Browsing by Author "Gomez, Miguel"

Now showing 1 - 11 of 11
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    Antibacterial potential assessment of Nalca (Gunnera tinctoriaMol.) ethanolic extracts
    (2021) Velasquez, Patricia; Riquelme, Karla; Leyton, Felipe; Giordano, Ady; Gomez, Miguel; Montenegro, Gloria
    Nalca is an edible rhubarb-type plant from the southern of Chile; with studies focussing on petiole chemical and biological properties. This work evaluated for the first time the antibacterial capacities of three organs of nalca againstEscherichia coli,Staphylococcus aureusandPseudomonas aeruginosa. Petiole (P), root (R) and flower (F) ethanolic extracts at three different concentrations (25, 50, 100 mg/mL) were evaluated by means of agar diffusion assay and MIC. The result showed that antibacterial activities are bacteria and concentration dependent, with root having the highest antimicrobial activity of the organs plant studied. Compared to commercial antibiotics, nalca extracts show promising control overPs. aeruginosa. The main polyphenolics of the extracts were identified by UPLC-MS/MS, observing for the first time caffeic, coumaric and gallic acids presence in all samples, with quercetin and rutin determined in petiole and flower extracts only. Our results contribute to better understanding of nalca attributes as potential source of antibacterial compounds to be used in nutraceutical, cosmetic and food industry.
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    Biological activity of native Myrtaceae fruits from Chile as a potential functional food
    (2022) Velasquez, Patricia; Orellana, Jocelyn; Munoz-Carvajal, Eduardo; Faundez, Mario; Gomez, Miguel; Montenegro, Gloria; Giordano, Ady
    Myrtaceae fruits (Myrceugenia obtusa, Luma apiculata, and Luma chequen) were used as food and medicine by Chilean indigenous people. This study aimed to evaluate the bioactive properties of these berry-type fruits. The antioxidant capacity determined by the FRAP assay varied between 10.4 and 646.9 mmol Fe+2/g, while the antibacterial activity against Staphylococcus aureus and Salmonella typhi was 0 - 33 mm and 0 - 7.33 mm, respectively. All the extracts were rich in polyphenols and showed low cytotoxicity. Overall, M. obtusa presented dissimilar results compared to those of L. apiculata and L. chequen, encouraging the use of these native fruits as food, nutraceutical, or pharmacological ingredients.
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    Characterisation of seed dormancy of 12 Chilean species of Nolana (Solanaceae) from the coastal Atacama Desert
    (CAMBRIDGE UNIV PRESS, 2021) Hepp, Josefina; Gomez, Miguel; Leon Lobos, Pedro; Montenegro, Gloria; Vilalobos, Luis; Contreras, Samuel
    The genus Nolana (Solanaceae) comprises numerous species endemic to the coastal Atacama Desert of Chile and Peru of high ornamental potential and conservation value. The environments in which these species have evolved and are present today correspond to particular conditions in the midst of a hyper-arid habitat, so the study of their germination requirements and characterisation of seed dormancy becomes important in terms of conservation but also for ecological and evolutionary purposes. Different treatments were performed on mericarps of 12 species of Nolana: control (intact seeds imbibed in distilled water), scarification in funicular plug and distilled water and scarification in funicular plug and addition of GA(3) (500 ppm); their permeability to water was also tested. It was determined that the species did not present physical dormancy, as had been previously reported, but rather physiological dormancy (PD). Germination results after treatments were not homogeneous among all 12 species, indicating differences in their dormancy levels. Also, the important role of the endosperm in the prevention of germination for the studied Nolana species was highlighted. Regarding the relationship between the level of PD (expressed as the percentage of germination for the most successful treatment) and the latitudinal distribution of the species or their phylogenetic closeness, it was determined that, for the studied species, their proximity in terms of clades was more relevant than their latitudinal distribution.
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    Exudate and Propolis from Escallonia pulverulenta: Phytochemical Characterization and Antibacterial Activity
    (2024) Jorquera, Bairon; Valenzuela-Barra, Gabriela; Mayorga, Ailin; Mejia, Jessica; Nunez, Gabriel; Gomez, Miguel; Montenegro, Gloria; Quezada, Waleska E. Vera; Echeverria, Javier; de Camargo, Adriano Costa; von Poser, Gilsane Lino; Bridi, Raquel
    Propolis is a complex mixture formed from exudates that bees collect from plants and then mix with beeswax and their own salivary enzymes. Chilean propolis is characterized by the presence of phenolic compounds, which are considered responsible for the biological activities. The endemic species Escallonia pulverulenta (Ruiz and Pav.) Pers. [Escalloniaceae] is a recognized source of exudate to produce propolis. This study reports for the first time the chemical profile and antibacterial activity of E. pulverulenta exudate and leaves, as well as two samples of Chilean propolis. Palynological and morphological analysis showed the presence of E. pulverulenta as one of the main species in the propolis samples. UPLC-MS/MS analyses enabled the identification of phenolic acids in the leaves and in the propolis. Conversely, flavonoids are mainly present in exudates and propolis. Quercetin is the most abundant flavonol in the exudate, with similar concentrations in the propolis samples. Nevertheless, the main compound present in both samples of propolis was the flavanone pinocembrin. The antibacterial results obtained for exudate and propolis have shown a similar behavior, especially in the inhibition of Streptococcus pyogenes. These results show the importance of the exudates collected by the bees in the chemical composition and antibacterial capacity of propolis.
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    Hepatoprotective species from the Chilean medicinal flora: Junellia spathulata (Verbenaceae)
    (2021) Bridi, Raquel; von Poser, Gilsane Lino; Gomez, Miguel; Andia, Marcelo E.; Esteban Oyarzun, Juan; Nunenz, Paula; Vasquez Arias, Ariadsna Jael; Espinosa-Bustos, Christian
    Ethnopharmacological relevance: Chilean population relies on medicinal plants for treating a wide range of illnesses, especially those of the gastrointestinal system. Junellia spathulata (Gillies & Hook.) Moldenke var. spathulata (Verbenaceae), called as "verbena-azul-de-cordilleira", is a medicinal plant native to Argentina and Chile traditionally used for treating digestive disorders. Although the species of the genus ar e important as therapeutic resources for the Andean population, the plants are ver y scarcely studied.
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    Histochemical Analysis of Anthocyanins, Carotenoids, and Flavan-3-ols/Proanthocyanidins in Prunus domestica L. Fruits during Ripening
    (AMER CHEMICAL SOC, 2020) Vio Michaelis, Sofia; Feucht, Walter; Gomez, Miguel; Hadersdorfer, Johannes; Treutter, Dieter; Schwab, Wilfried
    As a result of the high variability of fruit properties in the European plum Prunus domestica, a histochemical analysis of fruits at different stages of development was performed to understand the ripening process in cv. 'Colora' (yellow-red skinned) and cv. 'Topfive' (purple skinned). Histological analysis showed that carotenoids in the fruit had two different origins. In the fruit flesh, they derived from chloroplasts that turned into chromoplasts, whereas carotenoids in the fruit skin derived probably from proplastids. Flavan-3-ols and proanthocyanidins showed differential localization during ripening. They were visible in the vacuole in different fruit tissues or organized in tannosomes in the fruit flesh. Tanninoplasts were observed only in hypodermal cells of 'Colora'. Toward maturity, anthocyanins were detected in the epidermis and later in the hypodermis of both cultivars. The study forms a basis for the analysis of the biosynthesis of secondary metabolites in European plums and their biological effects.
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    Nutritional and antioxidant potential of Chilean native fruits: lleuque (Prumnopitys andina) and copihue (Lapageria rosea)
    (VUP FOOD RESEARCH INST, BRATISLAVA, 2021) Giovagnoli vicuna, Claudia; Velasquez, Patricia; Montenegro, Gloria; Espejo, Jaime; Gomez, Miguel; Cabrera barjas, Gustavo; Giordano, Ady
    Nutritional and antioxidant properties of pulp and seeds of lleuque (Prumnopitys andina) and copihue (Lapageria rosea) were investigated. Proximal analysis revealed that the pulps are rich in carbohydrates, whereas the seeds are a good source of fibre. Both pulps exhibited higher phenolics content (PC) and flavonoids content (FC), as well as antioxidant capacities, compared to seeds. The data showed that PC correlated with antioxidant capacity the strongest, followed by FC and anthocyanins content. It was observed that global antioxidant score and relative antioxidant capacity index represented the antioxidant capacity behaviour of the extracts. According to the polyphenol antioxidant coefficients calculation, PC was an important contributor to antioxidant capacity of all extracts. The results of this study confirmed that the native Chilean fruits lleuque and copihue are an excellent source of antioxidants.
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    Propagation of Sophora toromiro through interspecific grafting to support species conservation
    (2013) Espejo, Jaime; Baeza, Marcelo; Ruiz, Eduardo; Mora, Freddy; Gomez, Miguel; Montenegro, Gloria
    J. Espejo, M. Baeza, E. Ruiz, F. Mora, M. Gomez, and G. Montenegro. 2013. Propagation of Sophora toromiro through interspecific grafting to support species conservation. Cien Inv. Agr. 40(1):213-221. This report provides information on applying the cleft grafting technique in the species Sophora toromiro (Phil.) Skottsb., focused on its propagation, and contributes to the conservation of the genetic base of this species in the medium and long term. A germplasm collection was obtained via interspecific grafting using Sophora cassioides (Phil.) Sparre as rootstock, employing two variations of cleft grafting sealing. The survival of 301 S. toromiro grafts of the Titze line at ten months was 64% or 95%, according to the type of sealing performed. A second experiment, comparing the origin of the material, indicated that the plants of Goteborg origin showed survival values close to 63%, versus 58% for those from the Jardin Botanic Nacional de Vina del Mar (Chile). This work presents a new approach for the recovery of S. toromiro and other woody species that are classified as endangered or highly threatened through the cleft grafting technique, in this case, onto S. cassioides.
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    Seed Morpho-Anatomy, Dormancy and Germination Requirements in Three Schizanthus Species (Solanaceae) with Ornamental Potential
    (2024) Moreno, Joaquin; Gomez, Miguel; Contreras, Samuel
    Schizanthus carlomunozii, S. hookeri, and S. porrigens are herbaceous species native to Chile and Argentina and have high ornamental potential. Their propagation through seeds is challenging due to low and uneven germination percentages. This study aimed to determine the morpho-anatomical characteristics, dormancy, and germination requirements of the seeds of these three species. The seeds from all three species have a flattened and reniform shape with a foveolate testa. However, the seeds of S. hookeri are distinguished by their larger size, more pronounced C-shape, seed coat with more marked prominences, and symmetrically arranged areoles. Histological analysis and imbibition tests with methylene blue revealed that the seeds have well-developed embryos and permeable seed coats, ruling out physical and morphological dormancy. Germination tests under various conditions showed that the seeds of the three species exhibit physiological dormancy. Imbibition in gibberellic acid (200 ppm) proved to be an effective treatment to promote germination. When evaluated in S. hookeri seeds, cold stratification and after-ripening also improved germination. The optimal temperatures for seed germination were calculated to be 26 degrees C for S. carlomunozii, 19 degrees C for S. hookeri, and 23 degrees C for S. porrigens.
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    Species richness, diversity and human activities in an elevation gradient of a high-ecosystem in Lagunas Huascoaltinas, Atacama Region, Chile
    (2009) Sanhueza, Doris; Miranda, Marcelo; Gomez, Miguel; Bonacic, Cristian
    D. Sanhueza, M. Miranda, M. Gomez, and C. Bonacic. 2009. Species richness, diversity and human activities in an elevation gradient, a high-ecosystem, Lagunas Huascoaltinas, Atacama Region, Chile. Cien. Inv. Agr. 36(3):411-424. The relationship between species richness, diversity and grazing frequency along an altitudinal gradient (1900-3400 m) of an Andean ecosystem indicates that there is an intense human pressure on vegetation use. To identify the vascular flora and its conservation, 20 sites were sampled in two visits during 2006. We identified 79 taxa, including 62.03% native species, 22.78% adventitious and 8.86% endemic (the remaining 6.33% was identified only at the genus level). Some genera were underrepresented. We also observed latitudinal limits (Alstremeria andina), monotypic genera (Geoffroea, Kurzamra, Phragmiles, Tessaria and Salix) and monogeneric families (Buddlejaceae, Ephedraceae, Equisetaceae, Malesherbiaceae, Salicaceae and Oxalidaceae). Moreover, we found differences in the species distribution patterns during periods of grazing use and identified statistically significant differences in the species richness (p < 0.001), diversity (p = 0.010) and grazing frequency (p = 0.047).