Evaluation of antibacterial efficacy of Nigella sativa seed extract on periodontal pathogens.

BACKGROUND AND OBJECTIVES: Nigella sativa, a medicinal plant of the Ranunculaceae family, is widely used for its antimicrobial and anti-inflammatory properties. This study aimed to evaluate the antibacterial activity of N. sativa seed extract against two major periodontal pathogens: Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. MATERIALS AND METHODS: In this study, bacterial samples were collected from 30 patients with moderate-to-severe chronic periodontitis. Pure cultures of anaerobic bacteria were used to assess susceptibility to N. sativa extract and to amoxicillin-metronidazole. Antibacterial activity was evaluated using broth microdilution and agar dilution methods. RESULTS: From the previous experiments conducted, it was determined that the extract from the plant has an inhibitory effect at a concentration of mg/mL, but not at concentrations of 4 and 8 mg/mL. Furthermore, from previous experiments, it was determined that the growth inhibition was from 14 mg/mL for A. actinomycetemcomitans and was 52 mg/mL for P. gingivalis. Furthermore, it was determined that at a concentration of 100-210 mg/mL, the growth of both pathogens was inhibited. Assessment of the FIC index for synergistic and antagonistic interactions showed synergism for the combination of N. sativa and metronidazole for the A. actinomycetemcomitans, antagonism for P. gingivalis, and no interaction with amoxicillin. CONCLUSION: The antibacterial property of N. sativa has positive implications and can probably be used in herbal medicine for periodontal diseases, where it can be used for the formulation of mouthwashes and toothpastes. More studies should be done.