Examinando por Autor "Poveda, Luis"

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Antimicrobial activities of Marcgraviaceae species and isolation of a naphthoquinone from Marcgravia nervosa (Marcgraviaceae)
(NRC Research Press, 2015) Carballo Arce, Ana Francis; Chieu Anh, Kim Ta; do Nascimento Rocha, Marco Eduardo; Rui, Liu; Harmsen, Irene; Mogg, Christopher; Otárola-Rojas, Marco; Garcia, Mario; Sánchez Vindas, Pablo; Poveda, Luis; Rajagopal Subramaniam; Smith, Myron; Coelho Kaplan, Maria Auxiliadora; Figueiredo, Maria Raquel; Durst, Tony; Arnason, John
The Marcgraviaceae is a neotropical plant family of lianas and shrubs distributed throughout Central and South America, mainly in evergreen and semi-evergreen tropical forests. In this study, extracts of 12 Marcgraviaceae species were assessed for inhibition of bacterial quorum sensing (QS) in Chromobacterium violaceum, bacterial biofilm formation in Pseudomonas aeruginosa PA14, and fungal growth in Saccharomyces cerevisiae. Six species showed promising inhibitory activities in at least one of the three bioassays (Marcgravia nervosa Triana & Planch., Marcgravia polyantha Delp., Marcgravia schippii Standl., Marcgraviastrum subsessile (Benth.) Bedell, Schwartzia brasiliensis (Choisy) Bedell ex Gir-Cañas, and Schwartzia costaricensis (Gilg.) Bedell). Analyses of the crude extract of the leaves of Marcgravia nervosa using HPLC–APCI–MS showed the presence of five pentacyclic triterpenes: ursolic acid (2), betulinic acid (3), α–amyrin (4), β–amyrin (5), lupeol (6). Bioassay-guided fractionation of this plant resulted in the isolation and identification of 2-methoxy-1,4-naphthoquinone (1) as the active principle with a minimum inhibitory concentration (MIC) of 85–100 μmol·L−1 against Saccharomyces cerevisiae BY4741 (haploid) and BY4743 (diploid).
Antimicrobial activity and physicochemical characterization of thermoplastic films based on bitter cassava starch, nanocellulose and rosemary essential oil
(SAGE Publications (Estados Unidos), 2022) Araya, Josette; ESQUIVEL, MARIANELLY; Jimenez, Guillermo; Navia, Diana; Poveda, Luis
Extended shelf-life of many foods is a modern requirement that has been achieved by means of fossil-based plastic films despite their environmental issues. Recently, starchbased, fully biodegradable thermoplastics are gaining momentum as packaging material; however, if they are in contact with food, aspects such storage, water interaction and spoilage due to microorganisms must be considered. Essential oils are of great interest due to their antimicrobial action, so incorporating these compounds into natural polymers can promote a longer shelf life through active packaging. In this study, antibacterial activity, optical, mechanical and barrier properties of thermoplastic starch (TPS) films based on cassava starch (Manihot esculenta Crantz) and rosemary essential oil (REO) were studied. Furthermore, the effect of cellulose nanocrystals (CNC) on TPS properties were surveyed. Film mechanical properties and those related to the interaction with water, showed that the highest resistance and barrier properties corresponded to the TPS/CNC 15% film, while adding oil to the films increased morphological heterogeneity, contributed to reduce tensile strength, and increased water solubility and water vapor permeability. Likewise, TPS films containing rosemary oil showed enhanced antibacterial activity mostly against E. coli and S. aureus bacteria and A. niger fungus. Therefore, adding essential oils as natural additives favors using these biocomposites as functional packaging, and as potential replacements for singleuse plastics.
Chemical constituents from Zanthoxylum setulosum (Rutaceae)
(Universidad Nacional, Costa Rica, 2011-02-10) Castro, Víctor; Poveda, Luis; Chavarria, Max; Mora Vasquez, Soledad; Murillo, Renato
Following our phytochemical studies of Costa Rican plants, in this work we report the isolation and identification of eight compounds from aerial parts of Zanthoxylum setulosum (Rutaceae). They were identified as the alkaloid skimmianine, the lignans savinin, kusunokinin, sesamin, syringaresinol and the isopentenyl ether of pluviatol, the amide aurantiamide acetate, and the triterpen lupeol. This is the first report of isolation of skimmianine from the leaves of Z. setulosum and its presence confirm that quinoline and benzophenanthridine alkaloids, can be considered as chemotaxonomic markers of this genus. All the isolated compounds were characterized by spectroscopic methods (including 1H-NMR, 13C-NMR, HMQC, HMBC and NOESY) and comparison with the literature data. © 2011 Boletín Latinoamericano y del Caribe de Plantas Medicinales y Aromáticas.
Cuatro compuestos nuevos del extracto no polar de la planta Amyris brenesii (Rutaceae) de Costa Rica
(Universidad de Costa Rica., 2008) Chavarría, Max; Castro, Victor; Poveda, Luis; Murillo, Renato
El estudio fitoquímico de las partes aéreas de Amyris brenesii (Rutaceae) recolectadas en Río Cuarto, Grecia, Alajuela (Costa Rica) mostró la presencia de cuatro nuevos compuestos: la 6-hidroxi-6-O-(3-hidroximetil-3-metilalil)- angelicina 1, el 6-(N-acetil-etanamin) -2,2-dimetil-2Hcromeno 2, el lignano 2,5-deshidrohinokinina 3 y la N-acetil-O-(geranil)-tiramina 4. Adicionalmente se aislaron los lignanos hinokinina 5, y justicidina E 6, las cumarinas escopoletina 7 y marmesina 8, el ácido 24-moretenoico 9 y el O-(3,3-dimetilalil)-halfordinol 10. Las separaciones se llevaron a cabo mediante la aplicación de técnicas cromatográficas y la elucidación de las estructuras se realizó con la ayuda de técnicas espectroscópicas de Resonancia Magnética Nuclear (RMN) de una y dos dimensiones.
New Botanical Anxiolytics for Use in Companion Animals and Humans
(Springer (Alemania), 2017-11) Liu, Rui; Ahmed, Fida; Cayer, Christian; Mullally, Martha; Carballo Arce, Ana Francis; Otarola Rojas, Marco; Garcia, Mario; Baker, John; Masic, Aleksandar; Sanchez, Pablo E.; Poveda, Luis; Merali, Zul; Durst, Tony; Arnason, John T.
As part of our ongoing research into botanical therapies for anxiety disorders, the neotropical vine Souroubea sympetala was chosen for study as a phytochemical discovery strategy focusing on rare Central American plant families. When orally administered to male Sprague-Dawley rats, the crude plant extract, its ethyl acetate fraction, supercritical carbon dioxide fraction, or its isolated triterpenes reduced anxiety and/or fear-related behavior in standardized behavioral models. Pharmacological studies showed that the extracts acted at the benzodiazepine GABAA receptor and reduced corticosterone levels. A preparation containing Souroubea fortified with a second triterpene containing plant, Platanus occidentalis, was shown to be safe in a 28-day feeding trial with beagles at 5 times the intended dose. Subsequent trials with beagles in a thunderstorm model of noise aversion showed that the material reduced anxiety behaviors and cortisol levels in dogs. The formulation has been released for the companion animal market in Canada and the USA under the Trademark "Zentrol". Ongoing research is exploring the use of the material in treatment of anxiety and post-traumatic stress in humans.
Phenolic variation among Chamaecrista nictitans subspecies and varieties revealed through UPLC-ESI(-)-MS/MS chemical fingerprinting
(Springer New York LLC, 2019-02) Chavarría, Max; Quirós‑Guerrero, Luis; Albertazzi, Federico; Araya‑Valverde, Emanuel; Romero, Rosaura M; Villalobos, Heidy; Poveda, Luis; Tamayo-Castillo, Giselle
Introduction Comparative analysis of metabolic features of plants has a high potential for determination of quality control of active ingredients, ecological or chemotaxonomic purposes. Specifically, the development of efficient and rapid analytical tools that allow the differentiation among species, subspecies and varieties of plants is a relevant issue. Here we describe a multivariate model based on LC–MS/MS fingerprinting capable of discriminating between subspecies and varieties of the medicinal plant Chamaecrista nictitans, a rare distributed species in Costa Rica. Methods Determination of the chemical fingerprint was carried out on a LC–MS (ESI-QTOF) in negative ionization mode, in detected and putatively identified compounds included proanthocyanidin oligomers, several flavonoid C- and O-glycosides, and flavonoid acetates. Principal component analysis (PCA), partial least square-discriminant analysis (PLS-DA) and cluster analysis of chemical profiles were performed. Results Our method showed a clear discrimination between the subspecies and varieties of Chamaecrista nictitans, separating the samples into four fair differentiated groups: M1=C. nictitans ssp. patellaria; M2=C. nictitans ssp. disadena; M3=C.nictitans ssp. nictitans var. jaliscensis and M4=C. nictitans ssp. disadena var. pilosa. LC–MS/MS fingerprint data was validated using both morphological characters and DNA barcoding with ITS2 region. The comparison of the morphological characters against the chemical profiles and DNA barcoding shows a 63% coincidence, evidencing the morphological similarity in C. nictitans. On the other hand, genetic data and chemical profiles grouped all samples in a similar pattern, validating the functionality of our metabolomic approach. Conclusion The metabolomic method described in this study allows a reliably differentiation between subspecies and varieties of C. nictitans using a straightforward protocol that lacks extensive purification steps.