Understanding and predicting the likely response of ecosystems to climate change are crucial challenges for ecology and for conservation biology. Nowhere is this challenge greater than in the tropics ...as these forests store more than half the total atmospheric carbon stock in their biomass. Biomass is determined by the balance between biomass inputs (i.e., growth) and outputs (mortality). We can expect therefore that conditions that favor high growth rates, such as abundant water supply, warmth, and nutrient-rich soils will tend to correlate with high biomass stocks. Our main objective is to describe the patterns of above ground biomass (AGB) stocks across major tropical forests across climatic gradients in Northwestern South America. We gathered data from 200 plots across the region, at elevations ranging between 0 to 3400 m. We estimated AGB based on allometric equations and values for stem density, basal area, and wood density weighted by basal area at the plot-level. We used two groups of climatic variables, namely mean annual temperature and actual evapotranspiration as surrogates of environmental energy, and annual precipitation, precipitation seasonality, and water availability as surrogates of water availability. We found that AGB is more closely related to water availability variables than to energy variables. In northwest South America, water availability influences carbon stocks principally by determining stand structure, i.e. basal area. When water deficits increase in tropical forests we can expect negative impact on biomass and hence carbon storage.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Malaria is an infectious disease caused by parasites of the genus Plasmodium, of which Plasmodium vivax and Plasmodium falciparum are the major species that cause the disease in humans. As there are ...relatively few alternatives for malaria treatment, it is necessary to search for new chemotherapeutic options. Colombia possesses a great diversity of plants, which are potential sources of new compounds of medical interest. Thus, in this study the antiplasmodial effect of extracts from two species of plants from the families Simaroubaceae and Picramniaceae (Picramnia latifolia and Picrolemma huberi) was evaluated in vitro and in vivo. These plants were chosen because they contain secondary metabolites with interesting medicinal effects.
The ethanolic extracts of both species were highly active with IC
: 1.2 ± 0.19 µg/mL for P. latifolia and IC
: 0.05 ± 0.005 µg/mL for P. huberi. The P. latifolia extract had a stage specific effect on trophozoites and inhibited parasite growth in vivo by 52.1 ± 3.4%, evaluated at 1000 mg/kg in Balb/c mice infected with Plasmodium berghei. On the other hand, evaluated at 150 mg/kg body weight in the same murine model, the ethanolic extract from P. huberi had an antiplasmodial effect in all the asexual intraerythrocytic stages of P. falciparum FCR3 and inhibited the parasitic growth in 93 ± 32.9%.
This is the first report of anti-malarial activity for these two species of plants. Thus, P. latifolia and P. huberi are potential candidates for the development of new drugs for treating malaria.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A new alkaloid, Canthin-6-one, Huberine (
), together with three known compounds including 1-Hydroxy-canthin-6-one (
), Canthin-6-one (
) and stigma sterol (
), were isolated from the stem bark of
. ...The isolation was achieved by chromatographic techniques and the purification was performed on a C18 column using acetonitrile/water (90:10,
/
) with 0.1% formic acid as the mobile phase. The structural elucidation was performed via spectroscopic methods, notably 1D- and 2D-NMR, UV, IR, MS and HRMS. The antiplasmodial activity of the compounds was studied.
Ecology, geography, morphology, and a combined phylogenetic analysis of DNA sequence variation support the recognition of the new species Luetzelburgia jacana (Leguminosae, Papilionoideae, vataireoid ...clade). This species is found in the inter-Andean Rio Cauca Valley in Colombia. Phylogenetic analyses of nine plastid and nuclear DNA sequences from 44 accessions representing all known Luetzelburgia species show that L. jacana is sister to the rest of the genus and has a mean estimated stem age of ca. 4 Ma, much older than other Luetzelburgia species. Luetzelburgia jacana is distinguished by a combination of mostly 7–9-foliolate, glabrous leaves with leaflets obtuse to shortly acute at the apex, flowers up to 9.6 mm long, and samaras bearing two small lateral wings on the seed chamber. Luetzelburgia jacana, along with two other earliestbranching species in the genus, L. guaissara and L. trialata, are geographical outliers in the genus, with L. jacana having the northernmost distribution and L. guaissara and L. trialata having the southernmost distributions. These three earliest-branching species are also ecological outliers within Luetzelburgia by occurring in wetter and less seasonal settings than other species. The discovery of L. jacana resolves these three earliest-branching species in Luetzelburgia as ecologically transitional between most species of the vataireoid clade that inhabit wet forests and most species of Luetzelburgia that inhabit highly seasonal dry forests and woodlands.
Oil from Lecythis tuyrana oilseeds is extracted for its potential use in food industry. The aim of this study was to gain knowledge on composition, antioxidant activity and thermal oxidative ...stability of this type of oil. Compositional parameters were evaluated. Antioxidant activity was evaluated by oxygen radical absorbance capacity and 2,2-diphenyl-1-picrylhydrazyl radical. Oxidative stability was evaluated by peroxide value, thiobarbituric acid reactive substances values and oxidative stability index (OSI). Thermal stability was determined by thermogravimetric assay and differential scanning calorimetry. Almonds were found to have a high oil content of 732 g·kg-1. Total carotenoids, tocopherols and phenols were also quantified. OSI showed an induction time of 3.47 h and it was thermostable up to 200 °C. It was possible to improve the stability of oil by 27.5 % under accelerated conditions, using butylated hydroxytoluene as an antioxidant. L. tuyrana is a good source of unsaturated fatty acids (oleic acid 369.0 g·kg-1, linoleic acid 272.0 g·kg-1, palmitic acid 171.0 g·kg-1, stearic acid 149.0 g·kg-1, arachidonic acid 10.0 g·kg-1, palmitoleic acid 7.0 g·kg-1), which are oxidatively stabilized by the presence of carotenoids, phenols and tocopherols. In this way, the new oil with interesting nutraceutical properties is proposed to be used in the food, cosmetic and pharmaceutical industry.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A synoptic review of Chionanthus species (Oleaceae) from Colombia and neighboring countries is presented, in which new information, taxonomic and chorological, is disclosed, and a new species, Ch. ...vargasii, from the Central Cordillera of Colombia. This species resembles Ch. abriaquiensis, but has coriaceous leaves, with shorter petioles and woolly domatia along the veins of the underside, and shorter inflorescences. Chionanthus guianensis and Ch. panamensis are cited for the first time in Colombia and the known distribution in Colombia of Ch. compactus, Ch. implicatus, and Ch. pubescens is extended. In addition, the reviewed material of Ch. avilensis, Ch. colonchensis, Ch. ligustrinus, and Ch. wudackii, all present in neighboring countries, is also commented. Finally, a key is included to facilitate the identification of the species of the north of South America.
La cuenca del río Claro en Antioquia, Colombia, es una región con gran importancia biológica, dado que alberga ecosistemas singulares, y una gran diversidad de especies de plantas, las cuales tienen ...un gran potencial de uso para las comunidades de la región. No obstante, hasta la fecha no se ha realizado una lista de las plantas útiles para la cuenca y este conocimiento aún permanece disperso. A fin de compilar, catalogar y dar a conocer este conocimiento, se construyó un listado de las especies nativas con el reporte de usos en información secundaria y primaria, con lo cual se generó un insumo de conocimiento que permita orientar esfuerzos de investigación y uso sostenible de la biodiversidad. Con este propósito, se consultaron fuentes tales como herbarios en los que reposan especímenes debidamente preservados y referencias de literatura especializada. Asimismo, se realizaron talleres con las comunidades para indagar sobre los usos locales, y posteriormente se categorizaron los tipos de uso. Se registraron 650 especies de la cuenca del río Claro con usos reportados en literatura, de las cuales 31 son endémicas de Colombia. En cuanto a los usos locales, se registraron 58 especies.
El estudio de los sistemas de dispersión de las plantas permite entender la regeneración de los bosques, la dinámica poblacional de las especies vegetales y las relaciones ecológicas que emergen ...dentro de los ecosistemas. En el presente estudio se analizaron los patrones de sistemas de dispersión de semillas para Colombia, en relación con las regiones geográficas Amazónica, Andina, Caribe, Magdalena Alto, Magdalena Medio, Orinoquía y Pacífica. A partir de la información sobre la identidad y abundancia de plantas encontradas en 101 parcelas de vegetación de 1-ha, se exploraron los cambios en la frecuencia relativa y abundancia relativa de sistemas de dispersión entre las regiones geográficas. Adicionalmente, se determinaron las afinidades florísticas entre las regiones, así como
Se describe una nueva especie del género Cordia, Cordia nicandroides, del norte de Colombia, la cual se distingue por sus frutos grandes, drupáceos, nuciformes, y protegidos por un amplio cáliz ...acrescente y pentacostado. Es un árbol que se da principalmente en bosques húmedos o de transición a bosque seco, asociado a cursos de agua. Tiene afinidades notables con Cordia oncocalyx, especie anemócora, endémica de los biomas Caatinga y Mata atlántica del oriente de Brasil, pero se diferencia bien de esta porque, primero, presenta cálices fructíferos de menor tamaño (43-45 x 53-56 mm) y estrechamente ceñidos al fruto, en tanto que en C. oncocalyx su tamaño es mayor (43-80 x 45-75 mm) y no están ceñidos al fruto; además, en C. nicandroides los frutos son anchamente ovoides y de mayor tamaño (40-42 x 38-40 mm), y en C. oncocalyx son anchamente elipsoides y más pequeños (17-21 x 16–19 mm). Si se considera el hábitat de esta especie, estos frutos, más grandes y compactos, con envoltura calicina rígida y apergaminada, sugieren la presencia del síndrome de hidrocoría en el tipo de dispersión de las diásporas.
A new species of
Magnolia
(Magnoliaceae), from Antioquia Province, Colombia is described.
Magnolia frontinoensis
, only known from a restricted area of the Western Cordillera, from 1700–1940 m, is ...recognized by the lamina bases decurrent and revolute, and the fruits small (11.7–29 × 8.4–21.5 mm). Besides the new species, two new records for Colombia are presented:
Magnolia gloriensis
, initially known to be found in Central America, from Nicaragua to Panama, it is now recorded in the Pacific region of Colombia. Also,
M. venezuelensis
, only known from the type collection in Venezuela Lara region, is now recorded in the Eastern Cordillera of Colombia. With these new records, the number of
Magnolia
species in Colombia increases to 38.
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