Marysol Alvear

The antifungal effect of six commercial extracts of Chilean propolis on Candida spp

Propolis has been used in traditional medicine for many centuries because of its beneficial health properties, including its antimicrobial capacity. Prosthesis stomatitis affects a significant percentage of users of removable dentures; Candida albicans is the most common fungal species associated with the development of this pathology. Thus, the objectives of this study were: a. To evaluate the antifungal activity of six commercial propolis extracts against Candida spp. that was isolated from the oral cavity of removable dentures users, and b. To determine chemical characteristics of the propolis extracts evaluated. Among the results, we note that these concentrations of polyphenols varied between 9 ± 0.3 and 85 ± 2.1 mg mL-1. Chromatographic analysis was able to detect 35 compounds, among which were caffeic acid, myricetin, quercetin, kaempferol, apigenin, pinocembrin, galangin, and caffeic acid phenyl ester (CAPE). All strains tested were inhibited by the liquid extracts of propolis. The MID ranged between 1:40 and 1:1280, and the MIC for C. albicans ranged from 197 µg mL-1 to 441 µg mL-1. From the results obtained in this investigation, we can conclude that all propolis extracts evaluated are capable of inhibiting the development of Candida spp. However, they show significant differences in the concentration of polyphenols present and in antifungal activity. El propoleo ha sido utilizado por la medicina tradicional desde hace muchos siglos debido a sus propiedades beneficas para la salud, entre las que destaca su capacidad antimicrobiana. La estomatitis subprotesica, afecta a un porcentaje importante de usuarios de protesis dental removible, siendo Candida albicans la especie fungica mas comun asociada al desarrollo de esta patologia. Asi, los objetivos de este estudio fueron: a) evaluar la actividad antifungica de seis extractos de propoleos comerciales sobre cepas de Candida spp. aisladas de la cavidad oral de usuarios de protesis dental removible, y b) determinar algunas caracteristicas quimicas de los extractos de propoleos utilizados. Entre los resultados obtenidos, podemos senalar que estos mostraron concentraciones de polifenoles que variaron entre 9 ± 0,3 y 85 ± 2,1 mg/mL. El analisis cromatografico permitio detectar 35 compuestos, entre los cuales se logro identificar la presencia de acido cafeico, miricetina, quercetina, kaempferol, apigenina, pinocembrina, galangina y acido cafeico fenil ester (CAPE). Todas las cepas de Candida spp. evaluadas fueron inhibidas por los seis extractos liquidos de propoleos, observandose que la DIM vario entre 1/40 y 1/1280, y la CIM para C. albicans vario entre 197 µg/mL y 441 µg/mL. A partir de los resultados obtenidos en esta investigacion podemos concluir que todos los propoleos evaluados son capaces de inhibir el desarrollo de Candida spp. , sin embargo, estos muestran importantes diferencias en la concentracion de los polifenoles presentes y en la actividad antifungica.

Antifungal activity of volatile metabolites emitted by mycelial cultures of saprophytic fungi

The antifungal activity of molecular identified Chilean saprobiontic fungi, Trichoderma viride, Schizophyllum commune and Trametes versicolor, on the fungal plant pathogens Botrytis cinerea and Fusarium oxysporum, and the saprotrophic mould Mucor miehei was investigated using two types of inhibition bioassay: (1) bi-compartmented Petri dishes and (2) two Erlenmeyer flasks connected by their upper parts. The chemical composition of volatile organic compounds (VOCs) released by saprobiontic fungi was also investigated using headspace solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC-MS) analysis. Of the saprobiontic fungi evaluated, one isolate of S. commune showed the highest inhibitory activity against B. cinerea and M. miehei, 86.0±5.4 and 99.5±0.5% respectively. The volatile profiles of fungal isolates were shown to contain a different class of compounds. The major components in the headspace of mycelial cultures were 6-pentyl-α -pyrone (T. viride), ethanol and β -bisabolol (S. commune), and a sesquiterpene alcohol (Tr. versicolor). This is the first study reported on the release of VOCs by Chilean native fungi and their antifungal activity wrt. plant pathogenic fungi.

Evaluation of aluminum tolerance of three barley cultivars by two short-term screening methods and field experiments

Abstract Productivity of cereal crops growing in acid soils of Southern Chile have adversely being affected by acidification and aluminum phytotoxicity. For overcoming such constraints, farmers need to apply heavy amounts of lime and/or use AI-tolerant plants especially with AI-sensitive crops, as barley is. The objectives of this study were to determine the degree of Al tolerance of . three barley cultivars commonly grown in volcanic soils by using two shortterm screening methods and to relate their rankings with field experiments. Additionally, the amounts of citric and malic acids exuded from roots were determined for studying the mechanism involved in Al tolerance. Relative root length (RRL) was the criterion used to evaluate Al tolerance both in nutrient solution and in soil-based culture and yield for field experiments. Results showed a close relationship between the RRL values obtained with the three barley cultivars by applying the two short-term screening methods. Barley yields obtained in field ...

Identification of pharmacogenetic predictors of lipid-lowering response to atorvastatin in Chilean subjects with hypercholesterolemia.

BACKGROUND Statins are normally the first-line therapy for hypercholesterolemia (HC); however, the lipid-lowering response shows high interindividual variation. We investigated the effect of four polymorphisms in CYP3A4, CYP3A5 and ABCB1 genes on response to atorvastatin and CYP3A4 activity in Chilean subjects with HC. METHODS A total of 142 hypercholesterolemic individuals underwent atorvastatin therapy (10mg/day/1month). Serum lipid levels before and after treatment were measured. Genetic variants in CYP3A4 (-290A>G, rs2740574), CYP3A5 (6986A>G, rs776746) and ABCB1 (2677G>A/T, rs2032582 and 3435C>T, rs1045642) were analyzed by PCR-RFLP. CYP3A4 enzyme activity in urine samples was assessed through determination of 6β-hydroxycortisol/cortisol free ratio (6βOHC/FC). RESULTS After 4weeks of therapy, a significant reduction in total cholesterol (TC) and LDL-c was observed (P<0.001). The G allele for -290A>G polymorphism was related to higher percentage of variation in TC and LDL-c (P<0.001). Moreover, same allele was associated with higher HDL-c variation (P=0.017). In addition, CYP3A4 enzyme activity was lower in subjects carrying this polymorphism (P=0.009). No differences were observed for CYP3A5 and ABCB1 variants. CONCLUSION Our results suggest that presence of G allele for -290A>G polymorphism determines a better response to atorvastatin, being also associated with lower CYP3A4 activity in vivo, causing an increased atorvastatin activity.

Chemical and botanical characterization of Chilean propolis and biological activity on cariogenic bacteria Streptococcus mutans and Streptococcus sobrinus

Propolis is a non-toxic natural substance with multiple pharmacological properties including anti-cancer, antioxidant, fungicidal, antibacterial, antiviral, and anti-inflammatory among others. The aim of this study was to determine the chemical and botanical characterization of Chilean propolis samples and to evaluate their biological activity against the cariogenic bacteria Streptococcus mutans and Streptococcus sobrinus. Twenty propolis samples were obtained from beekeeping producers from the central and southern regions of Chile. The botanical profile was determined by palynological analysis. Total phenolic contents were determined using colorimetric assays. Reverse phase HPLC and HPLC-MS were used to determine the chemical composition. The minimum inhibitory concentration (MIC) was determined on S. mutans and S. sobrinus. All propolis samples were dominated by structures from native plant species. The characterization by HPLC/MS, evidenced the presence of quercetin, myricetin, kaempferol, rutine, pinocembrin, coumaric acid, caffeic acid and caffeic acid phenethyl ester, that have already been described in these propolis with conventional HPLC. Although all propolis samples inhibited the mutans streptococci growth, it was observed a wide spectrum of action (MIC 0.90 to 8.22 μg mL−1). Given that results it becomes increasingly evident the need of standardization procedures, where we combine both the determination of botanical and the chemical characterization of the extracts. Research conducted to date, describes a promising effectiveness of propolis in the prevention of caries and other diseases of the oral cavity, making it necessary to develop studies to identify and understand the therapeutic targets or mechanisms of molecular action of the various compounds present on them.

Screening, evaluation and selection ofphosphate-solubilising fungi as potential biofertiliser

Phosphate-solubilising saprophytic fungi have a potential application in plant nutri- tion; therefore, the aim of this study was 1) to perform a screening and isolation of native phosphofungi from volcanic soils of southern Chile, 2) to select a liquid medium for the evaluation of these phosphofungi and 3) to test a selected phospho- fungus as a biofertiliser in a volcanic soil. The phosphofungi were screened using Martin medium (rose bengal-streptomycin agar) with calcium phosphate (Ca 3 (PO 4 ) 2 ) or calcium phytate as the phosphorus source. Six promising strains (Penicillium sp., Penicillium albidum, Penicillium thomii, Penicillium restrictum, Penicillium frequentans and Gliocladium roseum) were evaluated in the liquid media of Agnihotri, Asea-Wakelin, Pikovskaya and Na- has. The soluble phosphorus, acid phosphatase activity, pH and fungal biomass were determined. In most soils, the greatest proportion of phosphofungi solubilised organic P. The Asea-Wakelin medium appears to be the medium of choice for the quantitative evaluation of phosphofungi isolated from the volcanic soils tested. Penicillium al- bidum was selected as a potential biofertiliser due to its capacity to solubilise both inorganic and organic P via its specific solubilising activity (64 mg P/g fungus), phosphatase secretion and enhancement of the growth and mineral nutrition of let- tuce plants growing in a volcanic soil.

Effect of Chilean propolis on cariogenic bacteria Lactobacillus fermentum

La caries dental es una de las enfermedades infecciosas mas prevalentes en el mundo. Entre las bacterias involucradas en esta patologia se encuentran Streptococcus mutans, Streptococcus sobrinus, Actinomyces spp. y Lactobacillus spp. La industria farmaceutica ha volcado sus esfuerzos al descubrimiento de nuevos productos antibacterianos ante el aumento de resistencia a los ya conocidos. El propoleos se ha utilizado como tal, desde tiempos antiguos, por lo que se ha investigado su efecto contra variados microorganismos. En este estudio se evaluo el efecto antimicrobiano de seis extractos etanolicos comerciales de propoleos, sobre la bacteria Lactobacillus fermentum. Esta fue aislada luego de su identificacion mediante PCR con el uso de primers especie especificos, posterior al cultivo microbiologico de muestras de caries de pacientes con indicacion de extraccion de pieza dental, y se detecto en 9 de 40 pacientes, correspondiendo a un 22%. El estudio de susceptibilidad se realizo mediante dilucion en microplacas y se comprobo la actividad antimicrobiana en cuatro de los seis extractos etanolicos de propoleos utilizados, difiriendo en la concentracion efectiva contra el microorganismo, lo que puede ser atribuido a factores como el origen botanico, el lugar geografico y la estacion de recoleccion. Los propoleos mostraron concentraciones de polifenoles que variaron entre 9 ± 0,3 y 85 ± 2,1 mg/mL. El analisis cromatografico permitio detectar la presencia de acido cafeico, miricetina, quercetina, kaempferol, apigenina, pinocembrina, galangina y acido cafeico fenil ester (CAPE). Nuestro estudio demuestra la accion antimicrobiana del propoleos sobre L. fermentum, patogeno relacionado al desarrollo de caries.

ACTIVIDADES BIOLÓGICAS Y ESTABILIDAD DE AGREGADOS EN UN SUELO DEL BOSQUE TEMPLADO CHILENO BAJO DOS ETAPAS SUCESIONALES Y CAMBIOS ESTACIONALES

La actividad microbiana es afectada por variables ecologicas primarias, tales como la densidad y composicion de la flora, etapa sucesional y variables secundarias, como las estaciones del ano. Dentro de las actividades biologicas del suelo las mas importantes estan relacionadas con la materia organica (MO) y el ciclado de nutrientes, las que nos permiten detectar, junto a otros parametros fisicos del suelo, cambios tempranos en su bioquimica, grado de compactacion de suelos y actividades biologicas producidas por el impacto antropico. En este estudio cuantificamos y comparamos un numero de actividades biologicas y el porcentaje de agregados estables al agua bajo dos etapas sucesionales y dos estaciones de crecimiento en un bosque templado del centro-sur de Chile. Las actividades biologicas evaluadas fueron la hidrolisis de la fluoresceina diacetato (FDA), carbono (CBM) y nitrogeno (NBM) en la biomasa microbiana y la actividad de tres enzimas: carboximetilcelulasa y s-glucosidasa, (ambas involucradas en el ciclo del carbono), y la fosfatasa acida (involucrada en el ciclo del fosforo). En general, las actividades biologicas evaluadas presentaron diferencias significativas (p<0.05) entre los dos estados sucesionales. En la estacion de otono se registraron los valores mas altos para todas las actividades evaluadas, excepto para el CBM. En primavera el porcentaje de agregados estables fue mayor en ambas etapas sucesionales, no existiendo diferencias significativas entre ellas. Nuestros resultados indican que las actividades biologicas del suelo se vieron influenciadas por el contenido de humedad, nutrientes y niveles de MO. De manera de promover la conservacion del medioambiente del suelo, algunos indicadores biologicos y fisicos son muy importantes para monitorear la perturbacion del suelo en ecosistemas forestales

Actividad biológica del suelo en dos bosques de Nothofagus del centro sur de Chile

Los bosques templados pristinos del sur de Chile tienen un bajo ingreso de nitrogeno (N) via depositacion atmosferica, por lo que la productividad del ecosistema depende principalmente del reciclaje interno de nutrientes, contenido en la materia organica del suelo (MOS). Se postula que existen diferencias en la actividad biologica del suelo entre un bosque secundario de Nothofagus obliqua de la Depresion Intermedia en Chile, influenciado por la actividad agricola-ganadera y condiciones microclimaticas templadas favorables para la descomposicion de la MOS, al comparar con un bosque pristino de Nothofagus betuloides de la Cordillera de los Andes, con microclima extremo. El presente estudio compara la tasa de mineralizacion de carbono (C-min), N (N-min) y las actividades enzimaticas del suelo (deshidrogenasas y fosfatasa acida), entre ambos bosques templados y su correlacion con la temperatura del suelo. Las mediciones bimensuales se realizaron durante un ciclo estacional. MANOVA mostro que las variables estudiadas fueron significativamente diferentes entre los bosques (Wilks Lambda, F 4; 55 = 20,2, p = 0,000) y durante los meses a traves del periodo de estudio (Wilks Lambda, F 76; 148 = 118,9, p = 0,000), siendo los menores valores para el bosque de N. betuloides. El comportamiento de las variables de actividad biologica con la temperatura del suelo fue diferente entre ambos ecosistemas. Los menores valores observados en el bosque de N. betuloides, se deberian a: las condiciones rigurosas del clima de montana, caracteristicas cuali - cuantitativas de la hojarasca y su velocidad de descomposicion, que pueden restringir la actividad de la biota y en especial, los microorganismos del suelo. Sin embargo, la temperatura del suelo, unica variable microclimatica considerada, no puede predecir o explicar toda la variacion de las actividades biologicas del suelo en los bosques estudiados

Antibiofilm Activity of Chilean Propolis on Streptococcus mutans Is Influenced by the Year of Collection

The chemical composition of propolis varies according to factors that could have an influence on its biological properties. Polyphenols from propolis have demonstrated an inhibitory effect on Streptococcus mutans growth. However, it is not known if different years of propolis collection may affect its activity. We aimed to elucidate if the year of collection of propolis influences its activity on Streptococcus mutans. Polyphenol-rich extracts were prepared from propolis collected in three different years, characterized by LC-MS and quantified the content of total polyphenols and flavonoids groups. Finally, was evaluated the antibacterial effect on Streptococcus mutans and the biofilm formation. Qualitative differences were observed in total polyphenols, flavones, and flavonols and the chemical composition between the extracts, affecting the strength of inhibition of biofilm formation but not the antimicrobial assays. In conclusion, chemical composition of propolis depends on the year of collection and influences the strength of the inhibition of biofilm formation.