Browsing by Author "Olivares, Belen"

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    Betaine-urea deep eutectic solvent improves imipenem antibiotic activity
    (2022) Olivares, Belen; Martinez, Fabian A.; Ezquer, Marcelo; Morales, Bernardo J.; Fuentes, Ignacia; Calvo, Margarita; Campodonico, Paola R.
    Beta-lactam antibiotics are highly unstable in aqueous media, which may lead to subclinical concentrations, antimicrobial resistance and therapeutic failure. In previous work we demonstrated that a natural deep eutectic solvent consisting of betaine and urea (BU) is capable of improving the stability of some beta-lactams, including imipenem (IMP), the most unstable antibiotic of the family. Here, IMP-BU was studied by selective protonic Nuclear Overhauser Effect Spectroscopy Magnetic Resonance (H-1 NOESY NMR) to gain insight into the mechanism by which BU protects IMP. The kinetics of IMP release and its antibacterial activity were evaluated in diffusional, time-kill and antibiofilm assays. It was found that BU is a protective matrix which allows a fast release of IMP, resulting in superior antibacterial activity when compared to IMP in aqueous solution, both against bacteria growing in planktonic form and in biofilms. Furthermore, it was shown that BU is nontoxic when evaluated in fibroblast primary cell cultures and in organotypic skin cultures, and is not immunogenic when tested in vitro in macrophage cultures, suggesting that BU has potential application as a biomaterial or excipient. (C) 2022 Published by Elsevier B.V.
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    Experimental Analyses Emphasize the Stability of the Meisenheimer Complex in a SNAr Reaction Toward Trends in Reaction Pathways
    (2020) Campodonico, Paola R.; Olivares, Belen; Tapia, Ricardo A.
    The mechanism of SNAr reactions between 2-chloro-5-nitropyrimidine with primary and secondary alicyclic amines, respectively, have been studied by kinetic measurements. The kinetic data obtained in aqueous media opens a controversial discussion based on Bronsted-type plots analysis. The first approach based on the kinetic data reveals a non-catalyzed pathway. Then, the subtlety of the mathematical treatment of the kinetic data is discussed over a concerted or stepwise mechanism, respectively.
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    Aloe vera peel-derived nanovesicles display anti-inflammatory properties and prevent myofibroblast differentiation
    (2024) Ramirez, Orlando; Pomareda, Florencia; Olivares, Belen; Huang, Ya-Lin; Zavala, Gabriela; Carrasco-Rojas, Javiera; Alvarez, Simon; Leiva-Sabadini, Camila; Hidalgo, Valeria; Romo, Pablo; Sanchez, Matias; Vargas, Ayleen; Martinez, Jessica; Aguayo, Sebastian; Schuh, Christina M. A. P.
    Background: Aloe vera (AV) is a medicinal plant, most known for its beneficial effects on a variety of skin conditions. Its known active compounds include carbohydrates and flavonoids such as quercetin and kaempferol, among others. In the past decade, plant nanovesicles (NVs) have gained considerable interest as interkingdom communicators, presenting an opportunity for clinical standardization of natural products. In this study, we aimed to assess the potential of AVpNVs for the treatment of burn wounds.