Short-term effects of green tea chronotherapy on the metabolic homeostasis of mice on different diets.

Biological rhythms can be defined as changes in physiological or behavioral variables that repeat at certain time intervals. Rhythms that last approximately 24 h are referred to as circadian rhythms. Modern lifestyles have drastically affected human habits, as well as the population's eating habits. These changes have generated an epidemic of metabolic syndromes, such as obesity and diabetes. In an attempt to combat obesity, populations have attempted to use many different herbal remedies and plant-based drugs, the most common of which is Camellia sinensis, or green tea. Most of the studies on the effects of C. sinensis on maintaining body weight have reported the involvement of this substance in lipid oxidation. The objective of this study was to evaluate how the administration of C. sinensis at different times of day influenced changes in body weight, blood glucose levels, and food intake of mice kept under different diet conditions. The structural organization of abdominal adipose tissue was also evaluated, as were certain aspects of lipid metabolism and overall synthetic activity in the liver, adipose tissue, and ovaries. The results obtained suggest that the intake of green tea in the light phase of the day stimulates weight loss, regardless of the diet ingested. Neither glucose levels nor the structural organization of adipose tissue was found to be altered in any of the experimental groups. Neither diet nor the time at which the green tea was administered was found to have any effects on the amount of food the mice consumed. The time at which green tea was consumed and the type of diet both influenced LXRαß nuclear receptor expression, as well as the expression of fibrillarin in the liver and ovaries, although this influence was tissue specific.

Anti-clastogenic effect of beta-glucan extracted from barley towards chemically induced DNA damage in rodent cells.

beta-Glucan (BG) was tested in vitro to determine its potential clastogenic and/or anti-clastogenic activity, and attempts were made to elucidate its possible mechanism of action by using combinations with an inhibitor of DNA polymerase. The study was carried out on cells deficient (CHO-k1) and cells proficient (HTC) in phases I and II enzymes, and the DNA damage was assessed by the chromosomal aberration assay. BG did not show a clastogenic effect, but was anti-clastogenic in both cell lines used, and at all concentrations tested (2.5, 5 and 10 microg/mL) in combination with damage inducing agents (methylmethane sulfonate in cell line CHO-k1, and methylmethane sulfonate or 2-aminoanthracene in cell line HTC). BG also showed a protective effect in the presence of a DNA polymerase beta inhibitor (cytosine arabinoside-3-phosphate, Ara-C), demonstrating that BG does not act through an anti-mutagenic mechanism of action involving DNA polymerase beta.

Atividade clastogênica e genotóxica de altas concentrações do extratoaquoso de Agaricus brasiliensis e diferentes respostas quando associadoaos inibidores de reparo de DNA, ARA-C e 3DEOT, in vitro / Clastogenic and genotoxic activity of high concentrations of Agaricus

O Agaricus brasiliensis Wasser & Didukh – Ab (=Agaricus blazei Murrill ss. Heinemann) é um basidiomiceto que vem sendo consumido em diversas partes do mundo no combate e tratamento de muitas doenças. Neste estudo, foram testados, em células de ovário de hamster chinês (CHO-k1), os efeitos clastogênicos e genotóxicos de altas concentrações de Ab e seu potencial protetor, por meio dos ensaios de aberração cromossômica (AC) e cometa (SCGE), associados a dois bloqueadores de reparodo DNA (citosina arabinoside trifosfato - Ara-C - inibidor de DNA polimerase α e 3’deoxitimidina5’trifosfato - 3DeoT - inibidor de DNA polimerase β), na presença ou não de um agente alquilante(metilmetanosulfonato). No teste de clastogenicidade, verificou-se que as concentrações 0,2 e 0,4 não se mostraram indutoras de dano, ao contrário da maior concentração (0,6). Nos tratamentos de genotoxicidade no SCGE, a concentração de 0,2 do extrato não mostrou atividade genotóxica, ao contrário das concentrações de 0,4 e 0,6, as quais foram efetivas indutoras de danos no DNA. Os resultados de anticlastogenicidade indicaram que, na maioria dos tratamentos realizados, o extrato aquoso de Ab não apresentou atividade protetora contra danos no DNA, induzidos pela Ara-C e Ara-C + MMS. Pelo SCGE, Ab, nas três concentrações testadas, não mostrou atividade antigenotóxica. Os dados sugerem cuidado no consumo e ingestão de Ab por seres humanos, principalmente em altas concentrações.

Antigenotoxicity of Agaricus blazei mushroom organic and aqueous extracts in chromosomal aberration and cytokinesis block micronucleus assays in CHO-k1 and HTC cells.

Agaricus blazei (Ab) has become popularly known for its medicinal properties. Scientifically, it has been tested with regard to its capacity to protect genetic material against damage. We examined different organic extracts (methanolic extract -- ME, hexanic extract -- HE and n-butanolic extract -- BE) and an aqueous extract (AE) of Ab, for their capacity to induce DNA damage as well as for their protective effect. Genetic damage was determined by the chromosomal aberration assay (CA) in CHO-k1 cells for all extracts and the cytokinesis block micronucleus assay (CBMN) in non drug-metabolizing (CHO-k1) and drug-metabolizing (HTC) cell lines for extract BE only. The extracts did not show clastogenicity but showed anticlastogenicity. The greatest percent reduction obtained were with BE (105%) and AE (126%) treatments in CA. BE treatment did not display genotoxicity in CHO-k1, but was genotoxic in HTC. However, BE was shown to be antigenotoxic causing decreased micronucleus frequency in HTC and CHO-k1 cells. These results suggest that all the extracts contained protective substances, but in some cases they could show a genotoxic effect with regard to metabolism. Therefore, these findings warrant caution in the use of this mushroom by the population.

Anticlastogenic effect of aqueous extracts of Agaricus blazei on CHO-k1 cells, studying different developmental phases of the mushroom.

The Agaricus blazei Murill (ABM) mushroom, known as the sun mushroom, is native to Brazil and has become known for its medicinal properties. This study examined the anticlastogenic effect of Agaricus blazei in Chinese hamster ovary cells, CHO-k1, by means of a chromosome aberration test using methyl methanesulphonate (MMS, 10(-4)M) as the DNA damage inducing agent. Two mushroom lines were used, ABM 99/26 and ABM 97/11, and the latter was used in the young (Y) and sporulating (S) developmental phases. The cells were treated for 12 h with MMS alone or combined with aqueous extracts of A. blazei at a final concentration of 0.15%, which were prepared at three different temperatures: (a) hot (60 degrees C), (b) room temperature (25 degrees C) and (c) chilled (4 degrees C). Mushroom extracts showed a marked anticlastogenic effect against DNA damage, as evidenced by a decrease in the number of cells with breaks, regardless of the line used, or the developmental stage or the temperature at which the extract was prepared. Generally, the extracts were more effective in reducing the isochromatid type breaks. The data obtained suggest that extracts of A. blazei mushroom are anticlastogenic under the conditions tested, mainly during the G1 and S stages of the cell cycle, where chromosome breaks of the isochromatid type are produced by the MMS agent.