Antibacterial effects of green tea extracts on Aggregatibacter actinomycetemcomitans (In-Vitro study)

Abstract

Background: Green Tea is made from the leaf of the plant “Camellia sinensis”. Green tea is reported to containthousands of bioactive ingredients including catechins which have shown great promise for having antimicrobialeffects. Periodontal diseases represent one of the most prevalent diseases around the world and the main etiologicfactor behind it, is plaque accumulation, in addition certain kinds of bacteria have been detected frequently insubjects suffering from periodontitis, Several studies suggested that the outcome of periodontal treatment is better ifparticular pathogens including Aggregatibacteractinomycetemcomitans can no longer be detected after therapy.Materials and Methods: plaque samples were collected from 20 patients suffering from chronic periodontitis withprobing pocket depth of at least 6 mm, Aggregatibacteractinomycetemcomitans (A.A) was isolated anddiagnosed according to morphological characteristics and biochemical tests. Green tea leaves were extracted byusing water and alcohol. The first experiment involved testing the sensitivity of A.A to different concentrations of theextracts using agar well diffusion method,the second experiment involved determination of the minimum inhibitoryconcentration and then determination of the minimum bactericidal concentration of the extract against thebacteria, laboratory analysis of green tea extracts using high pressure liquid chromatography (HPLC) wasperformed.Results: Both green tea extracts were effective in inhibition of Aggregatibacteractinomycetemcomitans using agarwell diffusion method, 90% and 100% concentrations of alcoholic extract showed larger inhibition zones thanchlorhexidinegluconate 0.2% with statistically significant difference, CHX showed higher inhibition zones than allaqueous extract concentrations.The MIC (minimum inhibitory concentration) of alcoholic green tea extract thatinhibit Aggregatibacteractinomycetemcomitans growth was 60%, The MIC of aqueous green tea extract thatinhibits Aggregatibacteractinomycetemcomitans growth was 70%.The MBC (minimum bactericidal concentration)of alcoholic green tea extract that killsAggregatibacteractinomycetemcomitans was 80%, the MBC of aqueousgreen tea extract that kills Aggregatibacteractinomycetemcomitans growth was 90%.HPLC analysis of aqueous and alcoholic green tea extracts revealed that alcoholic extract contained higherconcentration of EGCG while aqueous extract had higher content of catechin and epicatechin.Conclusion: Green tea extracts were effective against Aggregatibacteractinomycetemcomitans, alcoholic greentea extract showed inhibition ability more than the aqueous green tea extract and more than CHX and it showedbactericidal activity at 80%,90% and 100% concentrations