A Preliminary Evaluation of the Antibacterial Activity of Lemon Fruit Juice, Mondia whitei Ethanolic Extract, and Their Combination Against Streptococcus mutans.

Background: Dental caries has gained momentum as one of the main public healthcare concerns worldwide. Although the occurrence of dental caries in Uganda is on the rise, little attention has been paid to promoting oral healthcare in the country. Thus, this study aimed to evaluate the citrus lemon extracts, and Mondia whitei root bark ethanolic extract as candidate alternative therapeutic agents for streptococcus mutans, the causative agent of dental caries.

Methods: In this study, the citrus lemon juice, pulp citrus lemon juice, and Mondia whitei ethanolic extract were screened for phytochemicals. Furthermore, the anti-Streptococcus mutans activity of the citrus lemon juice, citrus lemon pulp juice, and Mondia whitei ethanolic extract was determined by the agar well diffusion method while the minimum inhibitory concentration and minimum bactericidal concentration were determined by serial broth dilution.

Results: Phytochemical screening revealed the presence of alkaloids, flavonoids, terpenoids, and tannins in the Mondia whitei ethanolic extract and citrus lemon juices, while glycosides were only detected in lemon extracts. The zones of inhibition of Mondia whitei ethanolic extract, citrus lemon juice, citrus lemon pulp juice, and the cocktail were 13.67 ± 0.33 mm, 18.67 ± 0.33 mm, 18.33 ± 0.67 mm, and 18.00 ± 0.58 mm, respectively. The citrus lemon juice and citrus lemon pulp juice exhibited significantly lower MIC of 0.195 mg/mL, and 0.391mg/mL, respectively. The efficacy of the extract/juices increased with an increase in the concentration.

Conclusion: The study findings revealed that Mondia whitei ethanolic extract and lemon extracts have potent antibacterial activity against streptococcus mutans, the main causative agent of dental caries; thus, can be further explored to formulate a herbal concoction for the prevention and treatment of oral cavity infections in resources-limited low-income communities.