In vitro chemopreventive and cytotoxic effects of Amazon mosses Leucobryum martianum (Hornsch.) and Leucobryum laevifolium (Broth) extracts.

Several bioactive compounds, such as polyphenols, demonstrate low toxicity and prominent effects on cancer cells with antioxidant, anti-inflammatory, and antitumor activities. Such compounds can be found in Amazon mosses Leucobryum martianum (Hornsch.) Hampe ex Müll. Hal. (Hornsch.) and Leucobryum laevifolium (Broth). Antimutagenic assay with Salmonella enterica serovar Typhimurium and cytotoxicity with different eukaryotic cell lines were carried out to screen aqueous, hydroalcoholic, and ethanolic extracts of those Amazon mosses for anticancer potential. The results indicate the capacity of all extracts of both mosses to exert chemopreventive effects against 4-nitroquinoline-N-oxide (4NQO) and 2-aminoanthracene (2-AA), which are direct or indirect mutagens. In particular, the ethanolic and aqueous extract from L. martianum. The ethanolic extract from L. martianum induces significant cytotoxicity by mitochondrial metabolism and cell membrane disruption pathways to tumor or non-tumor cells. The aqueous extract from L. martianum showed a mainly cytotoxic response in the HepG2 cells, a human liver carcinoma, reaching ~90% cytotoxicity. The same extract did not induce significant damage to normal liver cells (F C3H cells) by membrane interaction pathway. The selective cytotoxicity in the aqueous extract of L. martianum makes it a candidate against liver cancer. Further studies, including in vivo models, are necessary to validate the efficacy and safety of the aqueous extract of L. martianum.

In vitro genotoxicity assessment of graphene quantum dots nanoparticles: A metabolism-dependent response.

Nanomaterials are progressively being applied in different areas, including biomedical uses. Carbon nanomaterials are relevant for biomedical sciences because of their biocompatibility properties. Graphene quantum dots (GQD) have a substantial potential in drug-delivery nanostructured biosystems, but there is still a lack of toxicological information regarding their effects on human health and the environment. We thus evaluated the mutagenicity, cytotoxicity and genotoxicity of this nanomaterial using alternative methods applied in regulatory toxicology guidelines. The Ames test was carried out in the presence and absence of exogenous metabolization. Salmonella enterica serovar Typhimurium strains TA97a, TA98, TA100, TA102, TA104, and TA1535 were exposed to GQD with concentrations ranging from 1 to 1000 µg/plate. The mammal cell viability assays were carried out with HepG2 and 3T3BalbC cell lineages and the in vitro Cytokinesis-Block Micronucleus assay (CBMN) was applied for 24 h of exposure in non-cytotoxic concentrations. Mutagenicity was induced in the TA97a strain in the absence of exogenous metabolization, but not in its presence. Mutagenicity was also detected in the TA102 strain in the assay with exogenous metabolization, suggesting redox misbalance mutagenicity. The WST-1 and LDH assays demonstrated that GQD decreased cell viability, especially in 3T3BalbC cells, which showed more sensitivity to the nanomaterial. GQD also increased micronuclei formation in 3T3BalbC and caused a cytostatic effect. No significant impact on HepG2 micronuclei formation was observed. Different metabolic systems interfered with the mutagenic, cytotoxic, and genotoxic effects of GQD, indicating that liver metabolism has a central role in the detoxification of this nanomaterial.

Risk assessment of coffees of different qualities and degrees of roasting.

During the coffee beans roasting process, occurs the formation of polycyclic aromatic hydrocarbons, which are associated with the incidence of cancer in humans. This study aimed to evaluate the influence of coffee bean quality and roasting degree regarding mutagenicity, cytotoxicity and genotoxicity. Six samples of coffee drink made with roasted and ground Coffea arabica beans from different qualities and roast degrees were used after freeze-drying. Both commercial and special quality grains suffered light, medium and dark roasting. According to the Salmonella/microsome assay, the highest concentration of commercial grain sample (dark roast) significantly increased the number of revertants of the TA98 strain in the absence of metabolization. All the samples induced cytotoxicity to HepG2 cells. These effects can be ranked in the following order from most to least toxic: medium roast - special grain > light roast - special grain > dark roast - commercial grain > dark roast - special grain > light roast - commercial grain > medium roast - commercial grain. None of the samples induced genotoxicity in HepG2 cells. Our findings show that the harmful effects of coffee depend not only on the degree of roasting but also on the grain quality.

Toxicological evaluation of nail polish waste discarded in the environment.

Nail polish has been widely used around the world. However, the hazards of nail polishes discarded in the environment are still poorly investigated. Thus, the toxicogenetic effects of solubilized (SE) and leached (LE) extracts from nail polishes were investigated, simulating their disposal on water and landfill, respectively, and identifying their physicochemical properties and chemical constituents. Organic compounds and metals were detected in both extracts. SE and LE only induced mutagenic effects in TA98 Salmonella strain in the presence and absence of exogenous metabolic activation. Although both extracts did not significantly increase the frequency of micronucleated HepG2 cells, the cell viability was affected by 24-h exposure. No DNA damage was observed in gonad fish cells (RTG-2) exposed to both extracts; however, the highest SE and LE concentrations induced significant lethal and sublethal effects on zebrafish early-life stages during 96-h exposure. Based on our findings, it can be concluded that if nail polishes enter aquatic systems, it may cause negative impacts to the environment.

Mutagenic and Cytotoxicity LQB 123 Profile: Safety and Tripanocidal Effect of a Phenyl-t-Butylnitrone Derivative.

The therapeutic options for Chagas disease are limited and its treatment presents a number of drawbacks including toxicity, drug resistance, and insufficient effectiveness against the chronic stage of the disease. Therefore, new therapeutical options are mandatory. In the present work, we evaluated the effect of a phenyl-tert-butylnitrone (PBN) derivate, LQB 123, against Trypanosoma cruzi forms. LQB 123 presented a trypanocidal effect against bloodstream trypomastigotes (IC50 = 259.4 ± 6.1 µM) and intracellular amastigotes infecting peritoneal macrophages (IC50 = 188.2 ± 47.5 µM), with no harmful effects upon the mammalian cells (CC50 values greater than 4 mM), resulting in a high selectivity index (CC50/IC50 > 20). Additionally, metacyclic trypomastigotes submitted to LQB 123 presented an IC50 of about 191.8 ± 10.5 µM and epimastigotes forms incubated with different concentrations of LQB 123 presented an inhibition of parasite growth with an IC50 of 255.1 ± 3.6 µM. Finally, we investigated the mutagenic potential of the nitrone by the Salmonella/microsome assay and observed no induction of mutagenicity even in concentrations as high as 33000 µM. Taken together, these results present a nonmutagenic compound, with trypanocidal activity against all relevant forms of T. cruzi, offering new insights into CD treatment suggesting additional in vivo tests.

Photoprotective and toxicological activities of extracts from the Antarctic moss Sanionia uncinata.

BACKGROUND: The Antarctic moss Sanionia uncinata (Hedw.) Loeske has shown high ultraviolet (UV)-absorbers content after exposition to high levels of UV-B radiation and can be an important source of antioxidants. OBJECTIVE: The aim was to investigate photoprotection and mutagenicity by the aqueous extract (AE) and hydroethanolic extract (HE) from the Antarctic moss S. uncinata. MATERIALS AND METHODS: Photoprotective activities were determined through survival curves of Escherichia coli strains, after UV irradiation in an aqueous solution of thymine and in vitro sun protection factor (SPF). The Salmonella/microsome assays were applied to assess the mutagenicity. RESULTS: Both extracts induced photoprotection against UV-C radiation. The AE showed a higher protection than the hydroethanolic one against UV-induced thymine dimerization. The SPFs were low in both extracts. In association to benzophenone-3 a significant increase in the SPF was detected for the AE, and a significant decrease was induced by the HE. No mutagenicity was found in the both extracts. Furthermore, it was observed absence of cytotoxicity. CONCLUSION: Water-extractable compounds seem to contribute on photoprotection of this Antarctic moss.

Effects of Sanionia uncinata extracts in protecting against and inducing DNA cleavage by reactive oxygen species.

When mosses are exposed to increased quantities of ultraviolet (UV) radiation, they produce more secondary metabolites. Antarctica moss Sanionia uncinata (Hedw.) Loeske has presented high carotenoid contents in response to an increase in UVB radiation. This moss has been recommended as a potential source of antioxidants. In the present work, the protective and enhancing effects of aqueous (AE) and hydroalcoholic (HE) extracts of S. uncinata on the cleavage of supercoiled DNA were evaluated through topological modifications, quantified by densitometry after agarose gel electrophoresis. Total phenolic contents reached 5.89 mg/g. Our data demonstrated that the extract does not induce DNA cleavage. Furthermore, both extracts showed antioxidant activity that protected the DNA against cleavage induced by (i) O(2)(•-), 89% (AE) and 94% (HE) (P<0.05), and (ii) (.)OH, 17% (AE) and 18% (HE). However, the extracts intensified cleavage induced by Fenton-like reactions: (i) Cu(2+)/H(2)O(2), 94% (AE) and 100% (HE) (P<0.05), and (ii) SnCl(2), 62% (AE) and 56% (HE). DNA damages seem to follow different ways: (i) in the presence of Fenton-like reactions could be via reactive oxygen species generation and (ii) with HE/Cu(2+) could have also been triggered by other mechanisms.