Comparison of time-kill assay to evaluate the antimicrobial efficacy of garlic (allium sativum) and guava (psidium guajava) extracts on periodontal pathogens

Background: The role of Gram-negative anaerobic periodontal pathogens in periodontal diseases has led to the loss of tooth-supporting structures. These diseases can be prevented by the inhibition of bacterial biofilm on the tooth surfaces. Many treatment modalities have been tried to prevent periodontal diseases. With the rise in resistance to synthetic antimicrobials, there is a requirement to develop natural antimicrobials for the control of periodontitis. Aim: The aim of the study was to evaluate and compare the efficacy of garlic (Allium sativum) and guava (Psidium guajava) extracts on Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans using time-kill assay. Materials and Methods: Aqueous garlic extract (AGaE), ethanolic garlic extract (EGaE), aqueous guava extract (AGuE), and ethanolic guava extract (EGuE) were prepared. Time-kill assays were performed on P. gingivalis and A. actinomycetemcomitans. The aqueous and ethanolic extracts of guava and garlic were compared to assess the maximum bactericidal potency. Results: The comparison of time-kill assay of AGaE and AGuE on P. gingivalis showed a statistically significant difference at 2 h (t = 5.29, P < 0.01), 4 h (t = −4.867, P < 0.01), and 6 h (t = −3.647, P < 0.001). The comparison of time-kill assay of EGaE and EGuE on A. actinomycetemcomitans showed a statistically significant difference at 2 h (t = 4.54, P < 0.01) and highly significant difference at 4 h (t = 6.57, P < 0.001). Conclusions: The, judicious use of these phytomedicinal products could be cost-effective and also the adverse effects caused due to the long-term usage of synthetic antimicrobials can be avoided.