resumo
Satureja montana is a worldwide consumed aromatic plant whose essential oils (EOs) are used as spice and preservative by food industry. Only the leaves are marketed, generating a large amount of stems as byproducts. It is possible that the EOs present in these byproducts represent a source of compounds with antimicrobial activity, as observed for the leaves. In this work, dried S. montana byproducts were used to extract EOs. Although dif- ferences were observed for the harvest year (0.42 ± 0.11 mg/g in 2016 and 0.14 ± 0.07 mg/g in 2017), monoterpenoids were the major components, accounting for 84.4–97.6%, being carvacrol the most abundant component (825–950 μg/mg). Sesquiterpenoids accounted for 0.3 to 0.5%. Similar EOs yield and composition were obtained using solvent-free microwave extraction (16 min using 100 g of S. montana stems, previously, soaked in water and drained) or hydrodistillation (120 min using 1000 mL of water/ 100 g of dried S. montana stems). The in vitro minimal inhibitory concentrations (MICs) of S. montana EOs against Escherichia coli ATCC 25922, Salmonella enterica sv Anatum SF2, and Staphylococcus aureus ATCC 6538, which belong to pathogenic species with economic impact in poultry industry, were 225 μg/mL, 250 μg/mL, and 150 μg/mL, respectively. As these MICs are similar to the ones reported for carvacrol against the same or related strains, it can be concluded that carvacrol is the active compound in S. montana byproducts.
autores
Jéssica D.C. Santos, Elisabete Coelho, Rita Silva, Cláudia P. Passos, Pedro Teixeira, Isabel Henriques, Manuel A. Coimbra
nossos autores
Elisabete Verde Martins Coelho
Bolseiro de pós-Doutoramento
Jéssica Daniela Carvalho dos Santos
Estudante de doutoramentoagradecimentos
The application of the microwave technology is the result of a sci- entific collaboration with Unicam and Milestone srl (Italy). The authors gratefully acknowledge Ervital - infusões e condimentos biológicos for kindly providing agroindustrial aromatic plant byproducts. Thanks are due to the University of Aveiro and FCT/MCT for the financial support for the QOPNA research Unit (FCT UID/QUI/00062/2019) and Waste2Value project (PDR2020-101-031828, Partnership no. - 94 / Initiative n. - 189, 1.0.1 - Operational Groups - n. - 01 / Action 1.1 / 2016) through national founds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement. Thanks are due for the financial support to CESAM (UID/AMB/50017 - POCI-01-0145- FEDER-007638), to FCT/MCTES through national funds (PIDDAC), and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. Pedro Teixeira thanks FCT for the doctoral grant (SFRH/BD/132046/2017). Elisabete Coelho(SFRH/ BPD/70589/2010) and Cláudia Passos (CEECIND/00813/2017) thank, they also thank the research contract funded by national funds (OE), through FCT, in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19