Orellanine Research Articles

Toxicity induced by orellanine from the mushroom Cortinarius orellanus in primary renal tubular proximal epithelial cells (RPTEC): Novel mechanisms of action

The toxicity of Orellanine (OR), a significant factor in mushroom poisoning, has severe effects on the kidneys, particularly the proximal tubules. This study investigated the acute toxicity of OR from the Cortinarius orellanus mushroom in human Primary Renal Tubular Proximal Epithelial Cells (RPTEC). Additionally, the half maximal inhibitory concentration (IC50) of OR in MCF-7 cells was established. RPTEC were subjected to a 6.25 μg/ml dose of orellanine for 24 h, while Control cells were exposed to 0.05% DMSO (vehicle). The RT2 Profiler™ PCR Array Human Nephrotoxicity was utilized to identify genes that were upregulated or downregulated. Western blotting confirmed the protein product of some significantly regulated genes compared to control cells. The IC50 of OR was found to be 319.2 μg/ml. The mechanism of OR toxicity involved several pathways including apoptosis, metal ion binding, cell proliferation, tissue remodeling, xenobiotic metabolism, transporters, extracellular matrix molecules, and cytoskeleton pathways. Other genes from non-specific pathways were also identified. These findings enhance our understanding of OR nephrotoxicity and pave the way for future research into potential treatments or antidotes for natural mushroom poisoning.

Evaluation of orellanine-induced toxicity from the mushroom Cortinarius orellanus and the antagonistic effect of Petroselinum crispum

Mushroom poisoning is a worldwide public health problem that may cause serious toxic consequences on renal functions. The study aimed to evaluate the acute toxicity (24 h) of orellanine (OR) from Cortinarius orellanus in rat kidney and the ameliorative effect of parsley ethanolic extract. Twelve adult male Wistar rats were used to determine intraperitoneal (ip) median lethal dose (LD50) of OR, and 32 rats were divided into 4 groups (n = 8): OR group had 500 mg OR per kg bwt; OR + parsley group had the same dose of OR and after 1 h had 500 mg/kg parsley orally; parsley group had parsley only; and control had the vehicle 0.1% DMSO. Blood and kidney samples were collected at Hour 48. The LD50 dose was 1430 mg/kg for an observation period of 24 h. There were significant reductions (p < 0.01) in the body weight, and relative kidney weight of intoxicated rats compared to parsley treated rats and to controls. Similarly, this group had significantly higher levels of creatinine (p < 0.001), uric acid and urea (p < 0.05). The antioxidant glutathione peroxidase activity was significantly reduced (p < 0.01), while Cystatin C serum levels were significantly higher (p < 0.001) in the intoxicated untreated rats compared to all groups. Histopathological examination indicated necrotic damage in glomeruli and proximal tubules of rats given OR, which was relieved by parsley extract. Overall, the study showed that parsley extract ameliorated OR-induced kidney toxicity. This could be utilized in future research on adjunct therapy for toxicity-induced renal injury.

Improved Tissue-Based Analytical Test Methods for Orellanine, a Biomarker of Cortinarius Mushroom Intoxication

Orellanine (OR) toxin is produced by mushrooms of the genus Cortinarius which grow in North America and in Europe. OR poisoning is characterized by severe oliguric acute renal failure, with a mortality rate of 10%–30%. Diagnosis of OR poisoning currently hinges on a history of ingestion of Cortinarius mushrooms and histopathology of renal biopsies. A key step in the diagnostic approach is analysis of tissues for OR. Currently, tissue-based analytical methods for OR are nonspecific and lack sensitivity. The objectives of this study were: (1) to develop definitive HPLC and LC-MS/MS tissue-based analytical methods for OR; and (2) to investigate toxicological effects of OR in mice. The HPLC limit of quantitation was 10 µg/g. For fortification levels of 15 µg/g to 50 µg/g OR in kidney, the relative standard deviation was between 1.3% and 9.8%, and accuracy was within 1.5% to 7.1%. A matrix-matched calibration curve was reproduced in this range with a correlation coefficient (r) of 0.97–0.99. The limit of detection was 20 ng/g for LC-MS/MS. In OR-injected mice, kidney OR concentrations were 97 ± 51 µg/g on Day 0 and 17 ± 1 µg/g on termination Day 3. Splenic and liver injuries were novel findings in this mouse model. The new tissue-based analytical tests will improve diagnosis of OR poisoning, while the mouse model has yielded new data advancing knowledge on OR-induced pathology. The new tissue-based analytical tests will improve diagnosis of OR poisoning, while the mouse model has yielded new data advancing knowledge on OR-induced pathology.

The fungal nephrotoxin orellanine simultaneously increases oxidative stress and down-regulates cellular defenses

Confusion of various nephrotoxic Cortinarius species with edible mushrooms occurs every year throughout Europe and North America. The toxin, orellanine (OR), accumulates selectively in renal tubular epithelium with ensuing renal failure after several days as the only clinical manifestation. This study was performed to clarify the mechanisms behind the kidney damage. Sprague–Dawley rats, 100 g bw, received various doses of purified OR ip (0–5 mg/kg bw). One week later, renal function (GFR) was determined (51Cr-EDTA), ascorbyl radicals in venous blood were analyzed using electron spin resonance, and oxidative protein damage was evaluated immunohistochemically. One OR-treated group (3.5 mg/kg) simultaneously received superoxide dismutase (SOD) targeted to tubular epithelium (HC-SOD; 10 mg/kg ip daily for 5 days). RT-PCR was used for analysis of mRNA expression of genes related to oxidative stress. OR caused a dose-dependent decrease in GFR, paralleled by increased levels of ascorbyl radicals and oxidative protein damage. Antioxidant treatment with HC-SOD decreased renal function even more and also increased tissue damage and mortality. Renal mRNA levels for key components in the antioxidative defense were strongly decreased, whereas those for several cytokines were increased. The data strongly suggest that OR nephrotoxicity in vivo is mediated by oxidative stress, including a virtual shutdown of important antioxidative enzymes. We interpret the unexpected effect of HC-SOD in terms of unbalanced SOD and catalase levels in the presence of OR, leading to massive generation of ·OH and cell death.

The Presence of Orellanine in Spores and Basidiocarp from Cortinarius orellanus and Cortinarius rubellus

The Presence of Orellanine in Spores and Basidiocarp from Cortinarius orellanus and Cortinarius rubellus