Escuela de Química

URI permanente para esta comunidadhttp://10.0.96.45:4000/handle/11056/14435

Misión Contribuir con el desarrollo integral de la sociedad costarricense en un marco de solidaridad y armonía con la naturaleza, por medio de su quehacer en investigación, extensión, docencia y producción, lo que permite la generación de conocimiento, la vinculación externa y la formación y actualización de profesionales en Enseñanza de la Química, Química y sus aplicaciones. Visión Es la Escuela de Química con liderazgo por su excelencia académica, innovación, y vocación de servicio en las áreas de Enseñanza de la Química, Química y sus aplicaciones. Goza de prestigio, a partir de una oferta académica (investigación, docencia, extensión y producción) actualizada, flexible y que responde a las necesidades emergentes del desarrollo nacional e internacional.

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Mostrando 1 - 4 de 4

Antioxidant and antibacterial extracts from rambutan (Nephelium lappaceum) skins: Exploring the Potential of Transforming Agricultural Byproducts into Functional Supplements
(Tecnológico de Costa Rica (TEC) (Costa Rica), 2024) Álvarez-Valverde, Victor; Alfaro-Zúñiga, Carlos; Passos Pequeño, Andréia; Carvajal-Miranda, Yendri; Rodríguez Rodríguez, Jorengeth Abad; Rodríguez, Gerardo; Jiménez-Bonilla, Pablo
Abstract. Rambutan (Nephelium lappaceum L.) is a tropical fruit characterized by its oval shape and hairy skin, primarily valued for its juicy pulp. The peels, constituting 45% of the fruit’s weight, are a source of valuable compounds like geraniin, ellagic acid, and quercetin. These peels possess antimicrobial properties effective against various bacteria, making them suitable for food preservation and packaging. Additionally, rambutan extracts hold promise as supplements in animal feed, enhancing growth and reducing methane production. This research delves into the antioxidant and antimicrobial attributes of diverse rambutan varieties. The skin (exocarp) of rambutan fruits from three Costa Rican cultivars -Creole, Rongrein, and Yellow- were collected and processed. Total polyphenolic content (TPC), proanthocyanidins, antioxidant activity, geraniin content, and antimicrobial activity were determined for the three varieties. Also, proanthocyanidin-enriched fractions from rambutan extracts were generated and analyzed. The results revealed TPC and antioxidant activity variations among different rambutan varieties and harvest years. All rambutan extracts displayed antimicrobial activity. In conclusion, the research underscores the rich antioxidant content in rambutan peels, irrespective of the variety, and underscores their potential for use in both human and animal nutrition due to their chemical composition.
Bioguided Phytochemical Study of Ipomoea cairica Extracts with Larvicidal Activity against Aedes aegypti
(MDPI, 2022-02-16) Álvarez Valverde, Víctor; Rodríguez Rodríguez, Gerardo; Argüello-Vargas, Silvia
Vector-borne diseases, such as those transmitted by Aedes aegypti, are a constant threat to inhabitants of tropical regions of the planet. Synthetic chemicals are commonly used as a strategy to control them; however, these products are known to persist in ecosystems and drive the appearance of resistance genes in arthropod vectors. Thus, the use of natural products has emerged as an environmentally friendly alternative in integrated vector control strategies. The present bioguided study investigated the larvicidal potential of Ipomoea cairica extracts, fractionated using thin-layer and open-column chromatography, because this species has been shown to exert larvicidal effects on the genus Aedes. The objective of this study was to evaluate the nonvolatile components in ethanolic extract of I. cairica stems as a potential natural larvicidal, and coumarins, such as 7-hydroxy- 6-methoxychromen-2-one (scopoletin) and 7-hydroxychromen-2-one (umbelliferone), were identified as major compounds; however, they were not shown to be responsible for the larvicidal activity. Based on the results of the larvicidal action tests, these coumarins are not directly responsible for the larvicidal activity, but this activity might be attributed to a synergistic effect of all the compounds present in the most active secondary fraction, called F.DCM, which had an LC50 value of 30.608 mg/L. This type of study has yet not been conducted in the region; therefore, it is an important contribution to recognizing a natural and easy-to-cultivate source of vector control, such I. cairica.
Insecticidal activity of ethanolic plant extracts on Aedes aegypti larvae
(Universidad Nacional (Costa Rica), 2023-06-01) Álvarez-Valverde, Victor; Rodríguez, Gerardo; Argüello-Vargas, Silvia
The objective of this study was to determine the larvicidal activity against A. aegypti of ethanolic extracts of plants commonly found in Costa Rica. [Methodology] Larvicidal activity of ethanolic extracts of plants was determined in this study using the WHO/VBC/81.807: WHO/VBC/81. from 1981. An analysis PROBID for dose response was conducted to determine LC50 of the most prominent extracts. [Results] A total of six extracts with the highest toxicity were chosen, with the stem extract of Ipomoea cairica having the lowest LC50 of 0.0341 mg/mL, followed by I. cairica leaf extract with an LC50 of 0.121 mg/mL. The larvicidal activity of ethanolic extracts of plants was determined in this study, with an emphasis on the larvicidal potential of I. cairica as an environmentally friendly alternative for the control of A. aegypti.[Conclusions] The larvicidal activity for ethanolic extracts of different plants, with an emphasis on the larvicidal potential of I. cairica as an environmentally friendly alternative for the control of A. aegypti
Quimioprospección de la resina de la flor de Clusia valerioi (Standl.) y su relación con la composición química de propóleos de una región de la zona sur de Costa Rica
(Universidad Nacional (Costa Rica), 2024) Segura Víquez, Andrea; Soto-Fallas, Roy; Borbón Alpízar Henry; Valdés Díaz, Sandra; Umaña Rojas Eduardo; Zamora Fallas, Luis G.; Sánchez Chaves, Luis; Fallas Matamoros, Natalia; Montenegro Hidalgo, Víctor M.; Alfaro-Alarcon, Alejandro; Guevara González, Mariana; Romero Vega, Luis; Loaiza Montoya Randall; Picado Canales, Natalín; Barrantes Murillo, Erika; Soto Fallas, Roy
Resumen. Los propóleos son subproductos apícolas elaborados por abejas del género Apis mellífera y de otras especies, que presentan muchos tipos de bioactividad. Su origen y composición puede relacionarse con el entorno botánico del sitio de anidación de las abejas, tal es el caso de la planta Clusia valerioi (Standl.), especie endémica de Costa Rica, cuya flor produce una resina utilizada por las abejas que la visitan para la producción de propóleos. Lo anterior implica la posibilidad de establecer una trazabilidad de la composición química de la resina de la flor de C. valerioi (Standl.) y de los propóleos recolectados de apiarios ubicados en la Zona Sur de Costa Rica, en términos de relacionar la presencia de compuestos tipo flavonoides, ácidos fenólicos y del tipo benzofenonas policíclicas polipreniladas (nemorosona) en ambos tipos de matrices, para la identificación de posibles biomarcadores activos para futuros estudios. Extractos metanólicos de muestras de propóleos de ocho apiarios visitados y extractos etanólicos de resina floral de C. valerioi (Standl.) de cuatro sitios cercanos a dos de estos apiarios, muestreados en la zona de Coto Brus (Costa Rica), fueron analizados y derivatizados con técnicas de HPTLC estableciéndose la presencia de 3 marcadores químicos importantes (compuestos A, B y C), a partir de análisis de espectros de resonancia magnética nuclear de protones (1H-NMR) y carbono-13 (13C-RMN), espectros de absorción y cromatografías para 16 extractos de propóleos, resinas y flores C. valerioi (Standl.). Se identificó el compuesto A como un compuesto derivado de los terpenos, el compuesto B como nemorosona y el compuesto C como un derivado de los flavonoides del tipo flavonol o flavonona.

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Examinando Escuela de Química por browse.metadata.procedence "Escuela de Medicina Veterinaria"