Biotoxicological Analyses of Trimeroside from Baccharis trimera Using a Battery of In Vitro Test Systems.

The use in folk medicine of Baccharis trimera and recent studies on DNA damage by oxidative stress mechanisms have motivated this study. We investigated the biotoxicological effects of trimeroside from this plant. Aqueous extract from aerial parts of B. trimera was fractioned by flash chromatography for further isolation by thin-layer chromatography. The novel nor-monoterpene glycoside, trimeroside, and three flavonoids, cirsimaritin, luteolin and quercetin, were isolated. The genotoxic and mutagenic potential of trimeroside was determined by Salmonella/microsome (TA98 and TA100), comet assay, and cytokinesis-block micronucleus cytome assay (CBMN-cyt) in HepG2 cells. We also screened trimeroside into different human tumoral cell lines by sulforhodamine B (SRB) assay. Mutagenicity was detected in TA100 strain with metabolic activation. Genotoxic effects were not observed in HepG2 by comet assay. However, a decrease in the nuclear index division in the 2.0 mg·mL-1 concentration and an increase of nucleoplasmic bridges in the 1.5 mg·mL-1 concentration were detected by CBMN-cyt assay indicating cytotoxic and mutagenic effects. In SRB assay, trimeroside showed weak antiproliferative activity against the cell lines.

DNA damage induced by coal dust, fly and bottom ash from coal combustion evaluated using the micronucleus test and comet assay in vitro.

Coal mining and combustion generating huge amounts of bottom and fly ash are major causes of environmental pollution and health hazards due to the release of polycyclic aromatic hydrocarbons (PAH) and heavy metals. The Candiota coalfield in Rio Grande do Sul, is one of the largest open-cast coal mines in Brazil. The aim of this study was to evaluate genotoxic and mutagenic effects of coal, bottom ash and fly ash samples from Candiota with the comet assay (alkaline and modified version) and micronucleus test using the lung fibroblast cell line (V79). Qualitative and quantitative analysis of PAH and inorganic elements was carried out by High Performance Liquid Chromatography (HPLC) and by Particle-Induced X-ray Emission (PIXE) techniques respectively. The samples demonstrated genotoxic and mutagenic effects. The comet assay modified using DNA-glicosilase formamidopirimidina (FPG) endonuclease showed damage related to oxidative stress mechanisms. The amount of PAHs was higher in fly ash followed by pulverized coal. The amount of inorganic elements was highest in fly ash, followed by bottom ash. It is concluded that the samples induce DNA damage by mechanisms that include oxidative stress, due to their complex composition, and that protective measures have to be taken regarding occupational and environmental hazards.

Evaluation of acute and subacute toxicity and mutagenic activity of the aqueous extract of pecan shells [Carya illinoinensis (Wangenh.) K. Koch].

The infusion of pecan shells has been used to prevent and control hypercholesterolemia, diabetes and toxicological diseases. The aim of the present study was to evaluate toxicity and mutagenic effects of pecan shells aqueous extract (PSAE). Wistar rats were treated with a single dose of 300 or 2000 mg/kg of PSAE in the acute toxicity test. For the subacute test, the animals received 10 or 100 mg/kg of PSAE for 28 days. The mutagenicity was evaluated using Salmonella/microsome assay in TA1535, TA1537, TA98, TA100 and TA102 S. typhimurium strains in the presence and absence of metabolic activation (S9 mix) and micronucleus test in bone marrow. HPLC analyses indicated the presence of tannins, flavonoids, gallic and ellagic acids. Except for triglycerides, all treated groups presented normal hematological and biochemical parameters. Lower levels of triglycerides and weight loss were observed in the 100 mg/kg group. Mutagenic activities were not detected in S. typhimurium strains and by the micronucleus test. Based on these results, PSAE was not able to induce chromosomal or point mutations, under the conditions tested. The 100mg/kg dose showed significant antihyperlipidemic action, with no severe toxic effects.

Antiproliferative effect of a traditional remedy, Himatanthus articulatus bark, on human cancer cell lines.

ETHNOPHARMACOLOGICAL RELEVANCE: Himatanthus articulatus (Vahl) Woodson (Apocynaceae) is a tree occurring in the Amazon region. The local population uses its bark against to external tumors and cancer. AIM OF THE STUDY: Evaluated the antiproliferative activity of the crude extract and their fractions against human tumors cells. MATERIALS AND METHODS: The antiproliferative responses of the crude extract and their fractions were colorimetrically evaluated by sulforhodamine B (SRB) assay against HT-29 (colon adenocarcinoma); NCI-H460 (non-small cell lung carcinoma); MCF-7 (breast cancer); OVCAR-3 (ovarian adenocarcinoma) and RXF-393 (renal cell carcinoma) as well as against NIH-3T3 (mouse embryo fibroblast cell). RESULTS: The cytotoxicity data from the crude extract allowed considering active only in the NCI-H460 cell line. However, the antiproliferative activity was much more pronounced at the chloroformic fraction in all cell lines tested. The butanolic fraction demonstrated activity against to HT-29, MCF-7, RXF-393 and OVCAR-3 cells. The ethyl acetate fraction demonstrated activity only in RXF-393 and the aqueous residue did not present antiproliferative effect. CONCLUSIONS: Through the popular use we find that the crude extracts of Himatanthus articulatus bark displayed weak cytotoxic. However, the butanolic fraction showed to be active only against to tumor cell lines while chloroformic fraction possesses high activity being similar to the positive control. Both fractions have been selected for future bio-guided fractionation and isolation of active compounds.