Comparative Antimicrobial Efficacy of Garlic and Guava Extracts on Oral Pathogens Using a Time Kill Assay: An In Vitro Study

Background: Periodontal disease is characterized by inflammation mediated by the host and related microbes, which leads to the loss of periodontal attachment and tooth loss. Due to an increase in bacterial resistance to antibiotics, there is a shift toward use of herbal medicines. Aim: The aim of the study is to compare the antimicrobial effect of aqueous garlic extract (AGE) and ethanolic guava extract (EGuE) on Tanerella forsythia and Porphyromonas gingivalis using the time kill assay Materials and Methods: AGE and EGuE are prepared. Ciprofloxacin was taken as the control. The MIC was performed for garlic, guava extract, and ciprofloxacin. P. gingivalisand T. forsythia were cultured, and the time kill assay was performed at 0 h, 5 min, 30 min, 1 h, and 2 h. Colonies were counted after 48-72 h for growth. Results: The minimal inhibitory concentration (MIC) results indicated that both EGuE and AGE exhibited superior antibacterial activity compared to ciprofloxacin, suggesting their potential as alternative or complementary antimicrobial agents. In a time kill assay, EGuE demonstrated a significant reduction in colony forming units (CFUs) at 30 min, 1 h, and 2 h, outperforming AGE and ciprofloxacin. Intragroup comparisons revealed that EGuE significantly reduced CFUs at 0 h and 5 min, while AGE showed no notable reduction over time. Conclusion: Overall, the study demonstrates the antimicrobial efficacy of EGuE and AGE against T. forsythia and P. gingivalis at higher concentrations. Hence, these extracts may serve as alternative antimicrobial agents against periodontal pathogens.