2022, Gwiazdowska, Daniela, Uwineza, Pascaline Aimee, Frąk, Szymon, Juś, Krzysztof, Marchwińska, Katarzyna, Gwiazdowski, Romuald, Waśkiewicz, Agnieszka

Glechoma hederacea var. longituba is a herbaceous plant from the Lamiaceae family, used in herbal medicine. In this work, we aimed to assess the total phenolic content, antioxidant, antimicrobial and antibiofilm activity of extracts obtained from G. hederacea via supercritical dioxide extraction with methanol as a co-solvent under different extraction conditions. The results showed that the activity of the obtained SC-CO2 extracts is strongly dependent on the extraction temperature. Significantly higher total polyphenol content, as well as antioxidant and antimicrobial activity towards bacteria and yeasts, was observed in the extract obtained at 40 °C, compared to extracts obtained at 50 °C and 60 °C; however, antifungal activity against filamentous fungi was not dependent on the extraction conditions. Antimicrobial activity also depended on the microorganism type. Higher sensitivity was exhibited by Gram-positive bacteria than by Gram-negative bacteria, with S. aureus and P. aeruginosa being the most sensitive species among each group. The most susceptible fungi were Candida albicans and Sclerotinia sclerotiorum. The antibiofilm activity was differentiated and depended on the extraction conditions, the microorganism and the method of biofilm treatment. All tested extracts inhibited biofilm formation, with the extract obtained at 40 °C showing the highest value, whereas only extract obtained at 60 °C efficiently removed mature biofilm.

2024, Gwiazdowska, Daniela, Waśkiewicz, Agnieszka, Juś, Krzysztof, Marchwińska, Katarzyna, Frąk, Szymon, Popowski, Dominik, Pawlak-Lemańska, Katarzyna, Uwineza, Pascaline Aimee, Gwiazdowski, Romuald, Padewska, Daria, Roszko, Marek, Bryła, Marcin

Sustainable management of agri-food product safety presents a major challenge requiring extensive action to ensure food safety and consumer health. The pursuit of environmentally friendly solutions that will constitute an alternative to the chemical compounds commonly used in agriculture and the food industries is one of the most important problems. One solution is plant extracts containing various biologically active compounds and exhibiting antimicrobial activity. This study aims to determine the biological activity of extracts obtained from Origanum vulgare L. (leaves) by supercritical CO2 (SC-CO2) extraction using different reaction conditions and compositions. In vitro studies revealed antimicrobial activity against selected bacteria (including Salmonella Enteritidis, Listeria monocytogenes, and Staphylococcus aureus) and fungi (Fusarium spp.), depending mainly on the microorganism species; however, extraction conditions also influenced these properties. The microscopic observations established by optical and fluorescence microscopy showed the changes in the fungal cell’s viability and morphology. There was no observed significant release of intracellular material as stated based on ICP-MS analysis of sodium and potassium concentration. Antibiofilm properties of extract obtained by extraction at 40 °C were also demonstrated against S. aureus, P. aeruginosa, and L. monocytogenes, with stronger properties observed against Gram-positive bacteria. Phytochemical characterization of the extracts was determined using a liquid chromatography system with an orbitrap mass spectrometer (LC/MS), identifying, i.e., phenolic acids: protocatechuic, hydroxybenzoic, caffeic, and rosmarinic; flavonoids: luteolin, naringenin, and kaempferol; and terpenoids: oleanolic and ursolic acids.