Investigation of chemopreventive and apoptotic characteristics of turkish medicinal plant rheum ribes

Uyar, Pembegül
Rheum species are medicinally important plants due to the presence of anthracene derivatives and in this study antioxidative, cytotoxic, apoptotic and chemopreventive characteristics of R. ribes extracts were evaluated. R. ribes shoot and root dry powder samples were prepared and extracted with ethyl acetate, ethanol and water. The extracts were revealed to be a potential scavenger of DPPH radicals 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 hr. R. ribes inhibited the surviv al of HL-60 cells in a concentration- and time-dependent manner, shown by trypan blue and XTT. 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. The R. ribes induced apoptosis may be partially attributed to the activation of caspase-3 and up-regulation of caspase-3 expression was detected in western blot. The significant release of cytochrome c from the mitochondria into the cytosol was observed. The mRNA expression ratio of Bax/Bcl-2 was increased. The apoptosis was also demonstrated by DNA ladder and TUNEL. Chemopreventive effects of R.ribes were investigated at the gene level of CYP1B1 and CYP1A1, and GST enzyme activity against cDNB and concluded that R.ribes modulated activities of these enzymes generally at a time dependent level. T h ese findings suggest that Rheum ribes exhibits potential antioxidant and anticancer properties by inducing caspase-dependent cell death in HL-60 cells.


A phenetics study for infrageneric grouping of Limonium Mill. genus (Plumbaginaceae) in Turkey
Fazlıoğlu, Fatih; Doğan, Musa; Department of Biology (2011)
In this study, current infrageneric taxonomic status of Limonium Mill. in Turkey was assessed by using numerical taxonomy (phenetics) method. Herbarium materials belong to 21 species of Limonium Mill., collected all around Turkey, and were examined. In order to evaluate the infrageneric status, 52 characters based on ecological and morphological features of the genus were determined and recorded to construct a data matrix which was analyzed by MultiVariate Statistical Package (MVSP) and Statistica software ...
Investigation of neutron sensitivity of un-doped and Dy-doped CaB4O7 for thermoluminescence applications
Iflazoglu, Sera; Yılmaz, Ayşen; KAFADAR, VURAL EMİR; YAZICI, AHMET NECMEDDİN (2018-09-01)
In this study, thermoluminescence characteristics of un-doped and Dy-doped calcium tetraborate (CaB4O7) compounds are reported. The polycrystalline powder samples of un-doped and Dy-doped CaB4O7 were prepared by a solid-state reaction at high-temperature method. The identification and characteristics of the obtained compounds were determined by X-ray diffraction, Fourier transform infrared analysis, differential thermal analysis, thermogravimetric analysis, and scanning electron microscopy. The glow curves ...
Evaluation of photosynthetic performance of wheat cultivars exposed to boron toxicity by the JIP fluorescence test
Oz, M. T.; TURAN, ÖZLEM; Kayihan, C.; EYİDOĞAN, FÜSUN; EKMEKÇİ, YASEMİN; YÜCEL, MUSTAFA; Öktem, Hüseyin Avni (Institute of Experimental Botany, 2014-12-01)
The changes in growth and photosynthetic performance of two wheat (Triticum aestivum L.) cultivars (Bolal-2973 and Atay-85) differing in their sensitivity to boron (B) toxicity were investigated under toxic B conditions. Eight-day old seedlings were exposed to highly toxic B concentrations (5, 7.5, and 10 mM H3BO3) for 5 and 9 days. Fast chlorophyll a fluorescence kinetics was determined and analysed using JIP test. Growth parameters, tissue B contents, and membrane damage were measured at two stress durati...
Effect of salt stress on antioxidant defense systems of sensitive and resistance cultivars of lentil(Lens culinaris M.)
Cicerali, Işın Nur; Yücel, Ayşe Meral; Department of Biotechnology (2004)
In this study, two lentil cultivars (Lens culinaris, Medik.) (ILL5582-salt tolerant and ILL590) were characterized and compared due to their NaCl susceptibility and antioxidant mechanism was examined under laboratory conditions. Physiological parameters such as wet-dry weight, root-shoot lengths, cell membrane stability, lipid peroxidation in terms of malondialdehyde (MDA), H2O2, proline contents were determined. The activities of antioxidant enzymes such as superoxide dismutase (SOD: EC, catalase...
Synthesis of selenophene substituted benzodithiophene and fluorinated benzothiadiazole based conjugated polymers for organic solar cell applications
Cevher, Duygu; Taşkaya Aslan, Sultan; Bolayır, Eda; Hizalan Ozsoy, Gonul; UDUM, YASEMİN; Yıldırım, Erol; Toppare, Levent Kamil; Çırpan, Ali (2021-12-01)
A series of alternating conjugated copolymers which contain selenophene modified benzodithiophene and fluorine bearing benzothiadiazole have been synthesized via Stille polycondensation reaction to investigate the effect of the number of fluorine atoms substituted to the benzothiadiazole. Three different polymers, PBDTSe-BT, PBDTSe-FBT and PBDTSe-FFBT, were reported and their electrochemical, spectroelectrochemical, and photovoltaic behaviors were examined. Density functional theory calculations were perfor...
Citation Formats
P. Uyar, “Investigation of chemopreventive and apoptotic characteristics of turkish medicinal plant rheum ribes,” Ph.D. - Doctoral Program, Middle East Technical University, 2011.