The oxidative damage of butenolide to isolated erythrocyte membranes

A Novel Method for Measuring Mitochondrial Respiratory Parameters in Wheat Paleae (Paleae Superior) Using the XF24 Analyzer

Understanding the influence of secondary metabolites from fungi on the mitochondria of the host plant during infection is of great importance for the knowledge of fungus-plant interactions in general; it could help generate resistant plants in the future and in the development of specifically acting plant protection products. For this purpose, it must first be possible to record the mitochondrial parameters in the host plant. As of the date of this protocol, no measurements of mitochondrial respiration parameters have been performed in wheat paleae. The protocol shown here describes the measurements using the XF24 analyzer, which measures the rate of oxygen consumption in the sample by changes in the fluorescence of solid-state fluorophores. This procedure covers the preparation of samples for the XF24 analyzer and the measurement of mitochondrial parameters by adding specific mitochondrial inhibitors. It also shows the necessary approach and steps to be followed to obtain reliable, reproducible results. This is a robust protocol that allows the analysis of mitochondrial respiration directly in the wheat paleae. It demonstrates an important add-on method to existing screenings and also offers the possibility to test the effects of early infection of plants by harmful fungi (e.g., Fusarium graminearum) on mitochondrial respiration parameters. Key features This protocol offers the possibility of testing the effects of early infection of plants by pathogens on mitochondrial respiration parameters. This protocol requires a Seahorse XF24 Flux Analyzer with Islet Capture Microplates and the Seahorse Capture Screen Insert Tool. Graphical overview.

Suppression of Trichothecene-Mediated Immune Response by the Fusarium Secondary Metabolite Butenolide in Human Colon Epithelial Cells

Butenolide (BUT, 4-acetamido-4-hydroxy-2-butenoic acid gamma-lactone) is a secondary metabolite produced by several Fusarium species and is co-produced with the major trichothecene mycotoxin deoxynivalenol (DON) on cereal grains throughout the world. BUT has low acute toxicity and only very limited occurrence and exposure data are available. The intestinal epithelium represents the first physiological barrier against food contaminants. We aimed to elucidate the intestinal inflammatory response of the human, non-cancer epithelial HCEC-1CT cells to BUT and to characterize potential combinatory interactions with co-occurring trichothecenes, such as DON and NX-3. Using a reporter gene approach, BUT (≥5 μM, 20 h) was found to decrease lipopolysaccharide (LPS; 10 ng/mL) induced nuclear factor kappa B (NF-κB) activation in a dose-dependent manner, and in combinatory treatments BUT represses trichothecene-induced enhancement of this important inflammatory pathway. Analysis of transcription and secretion levels of NF-κB-dependent, pro-inflammatory cytokines, revealed a significant down-regulation of IL-1β, IL-6, and TNF-α in IL-1β-stimulated (25 ng/mL) HCEC-1CT cells after BUT exposure (10 μM). Trichothecene-induced expression of pro-inflammatory cytokines by the presence of 1 μM DON or NX-3 was substantially suppressed in the presence of 10 μM BUT. The emerging mycotoxin BUT has the ability to suppress NF-κB-induced intestinal inflammatory response mechanisms and to modulate substantially the immune responsiveness of HCEC-1CT cells after trichothecene treatment. Our results suggest that BUT, present in naturally occurring mixtures of Fusarium fungal metabolites, should be increasingly monitored, and the mechanism of inhibition of NF-κB that might affect the pathogenesis or progression of intestinal inflammatory disorders, should be further investigated.

Impact of glutathione modulation on the toxicity of the Fusarium mycotoxins deoxynivalenol (DON), NX-3 and butenolide in human liver cells

DON, NX-3 and butenolide (BUT) are secondary metabolites formed by Fusarium graminearum. Evidence for formation of DON-glutathione adducts exists in plants, and also in human liver (HepG2) cells mass spectrometric evidence for GSH-adduct formation was reported. NX-3 is a DON derivative lacking structural features for Thiol-Michael addition, while BUT has the structural requirements (conjugated double bond and keto group). In the present study, we addressed whether these structural differences affect levels of intracellular reactive oxygen species in HepG2 cells, and if intracellular GSH levels influence toxic effects induced by DON, NX-3 and BUT. Pre-treatment with an inhibitor of GSH bio-synthesis, L-buthionine-[S,R]-sulfoximine, aggravated substantially BUT-induced cytotoxicity (≥50 μM, 24 h), but only marginally affected the cytotoxicity of DON and NX-3 indicating that GSH-mediated detoxification is of minor importance in HepG2 cells. We further investigated whether BUT, a compound inducing alone low oral toxicity, might affect the toxicity of DON. Under different experimental designs with respect to pre- and/or co-incubations, BUT was found to contribute to the combinatorial cytotoxicity, exceeding the toxic effect of DON alone. The observed combinatorial effects underline the potential contribution of secondary metabolites like BUT, considered to be alone of low toxicological relevance, to the toxicity of DON or structurally related trichothecenes, arguing for further studies on the toxicological relevance of naturally occurring mixtures.

Protective Effect of Pitao (Pitavia punctata (R. & P.) Molina) Polyphenols against the Red Blood Cells Lipoperoxidation and the In Vitro LDL Oxidation

The oxidative stress is characterized by an imbalance between the oxidizing agents and antioxidants; meanwhile, the consumption of antioxidants has been considered as an important tool in the prevention of oxidative stress and its consequences. Pitavia punctata (R. & P.) Molina is an endemic arboreal species from the Chilean Coast Range, in which a large amount of flavonoids has been described. This work focused on characterizing and evaluating, in human erythrocytes, the antioxidant capacity and membrane protection of P. punctata extracts and the in vitro protection of the oxidation of the Low Density Lipoprotein (LDL). The phytochemical screening revealed the presence of Quercetin derivatives and flavonoids, such as (-)-Epicatechin, Kaempferol, and derivatives. The methanolic extract presented an important antioxidant activity, protecting the membrane integrity of the red blood cells against the oxidative damage caused by Hypochlorous acid and inhibiting the oxidation of the LDL lipoprotein.

Silymarin prevents the toxicity induced by benzo(a)pyrene in human erythrocytes by preserving its membrane integrity: an in vitro study

Silymarin, the purified extract from milk thistle Silybum marianum (L.) Gaertn, consists mainly of four isomeric flavonolignans: silibinin, isosilibinin, silidianin, and silichristin. The present study was carried out to evaluate the protective potential of silymarin in human erythrocytes against in vitro exposure to the carcinogen benzo(a)pyrene (B(a)P). Erythrocytes isolated from human blood were divided into four groups and treated with Vehicle [Group I], B(a)P (300 μM) [Group II], Silymarin (500 μM) + B(a)P (300 μM) [Group III], and Silymarin alone (500 μM)] [Group IV]. Silymarin treatment maintains the integrity of erythrocytes by preventing hemolysis, protein thiol oxidation and by decreasing the activity of AChE. SEM observations indicate that B(a)P induced significant alteration in the morphology of erythrocytes to echinocytes, which may be due to the interaction of B(a)P with the membrane's outer phopholipid monolayer. The light microscopic and SEM images show that silymarin treatment maintains the normal discocytic morphology of erythrocytes. The protective effect of silymarin might be attributed to its chemical structure and membranotrophic nature. The components silibinin, silydianin, and silychristin have OH in the 3rd, 5th, and 7th carbon atoms that may account for its increased antioxidant activity and removal of ROS formed during B(a)P metabolism.

Erythrocyte damage of crucian carp (Carassius auratus) caused by microcystin-LR: in vitro study

Fish suffer from anemia and hypovolemic hypotensive shock after in vivo exposure with microcystins.However, except for in vivo causes for anemia and hypotension, an in vitro study of fish erythrocytes exposed to MC is necessary. For a better understanding of hematology toxicity of MC, the main aim of the present study was to investigate the toxic effects of microcystin on fish erythrocytes in vitro. Crucian carp erythrocytes were incubated in vitro with microcystin-LR (MC-LR) at doses of 0, 1, 10, 100 and 1,000 nM.The level of lipid peroxidate significantly increased in MC-LR treatment groups. Glutathione decreased after exposure to MC-LR. The activities of antioxidative enzymes, including superoxide dismutase, catalase,glutathione peroxidase and glutathione-S-transferase,were significantly increased after exposure with MC-LR.The hemolysis was significantly increased, while the activities of acetylcholinesterase, Na?–K?-ATPase and Ca2?–Mg2?-ATPase were significantly decreased. In addition, pathological alterations in agglomerated and jagged erythrocytes were observed in blood smears. The findings indicate that damages to erythrocytes should also be responsible for anemia and hypotensive shock or even death.