In vitro evaluation of the effects of Pelargonium sidoides DC. root extract and proanthocyanidins on oral bacteria viability

Abstract

Elevated proportions of some subgingival microbial species have been associated with destructive periodontal disease activity. Biologically active compounds of Pelargonium sidoides root extract (PSRE) or Proanthocyanidins (PACNs) from this extract modulate bacterial virulence and stimulate host immune responses. There is no local delivery system of sustained release formulations with PSRE or PACNs available, however, bioactive capacities of these substances suggest them as promising prolonged local periodontitis treatment candidates. The purpose of this study: to evaluate the antimicrobial effect of different concentrations of PSRE and PACNs obtained from PSRE, against Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Streptococcus salivarius. Specific objective: Identification of the effective dose of PSRE and PACNs obtained from PSRE against i) the anaerobic strain P. gingivalis, major cause of periodontitis; ii) the putative periodontal pathogen A. actinomycetemcomitans and iii) the oral commensal (S. salivarius). Methodology: Preparation of different concentrations solutions from PSRE and (PACNs). Solutions were added in direct contact with bacteria at different concentration (v/v from mother solution). Bacteria and growth conditions: 1x105 /ml Bacteria were seeded in the log exponential growth phase (by o.d. evaluation). Metabolic evaluation: After 48 hrs bacteria viability was evaluated by metabolic colorimetric assay (alamar blue). Results: PSRE extract was effective in reducing P. gingivalis viability in a significant manner in comparison with untreated controls at all the tested concentrations. PSRE showed a strong antimicrobial effect also against A. actinomycetemcomitans and S. salivarius as the viability was significantly decreased in comparison with the untreated controls at all the tested concentrations. A statistically significant reduction of P. gingivalis viability was observ[...]