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United States Department of Agriculture

Agricultural Research Service

Research Project: MOLECULAR BIOLOGY AND GENOMICS OF FOODBORNE PATHOGENS

Location: Produce Safety and Microbiology Research

Title: L-cysteine, N-acetyl-L-cysteine, and glutathione protect xenopus laevis embryos against acrylamide-induced malformations and mortality in the frog embryo teratogenesis assay (FETAX)

Authors
item Rayburn, James -
item FRIEDMAN, MENDEL

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 11, 2010
Publication Date: October 27, 2010
Citation: Rayburn, J.R., Friedman, M. 2010. L-cysteine, N-acetyl-L-cysteine, and glutathione protect xenopus laevis embryos against acrylamide-induced malformations and mortality in the frog embryo teratogenesis assay (FETAX). Journal of Agricultural and Food Chemistry. 58:11/172-11/178.

Interpretive Summary: Acrylamide (CH2=CHCONH2) is a small, reactive compound. After consumption, it is absorbed in the circulation and is then distributed to various organs, where it can react with DNA, neurons, hemoglobin, and essential enzymes. These changes may be responsible for reported acrylamide-caused carcinogenesis, neurotoxicity, and developmental toxicity. Dietary acrylamide is largely derived from heat-induced reactions between the amino group of the free amino acid asparagine and carbonyl groups of glucose and fructose during heat processing (baking, frying) of plant-derived foods such as potato fries and cereals. These considerations induced us to explore the potential of amino acids and peptides (L-cysteine, N-acetyl-L-cysteine, glutathione, and glycine) to protect frog embryos against acrylamide-induced developmental toxicity. The results of the present collaborative study with Prof. James R. Rayburn at the Biology Department of Jacksonville State University, Alabama suggest that dietary cysteine and glutathione have the potential to protect against acrylamide-induced malformations (birth defects) of fetuses, that N-acetyl-cysteine has the potential to protect against acrylamide-induced toxicity (mortality), and that glycine had no protective effect.

Technical Abstract: Dietary acrylamide is largely derived from heat-induced reactions between the amino group of the free amino acid asparagine and carbonyl groups of glucose and fructose during heat processing (baking, frying) of plant-derived foods such as potato fries and cereals. After consumption, acrylamide is absorbed into the circulation and is then distributed to various organs, where it can react with DNA, neurons, hemoglobin, and essential enzymes. These changes may be responsible for reported acrylamide-caused carcinogenesis, neurotoxicity, and teratogenesis. In the present study, we explored the potential of L-cysteine (CySH), N-acetyl-L-cysteine (NAC), reduced glutathione (GSH), and the amino acid glycine (Gly) to protect frog embryos against acrylamide-induced developmental toxicity in the Frog Embryo Teratogenesis Assay - Xenopus (FETAX). To test the anti-teratogenic potential, based on concentration-response study ranging from 0.07 mM to 4.22 mM of acrylamide in FETAX solution (pH 8.1), we selected concentrations of acrylamide that induced 100% malformations and mortality. At the end of 96-h, we counted survivors, malformed embryos, and measured embryo length. The data show that CySH, NAC, and GSH protected the embryos against acrylamide induced malformations and mortality to different degrees. CySH and GSH protected the embryos against both malformations and mortality, whereas NAC protected only against mortality. Gly had no protective effect. Possible mechanisms of the protective effects and the dietary significance of the results of this and related studies for food safety and human health are discussed.

Last Modified: 7/25/2014
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