title: Antibacterial activity of Pinus elliottii against anaerobic bacteria present in primary endodontic infections.
abstract: Endodontic infections have a polymicrobial nature, but anaerobic bacteria prevail among the infectious microbes. Considering that it is easy to eliminate planktonic bacteria, biofilm-forming bacteria still challenge clinicians during the fight against endodontic diseases. The chemical constituents of the oleoresin of Pinus elliottii, a plant belonging to the family Pinaceae, stand out in the search for biologically active compounds based on natural products with potential application in the treatment of endodontic infections. Indeed, plant oleoresins are an abundant natural source of diterpenes that display significant and well-defined biological activities as well as potential antimicrobial action. In this context, this study aimed to (1) evaluate the in vitro antibacterial activity of the oleoresin, fractions, and subfractions of P. elliottii as well as the action of dehydroabietic acid against 11 anaerobic bacteria that cause endodontic infection in both their planktonic and biofilm forms and (2) assess the in vitro antibiofilm activity of dehydroabietic acid against the same group of bacteria. The broth microdilution technique helped to determine the minimum inhibitory concentration (MIC) of the oleoresin and fractions. This same technique aided determination of the MIC values of nine subfractions of Fraction 1, the most active fraction. The MIC, minimum bactericidal concentration, and antibiofilm activity of dehydroabietic acid against the tested anaerobic bacteria were also examined. The oleoresin and fractions, especially fraction PE1, afforded promising MIC values, which ranged from 0.4 to 50 μg/mL. Concerning the nine evaluated subfractions, PE1.3 and PE1.4 furnished the most noteworthy MIC values, between 6.2 and 100 μg/mL. Dehydroabietic acid displayed antibacterial activity, with MIC values lying from 6.2 to 50 μg/mL, as well as bactericidal effect for all the investigated bacteria, except for Prevotella nigrescens. Assessment of the antibiofilm activity revealed significant results--MICB50 lay between 7.8 and 62.5 μg/mL, and dehydroabietic acid prevented all the evaluated bacteria from forming a biofilm. Hence, the chemical constituents of P. elliottii are promising biomolecules to develop novel therapeutic strategies to fight against endodontic infections.
authors.affiliation: Laboratório de Pesquisa em Microbiologia Aplicada, Universidade de Franca, Franca, São Paulo, Brazil.
authors.forename: Sandro Donizete
authors.initials: SD
authors.lastname: Caetano da Silva
authors.affiliation: Laboratório de Pesquisa em Microbiologia Aplicada, Universidade de Franca, Franca, São Paulo, Brazil.
authors.forename: Maria Gorete
authors.initials: MG
authors.lastname: Mendes de Souza
authors.affiliation: Laboratório de Pesquisa em Microbiologia Aplicada, Universidade de Franca, Franca, São Paulo, Brazil.
authors.forename: Miguel Jorge
authors.initials: MJ
authors.lastname: Oliveira Cardoso
authors.affiliation: Laboratório de Pesquisa em Microbiologia Aplicada, Universidade de Franca, Franca, São Paulo, Brazil.
authors.forename: Thais
authors.initials: T
authors.lastname: da Silva Moraes
authors.affiliation: Grupo de Pesquisa em Produtos Naturais, Universidade de Franca, São Paulo, Brazil.
authors.forename: Sérgio Ricardo
authors.initials: SR
authors.lastname: Ambrósio
authors.affiliation: Grupo de Pesquisa em Produtos Naturais, Universidade de Franca, São Paulo, Brazil.
authors.forename: Rodrigo Cássio
authors.initials: RC
authors.lastname: Sola Veneziani
authors.affiliation: Laboratório de Pesquisa em Microbiologia Aplicada, Universidade de Franca, Franca, São Paulo, Brazil. Electronic address: carlos.martins@unifran.edu.br.
authors.forename: Carlos Henrique G
authors.initials: CH
authors.lastname: Martins
mesh_terms: D045784:Abietanes / Q000302:isolation & purification / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001421:Bacteria, Anaerobic / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D006801:Humans; D008826:Microbial Sensitivity Tests; D028223:Pinus / Q000737:chemistry*; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D011671:Pulpitis / Q000382:microbiology*
chemical_list: D045784:Abietanes; D000900:Anti-Bacterial Agents; D010936:Plant Extracts; C018620:oleoresins; C013913:dehydroabietic acid
keywords: Anaerobic bacteria; Antibacterial activity; Antibiofilm activity; Dehydroabietic acid; Diterpenes; Pinaceae