Garlic Allicin as a Means to Control Oral Pathogens

Introduction: Periodontal disease is a chronic bacterial infection that affects the gums and bone supporting the teeth. Porphyromonas gingivalis is a Gram-negative anaerobe that is implicated as the major etiologic agent of adult periodontitis. P. gingivalis produces cysteine proteinases termed gingipains, in cell-associated and secretory forms. Gingipains consist of arginine-X-specific proteinases (Arg-gingipains, Rgps) and lysine-X-specific proteinase (Lys-gingipain, Kgsp). Previous studies using various P. gingivalis mutants deficient in the Rgp- and/or Kgp-encoding genes revealed that these enzymes are important for the bacterium's virulence and survival in the periodontal pockets. Thus, development of gingipains inhibitors provides new therapeutic approaches to treat periodontal diseases. Herbal extracts have been used as therapeutic agents throughout the human history. Allicin is a powerful medicinal compound derived from garlic and provides reputed health benefits. Aim: In this study the potential of a unique garlic allicin extract was tested as a means to control oral pathogens. Materials and Methods: Allicin was extracted from garlic and stabilized by solvent extraction. Bacterial growth inhibition by allicin was determined using the broth dilution method. Allicin's antiproteolytic activity was determined using nondenaturing SDS-polyacrylamid gel zymography and by using the chromogenic substrate N-benzoyl –L-Arg-p-nitroanilide(pNA). Streptococcus mutans biofilm inhibition and killing was determined using live dead staining followed by confocal laser scanning microscopy. Results: 1- Allicin was found to inhibit growth of all tested bacteria (P. gingivalis, Fusobacterium nucleatum, Actinobacillus (Aggregatibacter) actinomycetemcomitans, Streptococcus mutans, S. sobrainus, Escherichia coli, and Actinomyces viscosus). 2 - Allicin was found to be a potent irreversible inhibitor of the P. gingivalis proteases. 3- Allicin was found capable of killing S.mutans growth in biofilm. Conclusion: Our results suggest that our Garlic allicin extract has a potential use for prevention and treatment of periodontal disease.

This work has been supported by the intramural Yissumit grant of the Hebrew University of Jerusalem.