Protective effect of (-)-epigallocatechin-3-gallate on capsaicin-induced DNA damage and oxidative stress in human erythrocyes and leucocytes in vitro

Pistacia lentiscus L. fruits showed promising antimutagenic and antigenotoxic activity using both in-vitro and in-vivo test systems

Pistacia lentiscus L. is one of the most popular medicinal plants attributed to its beneficial properties on human health. However, few toxicogenetic studies have been carried out. Therefore, the aim of this study was to examine the potential genotoxic/antigenotoxic and mutagenic/antimutagenic properties of oil, ethyl acetate and ethanolic extracts of P. lentiscus L. fruits using in vitro the Ames and Umu assays, as well as in vivo micronucleus (MN) test. Extracts did not exert any significant mutagenic/genotoxic effects but provided protection against standard mutagenic and genotoxic agents including 2 nitrofluorene (2-NF) at 2.5 and 5 µg/ml; sodium azide at 5 and 10 µg/ml; 3-methylcholanthrene (3-MC) at 25 and 50 μg/ml; cyclophosphamide (CP) at 50 and 100 μg/ml; 4-nitroquinoline 1-oxide (4-NQO) at 0.05 µg/ml and 2-amino-anthracene (AA) at 0.2 µg/ml. Further, cytotoxicity and selectivity were examined on human hepatocarcinoma (HepG2), and MCF-7 breast cancer cell lines as well as a human normal-like fibroblast cell line (TelCOFS02MA) using MTT assay. Among all extracts, PF1 (ethanolic) showed the most significant selectivity index (SI) (HepG2:11.98; MCF7:4.83), which led to further investigations using an animal model. Oral administration of PF1 (125-1000 mg/kg b.w.) significantly decreased the number of micronucleated cells in CP -initiated (50 mg/kg b.w.) mice, while the number of micronucleated reticulocytes (MNRET), micronucleated polychromatic erythrocytes (MNPCE) or mitotic index (MI) were not markedly affected. Further, PF1 significantly enhanced catalase (CAT) and superoxide dismutase (SOD) activities in the livers and kidneys of these animals. The obtained results indicated the beneficial properties of P. lentiscus L. fruits for use in therapy against harmful effects of genotoxic and mutagenic agents. However, while promising it should be noted that the obtained results are preliminary and need to be confirmed prior to therapeutic use.

DNA-binding activities of compounds acting as enzyme inhibitors, ion channel blockers and receptor binders

The DNA-binding activities of compounds used as remedies can display DNA-protection, but also damaging effects in biological systems. The current review compiles literature data on DNA-binding activities of drugs widely used as remedies with different therapeutic indications. The compounds are classified according their mechanism of action: enzyme inhibitors, ion channel inhibitors, inhibitors of viral RNA replication and HIV protease and receptor agonists. DNA binding was reported for such widely used drugs as paracetamol, aspirin, metformin, statins and many others. The capability of the drug to bind DNA is sometimes coupled to genotoxic effects, but in some cases - to genome protection. Data on atoms and chemical groups involved in the drug-DNA interactions are also presented. In many cases the same atoms are involved in both interactions of the compounds with proteins and DNA.

Genome-Protecting Compounds as Potential Geroprotectors

Throughout life, organisms are exposed to various exogenous and endogenous factors that cause DNA damages and somatic mutations provoking genomic instability. At a young age, compensatory mechanisms of genome protection are activated to prevent phenotypic and functional changes. However, the increasing stress and age-related deterioration in the functioning of these mechanisms result in damage accumulation, overcoming the functional threshold. This leads to aging and the development of age-related diseases. There are several ways to counteract these changes: 1) prevention of DNA damage through stimulation of antioxidant and detoxification systems, as well as transition metal chelation; 2) regulation of DNA methylation, chromatin structure, non-coding RNA activity and prevention of nuclear architecture alterations; 3) improving DNA damage response and repair; 4) selective removal of damaged non-functional and senescent cells. In the article, we have reviewed data about the effects of various trace elements, vitamins, polyphenols, terpenes, and other phytochemicals, as well as a number of synthetic pharmacological substances in these ways. Most of the compounds demonstrate the geroprotective potential and increase the lifespan in model organisms. However, their genome-protecting effects are non-selective and often are conditioned by hormesis. Consequently, the development of selective drugs targeting genome protection is an advanced direction.

All aspect of toxic effect of brilliant blue and sunset yellow in Allium cepa roots

Substances added to food are considerable for survival and are the oldest technologies used in preservation, sweetening and coloring. This work was conducted to evaluate the toxicity of the food additives sunset yellow (SY) and brilliant blue (BB) on Allium cepa root meristematic cells. Control and treatment groups were created from germinated roots. Group 1 (control group) did not receive chemicals. Group 2 (SY or BB-treatment group), received increasing doses of SY (25, 50, 100 and 500 ppm) and BB (100, 200, 400 and 500 ppm) with time periods of 24, 48 and 72 h. After different treatment periods, the roots were obtained from all groups and EC₅₀ concentrations, cell death, chromosome aberrations, mitotic index were observed by a light microscopy. Changing antioxidant capacity of roots was determined by FRAP and TEAC assay. Also, DNA damage was measured by comet assay and RAPD-PCR technique. Approximately 50 and 200 ppm were accepted as EC₅₀ value for SY and BB, respectively. Chromosome aberration values were obtained with increasing concentrations and longer treatment times such as chromosome bridge, C-mitosis, micronucleus, chromosome mis-segregation in both groups. Increasing exposure doses of SY and BB caused decreasing mitotic index values at 72 h. FRAP and TEAC assay showed that antioxidant capacity of roots was decreased by increasing concentrations of SY and BB. The tail DNA% and tail length significantly increased for all exposure times when compared to the control group. 50 and 200 ppm of SY and BB caused a genotoxic effect on genetic material at 72 h according to RAPD-PCR. Increasing the doses of SY and BB resulted in increased toxicity to all studied parameters of A. cepa. In conclusion, the SY and BB tested in this study have cytotoxic and mutagenic potential. Furthermore, SY is more harmful than BB for use in the A. cepa root meristematic cells.

Epigallocatechin-3-gallate Protects against Hydrogen Peroxide-Induced Inhibition of Osteogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells

Oxidative stress induces bone loss and osteoporosis, and epigallocatechin-3-gallate (EGCG) may be used to combat these diseases due to its antioxidative property. Herein, oxidative stress in human bone marrow-derived mesenchymal stem cells (BM-MSCs) was induced by H₂O₂, resulting in an adverse effect on their osteogenic differentiation. However, this H₂O₂-induced adverse effect was nullified when the cells were treated with EGCG. In addition, treatment of BM-MSCs with EGCG alone also resulted in the enhancement of osteogenic differentiation of BM-MSCs. After EGCG treatment, expressions of β-catenin and cyclin D1 were upregulated, suggesting that the Wnt pathway was involved in the effects of EGCG on the osteogenic differentiation of BM-MSCs. This was also confirmed by the fact that the Wnt pathway inhibitor, Dickkopf-1 (DKK-1), can nullify the EGCG-induced enhancement effect on BM-MSC's osteogenic differentiation. Hence, our results suggested that EGCG can reduce the effects of oxidative stress on Wnt pathway in osteogenic cells, which supported a potentially promising therapy of bone disorders induced by oxidative stress. Considering its positive effects on BM-MSCs, EGCG may also be beneficial for stem cell-based bone repair.