Cytometric Analysis of Cytotoxicity of Polyphenols and Related Phenolics to Rat Thymocytes: Potent Cytotoxicity of Resveratrol to Normal Cells

Abstract

Abstract:The chemopreventive and chemotherapeutic actions of polyphenols and related phenolics have received considerable attention since these compounds induce apoptosis in several types of cancer cells in vitro. A plausible criterion for the use of such compounds is that they should not exert any toxic effect on normal cells. However, information about the toxicity of polyphenols and related phenolics to normal cells is limited. In this study, the effects of polyphenols and related phenolics on rat thymocytes were examined by flow cytometric analysis with appropriate fluorescent probes. The compounds examined in this study were caffeic acid, rosmarinic acid, chlorogenic acid, (+)-catechin, 6-gingerol, sesamol, resveratrol, and eugenol. Of these, resveratrol was the most cytotoxic on rat thymocytes incubated for 24 hrs with 100 µM of this compound. Resveratrol at a concentration of 10 µM or more (up to 100 µM) led to a significant dose-dependent increase in the population of dead cells, shrunken living cells, annexin V-positive cells and cells with hypodiploidal DNA. In the presence of benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethylketone (Z-VAD-FMK), a pan-inhibitor of caspases, the resveratrol-induced increase in the population of cells with hypodiploidal DNA was partially inhibited. Overall, it is suggested that resveratrol at a concentration of 10 µM or more induces apoptosis in normal cells as well as cancer cells (previously reported elsewhere). Thus, at concentrations that are suitable for chemopreventive and chemotherapeutic actions, resveratrol may exert a cytotoxic effect on normal cells.

Resveratrol alters human endothelial cells redox state and causes mitochondrial-dependent cell death

“…Although further studies are necessary to improve our knowledge on the molecular mechanism of resveratrol-induced cytotoxicity, our novel findings both confirm and support the idea that resveratrol can have a potent non-specific toxicity toward normal cells (Fujimoto et al, 2009;Pasciu et al, 2010). In particular, our data showing the involvement of CYP2C9 suggest that ECs with a low oxidative condition may recognize resveratrol, in high concentration, as a dangerous compound rather than as an antioxidant, metabolizing it through anti-xenobiotic enzymes, thus producing ROS.…”

Polyphenols as possible bioprotectors against cytotoxicity and DNA damage induced by ochratoxin A

“…Luteolin caused toxicity from100 g/mL by altering organelles function in Vero cells and cytoplasmic membrane in lymphocytes. Others studies have also demonstrated lack of cytotoxic effect of chlorogenic acid and toxicity of luteolin on lymphocytes, Vero cells and kidney cells (Fujimoto et al, 2009;López-Posadas et al, 2008;Kang et al, 2011;Kanlayavattanakul et al, 2013). Caffeic acid was the more toxic compound.…”

Cytotoxic Characteristics of Two Isomeric Dimers Produced by Oxidation of Sesamol, an Antioxidant in Sesame Oil

“…28) Such spontaneous increase is completely attenuated by benzyloxycarbonyl-valylalanyl-aspartyl-luoromethylketone (Z-VAD-FMK), a pan-inhibitor for caspases. 14,[29][30][31] However, dimer A did not significantly attenuate the activity of caspase. Therefore, it may be hypothesized that the process of spontaneous apoptosis is promoted by dimer A and dimer A inhibits the activity of endonuclease activated by caspases.…”

“…Thymocyte was used for a model experiment of cytotoxicity induced by chemical compounds 13,14) because of the following reasons. First, cell membranes remain intact because single cells are prepared without enzymatic treatment.…”

“…The procedure to prepare cell suspension was similar to that reported previously. 13,14) In brief, thymus glands were dissected from anesthetized Wistar rats. The glands were sliced at a thickness of 0.4-0.5 mm.…”