title: Antimicrobial Activity of the Essential Oil of Plectranthus neochilus against Cariogenic Bacteria.
abstract: This work used the broth microdilution method to investigate the antimicrobial activity of the essential oil obtained from the leaves of Plectranthus neochilus (PN-EO) against a representative panel of oral pathogens. We assessed the antimicrobial activity of this oil in terms of the minimum inhibitory concentration (MIC). PN-EO displayed moderate activity against Enterococcus faecalis (MIC = 250 μg/mL) and Streptococcus salivarus (MIC = 250 μg/mL), significant activity against Streptococcus sobrinus (MIC = 62.5 μg/mL), Streptococcus sanguinis (MIC = 62.5 μg/mL), Streptococcus mitis (MIC = 31.25 μg/mL), and Lactobacillus casei (MIC = 31.25 μg/mL), and interesting activity against Streptococcus mutans (MIC = 3.9 μg/mL). GC-FID and GC-MS helped to identify thirty-one compounds in PN-EO; α-pinene (1, 14.1%), β-pinene (2, 7.1%), trans-caryophyllene (3, 29.8%), and caryophyllene oxide (4, 12.8%) were the major chemical constituents of this essential oil. When tested alone, compounds 1, 2, 3, and 4 were inactive (MIC > 4000 μg/mL) against all the microorganisms. These results suggested that the essential oil extracted from the leaves of Plectranthus neochilus displays promising activity against most of the evaluated cariogenic bacteria, especially S. mutans.
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901 Ribeirão Preto, SP, Brazil.
authors.forename: Eduardo José
authors.initials: EJ
authors.lastname: Crevelin
authors.affiliation: Núcleo de Pesquisas em Ciências Exatas e Tecnológicas, Universidade de Franca, 14404-600 Franca, SP, Brazil.
authors.forename: Soraya Carolina
authors.initials: SC
authors.lastname: Caixeta
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901 Ribeirão Preto, SP, Brazil.
authors.forename: Herbert Júnior
authors.initials: HJ
authors.lastname: Dias
authors.affiliation: Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901 Ribeirão Preto, SP, Brazil.
authors.forename: Milton
authors.initials: M
authors.lastname: Groppo
authors.affiliation: Núcleo de Pesquisas em Ciências Exatas e Tecnológicas, Universidade de Franca, 14404-600 Franca, SP, Brazil.
authors.forename: Wilson Roberto
authors.initials: WR
authors.lastname: Cunha
authors.affiliation: Núcleo de Pesquisas em Ciências Exatas e Tecnológicas, Universidade de Franca, 14404-600 Franca, SP, Brazil.
authors.forename: Carlos Henrique Gomes
authors.initials: CH
authors.lastname: Martins
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, 14040-901 Ribeirão Preto, SP, Brazil ; Núcleo de Pesquisas em Ciências Exatas e Tecnológicas, Universidade de Franca, 14404-600 Franca, SP, Brazil.
authors.forename: Antônio Eduardo Miller
authors.initials: AE
authors.lastname: Crotti