Análisis de los sitios de unión de la ivermectina en la estructura de importinas α humanas

La ivermectina demostró importantes acciones antivirales ante varios virus con genoma de ARN, inclusive contra el SARS-CoV-2. Este fármaco inhibe la actividad del heterodímero importina α/ß1, sin embargo, se desconoce los blancos específicos de interacción de la molécula. Objetivos: analizar in silico los blancos de interacción de la ivermectina en interacción con la estructura de la importina α humana, utilizando la estrategia del acoplamiento molecular. Métodos: se realizaron simulaciones del acoplamiento utilizando un modelo semiflexible y el algoritmo Broyden-Fletcher-Goldfarb-Shanno entre las estructuras de ivermectina y la importina α. Resultados: los datos obtenidos revelan una mayor afinidad de interacción de la ivermectina a la región mayor de unión (armadillo ARM2-ARM4) de las importinas α humanas, con energías de unión favorables de -9,5 a -8,0 kcal.mol-1. Los aminoácidos activos de importancia en las uniones fueron el Triptófano, Asparagina y Arginina, los cuales también son fundamentales para el reconocimiento de secuencias NLS (secuencias de localización nuclear) de las proteínas virales. También se registró afinidades por los dominios H1-ARM5, H2-ARM6 y H2-ARM7, con energía de unión de -7,5 kcal.mol-1. Conclusiones: los hallazgos demuestran que la ivermectina presenta afinidades de unión favorables a la región mayor de unión (ARM2-ARM4) de las importinas a el cual es un sitio importante de unión a proteínas virales.

Ivermectin has demonstrated significant antiviral actions against several RNA-genome viruses, including SARS-CoV-2. This drug inhibits the activity of the α/ß1 importin heterodimer; however, the specific interaction targets of the molecule are unknown yet. Objectives: to analyze in silico the interaction targets of ivermectin interacting with the human α-importin structure using the molecular docking strategy. Methods: simulations of the molecular docking were carried out using a semi-flexible model and the Broyden-Fletcher-Goldfarb- Shanno algorithm between the structures of ivermectin and importin α. Results: data obtained reveal a higher interaction affinity of ivermectin to the major binding region (armadillo ARM2-ARM4) of human importins α, with favorable binding energies of -9,5 to -8,0 kcal.mol-1. The active amino acids of importance in the bindings were Tryptophan, Asparagine and Arginine, which are also critical for the recognition of NLS sequences (nuclear location sequences) of viral proteins. Affinities for H1-ARM5, H2-ARM6 and H2-ARM7 domains were also recorded, with binding energy of -7,5 kcal.mol-1. Conclusions: the findings demonstrate that ivermectin exhibits favorable binding affinities to the major binding region (ARM2-ARM4) of importins a which is an important viral protein binding site.

Anthelmintic effect of four extracts obtained from Caesalpinia coriaria foliage against the eggs and larvae of Haemonchus contortus / Efeito anti-helmíntico de quatro extratos obtidos da folha de Caesalpinia coriaria contra ovos e larvas de Haemonchus contortus

Abstract To investigate the in vitro anthelmintic efficacy of dividivi (Caesalpinia coriaria), a traditional medicinal plant used in Central America and the northern part of South America, extracts from the foliage of this plant were subjected to the egg hatching test (EHT) and larval exsheathment inhibition test (LEIT), against Haemonchus contortus. Four different extracts were evaluated: acetone-water (AW), methanol-water (MW), acetone-water-dichloromethane (AWD) and methanol-water-dichloromethane (MWD). The concentrations used for the EHT and LEIT tests ranged from 500 to 4000 µg mL-1 and six repetitions per concentration. The effective concentrations (EC50) were calculated using Probit analysis. The EC50 for EHT were 2947.0, 3347.0, 3959.6 and 4538.7 µg mL-1 for MWD, MW, AW and AWD, respectively. The EC50 for LEIT were 2883.4, 5927.4, 9876.3 and 9955.4 µg mL-1 for AWD, AW, MWD and MW, respectively. The methanol extracts were the most effective in inhibiting the hatching of eggs, while the acetone extracts showed efficacy in inhibiting larval exsheathment. This study explains the importance that C. coriaria has as a medicinal plant in Central and South American countries.

Resumo Para investigar a eficácia anti-helmíntica de Divi-divi (Caesalpinia coriaria), uma planta medicinal tradicional usada na América Central e no norte da América do Sul. Extratos das folhas dessa planta foram utilizados em testes in vitro de inibição da eclosão de ovos (EHT) e desembainhamento larvar (LEIT) de Haemonchus contortus. Quatro diferentes extratos foram avaliados: acetona-água (AW), metanol-água (MW), acetona-água-diclorometano (AWD) e metanol-água-diclorometano (MWD). Para os testes EHT e LEIT, as concentrações utilizadas variaram de 500 a 4000 µg mL-1, em seis repetições por concentração. As concentrações efetivas (EC50) foram calculadas, usando-se a análise Probit. A EC50 para EHT foram 2947,0; 3347,0; 3959,6 e 4538,7 µg mL-1 para MWD, MW, AW e AWD, respectivamente. As EC50 para LEIT foram 2883,4; 5927,4; 9876,3 e 9955,4 µg mL-1 para AWD, AW, MWD e MW, respectivamente. Os extratos de metanol foram os mais eficazes em inibir a eclosão de ovos, enquanto os extratos de acetona mostraram-se eficazes em inibir a desembainhamento larvar. Este estudo ajuda a explicar a importância da C. coriaria como planta medicinal nos países da América Central e América do Sul.

Terapia com Levamisole em crianças e adolescentes com Síndrome Nefrótica Córtico dependentes ou recidivantes frequentes: experiência de um centro de referência em Minas Gerais / Levamisole therapy in dependent children and adolescents with Cortic Nephrotic Syndrome or frequent relapses: experience from a reference center in Minas Gerais

Introdução: A terapia poupadora de corticoide é a melhor estratégia para reduzir a exposição a esteroides a longo prazo em pacientes com síndrome nefrótica e o levamisole se mostrou um agente poupador de corticoide de baixo custo, fácil acesso e com baixo índice de eventos adversos. Objetivos: Sintetizar as evidências literárias sobre as estratégias poupadoras de corticoterapia em pacientes pediátricos com síndrome nefrótica. Avaliar a resposta ao uso de levamisole em pacientes pediátricos com síndrome nefrótica córtico dependentes ou recidivantes frequentes. Métodos: Revisão integrativa das evidências disponíveis na literatura em relação ao uso de poupadores de corticoide em pacientes pediátricos com síndrome nefrótica corticossensível recidivantes frequentes ou cortico dependentes. Levantamento de dados de pacientes em uso de levamisole para avaliação da resposta à medicação. Resultados: Não há uma medicação poupadora de corticoide de referência na população pediátrica. Quando necessária, a terapia poupadora de corticoterapia deve ser individualizada e compartilhada com familiares. O uso de corticoide continua sendo o tratamento inicial de escolha. Dos 30 pacientes selecionados para o estudo 86,7% não apresentaram efeitos adversos com uso de levamisole. O poupador de corticoide mais comumente utilizado antes do uso de levamisole foi a ciclofosfamida (26,7%). A biópsia renal foi realizada em 30% dos pacientes e o achado mais comum foi doença por lesões mínimas. Ao longo da avaliação em um ano, não houve piora de nenhum índice hematimétricos (P > 0,05) incluindo neutrófilos. Conclusões: Em nosso estudo o levamisole mostrou eficiência em reduzir o número de recidivas no primeiro ano de uso, além de manter estabilidade da função renal, com baixo índice de evento adverso.

Introduction: Corticosteroid-sparing therapy is the best strategy to reduce long-term steroid exposure in patients with nephrotic syndrome, and levamisole has been shown to be a low-cost, easily accessible, steroid-sparing agent with a low rate of adverse events. Objectives: To synthesize the literature evidence on steroid-sparing strategies in pediatric patients with nephrotic syndrome. To evaluate the response to the use of levamisole in pediatric patients with cortico-resistant nephrotic syndrome or frequent relapses. Methods: An integrative review of the evidence available in the literature regarding the use of steroid-sparing agents in pediatric patients with frequent relapsing or steroid-dependent cortico-sensitive nephrotic syndrome. Data collection of patients using levamisole to assess the response to medication. Results: There is no reference corticosteroid-sparing medication in the pediatric population. When necessary, steroid-sparing therapy should be individualized and shared with family members. Corticosteroid use remains the initial treatment of choice. Of the 30 patients selected for the study, 86.7% had no adverse effects with the use of levamisole. The most used corticosteroid sparing agent before the use of levamisole was cyclophosphamide (26.7%). Renal biopsy was performed in 30% of patients and the most common finding was focal segmental glomerulus sclerosis (FSGS), followed by minimal change disease. Over the course of the one-year evaluation, there was no worsening of any RBC index (P > 0.05) including neutrophils. Conclusions: In our study, levamisole showed efficiency in reducing the number of relapses in the first year of use, in addition to maintaining stability of renal function, with a low rate of adverse events.

Hepatotoxicidade de um fitoterápico contendoChenopodium ambrosioides, Mentha piperita e Rheumpalmatum em camundongos Swiss / Hepatotoxicity of an herbal product containing Chenopodiumambrosioides, Mentha piperita and Rheum palmatum in Swiss mice

Introdução: Entre as diversas plantas que possuem efeito antiparasitário,as espécies Chenopodium ambrosioides, Mentha piperitae Rheum palmatum vem sendo empregadas em associação comoproduto fitoterápico antiparasitário. Porém, esse tipo de preparo éutilizado de forma indiscriminada e abusiva, o que pode levar aosurgimento de danos à saúde.Objetivo: Avaliar a função hepática de camundongos Swiss submetidosa tratamento com um produto fitoterápico contento Chenopodiumambrosioides, Mentha piperita e Rheum palmatum, usadopopularmente como antiparasitário.Métodos: Foram utilizados 20 camundongos, distribuídos em doisgrupos: grupo tratamento, submetidos à terapia com fitoterápicopor via orogástrica por 9 dias, e grupo controle negativo, tratadoscom solução salina estéril pela mesma via, diariamente, durante omesmo período. Após tratamento, foram realizadas dosagens plasmáticasdas enzimas alanina aminotrasnferase (ALT) e aspartatoaminotransferase (AST) por metodologia cinético-UV em duplicata...

Introduction: Among the various plants having antiparasitic effect,the species Chenopodium ambrosioides, Mentha piperita andRheum palmatum has been used in combination as a herbal productantiparasitic . However, this type of preparation is used indiscriminatelyand improperly which can lead to the emergence ofhealth damage.Objective: Assess liver function of Swiss mice undergoing treatmentwith an herbal product containing Chenopodium ambrosioides,Mentha piperita and Rheum palmatum, popularly used as aantiparasitic.Methods: Were used 20 mice, distributed into two groups: treatmentgroup, underwent to herbal therapy by orogastric route for9 days, and a negative control group, treated with sterile saline bythe same route, daily, during the same period. After treatment, weremade plasmatic dosages of the enzymes alanine aminotransferase(ALT) and aspartate aminotransferase (AST) in duplicate. Resultsand conclusion: Was observed significant elevation of ALT, anddecreasing of AST (no significant), which means that the studiedproduct have may cause mild hepatocellular damage in animals...

Detección de metabolitos secundarios en Ambrosia peruviana Willd y determinación de la actividad antibacteriana y antihelmíntica / Secondary metabolite detection in Ambrosia peruviana Willd and determination of antibacterial and antihelmintic activity

En el conocimiento etnofarmacológico, Ambrosia peruviana es conocida como una planta antiinfecciosa y antihelmíntica. Dados los altos índices de resistencia bacteriana y parasitaria, se realizó la tamización fitoquímica preliminar siguiendo la metodología de Sanabria, y ensayos biológicos frente a aislamientos clínicos bacterianos, parásitos caninos y Artemia salina. Los ensayos de citotoxicidad en A. salina se realizaron por exposición de los adultos a concentraciones variables de los extractos. La actividad antibacteriana se realizó por los métodos de difusión en disco y concentración inhibitoria mínima (CIM). Se determinó el porcentaje de huevos que tenían el embrión del parásito, en el medio de cultivo se mantuvieron en lactato de Ringer con suplemento al 10% de RPMI y 1X ATM. Se determinó el porcentaje de huevos con embrión, o fecundados, liberados en el medio de cultivo con adición de extracto etanólico y acuoso secos de A. peruviana. Los ensayos de la especie vegetal frente a helmintos se realizaron al sumergir los adultos en medio con suplemento de extracto etanólico seco (usando diferentes concentraciones) y con fracciones ricas en alcaloides. Se identificó la presencia de alcaloides, glucósidos cardiotónicos, quinonas, flavonoides, carbohidratos, taninos y saponinas. La concentración letal media para el extracto etanólico seco fue 64,2 µg/ml, mientras que para el extracto acuoso fue de 840,4 µg/ml. Los extractos no presentaron actividad antibacteriana. Los ejemplares adultos de T. canis presentaron disminución de la motilidad frente a extractos secos, mientras que en la fracción de alcaloides murieron luego de 4 horas de exposición. Los extractos de A. peruviana sobre huevos de T. canis permitieron una disminución en el porcentaje de huevos con embrión que no dependía del extracto observado sino de la concentración empleada.

Ambrosia peruviana has been reported as an anti-infective and anti-parasitic plant in the ethno-pharmacological environment. Given the high rates of bacterial and parasitic resistance against commercial drugs recorded, we performed the preliminary phytochemical screening following Sanabria´s method and biological tests against clinical bacterial isolates, dog parasites, and Artemia salina. Cytotoxicity tests in Artemia salina were carried out by exposing adults to extracts of varied concentrations. The antibacterial activity was performed using the disk diffusion method and CIM. Toxocara canis nematodes were kept in Ringer´s lactate supplemented with 10% RPMI and 1X ATM. The embryo generation percentage of eggs released into the culture medium was evaluated adding ethanol and aqueous extracts of dried A. peruviana. The tests of A. peruviana against helminths were performed by immersing adults in a medium supplemented with dried ethanol extract (at various concentrations) and fractions rich in alkaloids. Phytochemical screening allowed preliminary identification of alkaloids, cardiotonic glucosides, quinones, flavonoids, carbohydrates, tannins and saponins. The LC50 for dry ethanol extract was 64.2µg/ml, while for the aqueous extract was 840.4µg/ml. The extracts did not show antibacterial activity. T. canis adults showed motility decrease against dried extracts, not so in alkaloid fraction where they died after a 4h exposure. The use of extracts from A. peruviana over Toxocara canis eggs caused a decrease in the percentage of embryo generation, which did not depend on the extract observed but on the concentration used.

Saponinas esteroidales de la planta Agave brittoniana (Agavaceae) con actividad contra el parásito Trichomona vaginalis

Steroidal saponins from the plant Agave brittoniana with activity against the parasite Trichomona vaginalis. The genus Agave (Agavaceae), includes more than 300 species; around 16 of them show an homogeneous distribution throughout Cuba. Agave brittoniana (ssp. brachypus), is an endemic subspecies that grows in the central region of the country and its leaves are traditionally used in the treatment of parasitic diseases. The parasite Trichomonas vaginalis causes the disease known as trichomoniasis, that infects the genital tract. To test in vitro the plant against Trichomona vaginalis, the dried and powdered leaves were extracted three times with ethanol-water (7 : 3) by maceration at room temperature. The solvent was removed under reduced pressure and the extract was suspended in distilled water, defatted with n-hexane, and extracted with water-saturated n-butanol. After solvent removal, a portion of the n-butanol extract was hydrolyzed. After extraction with ethyl acetate the hydrolysis products were compared with authentic sapogenins samples using thin layer chromatography (TLC). Most of the sapogenins (yuccagenin and diosgenin) were isolated and their structures were confirmed. using nuclear magnetic resonance (NMR) experiments. The n-butanol extract was subjected to a separation process through column chromatography to obtain five fractions. After multiple separation processes by reversed phase high performance liquid chromatography (HPLC), the most active one produced one refined fraction that contained two saponins with the same aglycone (diosgenin) and one yuccagenin based saponin. Best results of the activity were obtained with the yuccagenin derived glycoside. Rev. Biol. Trop. 56 (4): 16451652. Epub 2008 December 12.

El género Agave, familia Agavaceae, tiene más de 300 especies, con aproximadamente 16 distribuidas en toda Cuba. Una de ellas, el Agave brittoniana Trel. (ssp. brachypus), es una subespecie endémica y sus hojas son tradicionalmente utilizadas en el tratamiento de enfermedades parasitarias. Se realizaron estudios "in vitro" de la actividad de productos de esta planta frente a Trichomona vaginalis. Las hojas secas y pulverizadas fueron extraídas tres veces con una mezcla de etanol-agua (7: 3) mediante maceración a temperatura ambiente. El disolvente fue evaporado a presión reducida y el extracto fue suspendido en agua destilada, desengrasado con n-hexano, y extraído con n-butanol saturado con agua. Luego de una extracción con acetato de etilo, los productos de la hidrólisis fueron comparados con patrones de sapogeninas mediante la cromatografía de capa fina (CCD). Aislamos las sapogeninas mayoritarias (yuccagenina y diosgenina) y confirmamos sus estructuras utilizando técnicas de resonancia magnética nuclear. Por otra parte, el extracto n-butanólico fue sometido a un proceso de separación biodirigido mediante cromatografía de columna, obteniéndose cinco fracciones. Después de múltiples separaciones, la más activa rindió una fracción purificada con dos sapogeninas con el mismo aglicón (diosgenina) y un glicósido de yucagenina. Los mejores resultados de esta actividad fueron obtenidos con el glicósido derivado de la yucagenina.