In Vitro Assessment of Cytoprotective Effects of CANOVA against Cell Death Induced by the Anti-malarial Artesunate - A Preliminary Experiment.

BACKGROUND: Artesunate (ATS) is a semi-synthetic compound derived from artemisinin, which is widely accepted in the treatment of malaria. However, there is evidence that ATS, under certain in vitro conditions, induces several impairments to normal cell functions. Canova (CA) is a Brazilian homeopathic formulation indicated for patients with depressed immune system. CA shows both in vitro and in vivo protective effects against mutagenic/carcinogenic compounds. Therefore, we aimed to assess in vitro the cytoprotective effects of CA against the cytotoxicity of ATS in Vero cells. METHODS: Viability of Vero cells exposed to ATS was assessed by MTT assay, whereas the anti-cytotoxic effect of CA was evaluated by apoptosis and necrosis quantification with fluorescent dyes. RESULTS: After 24 hours of ATS treatment, a reduction in cell viability was observed at 32 and 64 µg/mL, the latter being statistically significant (p < 0.05) in relation to the negative control. The concentration of 64 µg/mL was chosen for the subsequent experiments. ATS significantly induced both apoptosis and necrosis in Vero cells in relation to controls (p < 0.01). We also observed a statistically significant decrease in the number of apoptotic cells observed in the CA 16% + ATS co-treatment compared with ATS treatment (p < 0.01). Treatment with CA alone also had no influence on either type of cell death. CONCLUSION: Our results demonstrated that ATS is cytotoxic in the assessed conditions. However, such cytotoxicity was attenuated when the cells were treated simultaneously with ATS and CA.

In vitro assessment of anticytotoxic and antigenotoxic effects of CANOVA(®).

BACKGROUND: CANOVA(®) (CA) is a homeopathic immunomodulator. It contains several homeopathic medicines prepares according to the Brazilian Pharmacopoeia. CA is indicated in clinical conditions in which the immune system is impaired and against tumors. N-methyl-N-nitrosourea (NMU) is an N-nitroso compound, with genotoxic/mutagenic properties. Although several studies have shown promising results in the use of CA, there are no studies reporting possible antigenotoxic effects. METHOD: This study evaluated the in vitro antigenotoxic and anticytotoxic effects of CA in human lymphocytes exposed to NMU. Samples of human lymphocytes that were subjected to different concentrations of a mixture containing CA and NMU were used. The genotoxicity/antigenotoxicity of CA was evaluated by the comet assay, anticytotoxicity was assessed by quantification of apoptosis and necrosis using acridine orange/ethidium bromide. RESULTS: CA significantly reduced DNA damage induced by NMU and reduced significantly the frequency of NMU-induced apoptosis after 24 h of treatment. CONCLUSION: CA has an important cytoprotective effect significantly reducing the DNA damage and apoptosis induced by the carcinogen NMU.

Statistical analysis of adaptive response in sister chromatid exchanges in human lymphocytes after treatment with very low and extremely low doses of N-methyl-N'-nitro-N-nitrosoguanidine using a study design to control variability.

Previous studies have been interpreted as suggesting that low concentrations of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) have an adaptive effect in the cultured lymphocytes of responsive donors (that is, the cells are protected against the mutagenic effects of a subsequent challenge with a higher concentration of MNNG). The objectives of the present study were to investigate, under stringent experimental conditions, whether a protective effect exists at very low and extremely low doses of MNNG (10(-8) and 10(-24) M, respectively). Peripheral blood lymphocytes from a donor considered responsive in a previous study were stimulated to divide and were cultured under standard conditions. Pre-adaptive treatments with dilutions of MNNG were added to the cultures repeatedly before a challenge treatment with MNNG. Bromodeoxyuridine was added at the same time as the challenge treatment and, following mitotic arrest, cells were differentially stained so that the number of sister chromatid exchanges (SCEs) could be counted. The study was designed to address potential criticisms of earlier studies which did not include replicate cultures. Samples of blood were divided into two identical batches for independent processing. Five replicate cultures were prepared for each combination of pre-adaptive and challenge treatments in each batch. The complete experiment was repeated to provide a further test of the consistency of results. Five replicates per treatment combination were chosen in an attempt to provide an experiment of adequate statistical power. Considerable precautions were taken to minimise the effect of factors outside experimental control on the results. Scoring was done by three scorers. In order to minimise inter-scorer variation, 240 cells were scored at each treatment observation (five cells per-scorer, three scorers per culture, four cultures per batch, two batches per experiment and two experiments). The study was designed in this way to take account of the sources of variability to ensure that any response obtained would exceed that obtainable by experimental variability alone. A high level of quality assurance monitoring was undertaken throughout the investigation. Two measures of SCE induction were used: (i) the mean frequency of SCEs; (iii) proportion of cells with at least 20 SCEs. In both experiments, the challenge concentration of MNNG significantly increased SCE frequency. There were, however, highly significant differences between the two experiments. The proportion of high frequency cells (HFCs) in Experiment 1 was increased significantly; the proportion of HFCs was also increased in Experiment 2, but the increase was not statistically significant. The pre-adaptive concentrations of MNNG included an extremely low dilution of 6.8 x 10(-24) M and a very low dilution of 6.8 x 10(-8) M in Experiment 1 and 1.4 x 10(-7) M in Experiment 2. The various pre-adaptive concentrations used had no consistent protective effect against the SCE-inducing capacity of the challenge concentration of MNNG of 6.8 x 10(-6) M. It is concluded that an adaptive response to the alkylating agent MNNG could not be demonstrated in cultured human lymphocytes. Neither a very low nor an extremely low dilution of MNNG elicited an adaptive response in terms of SCE induction (measured either as SCE frequency or as proportion of HFCs). This is in contradiction to previous reports published by us and other groups. This study was carefully designed with large numbers of replicates, a preliminary statistical power calculation, predefined comparisons and extensive quality assurance at each treatment administration. Despite these precautions the variability between scorers and between batches was much larger than anticipated. This resulted in some statistically significant differences, but these are likely to be false positives. Our findings indicate the need for such methodological refinement in human cell adaptive response studies.

Evaluación del efecto citoprotector gástrico y efecto hepatoprotector del extracto seco hidroalcohólico al 70% de Plantago major L. (Llantén) en animales de experimentación / Evaluation of the gastric cytoprotective effect and hepatoprotective effect of the 70% hydroalcoholic dry extract of Plantago major L. (Plantain) in experimental animals

Se realizó un estudio cuasi experimental de series cronológicas con repetición del estímulo y diseño con un grupo control y sin pre prueba. En el presente trabajo se evaluó el efecto citoprotector gástrico mediante la determinación del índice de inhibición ulcerogénica y estudio histopatológico en el modelo experimental de inducción de úlcera gástrica por etanol absoluto, realizadas con ratas albinas machos de la raza Holtzman, agrupadas en 5 grupos experimentales, a los cuales se les administró diferentes tratamientos respetivamente: suero fisiológico (1 ml), Omeprazol (20mg/kg), Sucralfato (400mg/kg), Extracto 1 (600mg/kg) y Extracto 11 (800 mg/Kg), luego de 1 hora se procedió a administrar etanol absoluto, y después de 1 hora se les extrajo los estómagos para los cortes histológicos y lecturas correspondientes. El tratamiento con el extracto a la dosis de 800 mg/Kg demostró ser un buen citoprotector gástrico por inhibir la formación de ulceras en un 100 %, similar al patrón Sucralfato (97.66%), a diferencia del patrón Omeprazol que inhibió en un 73.31%, estos datos coincidieron con el pertinente estudio histopatológico. Así también se evalúo el efecto hepatoprotector mediante el estudio histopatológico y la determinación de transaminasas (GOT y GTP), fosfatasa alcalina y bilirrubinas en el modelo experimental de intoxicación hepática por tetracloruro de carbono, con ratas albinas machos de la raza Holtzman en 6 grupos experimentales: blanco (suero fisiológico 1 mL), control (CCI4 0.5ml/kg), patrón (Silimarina 100 mg/kg) y el extracto a las dosis de 400, 600 y 800 mg/Kg. Cinco días previos al inicio de la intoxicación se administró el suero fisiológico, Silimarina, y las dosis del extracto, y luego durante 5 semanas (2 veces por semana), dos dosis por día: 2 horas antes y 2 horas después de la administración del tetracloruro de carbono. A la sexta semana se realizó la toma de muestra para las pruebas bioquímicas y se extrajo los hígados para el estudio histopatológico. En los resultados obtenidos se demostró que el extracto a las dosis de 600 y 800 mg/Kg tiene efecto hepatoprotector porque los niveles de transaminasas (GOT y GTP), fosfatasa alcalina y bilirrubinas se mantuvieron dentro de los parámetros normales, además el estudio histopatológico pudo corroborar estos resultados. Los resultados fueron sometidos a un análisis estadístico, para lo cual se aplicó el programa estadístico SPSS con un intervalo de confianza del 95%.

Avaliação da atividade citotóxica, antiviral e antimicrobiana de Apocynaceae amazônicas / Evaluation of the activity cytotoxic, antiviral and antimicrobial of Apocynaceae Amazonian

A necessidade de se introduzir novos fármacos quimioterápicos é patente. Para tanto, a modelagem molecular, a terapia gênica e os produtos naturais têm sido os caminhos escolhidos para a obtenção de novas moléculas. As florestas brasileiras estão entre os principais celeiros de biodiversidade, grande parte não estudada do ponto de vista fitoquímico e farmacológico. Isso implica em grandes possibilidades de identificação de novos fármacos, uma vez que a riqueza da biodiversidade biológica pode ser refletida na riqueza da biodiversidade química. Trinta e oito extratos provenientes de espécies de Apocynaceae foram submetidos a um estudo de triagem farmacológica antiviral, antimicrobiana e citotoxicidade, in vitro...(AU)

Avaliaçäo da atividade citotóxica, antiviral e antimicrobiana de Apocynaceae amazônicas / Evaluation of the activity cytotoxic, antiviral and antimicrobial of Apocynaceae Amazonian

A necessidade de se introduzir novos fármacos quimioterápicos é patente. Para tanto, a modelagem molecular, a terapia gênica e os produtos naturais têm sido os caminhos escolhidos para a obtenção de novas moléculas. As florestas brasileiras estão entre os principais celeiros de biodiversidade, grande parte não estudada do ponto de vista fitoquímico e farmacológico. Isso implica em grandes possibilidades de identificação de novos fármacos, uma vez que a riqueza da biodiversidade biológica pode ser refletida na riqueza da biodiversidade química. Trinta e oito extratos provenientes de espécies de Apocynaceae foram submetidos a um estudo de triagem farmacológica antiviral, antimicrobiana e citotoxicidade, in vitro...

Bioequivalência de comprimidos de nimesulida do mercado nacional / Bioquivalence of nimesulide tablets of the national market

A nimesulida, é um fármaco sintético, pouco solúvel em água (0,01 mg/mL), classificado como antiinflamatório não esteróide, com atividade analgésica e antipirética. No Brasil são comercializadas várias especialidades farmacêuticas orais, contendo nimesulida, na dosagem de 100 e 200 mg. Em termos de saúde pública tais produtos, prescritos pelo médico como similares intercambiáveis, deveriam apresentar, a mesma eficácia clínica, sendo a bioequivalência um requisito fundamental. Um estudo em que se verifique a qualidade biofarmacotécnica de uma amostragem destes produtos torna-se bastante útil para que se possa avaliar a situação atual...