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1.
Bioorg Chem ; 117: 105412, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34649153

RESUMO

This study aimed to synthesize a nano-structure between selenium, Vit. C, and Vit. E (Vit-E/C@SeNPs) as a promising protective and therapeutic agent for hepatocellular carcinoma. Vit-E/C@SeNPs were characterized using TEM and DLS and its zetapotential was measured to evaluate its stability. DPPH assay and SRB test were performed to estimate its antioxidant capacity and cytotoxicity, respectively. A radiosynthesis of 99mTc-Vit-E/C@SeNPs was done for further in-vivo pharmacokinetic studies on normal and solid tumor induced mice. Further, in-vivo studies were conducted to investigate Vit-E/C@SeNPs efficacy against hepatocellular damage in Wistar albino rats induced by diethylnitrosamine (DEN) / Carbon Tetra chloride (CCl4). The synthesis results showed spherical Vit-E/C@SeNPs with core size of 50 nm, radical scavenging activity (%RSC) of 75.9%, and IC50 of 27.9 µg/ml. The biochemical analysis results showed that the lower liver function biomarker values (ALT, AST, ALP, total bilirubin and GGT) has gone for the Vit-E/C@SeNPs prevention and treated group, which also showed significant depletion of liver tissue l-MDA, and obvious increase in GSH concentration and CAT activity and marked improvement in the histological feature of liver tissue. Additionally, a significant up-regulation of mRNA gene expression levels of inflammatory gene (TGFß1, NFκB, iNOS, PPAR-γ and TNFα) and Apoptotic gene (P53) were determined by using Quantitative real-time PCR (qPCR). The values down regulate and tend to normal in prevention and control group. All of these introduce Vit-E/C@SeNPs as a promising agent as protective and therapeutic agent against DEN/ CCl4-induced hepatocellular damage (Hepatocellular carcinoma).


Assuntos
Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Fígado/efeitos dos fármacos , Selênio/farmacologia , Vitamina E/farmacologia , Animais , Antioxidantes/administração & dosagem , Antioxidantes/farmacocinética , Ácido Ascórbico/administração & dosagem , Ácido Ascórbico/farmacocinética , Carcinoma Hepatocelular/tratamento farmacológico , Linhagem Celular , Humanos , Fígado/metabolismo , Neoplasias Hepáticas/tratamento farmacológico , Masculino , Nanopartículas/administração & dosagem , Nanopartículas/análise , Ratos , Ratos Wistar , Selênio/administração & dosagem , Selênio/farmacocinética , Vitamina E/administração & dosagem , Vitamina E/farmacocinética
2.
Int J Oncol ; 58(6)2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33955499

RESUMO

For glioblastoma, the treatment with standard of care therapy comprising resection, radiation, and temozolomide results in overall survival of approximately 14-18 months after initial diagnosis. Even though several new therapy approaches are under investigation, it is difficult to achieve life prolongation and/or improvement of patient's quality of life. The aggressiveness and progression of glioblastoma is initially orchestrated by the biological complexity of its genetic phenotype and ability to respond to cancer therapy via changing its molecular patterns, thereby developing resistance. Recent clinical studies of pharmacological ascorbate have demonstrated its safety and potential efficacy in different cancer entities regarding patient's quality of life and prolongation of survival. In this review article, the actual glioblastoma treatment possibilities are summarized, the evidence for pharmacological ascorbate in glioblastoma treatment is examined and questions are posed to identify current gaps of knowledge regarding accessibility of ascorbate to the tumor area. Experiments with glioblastoma cell lines and tumor xenografts have demonstrated that high­dose ascorbate induces cytotoxicity and oxidative stress largely selectively in malignant cells compared to normal cells suggesting ascorbate as a potential therapeutic agent. Further investigations in larger cohorts and randomized placebo­controlled trials should be performed to confirm these findings as well as to improve delivery strategies to the brain, through the inherent barriers and ultimately to the malignant cells.


Assuntos
Ácido Ascórbico/administração & dosagem , Neoplasias Encefálicas/tratamento farmacológico , Glioblastoma/tratamento farmacológico , Animais , Ácido Ascórbico/farmacocinética , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/patologia , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Glioblastoma/mortalidade , Glioblastoma/patologia , Humanos , Infusões Intravenosas , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Permeabilidade , Qualidade de Vida , Distribuição Tecidual , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Nutrients ; 13(4)2021 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-33801745

RESUMO

Vitamin C (ascorbic acid) is a normal liver metabolite in most animals, with humans being a notable exception due to random genetic mutations that have occurred during our evolution [...].


Assuntos
Ácido Ascórbico , Humanos , Ácido Ascórbico/administração & dosagem , Ácido Ascórbico/farmacocinética , Ácido Ascórbico/farmacologia , Infecções Bacterianas/tratamento farmacológico , Epigênese Genética , Neoplasias/tratamento farmacológico , Sepse/tratamento farmacológico
4.
Int J Med Sci ; 18(3): 835-845, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33437220

RESUMO

Chemotherapy and radiotherapy are the most frequent treatment for patients suffering from malignant progression of cancer. Even though new treatments are now being implemented, administration of these chemotherapeutic agents remains as the first line option in many tumor types. However, the secondary effects of these compounds represent one of the main reasons cancer patients lose life quality during disease progression. Recent data suggests that Ocoxin, a plant extract and natural compound based nutritional complement rich in antioxidants and anti-inflammatory mediators exerts a positive effect in patients receiving chemotherapy and radiotherapy. This mixture attenuates the chemotherapy and radiotherapy-related side effects such as radiation-induced skin burns and mucositis, chemotherapy-related diarrhea, hepatic toxicity and blood-infection. Moreover, it has been proven to be effective as anticancer agent in different tumor models both in vitro and in vivo, potentiating the cytotoxic effect of several chemotherapy compounds such as Lapatinib, Gemcitabine, Paclitaxel, Sorafenib and Irinotecan. The aim of this review is to put some light on the potential of this nutritional mixture as an anticancer agent and complement for the standard chemotherapy routine.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Ácido Ascórbico/administração & dosagem , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/prevenção & controle , Ácido Fólico/administração & dosagem , Neoplasias/terapia , Ácido Pantotênico/administração & dosagem , Extratos Vegetais/administração & dosagem , Lesões por Radiação/prevenção & controle , Vitamina B 12/administração & dosagem , Vitamina B 6/administração & dosagem , Sulfato de Zinco/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Ácido Ascórbico/farmacocinética , Quimiorradioterapia/efeitos adversos , Quimiorradioterapia/métodos , Ensaios Clínicos como Assunto , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Sinergismo Farmacológico , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/etiologia , Ácido Fólico/farmacocinética , Humanos , Ácido Pantotênico/farmacocinética , Extratos Vegetais/farmacocinética , Lesões por Radiação/etiologia , Tolerância a Radiação/efeitos dos fármacos , Resultado do Tratamento , Vitamina B 12/farmacocinética , Vitamina B 6/farmacocinética , Sulfato de Zinco/farmacocinética
5.
Anal Chem ; 92(10): 6984-6992, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32316724

RESUMO

Antioxidants have gained marked attention owing to their ability to prevent the oxidation of biological components and to protect the body from reactive oxygen species, thereby maintaining human health. Thus, antioxidant-rich dietary supplements and natural foods can be effective against oxidative stress and can even act as chemopreventive agents. Therefore, a simple and rapid assay for evaluation of antioxidant capacity and assessment of their distribution profile in natural sources is vital. Herein, we report a rapid, innovative chemiluminescence (CL) platform for evaluation and visualization of antioxidant capacity. We found that intense and long-lasting CL was formed upon the redox reaction of quinones, e.g., menadione, with antioxidants, e.g., l-ascorbic acid, in the presence of luminol. The produced CL intensities were proportional to the antioxidants' concentrations with a detection limit of 0.18 µM for the model antioxidant, l-ascorbic acid. As the formed CL was long-lasting, it could be easily captured and detected with a charge-coupled device (CCD) camera. To evaluate the quantification ability of the CCD camera, we developed a smart and fast microplate-based assay based on photographing the generated CL with a cooled CCD camera. The photographed CL intensities were linearly proportional with the antioxidant concentrations, and then the method was applied for photographing multiple food sample extracts. Ultimately, we utilized our method for the distribution profiling of antioxidant capacity in food cut sections. Samples were dipped in luminol and then in quinone, followed by CCD camera photography, without the need for any pulverization/extraction procedure, giving precise antioxidant distribution information.


Assuntos
Antioxidantes/análise , Ácido Ascórbico/análise , Medições Luminescentes , Antioxidantes/farmacocinética , Ácido Ascórbico/farmacocinética , Benzoquinonas/química , Humanos , Luminol/química , Estrutura Molecular , Distribuição Tecidual
6.
Food Chem ; 324: 126837, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32339791

RESUMO

Evidences have shown that phytosome assemblies are novel drug delivery system. However, studies of phytosomes in food applications are scarce. The characteristics of milk phospholipid assemblies and their functionality in terms of in vitro digestibility and bioavailability of encapsulated nutrients (ascorbic acid and α-tocopherol) were studied. The phytosomes were fabricated using ethanolic evaporation technique. Spectral analysis revealed that polar parts of phospholipids formed hydrogen bonds with ascorbic acid hydroxyl groups, further, incorporating ascorbic acid or α-tocopherol into the phospholipid assembly changed the chemical conformation of the complexes. Phospholipid-ascorbic acid phytosomes yielded an optimal complexing index of 98.52 ± 0.03% at a molar ratio of 1:1. Phytosomes exhibited good biocompatibility on intestinal epithelial cells. The cellular uptake of ascorbic acid was 29.06 ± 1.18% for phytosomes. It was higher than that for liposomes (24.14 ± 0.60%) and for ascorbic acid aqueous solution (1.17 ± 0.70%).


Assuntos
Antioxidantes/química , Ácido Ascórbico/química , Lipossomos/química , Leite/química , Fosfolipídeos/química , alfa-Tocoferol/química , Animais , Ácido Ascórbico/farmacocinética , Varredura Diferencial de Calorimetria , Linhagem Celular , Liberação Controlada de Fármacos , Células Epiteliais/efeitos dos fármacos , Ligação de Hidrogênio , Absorção Intestinal/efeitos dos fármacos , Fosfolipídeos/farmacocinética , Ratos , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier
7.
Nutrients ; 11(10)2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31601028

RESUMO

The pharmacokinetics of vitamin C (vitC) is indeed complex. Regulated primarily by a family of saturable sodium dependent vitC transporters (SVCTs), the absorption and elimination are highly dose-dependent. Moreover, the tissue specific expression levels and subtypes of these SVCTs result in a compartmentalized distribution pattern with a diverse range of organ concentrations of vitC at homeostasis ranging from about 0.2 mM in the muscle and heart, and up to 10 mM in the brain and adrenal gland. The homeostasis of vitC is influenced by several factors, including genetic polymorphisms and environmental and lifestyle factors such as smoking and diet, as well as diseases. Going from physiological to pharmacological doses, vitC pharmacokinetics change from zero to first order, rendering the precise calculation of dosing regimens in, for example, cancer and sepsis treatment possible. Unfortunately, the complex pharmacokinetics of vitC has often been overlooked in the design of intervention studies, giving rise to misinterpretations and erroneous conclusions. The present review outlines the diverse aspects of vitC pharmacokinetics and examines how they affect vitC homeostasis under a variety of conditions.


Assuntos
Ácido Ascórbico/farmacocinética , Ácido Ascórbico/administração & dosagem , Ácido Ascórbico/metabolismo , Deficiência de Ácido Ascórbico/complicações , Deficiência de Ácido Ascórbico/fisiopatologia , Difusão , Feminino , Homeostase , Humanos , Absorção Intestinal , Necessidades Nutricionais , Gravidez , Fumar , Transportadores de Sódio Acoplados à Vitamina C , Distribuição Tecidual
8.
Mater Sci Eng C Mater Biol Appl ; 105: 110096, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546344

RESUMO

The objective of this study is to understand the effect of sustained release of vitamin C from ß-tricalcium phosphate (ß-TCP) scaffold on proliferation, viability and differentiation of human fetal osteoblast cells (hFOB). The influence of pH, drug concentration, and presence of polymer on the sustained release of vitamin C from polycaprolactone (PCL) coated ß-TCP scaffolds are studied. Prolonged and sustained release of vitamin C, over 60 days is observed in PCL coated ß-TCP scaffolds compared to uncoated scaffolds. Presence of PCL helps to minimize the burst release of vitamin C from ß-TCP scaffolds in the initial 24 h of release. To evaluate the osteogenic potential of vitamin C incorporated ß-TCP scaffolds, osteoblast cells are cultured and cell morphology, proliferation, viability, and differentiation are assessed. Morphological characterization shows layer like osteoblast cell attachment in the presence of vitamin C compared to the control. MTT cell viability assay shows 2 folds increase in osteoblast cell density in the presence of vitamin C after 3,7 and 11 days of culture. Furthermore, increased ALP activity at 11 days of culture indicates the possible role of vitamin C on osteoblast differentiation. Additionally, a preliminary study shows vitamin C loaded scaffolds suppress osteosarcoma (MG-63) cell proliferation to 4 folds after 3 days compared to control. These results show a sustained release of vitamin C from PCL coated ß-TCP scaffolds improve proliferation, viability, and differentiation of osteoblasts cell as well as mitigate osteosarcoma cell proliferation, suggesting its potential application as synthetic bone graft substitutes in tissue engineering application.


Assuntos
Ácido Ascórbico , Neoplasias Ósseas , Fosfatos de Cálcio , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Osteoblastos/metabolismo , Osteossarcoma , Ácido Ascórbico/química , Ácido Ascórbico/farmacocinética , Ácido Ascórbico/farmacologia , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Fosfatos de Cálcio/química , Fosfatos de Cálcio/farmacocinética , Fosfatos de Cálcio/farmacologia , Linhagem Celular Tumoral , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/farmacologia , Humanos , Osteoblastos/patologia , Osteossarcoma/tratamento farmacológico , Osteossarcoma/metabolismo , Osteossarcoma/patologia
9.
Nutrients ; 11(2)2019 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-30691123

RESUMO

Iron deficiency is the most common form of malnutrition. Factors responsible for this so-called "hidden hunger" include poor diet, increased micronutrient needs and health problems such as diseases and infections. Body iron status can be increased by the intake of dietary supplements and fortified food. The aim of the present study was to compare iron bioaccessibility from commercial nutritional supplements and iron microcapsules. A comparison study was performed under conditions mimicking gastric and gastrointestinal digestion. A preparation of encapsulated ferrous sulphate or lactate and vitamin C, in a formula, showed bioaccessibility factors of up to 100% when digested individually, and around 60% in the presence of a food matrix. The degree of oxidation of the ferrous ions differed, depending on the type of preparation, the presence of vitamin C and the food matrix. The highest percentage content of ferrous ion, in the soluble fractions after gastrointestinal digestion, was shown by the preparation containing microencapsulated ferrous lactate or ferrous sulphate and vitamin C. Encapsulation seems to limit the interaction of iron with the food matrix and protect it against oxidation, thus making it more accessible for intestinal uptake.


Assuntos
Suplementos Nutricionais/análise , Alimentos Fortificados/análise , Ferro/análise , Ferro/farmacocinética , Adulto , Ácido Ascórbico/análise , Ácido Ascórbico/farmacocinética , Disponibilidade Biológica , Digestão/fisiologia , Composição de Medicamentos , Compostos Ferrosos/análise , Compostos Ferrosos/farmacocinética , Análise de Alimentos , Humanos , Modelos Biológicos
10.
Cancer Cell ; 34(5): 700-706, 2018 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-30174242

RESUMO

Vitamin C (ascorbic acid, ascorbate), despite controversy, has re-emerged as a promising anti-cancer agent. Recent knowledge of intravenous ascorbate pharmacokinetics and discovery of unexpected mechanisms of ascorbate action have spawned many investigations. Two mechanisms of anti-cancer activity with ascorbate have gained prominence: hydrogen peroxide-induced oxidative stress and DNA demethylation mediated by ten-eleven translocation enzyme activation. Here, we highlight salient aspects of the evolution of ascorbate in cancer treatment, provide insights into the pharmacokinetics of ascorbate, describe mechanisms of its anti-cancer activity in relation to the pharmacokinetics, outline promising preclinical and clinical evidence, and recommend future directions.


Assuntos
Antineoplásicos/uso terapêutico , Antioxidantes/uso terapêutico , Ácido Ascórbico/farmacocinética , Ácido Ascórbico/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/prevenção & controle , Antineoplásicos/farmacocinética , Desmetilação do DNA/efeitos dos fármacos , Humanos , Peróxido de Hidrogênio/química , Oxigenases de Função Mista/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Proteínas Proto-Oncogênicas/metabolismo
11.
J Microencapsul ; 35(3): 301-311, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29781344

RESUMO

Vitamin C, as an antioxidant additive in pharmaceutical and food products, is susceptible to environmental conditions, and new design strategies are needed to enhance its stability. The aim of this study is to prepare vitamin C proliposome using film deposition on the carrier by applying different factors, and optimise the characteristics of the obtained powder using the design expert® software. The optimised formulation demonstrated acceptable flowability with 20% vitamin C loading. This formulation released about 90% vitamin C within 2 h and showed higher (1.7-fold) in-vitro antioxidant activity. Ex-vivo antioxidant activity was 1.9 and 1.6 times higher in brain and liver cells, respectively. A 27% reduction in malondialdehyde (MDA) level of liver cell was obtained comparing free vitamin C. Therefore, this study results suggest that the vitamin C-encapsulated proliposome powder might be an appropriate carrier for oral drug delivery of vitamin C with better antioxidant efficacy.


Assuntos
Antioxidantes/administração & dosagem , Antioxidantes/farmacologia , Ácido Ascórbico/administração & dosagem , Ácido Ascórbico/farmacologia , Lipossomos/química , Animais , Antioxidantes/farmacocinética , Ácido Ascórbico/farmacocinética , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Desenho de Fármacos , Liberação Controlada de Fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Malondialdeído/metabolismo , Ratos Wistar , Software , Solubilidade
12.
Biomacromolecules ; 19(6): 1990-1998, 2018 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-29420880

RESUMO

Relative to normal cells, tumor cells lack adequate capability of reactive oxygen scavenging. Thus, tumor cells can be selectively killed by increasing the concentration of reactive oxygen species in tumor tissue. In this report, we construct an integrated multifunctional polymeric nanoparticle which can selectively improve hydrogen peroxide (H2O2) levels in tumor tissue and convert them into more active hydroxyl radicals by Fenton reaction. First, the diblock copolymers containing polyethylene glycol (PEG) and poly(glutamic acid) modified by ß-cyclodextrin (ß-CD) were synthesized. The block copolymer, ferrocenecarboxylic acid hexadecyl ester (DFc), and ascorbyl palmitate (PA) were coassembled in aqueous solution to obtain stable core-shell micelles through the inclusion complexation between ß-CD moieties in the block copolymer and ferrocene (Fc) groups from DFc. After intravenous injection, the particles achieved significant accumulation in tumor tissue where ascorbic acid at the pharmacological concentration promotes the production of H2O2, and subsequently Fenton reaction was catalyzed by Fc groups to produce hydroxyl radicals to efficiently kill cancer cells and suppress tumor growth. The micellar systems possess great potentials toward cancer therapy through synergistic H2O2 production and conversion into hydroxyl radicals specifically in tumor tissue.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Nanopartículas/química , Polímeros/química , Animais , Ácido Ascórbico/análogos & derivados , Ácido Ascórbico/química , Ácido Ascórbico/farmacocinética , Ácido Ascórbico/farmacologia , Feminino , Compostos Ferrosos/química , Humanos , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/metabolismo , Radical Hidroxila/química , Radical Hidroxila/metabolismo , Injeções Intravenosas , Ferro/química , Células MCF-7 , Metalocenos , Camundongos Endogâmicos BALB C , Micelas , Nanopartículas/administração & dosagem , Polietilenoglicóis/química , Ácido Poliglutâmico/química , Polímeros/farmacocinética , Polímeros/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , beta-Ciclodextrinas/química
13.
Int J Mol Sci ; 19(2)2018 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-29439410

RESUMO

Intravenous administration of high-dose ascorbic acid (AA) has been reported as a treatment for cancer patients. However, cancer patients with renal failure cannot receive this therapy because high-dose AA infusion can have side effects. To solve this problem, we evaluated the antitumor activity of a lipophilic stable AA derivative, 2-O-α-d-glucopyranosyl-6-O-(2-pentylheptanoyl)-l-ascorbic acid (6-bOcta-AA-2G). Intravenous administration of 6-bOcta-AA-2G suppressed tumor growth in colon-26 tumor-bearing mice more strongly than did AA, even at 1/10 of the molar amount of AA. Experiments on the biodistribution and clearance of 6-bOcta-AA-2G and its metabolites in tumor-bearing mice showed that 6-bOcta-AA-2G was hydrolyzed to 6-O-(2-propylpentanoyl)-l-ascorbic acid (6-bOcta-AA) slowly to yield AA, and the results suggested that this characteristic metabolic pattern is responsible for making the antitumor activity of 6-bOcta-AA-2G stronger than that of AA and that the active form of 6-bOcta-AA-2G showing antitumor activity is 6-bOcta-AA. In in vitro experiments, the oxidized form of 6-bOcta-AA as well as 6-bOcta-AA showed significant cytotoxicity, while the oxidized forms of ascorbic acid showed no cytotoxicity at all, suggesting that the antitumor activity mechanism of 6-bOcta-AA-2G is different from that of AA and that the antitumor activity is due to the reduced and oxidized form of 6-bOcta-AA. The findings suggest that 6-bOcta-AA-2G is a potent candidate as an alternative drug to intravenous high-dose AA.


Assuntos
Antineoplásicos/uso terapêutico , Ácido Ascórbico/análogos & derivados , Ácido Ascórbico/uso terapêutico , Glucosídeos/uso terapêutico , Neoplasias Experimentais/tratamento farmacológico , Animais , Antineoplásicos/síntese química , Antineoplásicos/farmacocinética , Ácido Ascórbico/síntese química , Ácido Ascórbico/farmacocinética , Linhagem Celular Tumoral , Feminino , Glucosídeos/síntese química , Glucosídeos/farmacocinética , Camundongos , Camundongos Endogâmicos BALB C , Distribuição Tecidual
14.
Biochem Biophys Res Commun ; 493(3): 1184-1189, 2017 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-28958933

RESUMO

The anticancer potential of ascorbic acid (AA) has been controversially discussed for decades. Although the cytotoxic effect of pharmacologic concentrations of ascorbic acid has already been successfully demonstrated in numerous studies in vitro, it could not be verified to the same extent in vivo. We propose that the ubiquitous metabolite pyruvate diminishes the effect of AA by reacting with its presumable cytotoxic mediator hydrogen peroxide (H2O2). MTT assays confirm that co-incubation with 1.4 mM pyruvate abolishes the cytotoxic effect of pharmacologic concentrations of AA in all cancer cell lines tested (human melanoma (WM451-Lu), breast (MCF-7) and hypopharyngeal cancer cells (FaDu)). We further investigated whether pyruvate diminishes the anticancer effect of AA by interfering with the generation of H2O2. Therefore, we analyzed the concentration of AFR, a proposed intermediate in the AA-dependent formation of H2O2, by electron paramagnetic resonance spectroscopy, during incubation with AA and pyruvate in WM451-Lu cells as a model system. In addition, we measured H2O2 concentration by indirect detection with Clark-type oxygen electrode. AFR concentration was not significantly influenced by pyruvate, whereas H2O2 concentration was significantly reduced. In parallel, pyruvate concentrations of the stimulation medium declined with increasing AA and consequently H2O2 concentrations. In summary, pyruvate diminishes the cytotoxic activity of ascorbic acid in vitro. The AFR concentration measured remains unaffected by pyruvate whereas the H2O2 concentration is reduced; confirming that pyruvate directly reacts with AA-induced H2O2, without influencing its formation. However, further experiments are needed to elucidate the complex mechanisms being responsible for the reduced efficacy of AA in vivo.


Assuntos
Ácido Ascórbico/farmacologia , Ácido Pirúvico/metabolismo , Ácido Ascórbico/administração & dosagem , Ácido Ascórbico/farmacocinética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Interações Medicamentosas , Radicais Livres/metabolismo , Humanos , Peróxido de Hidrogênio/metabolismo , Peróxido de Hidrogênio/farmacologia , Células MCF-7 , Ácido Pirúvico/farmacologia
15.
Eur J Pharm Sci ; 109: 412-418, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-28847527

RESUMO

Ascorbic acid (AA) infusion and modulated electrohyperthermia (mEHT) are widely used by integrative cancer practitioners for many years. However, there are no safety and pharmacokinetics data in Chinese cancer patients. We carried out a clinical trial to evaluate the safety and pharmacokinetics of those methods in patients with stage III-IV non-small cell lung cancer (NSCLC). Blood ascorbic acid in the fasting state was obtained from 35 NSCLC patients; selecting from them 15 patients with stage III-IV entered the phase I study. They were randomized allocated into 3 groups, and received doses 1.0, 1.2, 1.5g/kg AA infusions. Participants in the first group received intravenous AA (IVAA) when mEHT was finished, in the second group IVAA was administered simultaneously with mEHT and in the third group IVAA was applied first, and followed with mEHT. Pharmacokinetic profiles were obtained when they received solely IVAA and when IVAA in combination with mEHT. The process was applied 3 times a week (every other day, weekend days off) for 4weeks. We found that fasting plasma AA levels were significantly correlated with stage of the disease. Peak concentration of AA was significantly higher in the simultaneous treatments than in other combinations with mEHT or in solely IVAA-managed groups. IVAA synergy with simultaneous mEHT is safe and the concomitant application significantly increases the plasma AA level for NSCLC patients.


Assuntos
Ácido Ascórbico/administração & dosagem , Carcinoma Pulmonar de Células não Pequenas/sangue , Terapia por Estimulação Elétrica , Hipertermia Induzida , Neoplasias Pulmonares/sangue , Administração Intravenosa , Idoso , Ácido Ascórbico/efeitos adversos , Ácido Ascórbico/sangue , Ácido Ascórbico/farmacocinética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Terapia Combinada , Feminino , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Ácido Oxálico/urina , Qualidade de Vida , Método Simples-Cego
16.
BMC Ophthalmol ; 17(1): 121, 2017 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-28693452

RESUMO

BACKGROUND: To measure ascorbic acid concentration in aqueous humor of patients with cataract after oral or intravenous vitamin C supplementation. METHODS: Forty-two eyes of 42 patients with senile cataract who underwent uncomplicated cataract surgery were enrolled. Patients (n = 14 each) were administered oral vitamin C (2 g), intravenous vitamin C (20 g) or no treatment (control group) on the day before surgery. Samples of aqueous humor (0.1 cm3) were obtained by anterior chamber aspiration at the beginning of surgery and stored at -80 °C. Ascorbic acid concentration in aqueous humor was measured by high-pressure liquid chromatography. RESULTS: The mean age at surgery was 62.5 years, with no difference among the three groups. The mean ± standard deviation concentrations of ascorbic acid in aqueous humor in the control and oral and intravenous vitamin C groups were 1347 ± 331 µmol/L, 1859 ± 408 µmol/L and 2387 ± 445 µmol/L, respectively. Ascorbic acid concentration was significantly lower in the control than in the oral (P < 0.01) and intravenous (P < 0.001) vitamin C groups and was significantly higher in the intravenous than in the oral vitamin C group (P < 0.05). CONCLUSIONS: Ascorbic acid concentration in aqueous humor is increased by systemic vitamin C supplementation, with intravenous administration being more effective than oral administration.


Assuntos
Humor Aquoso/química , Ácido Ascórbico/farmacocinética , Catarata/dietoterapia , Administração Oral , Antioxidantes/administração & dosagem , Antioxidantes/farmacocinética , Ácido Ascórbico/administração & dosagem , Biomarcadores/metabolismo , Catarata/metabolismo , Extração de Catarata , Cromatografia Líquida de Alta Pressão , Feminino , Seguimentos , Humanos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos
17.
Nutr Cancer ; 69(4): 521-533, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28362118

RESUMO

There are several extrinsic and intrinsic factors involving reactive oxygen species that play critical roles in tumor development and progression by inducing DNA mutations, genomic instability, and aberrant pro-tumorigenic signaling. There are various essential micronutrients including minerals and vitamins in the diet, which play pivotal roles in maintaining and reinforcing antioxidant performance, affecting the complex network of genes (nutrigenomic approach) and encoding proteins for carcinogenesis. A lot of these antioxidant agents are available as dietary supplements and are predominant worldwide. However, the best antioxidant micronutrient (or a combination of micronutrients) for reducing cancer risks is unknown. The purpose of this review is to survey the literature on modern biological theories of cancer and the roles of dietary antioxidants in cancer. The roles and functions of antioxidant micronutrients, such as vitamin C (ascorbate), vitamin E (alpha-tocopherol), selenium, and vitamin A, provided through diet for the prevention of cancer are discussed in the present work.


Assuntos
Antioxidantes/farmacologia , Suplementos Nutricionais , Neoplasias/prevenção & controle , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Inibidores da Angiogênese/farmacologia , Anticarcinógenos/farmacologia , Ácido Ascórbico/farmacocinética , Ácido Ascórbico/farmacologia , Dieta , Humanos , Neoplasias/dietoterapia , Neoplasias/metabolismo , Recomendações Nutricionais , Selênio/farmacologia , Transportadores de Sódio Acoplados à Vitamina C/metabolismo , Vitamina A/farmacologia , Vitamina E/farmacocinética , Vitamina E/farmacologia , alfa-Tocoferol/farmacologia
18.
Free Radic Biol Med ; 99: 451-462, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27567539

RESUMO

Despite recent evidence for an anti-tumour role for high-dose ascorbate, potential mechanisms of action are still unclear. At mM concentrations that are achieved with high-dose intravenous administration, autoxidation of ascorbate can generate cytotoxic levels of H2O2. Ascorbate is also a required co-factor for the hydroxylases that suppress the transcription factor hypoxia-inducible factor (HIF-1). HIF-1 supports an aggressive tumour phenotype and is associated with poor prognosis, and previous studies have shown that optimizing intracellular ascorbate levels down-regulates HIF-1 activation. In this study we have simultaneously measured ascorbate concentrations and the HIF-1 pathway activity in tumour tissue following high dose ascorbate administration, and have studied tumour growth and physiology. Gulo-/- mice, a model of the human ascorbate dependency condition, were implanted with syngeneic Lewis lung tumours, 1g/kg ascorbate was administered into the peritoneum, and ascorbate concentrations were monitored in plasma, liver and tumours. Ascorbate levels peaked within 30min, and although plasma and liver ascorbate returned to baseline within 16h, tumour levels remained elevated for 48h, possibly reflecting increased stability in the hypoxic tumour environment. The expression of HIF-1 and its target proteins was down-regulated with tumour ascorbate uptake. Elevated tumour ascorbate levels could be maintained with daily administration, and HIF-1 and vascular endothelial growth factor protein levels were reduced in these conditions. Increased tumour ascorbate was associated with slowed tumour growth, reduced tumour microvessel density and decreased hypoxia. Alternate day administration of ascorbate resulted in lower tumour levels and did not consistently decrease HIF-1 pathway activity. Levels of sodium-dependent vitamin C transporters 1 and 2 were not clearly associated with ascorbate accumulation by murine tumour cells in vitro or in vivo. Our results support the suppression of the hypoxic response by ascorbate as a plausible mechanism of action of its anti-tumour activity, and this may be useful in a clinical setting.


Assuntos
Antineoplásicos/farmacocinética , Antioxidantes/farmacocinética , Ácido Ascórbico/farmacocinética , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Regulação Neoplásica da Expressão Gênica , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Fator A de Crescimento do Endotélio Vascular/genética , Animais , Antineoplásicos/sangue , Antineoplásicos/farmacologia , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Ácido Ascórbico/sangue , Ácido Ascórbico/farmacologia , Carcinoma Pulmonar de Lewis/genética , Carcinoma Pulmonar de Lewis/metabolismo , Carcinoma Pulmonar de Lewis/patologia , Esquema de Medicação , Feminino , Subunidade alfa do Fator 1 Induzível por Hipóxia/antagonistas & inibidores , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Injeções Intraperitoneais , Isoenzimas/genética , Isoenzimas/metabolismo , Camundongos , Camundongos Knockout , Transdução de Sinais , Transportadores de Sódio Acoplados à Vitamina C/genética , Transportadores de Sódio Acoplados à Vitamina C/metabolismo , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/metabolismo
19.
Redox Biol ; 8: 298-304, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-26928133

RESUMO

BACKGROUND: Supra-physiological concentrations of ascorbate, vitamin C, in blood, greater than 1mM, achieved through intravenous administration (IV), are being tested in clinical trials to treat human disease, e.g. cancer. These trials need information on the high levels of ascorbate achieved in blood upon IV administration of pharmacological ascorbate so appropriate clinical decisions can be made. METHODS: Here we demonstrate that in the complex matrix of human blood plasma supra-physiological levels of ascorbate can be quantified by direct UV spectroscopy with use of a microvolume UV-vis spectrophotometer. RESULTS: Direct quantitation of ascorbate in plasma in the range of 2.9mM, lower limit of detection, up to at least 35mM can be achieved without any sample processing, other than centrifugation. CONCLUSIONS: This approach is rapid, economical, and can be used to quantify supraphysiological blood levels of ascorbate associated with the use of IV administration of pharmacological ascorbate to treat disease.


Assuntos
Ácido Ascórbico/sangue , Neoplasias/sangue , Espectrofotometria Ultravioleta , Administração Intravenosa , Ácido Ascórbico/administração & dosagem , Ácido Ascórbico/farmacocinética , Humanos , Neoplasias/tratamento farmacológico
20.
Blood Press Monit ; 21(3): 160-7, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26910646

RESUMO

BACKGROUND: Regular intake of vitamin C/ascorbate reduces blood pressure (BP) in hypertensives. High-dose intravenous vitamin C (IVC) achieves higher plasma levels; however, there is a paucity of research on acute BP effects. Our study is the first to investigate the effect of high-dose IVC, with or without concomitant i.v. nutrients, on BP during i.v. METHODS: A cohort of adult patients scheduled to receive IVC treatment for infection, cancer or fatigue, as prescribed by their treating doctor, participated at a Melbourne clinic, Australia. Ambulatory BP was assessed every 10 min over 90 min during i.v. TREATMENT: Patients received 15-100 g of IVC alone or in addition to i.v. vitamin B, glutathione, magnesium or zinc. BP change over time adjusted for baseline BP, IVC dosage, i.v. treatment and BMI was analysed. RESULTS: A total of 77 mostly normotensive patients participated, with a third receiving IVC alone (42±20 g), and two-thirds also received other i.v. nutrients. IVC alone (>30 g) reduced the mean BP up to 8-9 mmHg in prehypertensive patients. In contrast, concomitant intravenous vitamin B12 (IVB12) significantly increased the mean BP by 11-13 mmHg. Comparison of BP change during IVC versus IVC+IVB12 indicated a highly significant difference [systolic blood pressure: mean difference (SD)=16.6 (17.8) mmHg, P<0.001; diastolic blood pressure: mean difference (SD)=12.5 (16.7) mmHg, P=0.003]. CONCLUSION: Our study suggests an acute BP-reducing effect of high-dose IVC, particularly with dosages above 30 g, and in patients with prehypertension and normal BMI. Furthermore, our study indicated a marked and clinically relevant hypertensive effect of IVB12, suggesting routine BP monitoring during i.v. therapy in clinical practice.


Assuntos
Ácido Ascórbico/administração & dosagem , Pressão Sanguínea/efeitos dos fármacos , Glutationa/administração & dosagem , Hipertensão/fisiopatologia , Magnésio/administração & dosagem , Vitamina B 12/administração & dosagem , Zinco/administração & dosagem , Administração Intravenosa , Adulto , Idoso , Ácido Ascórbico/farmacocinética , Feminino , Glutationa/farmacocinética , Humanos , Hipertensão/sangue , Magnésio/farmacocinética , Masculino , Pessoa de Meia-Idade , Vitamina B 12/farmacocinética , Zinco/farmacocinética
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