Role of recombinant human erythropoietin in mitomycin C-induced genotoxicity: Analysis of DNA fragmentation, chromosome aberrations and micronuclei in rat bone-marrow cells

Optimization, characterization and biosafety of carotenoids produced from whey using Micrococcus luteus

This study aimed to optimize the production of carotenoid pigments from Micrococcus luteus (ATCC 9341) through the statistical screening of media components and the characterization of antimicrobial, antioxidant, cytogenetic and cytotoxic activities. A BOX-Behnken design was used to assess the effects of whey concentration, inoculum size, pH, temperature, and agitation speed on carotenoid yield. The optimum combination increased production to 2.19 g/L, with a productivity of 0.045 g L-1 h-1 and a productivity yield of 0.644 g/g, as confirmed by an observed carotene production of 2.19 g/L. The final response surface model fitting the data had an R2 of 0.9461. High-performance liquid chromatography (HPLC) analysis identified 12 carotenoid pigment compounds produced by M. luteus. The extracts displayed moderate antimicrobial efficacy against Gram-positive bacteria such as Bacillus cereus (ATCC 11778), Staphylococcus aureus (ATCC 6538), and E. faecalis (ATCC 19433), with inhibition zone diameters (IZD) of 29.0, 14.0, and 37.0 mm, respectively, at 1000 μg/mL. However, its effectiveness against Gram-negative bacteria is limited. In comparison, tetracycline exhibited greater antimicrobial potency. The IC50 value of carotenoids was used to indicate the antioxidant activity. IC50 value from the DPPH assay was 152.80 mg/100mL. An IC50 cytotoxicity value greater than 300 μg/mL was found against normal mouse liver cells, with over 68% cell viability even at 300 μg/mL, indicating low toxicity. Histological structure studies revealed normal myocardial muscle tissue, lung tissue, and kidney tissue sections, whereas liver tissue sections revealed ballooning degeneration of hepatocytes and disorganization of hepatic cords. Cytogenetic parameters revealed that the carotene treatment group had a mitotic index (70%) lower than that of the control but higher than that of the positive control, mitomycin, and did not substantially increase numerical (1.2%) or structural aberrations compared with those of the control, suggesting a lack of genotoxic effects under the experimental conditions. In conclusion, optimized culture conditions enhanced carotenoid yields from M. luteus, and the extracts displayed promising bioactivity as moderate antibiotics against certain gram-positive bacteria and as antioxidants. The high IC50 values demonstrate biosafety. Overall, this bioprocess for enhanced carotenoid production coupled with bioactivity profiling and low cytotoxicity support the application of M. luteus carotenoids.

Guidance for the use and interpretation of assays for monitoring anti-genotoxicity

Since DNA damage can occur spontaneously or be produced by the environmental genotoxins in living cells, it is important to investigate compounds that can reverse or protect DNA damage. An appropriate methodology is essential for the responsive identification of protection offered against DNA damage. This review includes information on the current state of knowledge on prokaryotic cell-based assays (SOS chromotest, umu test, vitotox assay) and cytogenetic techniques (micronucleus assay, chromosome aberration test and sister chromatid exchange assay) with an emphasis on the possibility to explore genoprotective compounds. Throughout the last decade, studies have extrapolated the scientific methodologies utilized for genotoxicity to assess genoprotective compounds. Therefore, shortcomings of genotoxicity studies are also mirrored in antigenotoxicity studies. While regulatory authorities around the world (OECD, US-EPA and ICH) continue to update diverse genotoxic assay strategies, there are still no clear guidelines/approaches for efficient experimental design to screen genoprotective compounds. As a consequence, non-synergetic and inconsistent implementation of the test method by the researchers to execute such simulations has been adopted, which inevitably results in unreliable findings. The review has made the first attempt to collect various facets of experimentally verified approaches for evaluating genoprotective compounds, as well as to acknowledge potential significance and constraints, and further focus on the assessment of end points which are required to validate such action. Henceforth, the review makes an incredible commitment by permitting readers to equate several components of their test arrangement with the provided simplified information, allowing the selection of convenient technique for the predefined compound from a central repository.

Triflumuron induces genotoxicity in both mice bone marrow cells and human Colon cancer cell line

Triflumuron (TFM) is an insect growth regulator (IGR), an insecticide commonly used over the world. It is known for its several toxic manifestations, such as reprotoxicity, immunotoxicity and hematotoxicity, which could affect public health. However, studies that reveal its toxic effects on mammalians are limited. To reach this purpose, our study aimed to elucidate the eventual genotoxic effects of TFM in mice bone marrow cells and in HCT 116 cells after a short term exposition. TFM was administered intraperitoneally to Balb/C male mice at doses of 250, 350 and 500 mg/kg bw for 24 h. Genotoxicity was monitored in bone marrow cells using the comet test, the micronucleus test and the chromosome aberration assay. Our results showed that TFM induced DNA damages in a dose-dependent manner. This genotoxicity was confirmed also in vitro on human intestinal cells HCT 116 using the comet test. It was then asked whether this genotoxicity induced by TFM could be due to an oxidative stress. Thus, we found that TFM significantly decreased HCT 116 cell viability. In addition, it induced the generation of reactive oxygen species (ROS) followed by lipid peroxidation as revealed by the increase in the malondialdehyde (MDA) levels. Similarly, the activation of the antioxidant enzymes (catalase and superoxide dismutase) was also observed. Our results indicated that, in our experimental conditions, TFM had a genotoxic effect on bone morrow cells and in HCT 116 cells. Moreover, we demonstrated that this genotoxicity passes through an oxidative stress.

Protective Effect of Chrysin, a Dietary Flavone against Genotoxic and Oxidative Damage Induced by Mitomycin C in Balb/C Mice

Anticancer drugs, such as Mitomycin C (MMC), can interact with biological molecules and cause genetic damage in normal cells. In this respect, we investigated the potential of chrysin, a flavone known as a potent scavenger of free radicals generated by anticancer agents, to protect mice against MMC-induced genotoxicity. The amount of DNA damage in the liver, kidney and bone marrow cells, in Balb/C mice treated with MMC (6 mg/kg, i.p) and the frequency of chromosomal aberrations indicated the genotoxic effect of MMC. Besides, a significant increase in the activities of antioxidant enzymes (SOD, CAT, GPx, GST) and lipid peroxidation is revealed. On the other hand, we noticed a regression of the genotoxic effect when studying the same parameters in Balb/C mice treated with chrysin (40 mg/kg b. wt., i.p) 24 h prior to MMC (6 mg/kg, i.p) injection. This study concluded that the protective effect of chrysin against genotoxicity of MMC results partly from its antioxidant effect.

50% Ethanol extract of Orthosiphon stamineus modulates genotoxicity and clastogenicity induced by mitomycin C

Herbal products contain a variety of compounds which may be useful in protecting against cellular damage caused by mutagens. Orthosiphon stamineus (O.s) also known as Cat whiskers. The herb has been shown anti-oxidative properties and can modulate key cellular proteins that have cytoprotective effect. The study aimed to evaluate the effects of different doses (250, 500 and 1000 mg kg^-1) of 50% ethanol extract of O.s (Et. O.s) on micro-nucleated polychromatic erythrocytes (MNPCE), Polychromatic to normachromatic erythrocytes ratio (PCE/NCE), Mitotic index (MI), and Chromosomal aberration (CA) in Bab/c mice. Moreover, these parameters were used to evaluate the anti-genotoxic and clastogenic potencies of (Et. O.s) against mitomycin c (MMC) that interact with biological molecules and induce genotoxic and clastogenic disorders in non-tumor cells. MMC (4 mg kg^-1) was injected intraperitoneally (i.p.) to the mice before and after treatment with three different doses of (Et. O.s). The results indicated that the extract at different doses did not show significant (p ≥ 0.05) differences in (MNPCE), (PCE/NCE) ratios, and (CA) values. The higher doses sowed high (MI) values compared with untreated control group. MMC showed significant increase (p ≤ 0.001) in (MNPCE), (CA) and reduce (PCE/NCE) and (MI) values compared with untreated control group. Treatment with (Et. O.s) at different doses before and after MMC injection showed to modulate MNPCE, PCE/NCE ratios, CA and MI values in mice bone marrow cells suggesting genoprotective potential of this plant extract.

Genotoxic and anti-genotoxic effects of esculin and its oligomer fractions against mitomycin C-induced DNA damages in mice

Mitomycin C is one of the most effective chemotherapeutic drugs against various solid tumors. However, despite its wide spectrum of clinical benefits, this agent is capable of inducing various types of genotoxicity. In this study, we investigated the effect of esculin and its oligomer fractions (E1, E2 and E3) against mitomycin C induced genotoxicity in liver and kidney cells isolated from Balb/C mice using the comet assay. Esculin and its oligomer fractions were not genotoxic at the tested doses (20 mg/kg and 40 mg/kg b.w). A significant decrease in DNA damages was observed, suggesting a protective role of esculin and its oligomer fractions against the genotoxicity induced by mitomycin C on liver and kidney cells. Moreover, esculin and its oligomer fractions did not induce an increase of malondialdehyde levels.

Synthesis of novel tetrahydrobenzazepine derivatives and their cytoprotective effect on human lymphocytes

Cytoprotective compounds such as amifostine play an important role in chemo- and radiotherapy due to their ability to reduce the side effects of these treatments. Our work was initiated with the intention to design, synthesise and test a new class of heterocyclic compounds that would have an antioxidative profile with the potential to be further developed as cytoprotective agents. The design was based on the privileged tetrahydrobenzazepine scaffold found in many natural products with a wide range of biological properties. This structure was further functionalised with moieties known to possess antioxidative features such as tertiary amine and styrene double bond. A series of eight tetrahydrobenzazepine derivatives of isoquinoline, 3,4-dihydro-β-carboline and pyridine were synthesised employing the Heck reaction as a key transformation. Some of the prepared compounds were tested for their in vitro effects on chromosome aberrations in peripheral human lymphocytes using the cytochalasin-B blocked micronucleus (MN) assay. Three tetrahydrobenzoazepine derivatives showed significant cytoprotective properties, comparable or even better to those of the radioprotective agent amifostine.