Oleas Gallo, Nora Helena
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Oleas Gallo, Nora Helena
Main Affiliation
Quito
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noraoleas@uti.edu.ec
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Scopus Author ID
12645534600

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Alkaloid Profiling and Anti-Cholinesterase Potential of Three Different Genera of Amaryllidaceae Collected in Ecuador: Urceolina Rchb., Clinanthus Herb. and Stenomesson Herb.

2024 , Luciana R. Tallini , Karen Acosta León , Raúl Chamorro , Edison H. Osorio , Jaume Bastida , Lou Jost , Oleas Gallo, Nora Helena

Ecuador is an important center of biodiversity for the plant subfamily Amaryllidoideae, known for its important bioactive molecules. This study aimed to assess the chemical and biological potential of four different Amaryllidoideae species collected in Ecuador: Urceolina formosa, Urceolina ruthiana, Clinanthus incarnatus, and Stenomesson aurantiacum. Twenty-six alkaloids were identified in the bulb extracts of these species using GC-MS. The extract of S. aurantiacum exhibited the greatest structural diversity and contained the highest amounts of alkaloids, particularly lycorine and galanthamine. Only for this species, identification of all the alkaloids belonging to this chemical profile was not possible. Six of them remain unidentified. The potential of these three Amaryllidoideae genera against Alzheimer’s disease was then evaluated by measuring their AChE and BuChE inhibitory activity, revealing that C. incarnatus and U. formosa (from Sucumbíos province) showed the best results with IC50 values of 1.73 ± 0.25 and 30.56 ± 1.56 µg·mL−1, respectively. Molecular dynamic assays were conducted to characterize the possible interactions that occurs among 2-hydroxyanhydrolycorine and the AChE enzyme, concluded that it is stabilized in the pocket in a similar way to galanthamine. This study expands our understanding of the biodiversity of Amaryllidoideae species from Ecuador, highlighting their potential as source of chemical compounds with pharmaceutical applications.

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Taxonomy based on science is necessary for global conservation

2018 , Thomson S.A. , Pyle R.L. , Ahyong S.T. , Alonso-Zarazaga M. , Ammirati J. , Araya J.F. , Ascher J.S. , Audisio T.L. , Oleas Gallo, Nora Helena

[No abstract available]

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Water quality assessment of the cutuchi river basin (Ecuador): A review of technical documents

2021 , Zapata D. , Oleas Gallo, Nora Helena , Páez-Vacas, Mónica , Tobes, Ibon

The Cutuchi River Basin extends over the inter-Andean valley south of the Cotopaxi Volcano, in Ecuador. It flows through two provinces, Cotopaxi and Tungurahua, and its waters are extensively used to irrigate crops that provide food to the main cities in the country. Unfortunately, the basin receives untreated domestic and industrial discharges. The need for an environmental quality assessment of the river has been acknowledged over the years. The aim of this study is to gather information about water quality of the Cutuchi River through a historical bibliographic review. A total of 57 works published between 2007 and 2018 were found, including books, articles, thesis and project reports. Only 18 documents provided biological, physical, or chemical data linked to water quality. The data obtained through the literature review were compared with maximum thresholds from national and international regulations. Unfortunately, revised studies were scattered on time and randomly along the basin and did not provide robust information to evaluate the state of the water-system. Some contamination was detected significantly exceeding safety thresholds. More exhaustive studies along the basin are needed as a baseline to help the decision makers to design management plans and mitigate human impacts. © 2020 Institute of Physics Publishing. All rights reserved.

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Recent diversification in the high Andes: Unveiling the evolutionary history of the Ecuadorian hillstar, Oreotrochilus chimborazo (Apodiformes: Trochilidae)

2021 , Bonaccorso E. , Rodríguez-Saltos C.A. , Freile J.F. , Peñafiel N. , Rosado-Llerena L. , Oleas Gallo, Nora Helena

Studying the genetic signatures of evolutionary diversification in young lineages is among the most promising approaches for unveiling the processes behind speciation. Here, we focus on Oreotrochilus chimborazo, a high Andean species of hummingbird that might have experienced rapid diversification in the recent past. To understand the evolution of this species, we generated a dataset of ten microsatellite markers and complementary data on morphometrics, plumage variation and ecological niches. We applied a series of population and coalescent-based analyses to understand the population structure and differentiation within the species, in addition to the signatures of current and historical gene flow, the location of potential contact zones and the relationships among lineages. We found that O. chimborazo comprises three genetic groups: one corresponding to subspecies O. c. chimborazo, from Chimborazo volcano and surroundings, and two corresponding to the northern and southern ranges of subspecies O. c. jamesonii, found from the extreme south of Colombia to southern Ecuador. We inferred modest levels of both contemporary and historical gene flow and proposed the location of a contact zone between lineages. Also, our coalescent-based analyses supported a rapid split among these three lineages during the mid-to-late Holocene. We discuss our results in the light of past and present potential distributions of the species, in addition to evolutionary trends seen in other Andean hummingbirds. © 2021 The Linnean Society of London, Biological Journal of the Linnean Society.

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Genotyping‐by‐sequencing informs conservation of Andean palms sources of non‐timber forest products

2024 , Nicolás Peñafiel Loaiza , Abigail H. Chafe , Mónica Moraes R , Oleas Gallo, Nora Helena , Julissa Roncal

Conservation and sustainable management of lineages providing non‐timber forest products are imperative under the current global biodiversity loss. Most non‐timber forest species, however, lack genomic studies that characterize their intraspecific variation and evolutionary history, which inform species' conservation practices. Contrary to many lineages in the Andean biodiversity hotspot that exhibit high diversification, the genus Parajubaea (Arecaceae) has only three species despite the genus' origin 22 million years ago. Two of the three palm species, P. torallyi and P. sunkha, are non‐timber forest species endemic to the Andes of Bolivia and are listed as IUCN endangered. The third species, P. cocoides, is a vulnerable species with unknown wild populations. We investigated the evolutionary relationships of Parajubaea species and the genetic diversity and structure of wild Bolivian populations. Sequencing of five low‐copy nuclear genes (3753 bp) challenged the hypothesis that P. cocoides is a cultigen that originated from the wild Bolivian species. We further obtained up to 15,134 de novo single‐nucleotide polymorphism markers by genotyping‐by‐sequencing of 194 wild Parajubaea individuals. Our total DNA sequencing effort rejected the taxonomic separation of the two Bolivian species. As expected for narrow endemic species, we observed low genetic diversity, but no inbreeding signal. We found three genetic clusters shaped by geographic distance, which we use to propose three management units. Different percentages of missing genotypic data did not impact the genetic structure of populations. We use the management units to recommend in situ conservation by creating new protected areas, and ex situ conservation through seed collection.

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In vitro and in silico analysis of galanthine from Zephyranthes carinata as an inhibitor of acetylcholinesterase

2022 , Sierra, K. , de Andrade, J.P. , R. Tallini, L. , Osorio, E.H. , Yañéz, O. , Osorio, M.I. , Oleas Gallo, Nora Helena , García-Beltrán, O. , de S. Borges, W. , Bastida, J. , Osorio, E. , Cortes, N.

Zephyranthes carinata Herb., a specie of the Amaryllidoideae subfamily, has been reported to have inhibitory activity against acetylcholinesterase. However, scientific evidence related to their bioactive alkaloids has been lacking. Thus, this study describes the isolation of the alkaloids of this plant, and their inhibition of the enzymes acetylcholinesterase (eeAChE) and butyrylcholinesterase (eqBuChE), being galanthine the main component. Additionally, haemanthamine, hamayne, lycoramine, lycorine, tazettine, trisphaeridine and vittatine/crinine were also isolated. The results showed that galanthine has significant activity at low micromolar concentrations for eeAChE (IC50 = 1.96 μg/mL). The in-silico study allowed to establish at a molecular level the high affinity and the way galanthine interacts with the active site of the TcAChE enzyme, information that corroborates the result of the experimental IC50. However, according to molecular dynamics (MD) analysis, it is also suggested that galanthine presents a different inhibition mode that the one observed for galanthamine, by presenting interaction with peripheral anionic binding site of the enzyme, which prevents the entrance and exit of molecules from the active site. Thus, in vitro screening assays plus rapid computer development play an essential role in the search for new cholinesterase inhibitors by identifying unknown bio-interactions between bioactive compounds and biological targets. © 2022 The Authors

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Phylogeny of Weinmannia (Cunoniaceae) reveals the contribution of the southern extratropics to tropical Andean biodiversity

2025 , Ricardo A. Segovia , Eduardo Aguirre-Mazzi , Christine E. Edwards , Alexander G. Linan , Alfredo Fuentes , Andrea Chaspuengal , Kyle G. Dexter , Francisco Fajardo-Gutiérrez , William Farfan-Rios , Oleas Gallo, Nora Helena , Juan C. Penagos Zuluaga , J. Sebastián Tello

The Andes are a relatively young mountain range with impressive biodiversity, but the biogeographic processes underlying its hyperdiversity are still being unraveled. Novel mid- to high-elevation climates may have served as a biological corridor for the immigration of temperate-adapted lineages to more equatorial latitudes, contributing unknown levels of diversity to this region. We tested the hypothesis that Weinmannia is a lineage of extratropical origin that recently reached and then diversified extensively in the tropical Andes. Using a 2bRAD seq approach to generate a time-calibrated phylogeny for the genus, we found that extratropical species were placed as sister to the rest of Weinmannia and that younger clades were distributed towards more equatorial latitudes. Although Weinmannia exhibited low niche conservatism in elevation and latitude, trait reconstructions of climatic variables showed that the common ancestor of Weinmannia occupied cool climates, with high conservatism of thermal and water availability niche across the phylogeny. Thus, Andean uplift likely created habitats with suitable environmental conditions, providing a dispersal route for extant Weinmannia to colonize the tropical Andes from the southern extratropics. These southern lineages likely converged with those originating in other tropical and extratropical centers of diversification, providing multiple origins for the hyperdiversity in the modern montane forests of the tropical Andes.

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Trees of Amazonian Ecuador: a taxonomically verified species list with data on abundance and distribution

2019 , Guevara Andino J.E. , Pitman N.C.A. , Ulloa Ulloa C. , Romoleroux K. , Fernández-Fernández D. , Ceron C. , Palacios W. , Neill D.A. , Oleas Gallo, Nora Helena , Rivas Torres G. , Altamirano P. , ter Steege H.

We compiled a data set for all tree species collected to date in lowland Amazonian Ecuador in order to determine the number of tree species in the region. This data set has been extensively verified by taxonomists and is the most comprehensive attempt to evaluate the tree diversity in one of the richest species regions of the Amazon. We used four main sources of data: mounted specimens deposited in Ecuadorian herbaria only, specimen records of a large-scale 1-hectare-plot network (60 plots in total), data from the Missouri Botanical Garden Tropicos® database (MO), and literature sources. The list of 2,296 tree species names we provide in this data set is based on 47,486 herbarium records deposited in the following herbaria: Alfredo Paredes Herbarium (QAP), Catholic University Herbarium (QCA), Herbario Nacional del Ecuador (QCNE), Missouri Botanical Garden (MO), and records from an extensive sampling of 29,768 individuals with diameter at breast height (dbh) ≥10 cm recorded in our plot network. We also provide data for the relative abundance of species, geographic coordinates of specimens deposited in major herbaria around the world, whether the species is native or endemic, current hypothesis of geographic distribution, representative collections, and IUCN threat category for every species recorded to date in Amazonian Ecuador. These data are described in Metadata S1 and can be used for macroecological, evolutionary, or taxonomic studies. There are no copyright restrictions; data are freely available for noncommercial scientific use (CC BY 3.0). Please see Metadata S1 (Class III, Section B.1: Proprietary restrictions) for additional information on usage. © 2019 The Authors. Ecology © 2019 The Ecological Society of America

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Alkaloids of Phaedranassa dubia (Kunth) J.F. Macbr. and Phaedranassa brevifolia Meerow (Amaryllidaceae) from Ecuador and its cholinesterase-inhibitory activity

2021 , León K.A. , Inca A. , Tallini L.R. , Osorio E.H. , Robles J. , Bastida J. , Oleas Gallo, Nora Helena

Alzheimer's disease is considered the most common cause of dementia and, in an increasingly aging population worldwide, the quest for treatment is a priority. Amaryllidaceae alkaloids are of main interest because of their cholinesterase inhibition potential, which is the main palliative treatment available for this disease. We evaluated the alkaloidal profile and the in vitro inhibitory activity on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) of bulb alkaloid extract of Phaedranassa dubia and Phaedranassa brevifolia collected in Ecuador. Using gas chromatography coupled to mass spectrometry (GC-MS), we identified typical Amaryllidaceae alkaloids in these species, highlighting the presence of lycorine-type alkaloids in P. dubia and haemanthamine/crinine-type in P. brevifolia. The species P. dubia and P. brevifolia showed inhibitory activities against AChE (IC50 values of 25.48 ± 0.39 and 3.45 ± 0.29 μg.mL−1, respectively) and BuChE (IC50 values of 114.96 ± 4.94 and 58.89 ± 0.55 μg.mL−1, respectively). Computational experiments allowed us to understand the interactions of the alkaloids identified in these samples toward the active sites of AChE and BuChE. In silico, some alkaloids detected in these Amaryllidaceae species presented higher estimated binding free energy toward BuChE than galanthamine. This is the first study about the alkaloid profile and biological potential of P. brevifolia species. © 2020 SAAB

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Typification of names of Weinmannia (Cunoniaceae) of species described by José Cuatrecasas from Colombian collections

2025 , Carmen Ulloa Ulloa , Andrea Chaspuengal-Morales , Francisco Fajardo-Gutiérrez , Oleas Gallo, Nora Helena

We propose 18 new lectotype designations for names of Weinmannia, five of which are second-step typifications involving four inadvertent first-step lectotype designations, and 13 of them are designations of one single duplicate at the herbarium where deposited. José Cuatrecasas described all, but one, of the taxa from collections made in Colombia. We clarify the lectotypification for Weinmannia parvifoliolata Cuatrec. Finally, we propose one lectotype designation for W. cochensis described by Georg Hieronymus.

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