RESUMO
AIM: To compare the cytotoxicity of materials used to repair perforations using permanent V79 fibroblasts and murine granulocyte-macrophage progenitor cells (CFU-GM). METHODOLOGY: Set specimens from amalgam, glass-ionomer, SuperEBA, N-Rickert, MTA and gutta-percha were eluted with culture medium for 72 h and their cytotoxicities were assessed by incubating the extracts with V79 and bone marrow-derived progenitors for 24 h and 7 days, respectively. Cytotoxicity on V79 cells was judged using the total nucleic acid content (NAC), neutral red uptake (NRU) and reduction of the tetrazolium salt (MTT). The number of bone marrow CFU-GM colonies determined in clonal cultures stimulated with recombinant murine granulocyte-macrophage colony-stimulating factor was used to assess cytotoxicity to progenitor cells. Statistical analyses were conducted using the one-way analysis of variance and Tukey's test where appropriate. RESULTS: All materials were cytotoxic in both cell systems; however, CFU-GM was more sensitive to the extracts than V79 cells. A similar rank order of toxicity was observed in V79 cells using the NAC and the MTT assays: glass-ionomer > N-Rickert congruent with SuperEBA > gutta-percha > amalgam congruent with MTA (P < 0.05). In contrast, the NRU test exhibited a lower sensitivity to MTA, gutta-percha and amalgam extracts. In the clonal culture assay, the toxicity was less pronounced in the presence of gutta-percha, SuperEBA and MTA. Similar cellular responses were found by placing the set specimens directly in the clonal culture dishes. CONCLUSIONS: The sensitivity of toxicity depended on the choice of the endpoint and the cell-culture system. Nevertheless, MTA was ranked as the least cytotoxic cement in both cell systems.
Assuntos
Compostos de Alumínio/toxicidade , Compostos de Cálcio/toxicidade , Fibroblastos/efeitos dos fármacos , Células-Tronco Hematopoéticas/efeitos dos fármacos , Óxidos/toxicidade , Materiais Restauradores do Canal Radicular/toxicidade , Silicatos/toxicidade , Resinas Acrílicas/toxicidade , Animais , Linhagem Celular , Cricetinae , Amálgama Dentário/toxicidade , Adesivos Dentinários/toxicidade , Combinação de Medicamentos , Células Precursoras de Granulócitos/efeitos dos fármacos , Guta-Percha/toxicidade , Macrófagos/efeitos dos fármacos , Camundongos , Dióxido de Silício/toxicidadeRESUMO
Given the importance of protein phosphorylation in the context of cellular functions, abnormal protein phosphatase activity has been implicated in several diseases, including cancer. These critical roles of protein phosphatases qualify them as potential targets for the development of medicinal compounds that possess distinct modes of action such as violacein. In this work, studies with this natural indolic pigment at a concentration of 10.0 micromol L(-1) demonstrated a 20% activation of total protein phosphatase extracted from human lymphocytes. Although no alteration was observed on protein tyrosine phosphatase (CD45), 30% of inhibition was achieved in cytoplasmatic protein phosphatase activity after incubation with 10.0 micromol L(-1) violacein. Additionally, 5.0 micromol L(-1) of violacein inhibited by 50% the serum tartrate-resistant acid phosphatase activity. Violacein presented toxic effect on lymphocytes with IC50 values of 3 and 10 micromol L(-1) for protein content and protein phosphatase activity, respectively. These findings suggest an important role for protein phosphatases in the mechanisms controlling proliferation and cell death.
Assuntos
Indóis/toxicidade , Linfócitos/efeitos dos fármacos , Linfócitos/enzimologia , Monoéster Fosfórico Hidrolases/antagonistas & inibidores , Monoéster Fosfórico Hidrolases/metabolismo , Células Cultivadas , Humanos , Indóis/química , Linfócitos/citologia , Estrutura Molecular , Monoéster Fosfórico Hidrolases/sangueRESUMO
Derivatives of dehydrocrotonin (DHC; Compound I) with different anti-ulcerogenic properties but less toxicity were produced by reducing the cyclohexenone moiety of DHC with NaBH4 (Compound II), reducing the cyclohexenone and lactone moieties with LiAlH4 (Compound III) and transforming the lactone moiety into an amide (Compound IV) using dimethylamine. Derivatives of DHC were assayed in cultured hepatocytes and V79 fibroblasts. Three independent endpoints assays for cytotoxicity were used, namely, the DNA content, tetrazolium reduction (MTT) and neutral red uptake (NRU). Compound III was less toxic than the other DHC derivatives in both cell cultures. ICso values ranging from 250 to 600 microM were obtained for Compounds II and IV in the NRU and DNA content tests evaluated in 4-hour hepatocyte cultures. Although Compound II showed relatively low cytotoxicity in rat hepatocytes based on the NRU and DNA content assays, a very high toxicity (IC50=10 microM) was observed in the MTT test. Metabolites of Compound II in conditioned medium from 4-hour old hepatocyte cultures enhanced the MTT-reducing ability of V79 fibroblasts. The cytotoxicity of the derivatives was greater in recently isolated hepatocytes (only a 4-hour incubation for cell attachment prior to treating with the derivatives) than in hepatocytes previously cultured (24-hour incubation) before the treatment. Thus, aging reduced the cytotoxic effects of DHC derivatives in isolated hepatocytes, suggesting that P450-mediated biotransformation of such derivatives may lead to the formation of more toxic metabolites.
Assuntos
Croton , Diterpenos Clerodânicos , Diterpenos/toxicidade , Fibroblastos/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Senescência Celular/fisiologia , Cimetidina/farmacologia , Cricetinae , Cricetulus , Meios de Cultivo Condicionados/farmacologia , DNA/análise , Diterpenos/administração & dosagem , Relação Dose-Resposta a Droga , Fibroblastos/metabolismo , Fibroblastos/patologia , Hepatócitos/metabolismo , Hepatócitos/patologia , Masculino , Vermelho Neutro/metabolismo , Plantas Medicinais , Ratos , Ratos Wistar , Succinato Desidrogenase/metabolismo , Sais de Tetrazólio/metabolismo , Tiazóis/metabolismoRESUMO
The derivatives of 3-(4'-bromo-[1,1'-biphenyl]-4-yl)-3-(4-X-phenyl)-N,N-dimethyl-2-propen-1-amine (5a-m) were synthesised through a Friedel-Crafts acylation followed by Wittig reaction. The effects of the compounds on standard strains of Mycobacterium sp. (ATCC) and M. tuberculosis isolated from clinical specimens were evaluated. Also the toxicity was determined on V79 cells line using neutral red uptake (NRU), nucleic acid content (NAC) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction to measure the cellular viability.
Assuntos
Alcenos/síntese química , Antituberculosos/síntese química , Compostos de Bifenilo/síntese química , Mycobacterium tuberculosis/efeitos dos fármacos , Alcenos/química , Alcenos/farmacologia , Animais , Antituberculosos/química , Antituberculosos/farmacologia , Compostos de Bifenilo/química , Compostos de Bifenilo/farmacologia , Linhagem Celular , Cricetinae , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Pulmão/citologia , Testes de Sensibilidade MicrobianaRESUMO
New derivatives from dehydrocrotonin (DHC, compound I), with the same anti-ulcerogenic properties but less toxicity were synthesised by reducing the cyclohexenone moiety of DHC with NaBH(4) (compound II), by reducing the cyclohexenone and lactone moieties with LiAlH(4) (compound III) and by transforming the lactone moiety into an amide (compound IV) using dimethylamine. The cytotoxicity of these derivatives from DHC was assayed on V79 fibroblast cell line. Three independent endpoints for cytotoxicity were evaluated; namely, the nucleic acid content (NAC), tetrazolium reduction (MTT) and neutral red uptake (NRU). IC(50) values of 540 and 350 microM were obtained for compound II in the NRU and NAC tests, respectively. Compound III was less toxic than the other DHC derivatives (IC(50)=1800 microM) on V79 cells based on NAC assay. Compound IV showed an IC(50) ranging from 350 to 600 microM based on the three endpoints evaluated. The three compounds were less toxic on V79 cells than DHC. DHC, compounds II, III and IV did not change the respiration rate of Escherichia coli on the acute toxicity assay.
Assuntos
Diterpenos Clerodânicos , Diterpenos/toxicidade , Escherichia coli/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Plantas Medicinais/toxicidade , Animais , Contagem de Células , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Escherichia coli/metabolismo , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Pulmão/citologia , Pulmão/metabolismo , Vermelho Neutro/metabolismo , Nitroazul de Tetrazólio/metabolismo , Ácidos Nucleicos/análise , Testes de ToxicidadeRESUMO
The antimycobacterial activity of nine biphenyl methanone (BPM) derivatives against standard strains of Mycobacterium kansasii, M. avium and M. malmoense was determined by colorimetric assay in microplates with the dye Alamar Blue. Acute toxicity of these compounds was also analyzed by determination of CO2 concentration in a respirometric assay using Escherichia coli. The compounds showed weak antimycobacterial activity with a minimal inhibitory concentration (MIC) over 0.038 mmol l-1 and no toxicity was found in E. coli up to 400 mmol l-1. No cytotoxicity was observed on V79 cells up to 0.35 mmol l-1 with 7 of the BPM derivatives, with two exceptions (X = SO2CH3, NO2) that showed some toxicity. The greatest antimycobacterial activity was observed with the SO2CH3 derivative and the application of Principal Component Analysis (PCA) showed a relationship between structure and antimycobacterial activity of the compounds. Two descriptors, nucleophilic superdelocalizability of carbon atom and pi-hydrophobic constant, were necessary to describe this relationship.
Assuntos
Antibacterianos/síntese química , Antibacterianos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Compostos de Bifenilo/síntese química , Compostos de Bifenilo/farmacologia , Mycobacterium/efeitos dos fármacos , Animais , Antibacterianos/toxicidade , Antineoplásicos/toxicidade , Compostos de Bifenilo/toxicidade , Células CHO , Corantes , Cricetinae , Ensaios de Seleção de Medicamentos Antitumorais , Escherichia coli/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Vermelho Neutro , Ácidos Nucleicos/biossíntese , Sais de Tetrazólio , Tiazóis , Células Tumorais CultivadasRESUMO
The cytotoxicity of prodigiosin, an antibiotic and potential trypanocide produced by Serratia marcescens, and Benznidazole, a trypanocidal drug, were assayed on V79 fibroblast cell line. Three independent endpoints for cytotoxicity were evaluated; namely, the nucleic acid content (NAC), MTT reduction and neutral red uptake (NRU). IC(50) values of 1-20 microM were obtained for prodigiosin in the NRU, MTT and NAC tests. Prodigiosin had greater trypanocidal activity (IC(50)=5 microM) than Nifurtimox (IC(50)=150 microM) a known trypanocide drug used in Chagas' disease therapy. Benznidazole was less toxic (IC(50)=2000 microM) than prodigiosin (IC(50)=1-20 microM) in V79 cells based on the MTT and NAC assays. Benznidazole stimulated the NRU until 2 mM. Indeed, the cell viability measured with the NRU was higher at all concentrations of benznidazole tested than that measured by MTT reduction and NAC assays.
Assuntos
Nitroimidazóis/toxicidade , Prodigiosina/toxicidade , Tripanossomicidas/toxicidade , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cricetinae , Cricetulus , Relação Dose-Resposta a DrogaRESUMO
The gastroprotective activity of the essential oil from the bark of Croton cajucara Benth (Euphorbiaceae) was assessed in three different models of experimentally induced gastric ulcer in mice. At oral dose of 100 mg/kg the essential oil reduced gastric lesions induced by hypothermic restraint stress and HCl/ethanol significantly. In the HCl/ethanol model a dose-dependent gastroprotective effect was found. Moreover, significant changes in gastric parameters such as pH, secretion rate and total gastric acid were found after intraduodenal administration of essential oil under ligated pylorus (Shay) conditions. The acute toxicity of essential oil was assessed in mice. The LD50 values were 9.3 and 680 mg/kg for oral and intraperitoneal administrations, respectively. The cytotoxicity of essential oil was studied also. A dose-dependent cell viability inhibition was found in V79 fibroblast cell cultures with an IC50 of 22.9 microg/ml. Our results support the pharmacological study of this essential oil.
Assuntos
Euphorbiaceae/química , Óleos Voláteis/farmacologia , Úlcera Gástrica/tratamento farmacológico , Estômago/efeitos dos fármacos , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cricetinae , Dose Letal Mediana , Camundongos , Óleos Voláteis/uso terapêuticoRESUMO
Xanthine oxidase (XO) has been investigated for its decreased activity in several cancerous tissues and constitutive generation of reactive oxygen species (ROS) in vivo seems to contribute significantly to its inactivation. Singlet oxygen (1O2) production has been suggested to be relevant when considering folic acid metabolism by cancer cells. Thus, the susceptibility of XO to inactivation by 1O2 generated either by the bioenergized systems folic acid/peroxidase/GSH/Mn2+/O2 and malonaldehyde/peroxidase/Mn2+/O2 or by methylene blue (MB) or eosin-sensitized photooxygenation was studied. Our results showed that other ROS were also responsible for XO inactivation when MB was used. In contrast, eosin produced almost exclusively 1O2. Kinetic studies of XO oxidation in the malonaldehyde/peroxidase system showed that histidine (His) is a competitive inhibitor with respect to XO. A similar result was observed in the eosin-photosensitized process, suggesting the involvement of 1O2 in both processes. In addition, an efficient quenching of XO oxidation by guanosine in the folic acid/peroxidase system was observed. Amino acid analysis revealed that cysteine (Cys) is more affected than other XO amino acids also prone to oxidation such as tyrosine (Tyr), methionine (Met) and His. These results indicate that 1O2 may cause oxidative damage to the Cys residues of XO, with loss of enzyme activity. Alteration of the flavin prosthetic site is hypothesized.
Assuntos
Cisteína/química , Peroxidase/química , Espécies Reativas de Oxigênio , Xantina Oxidase/química , Aminoácidos/química , Catálise , Ácido Fólico/química , Glutationa/química , Peroxidase do Rábano Silvestre/química , Indicadores e Reagentes , Malondialdeído/química , Oxirredução , Fotoquímica , Espectrometria de FluorescênciaRESUMO
Violacein, a pigment produced by Chromobacterium violaceum, is reported to be a potential drug for the treatment of Chagas' disease. Violacein is also effective against leukemia and lymphoma cells in culture (IC50 10(-8) M). Changes in the nuclear acid content, 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide reduction and neutral red uptake in these cells were used to evaluate the cytotoxicity of violacein in V79 Chinese hamster (M-8) fibroblasts. Violacein was highly cytotoxic to V79 fibroblasts (IC50 5-12 microM). Using the TUNEL method and the Feulgen reaction coupled to image analysis, violacein (5 and 10 microM) was found to trigger apoptosis but not necrosis in V79 cells. The morphological changes seen in the nuclei of these cells included chromatin condensation and a decrease in deoxyribonucleic acid content. These results demonstrating that violacein induces apoptosis in V79 cells strengthen its potential as a therapeutic agent.