RESUMO
ABSTRACT In order to reduce the excessive reliance on the toxic chemical fungicides, the present study aimed to isolate the total potato glycoalkaloids (TPAs), and the two steroidal alkaloids α-chaconine and α-solanine from potatoes, Solanum tuberosum L. Their structures were characterized using physical and spectroscopic methods including (UV, IR, 1H, 13C--NMR, 2D 1H-1H COSY, HMBC and NOESY). Silver nanoparticles (AgNPs) were prepared from potato alkaloids through a green synthesis approach. Potato alkaloids and their nanoparticles inhibited mycelial growth of the phytopathogenic fungi Alternaria alternate, Rhizoctonia solani, Botrytis cinerea and Fusarium oxysporum f. sp. lycopersici with low minimal inhibitory and minimal fungicidal concentrations. R. solani was the most susceptible, while F. oxysporum was the most resistant. TPAs was the most fungitoxic (EC50's were 19.8, 22.5, 26.5 and 32.3 µg/ml against R. solani, A. alternate, B. cinerea and F. oxysporum respectively). A mixture of α-solanine and α-chaconine (1:1) showed a marked antifungal activity. AgNPs (size 39.5-80.3 diameter) from alkaloids showed improved fungitoxic activity (EC50's of TPAs nanoparticles ranged between 10.9 and 16.1 µg/ml). Alkaloids exhibited no or a slight phytotoxicity against wheat and radish. Results recommend the potential of using potato alkaloids and their nanoparticles as biorational alternatives to conventional fungicides.
RESUMO
Objetivo. Implementar la utilización de Tinta China como alternativa para visualizar, cambios a nivel de matriz y pared celular, en células vivas adheridas en cultivo, antes y después de la exposición a una sustancia toxica. Métodos. Se implementó la Tinta China, como técnica de contraste en microscopia óptica, comparando la nitidez observada (adecuada apreciación del borde de las estructuras) entre frascos de cultivo de células troncales de médula ósea de rata (CTMO) expuestos al glicoalcaloide tóxico α-solanina. Las diferencias de nitidez se compararon entre los diversos tratamientos, con test exacto de Fisher. Resultados. La tinción con Tinta China permitió identificar con nitidez los cambios fenotípicos celulares anormales, secundarios a la exposición del citotóxico en células adherentes en cultivo (p <0.0001). Conclusiones. La Tinta China es útil en la visualización nítida de las células CTMO y de los efectos producidos por el glicoalcaloide α-solanina en células adheridas en cultivo. Es un método sencillo que aporta al entendimiento del efecto que diversas sustancias producen en las CTMO en cultivo.
Objective. To implement the use of China ink, as an alternative technique, to display morphological changes in cellular wall and cellular matrix in adherent living cells in culture flask, before and after exposure to a toxic substance. Methods. China Ink was implemented as a contrast technique in optical microscopy, by comparing observed sharpness (proper appreciation of edge structures) from cultures of bone marrow stem cells (CTMO) exposed to the toxic glycoalkaloid α-solanine. The sharpness differences were compared among the diverse treatments with Fisher's exact test. Results. China Ink staining clearly helps to identify abnormal phenotypic changes, secondary to cytotoxic exposure in adherent cells in culture (p <0.0001). Conclusions. China Ink is useful in clearly displaying the CTMO cells and the effects of the α-solanine glycoalkaloid in adherent cells in culture. It is a simple method that contributes to the understanding of the effect of various substances on CTMO in culture.
Assuntos
Humanos , Solanina , Células-Tronco , Substâncias Perigosas , Citotoxicidade ImunológicaRESUMO
This report presents evidence that the following Solanum steroids: solasodine, diosgenin and solanine interact with human erythrocytes and molecular models of their membranes as follows: a) X-ray diffraction studies showed that the compounds at low molar ratios (0.1-10.0mol%) induced increasing structural perturbation to dimyristoylphosphatidylcholine bilayers and to a considerable lower extent to those of dimyristoylphosphatidylethanolamine; b) differential scanning calorimetry data showed that the compounds were able to alter the cooperativity of dimyristoylphosphatidylcholine, dimyristoylphosphatidylethanolamine and dimyristoylphosphatidylserine phase transitions in a concentration-dependent manner; c) in the presence of steroids, the fluorescence of Merocyanine 540 incorporated to the membranes decreased suggesting a fluidization of the lipid system; d) scanning electron microscopy observations showed that all steroids altered the normal shape of human erythrocytes inducing mainly echinocytosis, characterized by the formation of blebs in their surfaces, an indication that their molecules are located into the outer monolayer of the erythrocyte membrane.