The Effect of Licorice Extract on Clinically Isolated Aggregatibacter actinomycetemcomitans and Porphyromonas...

Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (P. gingivalis) are key pathogens in periodontitis. Considering the antibacterial properties of licorice, this study investigated the prevalence of Aa and P. gingivalis in patients with chronic periodontitis using PCR and evaluated the antimicrobial effects of licorice root extract.

Subgingival samples were obtained from 50 patients with chronic periodontitis at the Faculty of Dentistry, Tabriz University of Medical Sciences. DNA was extracted, and specific primers were used for PCR detection. All positive isolates (n=24) were cultured, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of licorice extract (Barij Esans Co., Iran) were determined in triplicate using the microbroth dilution method. Statistical analyses were performed using one-way ANOVA and chi-square tests with SPSS 24.

Aa and P. gingivalis were detected in 48% of samples (Aa: 18%, P. gingivalis: 26%, both: 4%). The MIC and MBC values of licorice extract were 7.81 ± 0.42 mg/mL and 20.53 ± 0.61 mg/mL for Aa, and 4.69 ± 0.37 mg/mL and 10.94 ± 0.54 mg/mL for P. gingivalis, respectively. Statistical analysis confirmed significant differences in bacterial prevalence between localized and generalized periodontitis (p < 0.05).

Due to the potential toxicity of licorice, such as hypertension and hypokalemia, careful dose standardization and toxicity evaluation must be performed before clinical use.

Licorice extract demonstrated promising in vitro antibacterial activity against Aa and P. gingivalis. These findings suggest that licorice may serve as a potential adjunctive agent in the management of chronic periodontitis. However, further in vivo and clinical studies are required before clinical application.