Rubia cordifolia as an antimicrobial agent against periodontal pathogens - An in vitro microbiological study

Extensive research on the antimicrobial activity of medicinal plants for periodontal therapy has been conducted over the past decades. The gradual increase in antibiotic resistance necessitates research for new antimicrobial compounds. Rubia cordifolia has exhibited reassuring antimicrobial potential against Gram-positive and Gram-negative bacteria. However, no study has yet evaluated its therapeutic potential in periodontal diseases. Therefore, we aimed to design, formulate, and evaluate the antimicrobial activity of R. cordifolia root extract against periodontal pathogens.

Extract of the roots of R. cordifolia was prepared using cold maceration and methanol extraction. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill curve (TKC) analysis of R. cordifolia extract were assessed against Porphyromonas gingivalis (Pg), Tannerella forsythia, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum (Fn), and Prevotella intermedia, where chlorhexidine was utilized as a control drug.

The MIC value for Fn was 0.8 μg/mL, representing the lowest value observed, whereas Pg exhibited the highest MIC value at 6.25 μg/mL. The MBC values ranged from 6.25 μg/mL to 12.5 μg/mL. The TKC revealed a kill time of 2 h for all tested organisms except Pg.

The methanolic extract derived from the roots of R. cordifolia demonstrated bactericidal effects against keystone pathogens associated with periodontitis. Consequently, there is a critical requirement of additional clinical studies to assess its potential therapeutic application in the treatment of periodontal disease.