title: Chemical composition and bioactivity of different oregano (Origanum vulgare) extracts and essential oil.
abstract: BACKGROUND
  There is a growing interest in industry to replace synthetic chemicals by natural products with bioactive properties. Aromatic plants are excellent sources of bioactive compounds that can be extracted using several processes. As far as oregano is concerned, studies are lacking addressing the effect of extraction processes in bioactivity of extracts. This study aimed to characterise the in vitro antioxidant and antibacterial properties of oregano (Origanum vulgare) essential oil and extracts (in hot and cold water, and ethanol), and the chemical composition of its essential oil.
  
  
  RESULTS
  The major components of oregano essential oil were carvacrol, β-fenchyl alcohol, thymol, and γ-terpinene. Hot water extract had the strongest antioxidant properties and the highest phenolic content. All extracts were ineffective in inhibiting the growth of the seven tested bacteria. In contrast, the essential oil inhibited the growth of all bacteria, causing greater reductions on both Listeria strains (L. monocytogenes and L. innocua).
  
  
  CONCLUSIONS
  O. vulgare extracts and essential oil from Portuguese origin are strong candidates to replace synthetic chemicals used by the industry.
authors.affiliation: Division of Aquaculture and Upgrading, Portuguese Institute for the Sea and Atmosphere, I.P. (IPMA, I.P.), Avenida de Brasília, 1449-006, Lisbon, Portugal; Research Unit of Organic Chemistry, Natural and Agro-food Products (QOPNA), Chemistry Department, Aveiro University, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Bárbara
authors.initials: B
authors.lastname: Teixeira
authors.forename: António
authors.initials: A
authors.lastname: Marques
authors.forename: Cristina
authors.initials: C
authors.lastname: Ramos
authors.forename: Carmo
authors.initials: C
authors.lastname: Serrano
authors.forename: Olívia
authors.initials: O
authors.lastname: Matos
authors.forename: Nuno R
authors.initials: NR
authors.lastname: Neng
authors.forename: José M F
authors.initials: JM
authors.lastname: Nogueira
authors.forename: Jorge Alexandre
authors.initials: JA
authors.lastname: Saraiva
authors.forename: Maria Leonor
authors.initials: ML
authors.lastname: Nunes
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D009822:Oils, Volatile / Q000737:chemistry*; D031341:Origanum / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D009822:Oils, Volatile; D010936:Plant Extracts; D010938:Plant Oils
keywords: antibacterial activity; antioxidant activity; aqueous extracts; essential oil; ethanol extracts; oregano