Antibacterial Activity of Selected Traditional Medicinal Plants Against Periodontal Pathogens

Application of traditional medicinal plants for the treatment of various diseases is under investigation. Objective: This study determined the antibacterial activity of traditional medicinal plants that are used for the treatment of periodontal disease. Methods: Watery extracts of leaves, seeds and bark of Acacia karoo, Capobrotus edulis, Cotyledon orbiculata, Datura stramonium, Dodonaea angustifolia and Zanthoxylum capense were prepared according to standardized traditional recipes. These concentrated extracts as well as 1/10, 1/100 and 1/1000 dilutions of all extracts were tested against Actinobacillus actinomycetemcomitans (ATCC33384), Tannerella forsythensis (Bacteroides forsythus) (ATCC43037) and Porphyromonas gingivalis (ATCC33277). The spread plate technique with saturated filter paper discs was used in duplicate to determine inhibition zones. The inhibition zones were quantified and expressed as an index that was calculated from the ratio of the inhibition zone of the extract to the inhibition zone of 70% ethanol (Inhibition index of 70% ethanol = 1). Results: Variable antibacterial activities were observed. Only C. orbiculata showed no antibacterial activity against P. gingivalis and although some of the 1/1000 dilutions of some of the other plant extracts showed no antibacterial activity against all three organisms, all five of the other plant extracts showed antibacterial activity against all three organisms. In general A. karoo, C. edulis, C. orbiculata and D. angustifolia showed the highest activity against A. actinomycetemcomitans with an inhitition index ranging from 0.625 – 0.875 for the concentrated extract. D. stramonium was most active against P. gingivalis with an inhibition index of 0.5 for the concentrated extract. Z. capense was most effective against both P. gingivalis and T. forsythensis with an inhibition index of 0.75 for the concentrated extract. Conclusion: All six medicinal plants showed significant antibacterial activity against selected periodontal pathogens and this need to be investigated for possible future development of periodontal treatment and medicine.