Evaluation of the mutagenicity and antimutagenicity of soy phytoestrogens using micronucleus and comet assays of the peripheral blood of mice

Cytotoxic and Genotoxic Evaluation of the Aqueous and Hydroalcoholic Leaf and Bark Extracts of Crataegus oxyacantha in Murine Model

Crataegus oxyacantha has been mainly used in traditional medicine for the treatment of cardiovascular diseases. However, its safety profile has not been fully established, since only the genotoxic effects of C. oxyacantha fruit have been described. Therefore, the objective of this work was evaluating the cytotoxicity and genotoxicity of the aqueous and hydroalcoholic leaf and bark extracts of C. oxyacantha by means of the micronucleus test in a murine model. Doses of 2000, 1000, and 500 mg/kg of both extracts were administered orally for 5 days in mice of the Balb-C strain. Peripheral blood smears were performed at 0, 24, 48, 72, and 96 h after each administration. The number of polychromatic erythrocytes (PCEs), micronucleated polychromatic erythrocytes (MNPCEs), and micronucleated erythrocytes (MNEs) was determined at the different sampling times. Our results showed that the leaf and bark of C. oxyacantha increase the number of MNEs at the 2000 mg/kg dose, and only the aqueous leaf extract decreases the number of PCEs at the same dose. Therefore, the aqueous and hydroalcoholic leaf and bark extracts of C. oxyacantha showed genotoxic effects, and only the aqueous leaf extract exhibited cytotoxic effects.

Hepatoprotective and antineoplastic potencial of red propolis produced by the bees Apis mellifera in the semiarid of Rio Grande do Norte, Brazil

ABSTRACT: The objective of this study was to evaluate the hepatoprotective effect of the honey bee Apis mellifera ethanolic extract of the red propolis, obtained in four municipalities of the Rio Grande do Norte semi-arid region, through an in vitro evaluation of the antineoplastic potential in human hepatic carcinoma (HepG2) and normal cell lines (L929), and from the comet assay in hepatic cell lines (ZF-L hepatocytes) to evaluate the genoprotective potential of the extract. The hepatoprotective effect was also evaluated in vivo by the induction of chronic experimental hepatic lesions in rodents (Rattus norvegicus Berkenhout, 1769), Wistar line, by intraperitoneal administration of thioacetamide (TAA) at the dose of 0.2g/kg. The animals were distributed in the following experimental groups: G1 (control), G2 (treated with 500mg/kg ethanolic extract of propolis), G3 (treated with 500mg/kg of ethanolic extract and TAA) and G4 (treated with TAA). All rats were submitted to serum biochemical, macroscopic, histological and stereological biochemical exams of the liver. It was verified the genoprotective effect of red propolis since the mean damages promoted to DNA in cells tested with the extract were significantly lower than the mean of the positive control damage (hydrogen peroxide). The red propolis extract did not present cytotoxic activity to the tumor cells of human liver cancer, as well as to normal ones. The absence of cytotoxicity in normal cells may indicate safety in the use of the propolis extract. The results of the serum biochemical evaluation showed that the serum levels of the aminotransferase enzymes (AST) did not differ significantly between G1, G2 and G3 when compared to each other. G4 showed significant increase in levels compared to the other groups, indicating that the administration of the extract did not cause liver toxicity, as well as exerted hepatoprotective effect against the hepatic damage induced by TAA. The G3 and G4 animals developed cirrhosis, but in G3 the livers were characterized by the presence of small regenerative nodules and level with the surface of the organ, whereas in G4 the livers showed large regenerative nodules. The livers of the G1 and G2 animals presented normal histological appearance, whereas the livers of the G3 animals showed regenerative nodules surrounded by thin septa of connective tissue, and in G4 the regenerative nodules were surrounded by thick septa fibrous connective tissue. The analysis of the hepatic tissues by means of stereology showed that there was no statistical difference between the percentage of hepatocytes, sinusoids, and collagens in G1 and G2. In G3 the percentage of hepatocytes, sinusoids, and collagen did not differ significantly from the other groups. It was concluded that the ethanolic extract of the red propolis exerted a hepatoprotective effect, because it promoted in vitro reduction of the damage to the DNA of liver cells, antineoplastic activity in human hepatocellular carcinoma cell line (HepG2) and did not exert cytotoxic effect in normal cells or was able to reduce liver enzyme activity and the severity of cirrhosis induced by TAA in vivo.

Enhanced biosynthesis of O-desmethylangolensin from daidzein by a novel oxygen-tolerant cock intestinal bacterium in the presence of atmospheric oxygen

AIMS

To improve the oxygen-tolerant capability of a newly isolated anaerobic bacterium and to biosynthesize O-desmethylangolensin (O-Dma) from daidzein aerobically.

METHODS AND RESULTS

After a long-term domestication process, an oxygen-tolerant bacterium, which we named Aeroto-AUH-JLC108, was derived from the newly isolated obligate anaerobic bacterium Clostridium sp. AUH-JLC108. Strain Aeroto-AUH-JLC108 differed from the natively anaerobic wild-type strain AUH-JLC108 by various characteristics, including a change in bacterial shape, biochemical characteristics and 16S rRNA gene sequences. Both the growth speed and the maximal optical density (OD) value of strain Aeroto-AUH-JLC108 grown aerobically were significantly increased compared to that of the wild-type strain grown anaerobically. The maximal concentration of the substrate daidzein that the oxygen-tolerant strain Aeroto-AUH-JLC108 grown aerobically was able to convert efficiently was 2.0 mmol l(-1) and 0.6 mmol l(-1) for strain AUH-JLC108 that was grown anaerobically.

CONCLUSIONS

Strain Aeroto-AUH-JLC108 is a conditional oxygen-tolerant bacterium. The growth speed, bacterial growth mass and bioconversion capability of strain Aeroto-AUH-JLC108 grown aerobically was significantly increased compared to that of the wild-type strain AUH-JLC108 grown anaerobically.

SIGNIFICANCE AND IMPACT OF THE STUDY

Strain Aeroto-AUH-JLC108 is the first reported pure culture responsible for the formation of O-Dma from daidzein in the presence of atmospheric oxygen.

Antimutagenic activity of ipriflavone against the DNA-damage induced by cyclophosphamide in mice

In the present study we evaluated the potential of ipriflavone against the cytotoxic and mutagenic effects induced by cyclophosphamide chemotherapeutic agent in bone marrow cells of mice, using the micronucleus assay in vivo on cells of bone marrow. The study was performed following three protocols: pre-treatment, simultaneous treatment and post treatment. The results demonstrated that ipriflavone has a protective effect against mutagenicity induced by cyclophosphamide in the pre-treatment and post-treatment and against the cytotoxicity in all treatments. There was variation between the genders in some of the experimental groups. To evaluate their possible mechanisms of action, it was performed the DPPH assay, which showed no ability to donate hydrogens, suggesting that it acts through other mechanisms. Due to its ability to prevent chromosomal damage, ipriflavone is likely to open an interest field concerning its possible the use in clinical applications.