RESUMO
Context: Influenza is a severe, life-threatening viral disease that can be prevented by vaccination. However, the anti-influenza human vaccine failed to show the required efficacy both in infants under 5 years old and in the elder population, who are among those with the highest risk of developing severe complications after influenza infection. Therefore, it is of high importance to improve the vaccine efficacy and ensure its safety in these susceptible populations. GK-1, a novel 18-aa peptide adjuvant, has been proved to increase the immunogenicity of the human influenza vaccine in both young and aged mice. Objective: A preclinical study of the toxicity profile of GK-1 following the World Health Organization guidelines to support its use was herein conducted. Material and methods: GK-1 was synthetically produced following Good Manufacturing Practices. The toxicological evaluation of GK-1 peptide was performed in rats after repeated dose-ranging trials by the subcutaneous route. The mutagenic potential of GK-1 was assessed by the micronucleus, chromosomal aberration, and Ames tests, in accordance with OECD Guidelines. Results: GK-1 did not show toxic effects at doses up to 12.5mg/kg, corresponding to 25 times the dose intended for human use. No indications of mutagenic potential were observed. GK-1 after dermal administration was well tolerated locally. Conclusion: The efficacy of GK-1 to improve influenza vaccine protection, along with the absence of toxicity and mutagenicity, as reported herein, support the evaluation of this peptide in a clinical trial as a novel adjuvant for human use.
Assuntos
Adjuvantes Imunológicos/toxicidade , Aberrações Cromossômicas/efeitos dos fármacos , Dano ao DNA , Vacinas contra Influenza/imunologia , Peptídeos Cíclicos/toxicidade , Animais , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Feminino , Humanos , Influenza Humana/prevenção & controle , Injeções Subcutâneas , Masculino , Testes de Mutagenicidade , Peptídeos Cíclicos/imunologia , Ratos Wistar , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Testes de Toxicidade CrônicaRESUMO
Casiopeína III-Ea (Cas III-Ea(1)) is a copper complex with antiproliferative and antitumor activities, designed to act via alternative mechanisms of action different from Cisplatin. This compound has also been well characterized in preclinical test and pharmacokinetic analysis, being a good candidate for clinical phases. Since very little is known about the processes of biotransformation of therapeutic metal based drugs, this paper report the first approach to the study of the interaction between metal complex Cas III-Ea and cytochromes P450 with the aim to find out possible biotransformation pathways for this complexes and feasible drug-drug interactions. Results showed that Cas III-Ea is a strong irreversible competitive inhibitor of CYP1A1 (IC50 = 7.5 ± 1.0 µM; Ki = 240 nM). The magnitude of values indicate that it is necessary to be taken into account such effect when analyzing possible drug interactions with these new drugs in order to prevent adverse reactions derived from this inhibition.
Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Inibidores das Enzimas do Citocromo P-450/farmacologia , Sistema Enzimático do Citocromo P-450/metabolismo , Fenantrolinas/farmacologia , Animais , Cinética , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Ratos WistarRESUMO
On the basis of previous conformational and configurational studies of 4-aryl-substituted cyclophosph(on)ates derived from d-xylofuranose derivatives, wherein it was proposed that the anomeric effect is involved in the spontaneous isomerization of the P atom and the C4 carbon, and consequently, this unusual behavior was associated with the cleavage of the HepDirect prodrugs. We synthesized an analogous series of 2-amino-2-oxo-1,3,2-dioxaphosphorinanes and performed a conformational and configurational analysis in solution and the solid state followed by an examination of their mutagenic activity. The results showed that the 2-amino-2-oxo-1,3,2-dioxaphosphorinanes with the largest mutagenic activity contain either a 4-methoxyphenyl or 4-fluorophenyl group at C4 carbon and presented a major chair conformation, which is prone to weaken the C4-O3 bond via the anomeric effect and facilitates the cleavage for the release of the biologically active metabolite.
Assuntos
Ciclofosfamida/química , Compostos Organofosforados/química , Pró-Fármacos/química , Isomerismo , Modelos Moleculares , Conformação MolecularRESUMO
RecBCD and RecFOR homologous recombination pathways induced bacterial chromosomal duplication-segregation by sodium selenite (SSe) at sub-inhibitory concentrations. This evidence suggests that SSe induces both, double and single DNA strand damage with a concomitant DNA repair response, however the strong dependence for recombinogenic activity of RecB product suggests that the main DNA repair pathway copes with dsDNA breaks. A role for SSe recombinogenic induction is proposed to explain its effect on DNA instability.
Assuntos
Deleção Cromossômica , Cromossomos Bacterianos/efeitos dos fármacos , Cromossomos Bacterianos/genética , Exodesoxirribonuclease V/metabolismo , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Selenito de Sódio/toxicidade , Proteínas de Bactérias/metabolismo , Dano ao DNA , Reparo do DNA , Proteínas de Ligação a DNA/metabolismo , Genes Bacterianos , Recombinação Genética , Salmonella typhimurium/metabolismoRESUMO
beta-Carboline alkaloids are natural products widely distributed in plants and also found in alcoholic beverages, well-cooked foods and tobacco smoke. Various authors have reported genotoxic activities of several carboline in prokaryotic and eukaryotic cells that have been attributed to their abilities to intercalate into DNA. But studies on the genotoxic and on the cytotoxic potencies in human cells in vitro are not found in the literature. In the present study the toxicities of one full aromatic beta-carboline alkaloid (harmine) and one dihydro-beta-carboline alkaloid (harmaline) were evaluated by means of two in vitro human cell assays: the cytochalasin-B blocked micronucleus (CBMN) assay and the viability/colony formation assay with four different human cultured non-transformed (CCD18Lu) and transformed (HeLa, C33A and SW480) cells. Neither alkaloid was able to induce micronuclei levels above that of control levels in a wide range of doses tested; although, harmine at the highest concentrations assayed induced apoptotic as well as necrotic cells. Harmine produced a good viability of all cell lines assayed (control and tumor) while harmaline significantly reduced the viability of transformed and non-transformed cell lines in a dose-dependent manner. Harmine displayed a dose-dependent inhibitory effect on cell proliferation against all human carcinoma cells, but the SW480 transformed cell line showed a higher sensitivity. These results suggested that harmine was identified as a useful inhibitor of tumor development.
Assuntos
Estimulantes do Sistema Nervoso Central/toxicidade , Harmalina/toxicidade , Harmina/toxicidade , Adulto , Morte Celular/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Humanos , Técnicas In Vitro , Masculino , Testes para MicronúcleosRESUMO
UNLABELLED: Cancer is a very important national health problem in Mexico, while a significant increase in the total and childhood cancer mortality has been recorded during the last decades. Chemoprevention, defined as the use of natural or synthetic agents to prevent or to block the development of cancer in human beings, is a new and promising strategy in the battle against cancer. Saffron, obtained from the dried red-dark stigmas of Crocus sativus L., an important spice rich in carotenoids, is commonly consumed in different parts of the world and used as a medical drug to treat numerous diseases. OBJECTIVE: To test the toxicity of saffron extract in vivo; to separate different ingredients in saffron extracts; to examine the cytotoxic effect of saffron and its main components on the growth of different human malignant cells in vitro; to evaluate the mutagenic and antimutagenic activities of saffron extract. METHODS: HPLC with photodiode-array detection was used for semi-preparative separation of different ingredients of saffron crude extract. Colony formation assay was used to determinate the cytotoxic activity of saffron extract and its components on human tumor cells in vitro. Mutagenicity and antimutagenicity assays were performed by the Ames method. RESULTS: Saffron is not toxic, non-mutagenic, non-antimutagenic and non-comutagenic. Twelve components were isolated: crocin-1, crocin-2, crocin-3, picrocroein, acid form of picrocrocin, HTCC-diglycosil-kaempferol trans-crocin-4, trans-crocin-2, trans-crocin-3, safranal, crocetin and cis-crocin-3. Saffron extract itself and some of its ingredients displayed a dose-dependent inhibitory activity against different types of human malignant cells in vitro. HeLa cells were more susceptible to saffron than other tested cells. CONCLUSIONS: Taken together, our results and literature data indicate that saffron could be used as a potential cancer chemopreventive agent in clinical trials.
Assuntos
Anticarcinógenos/farmacologia , Crocus/química , Extratos Vegetais/farmacologia , Adenocarcinoma/patologia , Administração Oral , Animais , Antimutagênicos/farmacologia , Carcinoma Hepatocelular/patologia , Cromatografia Líquida de Alta Pressão , Neoplasias do Colo/patologia , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Feminino , Células HeLa/efeitos dos fármacos , Humanos , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Testes de Mutagenicidade , Extratos Vegetais/química , Extratos Vegetais/toxicidade , Rabdomiossarcoma/patologia , Salmonella typhimurium/efeitos dos fármacos , Células Tumorais Cultivadas/efeitos dos fármacos , Ensaio Tumoral de Célula-TroncoRESUMO
La reducción del grupo nitro presente en varios medicamentos, pesticidas y materiales de uso diario, produce especies reactivas del oxígeno capaces de interactuar con el ADN. El tinidazol, una droga antimicrobiana de la familia de los 5 nitroimidazoles, fue evaluada por el ensayo cometa. Se estudió la capacidad de la droga para inducir roturas de simple cadena y sitios sensibles al álcali, expresado como el porcentaje de células dañadas y el porcentaje de células en cada nivel de daño. En el ensayo in vitro a concentraciones de 100, 250 y 500 mg/mL se encontró inducción de roturas en los cromosomas de leucocitos de ratón a los 30 min de exposición, esto describió una relación dosis respuesta. La importancia de la reducción del grupo nitro, mediada por la acción de nitrorreductasas microsomales hepáticas, para la actividad mutagénica de los nitroimidazoles, ha sido estudiada. Sin embargo, estos resultados revelaron que el tinidazol no necesitaba ser metabolizado para inducir el daño. A los 30 min de reparación el daño en los leucocitos se mantuvo, a los 60 min solamente el daño producido con la concentración de 500 mg/mL de tinidazol había sido reparado. A concentraciones mayores se disparan diferentes mecanismos de reparación para no comprometer la viabilidad celular. Estos mecanismos pueden ser responsables de estos hallazgos, se reparan las roturas aunque se comprometa la fidelidad de la secuencia del ADN. In vivo se pudo observar que una dosis de 100 mg/kg de peso era capaz de inducir daño en el ADN de los leucocitos de ratón. Este efecto fue observado a las 24 y 48 h después del tratamiento con una dosis 3 veces superior a la dosis terapéutica (2 g/d). El mecanismo propuesto para explicar el efecto clastogénico de los 5 nitroimidazoles está relacionado con la formación de un anión nitro, que se reoxida y genera especies reactivas del oxígeno