Micromeria thymifolia Essential Oil Suppresses Quorum-sensing Signaling in Pseudomonas aeruginosa

The chemical composition, antimicrobial and antiquorum sensing activity of the essential oil of Micromeria thymifolia (Scop.) Fritsch were investigated. Limonene, piperitone epoxide and piperitenone epoxide were found as the main constituents using a gas chromatography-mass spectrometry technique. In vitro antimicrobial activity of the oil was tested against six bacterial and seven fungal strains and high antimicrobial potential was noticed. Minimum inhibitory concentration varied from 0.031 mg/mL to 0.5 mg/mL for bacterial and 0.062 mg/mL to 0.5 mg/mL for fungal strains. The antiquorum properties of the essential oil were evaluated on Pseudomonas aeruginosa PAO1. The oil was tested at subMiC concentrations for anti-quorum sensing activity. The analyses on quorum-sensing functions have been carried out by evaluating twitching and swarming of bacterial cultures and the total amount of pyocyanin production produced by P. aeruginosa. This study showed that M thymifolia essential oil exhibited antiquorum sensing activity and may be used as an antipathogenic drug

By-product recovery of Opuntia spp. peels: Betalainic and phenolic profiles and bioactive properties

[EN] Opuntia spp. are a tropical and subtropical plant that provides both edible green steams and fruits; however, the processing of this fruits results in the accumulation of enormous amount of by-products that can be a source of bioactive and pigmented compounds. Herein, three cactus pear from the species Opuntia focus-indica var. sanguigna (OS) and gialla (OG) and Opuntia engelmannii (OE) were fully characterized regarding their phenolic and betalain composition and correlated with their antioxidant and antimicrobial activities. The hydroethanolic extracts of OE gave the highest amount of phenolic compounds isorhamentin-O-(deoxyhexosyl-hexoside) and betacianins (betanin); however, no betaxanthins were identified in this sample. This sample also revealed the lowest EC50 values in all the antioxidant activity assays. Regarding antimicrobial activity, the hydroethanolic extracts of all species revealed to be more active than ampicillin. The pivotal objective of this work was to focus on exploring by-product biocompounds and possible outputs, thus, we could suggest the use of these natural colorants with intrinsic antioxidant and antimicrobial activity, which would grant industries to produce cleaner label products with functional benefits.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013) and L. Barros contract. This work is funded by the European Structural and Investment Funds (FEEI) through the Regional Operational Program North 2020, within the scope of Project NORTE-01-0145-FEDER-023289 (DeCodE) and ValorNatural (R). B. Melgar (No. 329930) also thanks CONACyT for his grant. The authors are grateful for a grant from the Serbian Ministry of Education, Sciences and Technological Development (no. 173032). The authors would also like to thank Dr. Carlos Aguiar for the botanical identification of these species.Melgar-Castañeda, B.; Dias, MI.; Ciric, A.; Sokovic, M.; Garcia-Castello, EM.; Rodríguez López, AD.; Barros, L.... (2017). By-product recovery of Opuntia spp. peels: Betalainic and phenolic profiles and bioactive properties. Industrial Crops and Products. 107:353-359. https://doi.org/10.1016/j.indcrop.2017.06.011S35335910

Antimicrobial Activity of the Freshwater Bryozoan Hyalinella Punctata (Hancock, 1850)

The antimicrobial activity of the freshwater bryozoan Hyalinella punctata (Hancock, 1850) was tested by microdilution method against eight bacteria and eight fungi for the first time. All five crude extracts (hexane, acetone, dimethyl sulfoxide, methanol and water) showed good antibacterial and antifungal potential in vitro wherein the acetone extract was the most active (MICs 0.50-7.00 mu g/ml and MBCs 2.50-10.00 mu g/ml)

Micromeria thymifolia Essential Oil Suppresses Quorum-sensing Signaling in Pseudomonas aeruginosa

The chemical composition, antimicrobial and antiquorum sensing activity of the essential oil of Micromeria thymifolia (Scop.) Fritsch were investigated. Limonene, piperitone epoxide and piperitenone epoxide were found as the main constituents using a gas chromatography-mass spectrometry technique. In vitro antimicrobial activity of the oil was tested against six bacterial and seven fungal strains and high antimicrobial potential was noticed. Minimum inhibitory concentration varied from 0.031 mg/mL to 0.5 mg/mL for bacterial and 0.062 mg/mL to 0.5 mg/mL for fungal strains. The antiquorum properties of the essential oil were evaluated on Pseudomonas aeruginosa PAO1. The oil was tested at subMiC concentrations for anti-quorum sensing activity. The analyses on quorum-sensing functions have been carried out by evaluating twitching and swarming of bacterial cultures and the total amount of pyocyanin production produced by P. aeruginosa. This study showed that M thymifolia essential oil exhibited antiquorum sensing activity and may be used as an antipathogenic drug

Bioactive characterization of Persea americana Mill. by-products: A rich source of inherent antioxidants

[EN] Avocado (Persea americana Mill.) is a worldwide consumed fruit, with great interest for cosmetic and pharmaceutical industries; however, 30% of avocado fruits are bio-wastes (peels and kernels), converting them into a potential source of bioactive compounds, such as phenolic compounds. Therefore, the hydroethanolic extracts of peels and kernels of Persea america Mill. var. Hass were analysed regarding their individual phenolic profile by HPLC-DAD/ESI-MS and correlated with their antioxidant, antimicrobial and cytotoxic activities. Avocado by-products presented a very distinct phenolic profile, presenting higher concentration in peels (227.9 mg/g of extract for total phenolic content), mainly in (epi)catechin derivatives (175 mg/g of extract), followed by chlorogenic derivatives (42.9 mg/g of extract). In this study hydrophilic and lipophilic antioxidant assays were performed together for the first time in P. americana by-products, and although kernels showed a great antioxidant potential (EC50 values ranging from 18.1 to 276 mu g/mL), peels presented the highest potential (EC50 ranging from 11.7 to 152 mu g/mL), mainly due to the presence of phenolic compounds, and an overall better performance in the antibacterial assays. Further studies needs to be conducted to better understand the correlation between the presence of phenolic compounds and bioactivities, however, the main objective is to implement these biocompounds in different products and industries, due to results obtained, P. americana peels could be a great alternative in the substitution of synthetic antioxidants.The authors are grateful to the Foundation for Science and Technology(FCT, Portugal) and FEDER under Program PT2020 for financial support to CIMO (UID/AGR/00690/2013) and L. Barros contract. The authors would like to thank the Interreg Espana-Portugal for financial support through the project 0377_Iberphenol_6_E. B. Melgar thanks CONACyT for his grant (No. 329930). The authors are also grateful to the Serbian Ministry of Education, Science and Technological Development, grant number 173032 for financial support.Melgar-Castañeda, B.; Dias, MI.; Ciric, A.; Sokovic, M.; Garcia-Castello, EM.; Rodríguez López, AD.; Barros, L.... (2018). Bioactive characterization of Persea americana Mill. by-products: A rich source of inherent antioxidants. Industrial Crops and Products. 111:212-218. https://doi.org/10.1016/j.indcrop.2017.10.024S21221811

Studies of isomeric phospholes : synthesis and application in transitionmetal and organic catalysis

The work described herein encompasses a few topics related to the studies of isomeric phospholes. Phospholes have been explored thoroughly over the past many years. They are now accepted as only weakly aromatic: the aromatic stabilization resulting from electronic delocalization of phosphole’s planar state is not sufficient enough to overcome its intrinsically high inversion barrier of phosphorus. This results in their pyramidal structure when in ground state and a very poor orbital overlap between the phosphorus lone pair np and the π orbitals of the diene unit. Therefore, they seem to resemble more cyclopentadienes than their nitrogen analogues - pyrroles. Though, only recently has the attention been shifted to the phosphole’s isomeric form - phospholene. Due to phosphole’s low aromaticity, there lies the opportunity to switch from slightly aromatic to slightly antiaromatic character of these heterocycles, which in turn changes the chemistry of this species.DOCTOR OF PHILOSOPHY (SPMS

Creation of a Conductive Surface-Layer on Polypropylene Samples by Low-Pressure Plasma Treatments

Antibacterial and antifungal activities of methanol extracts of the moss species Fontinalis antipyretica Hedw. var. antipyretica, Hypnum cupressiforme Hedw., and Ctenidium molluscum (Hedw.) Mitt. were analyzed. Antimicrobial activity was tested against Gram (+) (Bacillus subtilis, Micrococcus flavus, and Staphylococcus epidermidis) and Gram (-) (Escherichia coli and Salmonella enteritidis) bacteria. Antifungal activity of extracts was tested using the following micromycetes: Trichoderma viride, Penicillium funiculosum, P. ochrochloron, Aspergillus fumigatus, A. flavus, and A. niger. The methanol extract of Fontinalis antipyretica showed the strongest activity against the tested bacteria and micromycetes. The antibacterial effect of methanol extracts was higher against the G (-) (Escherichia coli and Salmonella enteritidis) than against the G (+) bacteria tested.Analizirana je antimikrobna i antifungalna aktivnost metanolnog ekstrakta vrsta Fontinalis antipyretica Hedw. var. antipyretica, Hypnum cupressiforme Hedw. i Ctenidium molluscum (Hedw.) Mitt. Antimikrobna aktivnost je testirana na gram (+) (Bacillus subtilis, Micrococcus flavus i Staphylococcus epidermidis) i gram (-) bakterije (Escherichia coli i Salmonella enteritidis). Kao podloga za antifungalnu aktivnost korišćene su gljive: Trichoderma viride, Penicillium funiculosum, P. ochrochloron, Aspergillus fumigatus, A. flavus i A. niger. Metanolni ekstrakt Fontinalis antipyretica pokazao je najjače dejstvo na testirane bakterije i mikromicete. Antibakterijski efekat metanolnih ekstrakata je bio znatno jači na gram (-) (Escherichia coli i Salmonella enteritidis) nego na gram (+) bakterije.Projekat ministarstva br. 143049 i 14304