Planta Med 2011; 77 - PM66
DOI: 10.1055/s-0031-1282824

Anti-biofilm Activity of Pimarane Diterpenoids Against Anaerobes

CG Martins 1, TS Moraes 1, S Marangoni 1, R Lucarini 1, RS Veneziani 1, NC Furtado 2, VG Heleno 1, SR Ambrósio 1
  • 1Núcleo de Pesquisa em Ciências Exatas e Tecnológicas, Laboratório de Pesquisa em Microbiologia Aplicada, Universidade de Franca, Av. Dr. Armando Salles de Oliveira, 201 CEP 14404–600 Franca-SP, Brazil
  • 2Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil

One of the greatest challenges in endodontic treatment is the presence of bacteria as a biofilm, which confers stronger bacterial resistance to antimicrobial compounds [1]. In the present work, the in vitro anti-biofilm activity of two natural pimarane-type diterpenes and one semi-synthetic derivative were investigated against nine bacteria responsible for dental root canal infections. The following anaerobic bacteria were evaluated in the present study: Porphyromonas gingivalis (ATCC and clinical isolate), Prevotella nigrescens (ATCC), Prevotella intermedia (clinical isolate), Prevotella buccae (clinical isolate), Bacteroides fragilis (ATCC), Actinomyces naeslundii (ATCC), Peptostreptococcus micros (clinical isolate), and Aggregatibacter actinomycetemcomitans (ATCC). The diterpenes ent-pimara-8(14),15-dien-19-oic acid (1), its sodium salt (2), and ent-8(14),15-pimaradien-3β-ol (3) (Figure 1) were used for determination of the minimum biofilm inhibition concentration (MBIC50) [2]. MBIC50 results varied between 6.25 and 25.0µg/mL for the studied compounds. All the examined compounds displayed 50% or higher inhibition activity concerning biofilm formation. A maximum value of approximately 20-fold the MIC was attained for P. gingivalis (ATCC) [3] in the case of compound 1, and a minimum value of approximately onefold the MIC was achieved for most of the tested bacteria. The present results suggest that pimarane-type diterpenes are able to inhibit biofilm formation in vitro, and that their structure influence this antimicrobial activity [3]. So this class of diterpenes should be considered in the search for new irrigating substances in the area of endodontic infections treatment. Studies of antibacterial activity linked to biofilm formation versus cytotoxicity of these compounds are being undertaken by our research group.

Figure 1: Chemical structure of diterpene type-pimarane

Keywords: Diterpene, Biofilm, Antibacterial activity, Anaerobe

Acknowledgement: FAPESP (Proc. 2009/18278–0)

References: 1. Stewart & Costerton (2001) Lancet 358: 135–138.

2. Wei et al (2006)J Antimicrob Chemother 57: 1100–1109.

3. Carvalho et al (2011) Molecules 16: 543–551.