Evaluation of in Vitro Antioxidative, Cytotoxic and Apoptotic Activities of Rheum ribes Ethyl Acetate Extracts

Abstract: Rheum species are medicinally important plants due to the presence of anthracene derivatives. This study was designed to determine the antioxidative, cytotoxic and apoptotic properties of Rheum ribes shoot and root ethyl acetate extracts using human promyelocytic leukemia (HL-60) cell line as a model system. R. ribes shoot and root dry powder samples were prepared and extracted with ethyl acetate. The extracts were revealed to be a potential scavenger of DPPH radicals (IC 50 value of 206.28 µg/ml for shoot and 10.92 µg/ml for root) and the chemical composition of the extracts was quantified by colorimetric determination of total phenol (GAE) and flavonoid (CAE) contents. HL-60 cells were cultured in the presence of various concentrations of extracts up to 72 h. R. ribes inhibited the survival of HL-60 cells in a concentration-and timedependent manner, shown by XTT assay. R. ribes caused HL-60 cells apoptosis via formation of phosphatidylserine externalization, as evidenced by flow cytometry. Exposure of HL-60 cells to higher concentrations of extracts for 72 h resulted in a shift of 87% of the cell population from normal to the early/late apoptotic stage. These findings suggest that Rheum ribes ethyl acetate root extracts exhibits potential antioxidant and cytotoxic properties against HL-60 cells better than shoot extracts and exert their toxicity via induction of apoptosis

Comparison of GST Isoenzyme Expression in Normal and Neoplastic Breast Tissue: Correlation with Clinical and Prognostic Factors

Sak, Serpil/0000-0003-3666-3095WOS: 000266892000001Glutathione S-transferases in breast tissue play an important role in the susceptibility to the mutagenic effects of chemical carcinogens and in the response of breast tumors to chemotherapy. In this study the immunohistochemical staining characteristics of glutathione S-transferase isoenzymes (alpha, mu, pi, and theta) were investigated in invasive duct carcinomas and in normal breast tissue of 43 patients. The relationships between the expression of the GST isoenzymes and some clinicopathological features were also examined. Diffuse cytoplasmic staining of varying intensity was observed for GST alpha, theta, and pi in normal and tumorous breast tissue in 100% of the samples. In normal epithelium there was a stronger intensity of staining for GST alpha, mu. and pi expression than in invasive tumor tissues (P 0.05). In this study significant relationships were observed between microcalcification status and GST mu, between menopause status and GST alpha, and between tumor grade and GST mu expression (P 0.05).Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); British CouncilThis study was supported by grants from the Scientific and Technological Research Council of Turkey (TUBITAK), and the British Council

Molecular characterization of zeta class glutathione S-transferases from Pinus brutia Ten.

WOS: 000363980200006PubMed: 26440080Glutathione transferases (GSTs; EC 2.5.1.18) play important roles in stress tolerance and metabolic detoxification in plants. In higher plants, studies on GSTs have focussed largely on agricultural plants. There is restricted information about molecular characterization of GSTs in gymnosperms. To date, only tau class GST enzymes have been characterized from some pinus species. For the first time, the present study reports cloning and molecular characterization of two zeta class GST genes, namely PbGSTZ1 and PbGSTZ2 from Pinus brutia Ten., which is an economically important pine native to the eastern Mediterranean region and have to cope with several environmental stress conditions. The PbGSTZ1 gene was isolated from cDNA, whereas PbGSTZ2 was isolated from genomic DNA. Sequence analysis of PbGSTZ1 and PbGSTZ2 revealed the presence of an open reading frame of 226 amino acids with typical consensus sequences of the zeta class plant GSTs. Protein and secondary structure prediction analysis of two zeta class PbGSTZs have shared common features of other plant zeta class GSTs. Genomic clone, PbGSTZ2 gene, is unexpectedly intronless. Extensive sequence analysis of PbGSTZ2, with cDNA clone, PbGSTZ1, revealed 87% identity at nucleotide and 81% identity at amino acid levels with 41 amino acids differences suggesting that genomic PbGSTZ2 gene might be an allelic or a paralogue version of PbGSTZ1.Tubitak; University of Anadolu Reseach ProjectThanks to Prof. Heinz Rennenberg and Dr Stanislav Kopriva from Forest Botanic and Tree Physiology Institute, Albert-Ludwigs University, Freiburg, Germany, for providing the initial EST sequences and their help in Northern blot and glutathione assays. Dr Elif Oztetik was supported by Tubitak short term fellowship. This work was financially supported by University of Anadolu Reseach Project

Comparison of two glutathione S-transferases used in capacitive biosensors for detection of heavy metals

This work describes the development of a heavy-metal biosensor based on either recombinant 6His-Tag glutathione S-transferase (GST-(His)(6)) or glutathione S-transferase Theta 2-2 (GST-theta 2-2), and a capacitive transducer. The dynamic range of the pure bovine liver GST-Theta 2-2 biosensor was 1 fM to 1mM for Zn2+, and 10pM to 1mM for Cd2+. The GST-(His) 6 biosensor was able to detect Zn2+ and Cd2+ in the range of 1 fM to 10 mu M, and Hg2+ in the range of 1 fM to 10mM. The bovine liver GST Theta 2-2 biosensor displays an increased selectivity and a wider dynamic range for Zn2+ compared with the GST-(His) 6 biosensor. Therefore, by using different GST isozymes, it is possible to modulate important characteristics of capacitive biosensors for the detection of heavy metals

Cellular uptake, genotoxicity and cytotoxicity of cobalt ferrite magnetic nanoparticles in human breast cells

Magnetic nanoparticles (MNPs) have been increasingly used for many years as MRI agents and for gene delivery and hyperthermia therapy, although there have been conflicting results on their safety. In this study, cobalt ferrite magnetic nanoparticles (CoFe-MNPs) were prepared by the co-precipitation method and their surfaces were modified with silica by the sol-gel method. The particle and hydrodynamic sizes, morphology and crystal structure of the bare and silica-coated CoFe-MNPs were evaluated by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction spectroscopy (XRD) and Fourier transform infrared spectroscopy (FTIR). The size of the bare CoFe-MNPs was in the range 8-20 nm and they were homogeneously coated with 3-4 nm silica shells. The bare and silica-coated CoFe-MNPs were agglomerated at physiological pH. However, the sizes of the agglomerates were below 200 nm both in water and complete medium. The cytotoxic and genotoxic potentials of the bare and silica-coated CoFe-MNPs were evaluated in a metastatic breast cancer cell line, MDA-MB-231, as well as a noncancerous mammary epithelial cell line, MCF-10A, by using XTT cytotoxicity, single-cell gel electrophoresis (comet), and cytokinesis-blocked (CB) micronucleus (CBMN) assays. Characterization studies with TEM, inductively coupled plasma optical emission spectroscopy (ICP-OES) and Prussian blue staining indicated that the CoFe-MNPs were internalized into the cells by energy-dependent endocytosis. The highest amount of uptake was observed in the cancer cells and the uptake of the silica-coated CoFe--MNPs was higher than that of the bare ones in both cell lines. The bare CoFe-MNPs showed higher levels of both cytotoxicity and genotoxicity than the silica-coated CoFe-MNPs. Moreover, the cancer cells seemed to be more susceptible to the CoFe-MNPs' toxicity compared to the noncancerous cells. There was a concentration and time-dependent increase in DNA damage and the micronucleus (MN) frequency, which was statistically significant starting with the lowest concentration of bare CoFe-MNPs (p < 0.05), while no significance was observed below the concentration of 250 mu g mL(-1) for the silica-coated MNPs. Also, the extent of both DNA damage and MN frequency was much higher in the cancer cells compared to the noncancerous cells. According to our results, the silica coating ameliorated both the cytotoxicity and genotoxicity as well the internalization of the CoFe-MNPs