1,721,018 research outputs found
High performance liquid chromatographic profiling of antioxidant and antidiabetic flavonoids purified from Azadirachta indica (neem) leaf ethanolic extract
No full textAzadirachta indica (neem) is a tropical and semi-tropical tree native to the whole Indian subcontinent. Neem leaves are rich in flavonoids, which exhibit important pharmacological activities targeting almost all human organs. In order to produce a purified extract of neem leaves enriched of antioxidant and antidiabetic flavonoids, the ethanolic extract of neem leaves has been further undergone to liquid-liquid extractions by using three different organic solvents, i.e. dichloromethane, n-butanol and ethyl acetate. Qualitative and quantitative analyses were performed on the extracts obtained by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Astragalin, quercitrin, isoquercitrin, nicotiflorin and rutin were the only flavonoids found among those screened. By comparing all HPLC chromatograms of purified extracts as obtained with different solvents, it was found that the qualitative-quantitative composition of flavonoids depends upon the extraction solvent used; in particular, dichloromethane allows extraction of 89.5 % quercitrin, 5.3 % isoquercitrin, 5.2 % rutin; n-butanol allows extraction of 6.0 % isoquercitrin, 6.2 % nicotiflorin, 87.8 % rutin; ethyl acetate allows extraction of 4.2 % astragalin, 12.0 % quercitrin, 50.3 % isoquercitrin, 6.7 % nicotiflorin, 26.9 % rutin. Thus, depending on the specific purposes and needs, each of these three extraction solvents has the potential to prepare formulations enriched with the most suitable flavonoids composition
The role of phagocytosis in cell deaths by photodynamic therapy
No full textResistance to cell death and the ability to overrule immunosurveillance represent two hallmarks of tumour cells. The optimal cancer treatment should combine the induction of cell death and immunostimulatory effects based on immune cells activation consequent to the immunogenic characteristics of dead cells and their removal. The dynamic interplay between dead cell and phagocytes leading to efficient phagocytosis is divided in four steps: 1) attraction and accumulation of phagocytes to the site of apoptotic cells, 2) recognition and tethering, 3) internalization and 4) processing of dead cells within the phagocytes avoiding phlogosis. Apoptotic cells secrete chemotactic signals attracting phagocytes and expose on plasma membrane ligands mediating receptor-specific physical contact with phagocytes. Indeed, the subsequent internalization steps and outcomes, i.e. immunotolerance or immunomodulation, profoundly depend on the phagocytic receptors involved. PhotoDynamic Therapy (PDT), a promising new cancer treatment, is based on the synergic action of photosensitizing drugs (PS) and light irradiation that allow to kill the cells respectively via chemical and physical stress. Highly Reactive Oxygen Species (ROS), formed by the transfer of energy absorbed by PS upon irradiation to molecular oxygen, mediate the destruction of target cells. The best feature of PDT is the ROS damage directionality, depending on PS localization that in turn is mediated by its hydrophilicity/hydrophobicity, and the precise delivery of light to the treated sites. Multiple advantages characterize PDT as cancer treatment modality and make it potentially capable to meet many currently unmet medical needs. Particularly, PDT elicits a strong acute inflammation, orchestrated by both the innate and adaptive immune system, ensuring a protective effect by containing the disruption of tissue homeostasis and removal of damaged cells. The acute inflammatory response depends on photosensitized dead cells. Indeed, PDT not only induces apoptosis, autophagy and necrosis in the tumour cells, but it is also effective to rapidly generate an abundance of alarm/danger signals, called Damage-Associated Molecular Patterns (DAMPs), detected by the innate immunity alert elements. These, recruited to the sites of dead cells, eliminate injured and dead cells by phagocytosis and trigger the antitumour immunity by maturation and activation of dendritic cells (DCs). Here we will discuss whether the multiple PDT-induced cell death types can result in an immune response, linked to the exposure and/or release of signals by dying cells, ending in the phagocytosis by the immune cells. © 2013 by Nova Science Publishers, Inc. All rights reserved
In vitro comparative study of the effects of silver and gold nanoparticles exploitable in the context of photodynamic therapy
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Synthesis and in vitro cytotoxicity of glycans-capped silver nanoparticles
No full textSilver nanostructures were successfully synthesized through a simple and “green” method using saccharides as reducing and capping agent. Transmission electron microscopy (TEM) and UV–Vis absorption were used to certify the quality of the silver nanoparticles obtained: first, size and dispersion.
In this work Silver NanoParticles (AgNPs) cytotoxicity related to saccharides capping (Glucose and Glucose-Sucrose) was explored. Human epitheloid cervix carcinoma cells (HeLa) were used for cytotoxicity test. The cells were incubated with increasing AgNPs number/cell and HeLa cells viability was monitored for a period of 48 h compared with the positive and negative controls.
We observed that the toxicity increases in a incubation time and AgNPs number/cell related manner. In addition, the AgNP-G are more toxic than AgNP-GS, suggesting that AgNPs citotoxicity could depend on the capping agent. in HeLa cells the highest AgNP-G number/cell induces , cell deathsoon after 1 hr of incubation; conversely the lowest AgNP-GS number/cell induces cell proliferation
Biocompatibility of Carbon Nanoparticles in HeLa Cells is Dictated by Synthesis and Sterilization Procedures
No full textDue to their unique chemical and physical properties, carbon-based NanoMaterials (C-NMs) are largely exploited in biomedicine, i.e., cell and tissue imaging, drug delivery and tissue engineering scaffold, even if reports regarding their toxicity are still conflicting. In fact, biological effects strictly depend on the dynamic physicochemical characteristics of C-NMs, which in turn are strongly influenced by the procedures of their synthesis, and nanometrological techniques, e.g., Electron Microscopy (EM)-based analysis, are becoming the main tool for researchers to characterize nanoproducts. The aim of the present work is the study of the influence of synthesis and sterilization protocols on the size, shape, stability and biocompatibility of carbon NanoParticles (C-NPs). C-NPs were synthesized by using graphite as bulk material through an electrochemical method applying a constant voltage of 30 V and different times of synthesis. The C-NPs solution was sterilized by adopting different sterilization protocols during and/or after the synthesis. Size, shape and stability were studied by TEM and spectroscopy, while biocompatibility was tested in HeLa cells. Synthesis and sterilization procedures did not influence size, shape and stability of C-NPs, but interfered with C-NPs biocompatibility. In fact, irrespective of time of electrolysis process, the NPs show spherical shape with an average diameter of 7 nm. UV-visible spectra show typical peak of carbonaceous materials that falls at 236 nm without aggregation and sedimentation. However, when NPs obtained at 90 min of synthesis were twice autoclaved the peak shifted to 257 nm. HeLa cells were incubated with different C-NPs solutions administered at different concentrations, ranging from 8×105 to 1.6×107 C-NPs/cell, for different times (4, 24 and 48h). Cell viability was C-NPs concentration- and time of culture-dependent; interestingly, also the time of electrolysis process used during particles synthesis and procedures adopted to sterilize C-NPs solutions largely influenced cells response
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