A espécie Celtis iguanaea (Jacq.) Sargent é popularmente conhecida como esporão de galo ou grão de galo. As folhas são indicadas pelo uso popular para o tratamento de dores no corpo e no peito, para ...reumatismo, asma, cólicas, má digestão e como diurético; as raízes são utilizadas para infecções urinárias e as cascas para a febre. O presente trabalho objetivou contribuir para o estudo fitoquímico e atividade fitotóxica com enfoque alelopático das cascas de Celtis iguanaea. O extrato etanólico foi submetido à partição com os solventes hexano, clorofórmio e acetato de etila. As substâncias friedelina e epifriedelinol (triterpenos) foram isoladas da fração hexano e identificadas por meio de métodos espectroscópicos de RMN de ¹H e 13C. O extrato bruto na concentração de 0,1 mg mL-1 causou inibição acentuada do hipocótilo em 34,97% e estimulou o crescimento da radícula em 29,64% de plântulas de Lactuca sativa. No ensaio de toxicidade frente à Artemia salina o extrato bruto e frações apresentaram uma CL50 superior a 1000 μg mL-1, indicando que o mesmo não possui efeito tóxico.
In experimental autoimmune encephalomyelitis, a classical model for multiple sclerosis, the cytokines provide the necessary signals to activate specific T cells for self-antigens. Gangliosides have ...multiple immunomodulatory activities, decreasing the lymphoproliferative responses and modulating cytokine production. Here, we tested the effects of gangliosides on the switching of Th1 to Th2 cytokine expression, in spleen cells obtained from Lewis rats during the acute phase of EAE, and after recovery from the disease. For this purpose, total RNA from spleen cells was isolated and submitted to RT-PCR to investigate Th1 (IL-2, TNF-α, and IFN-γ) and Th2/Th3 (IL-10 and TGF-β) cytokine gene expression. Results demonstrate that the group treated with gangliosides displays mild disease, with low expression of IFN-γ mRNA and high TGF-β mRNA expression. We conclude that the gangliosides may modulate Th1 cells by the synthesis of cytokines shifting the profile to the Th2/Th3 phenotype.
Surface-modified liposomes with gangliosides prolong their half life in blood stream that associated to the poor immunogenic properties of gangliosides are potentially useful for applications as ...immunotherapic vehicles. The physical characteristics of these biocolloids play an important role on their stability and exposition of the ganglioside antigens to the immunological system. The present work describes the physical characterization of liposomes incorporating a monosialoganglioside or a mixture of mono-, di- and trisialogangliosides. The liposomal matrix was composed of either dipalmitoylphosphatidylcholine and cholesterol, or in some preparations dihexadecylphosphate, which was added in order to provide a higher negative charge density on the liposome surface. Both types of liposomes were prepared by the dry phospholipids film hydration method and characterized by their phospholipid and ganglioside content, mean diameter, size distribution, morphology, membrane packing, lamellar structure and phase transition behavior.
Macroscopic chirality of strings Stovbun, S. V.; Zanin, A. M.; Skoblin, A. A. ...
Russian journal of physical chemistry. B,
12/2011, Letnik:
5, Številka:
6
Journal Article
Recenzirano
The macroscopic chirality of strings in xerogel obtained from a solution of
N
-trifluoroacetyl-R(+)-valinol in cyclohexane was revealed by atomic force microscopy and circular dichroism. The ...characteristic plots on different scales are reported, namely, large-scale “chaos” (∼100 μm), string commutation (∼10 μm), and “fine” structure (∼1 μm).
Large amounts of nanohydroxyapatite (nHAp)-multiwall carbon nanotube (MWCNT) nanocomposites are produced by two different aqueous precipitation methods. The ultrasonic irradiation (UI) and slow-drip ...addition under continuous magnetic stirring (DMS) methods were used to investigate the precipitation of nHAp acicular crystals. Calcium-nitrate, diammonium hydrogen phosphate, and ammonium hydroxide were used as precursor reagents. Superhydrophilic MWCNT were also employed. XPS analysis evidences that the functionalized MWCNTs are composed of 18 to 20at.% of oxygen and that this property influences the nHAp formation. The high surface area of the MWCNT decreases the mean free path of ions, favoring the nHAp formation assisted by UI. The crystallinity was evaluated using the Scherrer equation. Semi-qualitative energy dispersive spectroscopy (EDS) analysis showed that the main components of HAp powders were calcium and phosphorus in the ratio Ca/P around of 1.67. Bioactivity properties of the nHAp/MWCNT-UI nanocomposites could be evaluated after 14days soaking in simulated body fluid medium. Scanning electron microscopy, EDS, Fourier transform infrared attenuated total reflection spectroscopy, and X-ray diffraction techniques proved that the apatites formed on the surface and to points that the nHAp/MWCNT-UI have potential biological applications.
•Nanohydroxyapatite/multiwalled carbon nanotube nanocomposites were produced via aqueous precipitation.•Two methodologies were compared, such as: dropwise and ultrasound irradiation (UI).•Analysis found strong connections between UI and the crystallization process.
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