Examinando por Autor "Svetaz, Laura Andrea"
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Ítem Acceso Abierto Antimicrobial activity of quinoline-based hydroxyimidazolium hybrids(MDPI, 2019-11-28) Insuasty, Daniel; Vidal, Oscar; Bernal, Anthony; Marquez, Edgar; Guzman, Juan; Insuasty, Braulio; Svetaz, Laura Andrea ; Zacchino, Susana; Puerto, GloriaÍtem Acceso Abierto Botanical control of citrus green mold and peach brown rot on fruits assays using a persicaria acuminata phytochemically characterized extract(MDPI, 2021-02-24) Di Liberto, Melina G.; Seimandi, Gisela; Fernández, Laura; Ruiz, Verónica; Svetaz, Laura Andrea; Derita, Marcos G.; https://orcid.org/0000-0002-0162-2771; https://orcid.org/0000-0001-8148-936XPersicaria acuminata (Polygonaceae) is a perennial herb that grows in the central area of Argentina and it is commonly used by native populations to heal infected wounds and other conditions related to fungal infections. In this article, we explored the in vitro antifungal activity of its ethyl acetate extract against a panel of three fruit phytopathogenic fungi including: Penicillium digitatum, P. italicum, and Monilinia fructicola. The sesquiterpenes isolated from the extract were also evaluated against these strains, demonstrating that the dialdehyde polygodia was the responsible for this activity. In order to encourage the use of the extract rather than the pure compound, we displayed ex vivo assays using fresh oranges and peaches inoculated with P. digitatum and M. fructicola, respectively, and subsequently treated by immersion with an extract solution of 250 and 62.5 µg/mL, respectively. There were no statistically significant differences between the treatments with commercial fungicides and the extract over the control of both fruit rots. The concentration of the active compound present in the extract used on fruit experiments was determined by Gas Chromatography-Mass Spectroscopy. Finally, cytotoxicity evaluation against Huh7 cells showed that P. acuminata extract was less cytotoxic than the commercial fungicides at the assayed concentrations. After these findings we could conclude that a chemically characterized extract of P. acuminata should be further developed to treat fungal diseases in fruits from an agro-ecological model.Ítem Acceso Abierto Búsqueda de biofungicidas pos-cosecha a partir de fuentes vegetales autóctonas, aplicables a naranjas, frutillas y duraznos(2021) Di Liberto, Melina G.; Derita, Marcos G.; Svetaz, Laura AndreaLas causas de pérdidas de frutas durante la etapa de pos-cosecha son generalmente de orden fisiológico y/o patogénico. Las infecciones fúngicas más comunes y destructivas en naranjas, frutillas y duraznos, son causadas por hongos del género Penicillium, Botrytis cinerea y Monilinia fructicola, respectivamente. Además, Rhizopus stolonifer es un importante patógeno de pos-cosecha capaz de infectar tanto a duraznos como a frutillas, entre otras frutas y verduras. Se emplean habitualmente fungicidas de síntesis química para el control de estos patógenos, pero la exigencia de los mercados internacionales referida al límite de residuos de fungicidas para la importación de frutas, ha llevado a disminuir al máximo el empleo de este tipo de sustancias. El uso de productos naturales, menos nocivos para el ser humano y obtenidos por metodologías sencillas, podría representar una alternativa de manejo fitosanitario tanto en cultivos como en pos-cosecha. Los extractos vegetales han sido reconocidos como agentes antimicrobianos desde la antigüedad y recientemente han aumentado el interés científico para distintos fines terapéuticos tanto en la salud humana, animal o vegetal. Éstos representan una importante fuente de metabolitos secundarios que eventualmente podrían poseer efectos fungicidas. El objetivo de la presente tesis fue estudiar la actividad antifúngica de extractos y aceites esenciales vegetales obtenidos de 27 especies de la flora regional como también de productos naturales obtenidos por síntesis química, contra cinco hongos fitopatógenos responsables de importantes pérdidas económicas en la industria frutícola de la región. Para ello, se determinó el efecto de 58 extractos, 11 aceites esenciales y 54 compuestos de síntesis sobre el crecimiento micelial de los cinco hongos del panel. A través del método de microdilución en caldo, se logró determinar si los productos eran fungistáticos o fungicidas. Al menos un extracto de cada especie vegetal y 39 compuestos de síntesis presentaron actividad fungistática o fungicida contra al menos uno de los hongos del panel. Los cuatro extractos más activos fueron seleccionados para su fraccionamiento bioguiado y aislamiento de los compuestos responsables de la actividad. Se aislaron: poligodial (1) a partir de Persicaria acuminata; 2’,4’-dihidroxi-3’-metoxichalcona (DHMC) (2) y 2’,4’- dihidroxichalcona (DHC) (3) de Zuccagnia punctata; pinostrobina (4) y flavokawina B (5) de Polygonum stelligerum y solidagenona (6) de Solidago chilensis. El extracto acetato de etilo de P. acuminata y los compuestos de síntesis: el derivado N-demetilado del compuesto natural zantosimulina (12) y la metoxima derivada de propiofenona (45) fueron sometidos a ensayos ex vivo en naranjas, frutillas y duraznos, obteniéndose en todos los casos resultados comparables a los fungicidas comerciales. Los ensayos de toxicidad demostraron que el extracto vegetal y el compuesto de síntesis más activo, a las dosis evaluadas, presentaban menor citotoxicidad sobre células hepáticas que el antifúngico comercial carbendazim. Se concluye que los productos naturales evaluados en esta tesis presentan un alto potencial para ser desarrollados como fungicidas de pos-cosecha, destacando la importancia de su menor toxicidad comparada con la de los de uso habitual.Ítem Acceso Abierto Control of brown rot produced by Monilinia fructicola in peaches ssing a full-spectrum extract of Zuccagnia punctata Cav(Multidisciplinary Digital Publishing Institute (MDPI), 2023-10-17) Di Liberto, Melina G.; Stegmayer, María Inés; Fernández, Laura; Quiroga, Ariel Darío; Svetaz, Laura Andrea; Derita, Marcos G.Brown rot of stone fruit, caused by Monilinia spp., is one of the most important diseases worldwide, causing significant production losses. Currently, the standard practices for controlling this infection consist of repetitive use of synthetic fungicides. The global tendency encourages the demand for high-quality food products harmless to health and the environment, leading to a reduction in the use of these types of substances. Zuccagnia punctata (Fabaceae) is a perennial shrub extensively used for the treatment of fungal and bacterial infections in Argentinean traditional medicine. In this study, we isolated and characterized (morphologically and molecularly) a pathogenic and virulent strain of Monilinia fructicola, which is the most hostile species of the genus. Consequently, we explored the in vitro antifungal activity of the ethanolic extract of Z. punctata against this phytopathogen. The chalcones 2´,4´-dihydroxy-3´-methoxychalcone and 2´,4´-dihydroxychalcone were isolated from the extract and evaluated against M. fructicola demonstrating that they were responsible for this activity. To promote full-spectrum extract rather than pure compounds, we performed ex-vivo assays using fresh peaches inoculated with the pathogen, and then treated by immersion in an extract solution of 250 µg/mL concentration. Treatment with Z. punctata extract did not show a statistically significant difference from commercial fungicides in the control of fruit rot. In addition, Huh7 cell cytotoxicity evaluation showed that Z. punctata extract was less cytotoxic than commercial fungicides at the assayed concentrations. Based on our research, this plant extract could potentially offer a safer alternative to commercial fungicides for treating peach brown rot.Ítem Embargo Desarrollo de fitomedicinas antifúngicas a partir de plantas de la flora argentina(2021) Cordisco, Estefanía; Svetaz, Laura Andrea ; Sortino, Maximiliano AndrésLas infecciones fúngicas han aumentado considerablemente en los últimos años, siendo las ocasionadas por Candida albicans, la principal causa de muerte en individuos inmunocomprometidos. El tratamiento se ve dificultado por el limitado número de drogas antifúngicas en el mercado, cuya eficacia está comprometida por la toxicidad para el hospedero, el estrecho espectro de acción, la emergencia de resistencia y los altos costos. Es por ello que este trabajo se centró en la búsqueda de extractos bioactivos contra C. albicans utilizando nuevas metodologías, como la combinación de extractos naturales con drogas comerciales, con el fin de encontrar actividad antifúngica sinérgica o aditiva; y la irradiación de extractos con luz UV-A, con el fin de excitar moléculas fotoactivas que dañen la levadura mediante estrés oxidativo. Se realizó un screening de 266 extractos obtenidos a partir de 95 especies vegetales argentinas mediante la estrategia clásica (incubación del extracto en solitario con el hongo) y las dos estrategias planteadas anteriormente. Con la estrategia clásica, sólo 28 extractos mostraron actividad en solitario (10,53%). En combinación con antifúngicos comerciales, se obtuvieron 43 extractos activos (16,17%) con al menos uno de los antifúngicos evaluados. Se determinó el tipo de interacción entre 28 extractos activos con itraconazol (ITZ) mediante el método de Tablero de ajedrez, mostrando el 46,43% (13 extractos) interacciones sinérgicas. Se utilizó el programa estadístico Minitab® para evaluar mezclas ternarias manteniendo como componentes comunes, ITZ y un extracto de Zuccagnia punctata, y variando el tercer componente de a uno por vez entre los 12 extractos restantes que habían mostrado sinergismo. Se seleccionaron como mezclas ternarias óptimas aquellas que contenían como tercer componente a los extractos de Ameghinoa patagonica, Scoparia dulcis y Gaillardia megapotamica. Se demostró que las tres mezclas ternarias actuarían por el mecanismo de unión a ergosterol de la membrana fúngica. Mediante la estrategia en combinación con luz, se obtuvieron 31 extractos (11,65%) activos, siendo los extractos hexánico y diclorometánico de raíz de Thymophylla pentachaeta, los más activos. La evaluación de mecanismos fotodinámicos mostró que ambos extractos generan especies reactivas del oxígeno mediante mecanismos tipo I y tipo II. La determinación del espectro de acción evidenció que tanto las mezclas como los extractos fotoactivos poseen actividad contra la mayoría de las especies del género Candida, Cryptococcus neoformans y los dermatofitos ensayados. A través del estudio de la capacidad de inhibición de factores de virulencia fúngicos, se observó que tanto las mezclas como los extractos fotoactivos, disminuyen la adherencia a células epiteliales, la formación de tubo germinativo y pseudomicelio, y la secreción de enzimas hidrolíticas. También se observó que las mezclas inhiben la formación de biofilm y tanto las mezclas como los extractos actúan sobre células de biofilms preformados. Las mezclas formadas por Scoparia dulcis y Ameghinoa patagonica no presentaron actividad citotóxica tanto in vitro como in vivo. Las tres mezclas mostraron actividad antifúngica in vivo en el modelo Caenorhabditis elegans. Estos resultados sientan las bases para el desarrollo de tratamientos alternativos contra C. albicans, con disminuidos efectos adversos respecto de los fármacos antifúngicos ya establecidos.Ítem Acceso Abierto Design and characterization of chitosan nanoformulations for the delivery of antifungal agents(MDPI, 2019-07-27) Calvo, Natalia Lorena; Sreekumar, Sruthi; Svetaz, Laura Andrea ; Lamas, María Celina; Moerschbacher, Bruno M.; Leonardi, DaríoÍtem Acceso Abierto Effects of Larrea nitida nanodispersions on the growth inhibition of phytopathogens(Springer, 2023-09-21) Svetaz, Laura Andrea; Sortino, Maximiliano Andrés; Rocha, Felipe; Nunes Calumby, Rodrigo José; Teixeira Ribeiro Vidigal, Márcia Cristina; Campos Bermudez, Valeria A.; Rius, Sebastián Pablo; https://orcid.org/0000-0002-1023-1641; https://orcid.org/0000-0002-4271-1690Larrea nitida Cav. (Zygophyllaceae) is a plant endemic to Argentina and Chile, and its extract has been studied over the last years due to the presence of antimicrobial agents that can be used to control the growth of some pathogens in agriculture. However, the extract is highly hydrophobic, which strongly affects its fungicidal activity in aqueous media. In this sense, the solid dispersion technique was used to produce L. nitida extract nanodispersions with polyethylene glycol (PLE) and with polyethylene glycol and zinc acetate (PZLE). In order to further evaluate the activity of the extract in PLE and PZLE, blank nanodispersions containing only polyethylene glycol (PEG) and zinc acetate (PZ) without the addition of the extract were also produced. The fungicidal activity of the water-soluble nanoparticles was evaluated at different concentrations (0.037–0.110 g.mL−1). In general, the nanoparticles were successfully produced on a nanometric size and presented a significant inhibitory activity on the growth of the pathogens Fusarium oxysporum and Fusarium verticillioides in aqueous media. Compared to PLE, PZLE presented increased fungistatic activity, possibly due to their increased solubility in water. Even though their application in agriculture should be further investigated, the nanodispersions present great potential to be applied as a green biotechnological tool.Ítem Acceso Abierto First total synthesis of chromanone A, preparation of related compounds and evaluation of their antifungal activity against Candida albicans, a biofilm forming agent(Royal Society of Chemistry, 2021-06-01) Cortés, Iván; Cordisco, Estefanía; Kaufman, Teodoro Saúl ; Sortino, Maximiliano Andrés; Svetaz, Laura Andrea; Bracca, Andrea Beatriz Juana; https://orcid.org/0000-0002-8069-2793; https://orcid.org/0000-0002-6574-1702; https://orcid.org/0000-0003-3173-2178; https://orcid.org/0000-0002-4271-1690; https://orcid.org/0000-0002-1023-1641; https://orcid.org/0000-0003-2647-475XA straightforward and convenient approach for the first total syntheses of chromanone A and a related 7-OMe substituted natural product is reported. These unique C-3 substituted 2-hydroxymethyl chromones were recently isolated as fungal metabolites. Chromanone A was synthesized in 25.3% overall yield from the readily available pyrocatechol, whereas the second natural product was prepared in 39.7% global yield. A small library of chromones, including both natural products and some of their synthetic heterocyclic precursors, was evaluated against Candida albicans ATCC 10231, a biofilm forming agent. It was found that 8-methoxy-3-methyl-4-oxo-4H-chromene-2-carbaldehyde, a partially oxidized form of chromanone A, exhibited a minimum inhibitory concentration of 7.8 μg mL−1 and significantly inhibited the yeast's virulence factors, including the adherence to buccal epithelial cells and the secretion of phospholipases, as well as the formation of germ tubes and the generation of the hyphal pseudomycelium. In addition, despite the heterocycle exhibiting non-significant inhibition of the formation of the Candida biofilm, it completely inhibited the growth of C. albicans in preformed biofilms at 62.5 μg mL−1.Ítem Acceso Abierto Synergistic effects of Thymus vulgaris essential oil in combination with antifungal agents and inhibition of virulence factors of Candida albicans(Elsevier, 2023-08-29) Butassi, Estefanía; Blanc, Alan Roy; Sortino, Maximiliano Andrés; Svetaz, Laura Andrea; https://orcid.org/0000-0002-4271-1690; https://orcid.org/0000-0002-1023-1641Background: Combination antifungal therapy has become a prominent approach in medical practice as it takes advantage of synergistic interactions by interfering with multiple targets of the pathogen, broadening the spectrum of activity, reducing the development of resistance, and improving treatment outcomes. Therefore, combining conventional antifungal drugs with natural products can increase antifungal activity, reduce side effects, and optimize therapeutic effects. Purpose: The present study aimed to evaluate the antifungal activity of thyme essential oil (ThyEO) in combination with amphotericin B, caspofungin, fluconazole, itraconazole, and posaconazole (PSZ), as well as its inhibitory effect on Candida albicans virulence factors. Materials and Methods: The microbroth dilution assay was employed to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). Interactions were assessed using the microdilution checkerboard assay. Ergosterol and methylene blue assays were used to detect effects on fungal membrane, while the sorbitol assay was used to detect effects on fungal cell wall. Inhibition of yeast virulence factors (adherence to epithelial cells, germ tube and pseudomycelium formation, secretion of hydrolytic enzymes, and biofilm formation) was assessed with previously reported methods. Results: Almost all combinations showed additivism against C. albicans, except ThyEO/PSZ (31.25/0.0039 µg/ml), which showed partial synergism. Furthermore, all mixtures were fungicidal against C. albicans strains. ThyEO/PSZ, its components alone, and thymol were shown to disrupt the fungal cytoplasmic membrane, increasing its permeability. ThyEO/PSZ, at sub-inhibitory concentrations, significantly decreased the ability of C. albicans to adhere to buccal epithelial cells. ThyEO/PSZ, ThyEO, and PSZ were able to reduce the pseudomycelium production of C. albicans while thymol completely inhibited its formation. ThyEO/PSZ, each combination component on its own, and thymol inhibited biofilm formation and preformed biofilm of C. albicans. Notably, ThyEO/PSZ showed synergistic and fungicidal activity against a resistant strain of C. albicans, reducing the PSZ dose by 4-fold. Conclusion: These findings make ThyEO and ThyEO/PSZ mixture valuable candidates for the development of alternative antifungals with a lower incidence of adverse effects.Ítem Acceso Abierto Unravelling early events in the Taphrina deformans–Prunus persica interaction: an insight into the differential responses in resistant and susceptible genotypes(Wiley, 2017-07-12) Svetaz, Laura Andrea; Bustamante, Claudia Anabel; Goldy, Camila; Rivero, Nery Alberto; Müller, Gabriela Leticia; Valentini, Gabriel Hugo; Fernie, Alisdair R.; Drincovich, María Fabiana; Lara, María Valeria; https://orcid.org/0000-0003-4914-0242; Dr. Bellini, E.: provide P. persica selections DOFI-84.364.089 and DOFI-84.364.060; Dr. Giordani, E.: provide P. persica selections DOFI-84.364.089 and DOFI-84.364.060Leaf peach curl is a devastating disease affecting leaves, flowers and fruits, caused by the dimorphic fungus Taphrina deformans. To gain insight into the mechanisms of fungus pathogenesis and plant responses, leaves of a resistant and two susceptible Prunus persica genotypes were inoculated with blastospores (yeast), and the infection was monitored during 120 h post inoculation (h.p.i.). Fungal dimorphism to the filamentous form and induction of reactive oxygen species (ROS), callose synthesis, cell death and defence compound production were observed independently of the genotype. Fungal load significantly decreased after 120 h.p.i. in the resistant genotype, while the pathogen tended to grow in the susceptible genotypes. Metabolic profiling revealed a biphasic re-programming of plant tissue in susceptible genotypes, with an initial stage co-incident with the yeast form of the fungus and a second when the hypha is developed. Transcriptional analysis of PRs and plant hormone-related genes indicated that pathogenesis-related (PR) proteins are involved in P. persica defence responses against T. deformans and that salicylic acid is induced in the resistant genotype. Conducted experiments allowed the elucidation of common and differential responses in susceptible versus resistant genotypes and thus allow us to construct a picture of early events during T. deformans infection.