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Cherewyk JE, Blakley BR, Al-Dissi AN. Investigation of the relationship between ergocristinine and vascular receptors. Toxicol Rep 2023; 10:604-611. [PMID: 37213815 PMCID: PMC10199403 DOI: 10.1016/j.toxrep.2023.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 05/11/2023] [Accepted: 05/13/2023] [Indexed: 05/23/2023] Open
Abstract
Ergot alkaloids are secondary metabolites that exist in two configurations, the C-8-R-isomer (R-epimer), and the C-8-S-isomer (S-epimer). Toxic effects of ergot, such as vasoconstriction, have been primarily attributed to the R-epimer bioactivity, as compared to the S-epimer. Recent studies demonstrated potential bioactivity of S-epimers. Therefore, further cost-effective investigations of the S-epimers are needed. The present study investigated the S-epimer - vascular receptor binding relationship. An in silico molecular docking approach, utilizing AutoDock Vina and DockThor, was used to determine if the S-epimer (ergocristinine) binds to vascular receptors and to compare the binding affinity and interactions to the corresponding R-epimer (ergocristine) and a structural analogue (lysergic acid amide). The binding energy (kcal/mol) of ergocristinine was - 9.7 or - 11.0 to the serotonin (5-HT) 2 A receptor and - 8.7 or - 11.4 to the alpha 2 A adrenergic receptor, depending on the software used. A hydrogen bond was formed between ergocristinine and amino acid residues of the 5-HT 2 A and alpha 2 A adrenergic receptor binding sites, with bond lengths of 3.10 Å and 3.28 Å, respectively. Binding affinities and molecular interactions among the ligands to each receptor differed. Different affinities and interactions may relate to differences in the chemical structures. The binding affinities and strong molecular interactions of the S-epimer to vascular receptors may contribute to the observed physiological manifestations that occur after ergot alkaloid exposure. The results of the present study suggest further investigation on the receptor binding of the S-epimers of ergot alkaloids.
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Affiliation(s)
- Jensen E. Cherewyk
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5B4 Canada
- Corresponding author.
| | - Barry R. Blakley
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5B4 Canada
| | - Ahmad N. Al-Dissi
- Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5B4 Canada
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Stanford K, Schwartzkopf-Genswein KS, Meléndez DM, Ngo S, Harding M, McAllister TA, Schatzmayr D, Swift ML, Blakley B, Ribeiro GO. Effects of Heating, Pelleting, and Feed Matrix on Apparent Concentrations of Cereal Ergot Alkaloids in Relation to Growth Performance and Welfare Parameters of Backgrounding Beef Steers. Toxins (Basel) 2022; 14:toxins14090580. [PMID: 36136518 PMCID: PMC9500729 DOI: 10.3390/toxins14090580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/15/2022] [Accepted: 08/22/2022] [Indexed: 12/04/2022] Open
Abstract
As the contamination of cereal grains with ergot has been increasing in Western Canada, studies were undertaken to evaluate the impacts of heating (60, 80, 120, or 190 °C) alone or in combination with pelleting on concentrations of ergot alkaloids. Fifteen samples of ergot-contaminated grain from Alberta and Saskatchewan were assayed for R and S epimers of six alkaloids (ergocryptine, ergocristine, ergocornine, ergometrine, ergosine, and ergotamine) using HPLC MS/MS. Five samples with distinct alkaloid profiles were then selected for heating and pelleting studies. Heating resulted in a linear increase (p < 0.05) of total R and total S epimers with increasing temperature, although some individual R epimers were stable (ergometrine, ergosine, ergotamine). Pelleting also increased (p < 0.05) concentrations of total R and total S epimers detected, although ergometrine concentration decreased (p < 0.05) after pelleting. A feeding study arranged in a 2 × 2 factorial structure used 48 backgrounding Angus-cross steers fed four different diets: (1) Control Mash (CM, no added ergot), (2) Control Pellet (CP), (3) Ergot Mash (EM), or (4) Ergot Pellet (EP). Pelleting heated the ergot to 90−100 °C under 4 bars pressure, but the ergot used in the feeding study was not otherwise heated. Alkaloid concentrations of EM and EP varied by up to 1.1 mg/kg depending on the feed matrix assayed. No differences among treatments were noted for growth performance, feed intake, feed conversion, concentrations of serum prolactin and haptoglobin, hair cortisol, or in temperatures of extremities measured by infrared thermography. The only negative impacts of ergot alkaloids were on blood parameters indicative of reduced immune function or chronic inflammation. Pelleting did not heighten the negative clinical outcomes of ergot, although alkaloid concentrations of pelleted feed increased depending on the matrix assayed. It was hypothesized that the heat and pressure associated with pelleting may enhance the recovery of alkaloids from pelleted feed.
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Affiliation(s)
- Kim Stanford
- Department of Biological Sciences, University of Lethbridge, 4401 University Dr. Lethbridge, Lethbridge, AB T1K 3M4, Canada
- Correspondence:
| | - Karen S. Schwartzkopf-Genswein
- Agriculture and Agri-Food Canada Research and Development Center, 5401-1st Ave. S. Lethbridge, Lethbridge, AB T1J 4B1, Canada
| | - Daniela M. Meléndez
- Agriculture and Agri-Food Canada Research and Development Center, 5401-1st Ave. S. Lethbridge, Lethbridge, AB T1J 4B1, Canada
| | - Skyler Ngo
- Department of Biological Sciences, University of Lethbridge, 4401 University Dr. Lethbridge, Lethbridge, AB T1K 3M4, Canada
| | - Michael Harding
- Alberta Agriculture, Forestry and Rural Economic Development, Crop Diversification Center South, Brooks, AB T1R 1E6, Canada
| | - Tim A. McAllister
- Agriculture and Agri-Food Canada Research and Development Center, 5401-1st Ave. S. Lethbridge, Lethbridge, AB T1J 4B1, Canada
| | - Dian Schatzmayr
- DSM–BIOMIN Research Center, Technopark 1, 3430 Tulln, Austria
| | - Mary Lou Swift
- Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, AB T6G 2P5, Canada
| | - Barry Blakley
- Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A2, Canada
| | - Gabriel O. Ribeiro
- Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada
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Cherewyk JE, Parker SE, Blakley BR, Al-Dissi AN. Assessment of the vasoactive effects of the (S)-epimers of ergot alkaloids in vitro. J Anim Sci 2020; 98:5868065. [PMID: 32629472 PMCID: PMC7373324 DOI: 10.1093/jas/skaa203] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/04/2020] [Indexed: 11/14/2022] Open
Abstract
Ergot alkaloids are produced by the fungus Claviceps purpurea and their levels are carefully monitored in animal and human diets due to their harmful effects and widespread contamination of cereal crops. Ergot alkaloids exist in two forms known as the (R)- and (S)-epimers with only the former being monitored in diets in North America. The (S)-epimers of ergot alkaloids are thought to be biologically inactive and, therefore, harmless. A major mechanism by which the (R)-epimers of ergot alkaloids produce their toxic effect is through vasoconstriction. Therefore, the objective of this study was to examine the vasoactivity potential (contractile response) of four (S)-epimers, namely ergocryptinine, ergocristinine, ergocorninine, and ergotaminine utilizing an in vitro arterial tissue bath system. Bovine metatarsal arteries (n = 6, ergocryptinine and ergocorninine; n = 6, ergocristinine and ergotaminine; n = 6 arteries/(S)-epimer, total n = 12) were collected from healthy mixed-breed beef steers immediately after slaughter, cut into 3-mm arterial cross sections, and suspended in a tissue bath with continuously oxygenated Krebs–Henseleit buffer. To assess the contractile response of each (S)-epimer, a cumulative contractile dose–response curve was constructed by incubating arteries with increasing concentrations (1 × 10−11 to 1 × 10−6 M) of that (S)-epimer. Contractile responses were recorded as grams of tension and were normalized to an initial contraction of phenylephrine. Contrary to the widespread belief, all tested (S)-epimers were found vasoactive and produced a concentration-dependent arterial contractile response similar to what has been reported for the (R)-epimers. The arterial contractile response to ergotaminine was strongest and was significantly greater than that of ergocryptinine and ergocristinine at the highest concentration used (P ≤ 0.01). Our results indicate that the (S)-epimers are biologically active and are likely harmful similar to the (R)-epimers. The levels of (S)-epimers should be carefully monitored in human and animal diets worldwide.
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Affiliation(s)
- Jensen E Cherewyk
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada
| | - Sarah E Parker
- Centre for Applied Epidemiology, Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Barry R Blakley
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ahmad N Al-Dissi
- Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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