concentration where no growth of bacteria was observed. Immunofluorescence analysis was performed to evaluate cell viability in biofilms. Student's t-test for independent samples was used to compare groups.

Results: A zone of inhibition of 17.4±0.4 mm for S. mutans, and 13.1 ± 0.3 mm for S. gordonii was produced by Camellia sinensis, while chlorhexidine produced 23.6 ± 0.3 mm for S. mutans, and 13.2 ± 0.5 mm for S. gordonii. The minimum inhibitory concentration was 3.12 mg/dL for S. mutans and 1.56 mg/dL for S. gordonii. Analysis of cell viability after 48 hours of incubation showed that the Camellia sinensis extract reduced the viability of biofilm cells.

Conclusion: Despite the study's limitations, Camellia sinensis shows antibacterial activity against multispecies cariogenic biofilms, with sensitivity in the tested bacteria.