Quantification of metabolites for assessing human exposure to soapberry toxins hypoglycin A and methylenecyclopropylglycine.
Ingestion of soapberry fruit toxins hypoglycin A and methylenecyclopropylglycine has been linked to public health challenges worldwide. In 1976, over 100 years after Jamaican vomiting sickness (JVS) was first reported, the cause of JVS was linked to the ingestion of the toxin hypoglycin A produced by ackee fruit. A structural analogue of hypoglycin A, methylenecyclopropylglycine (MCPG), was implicated as the cause of an acute encephalitis syndrome (AES). Much of the evidence linking hypoglycin A and MCPG to these diseases has been largely circumstantial due to the lack of an analytical method for specific metabolites. This study presents an analytical approach to identify and quantify specific urine metabolites for exposure to hypoglycin A and MCPG. The metabolites are excreted in urine as glycine adducts methylenecyclopropylacetyl-glycine (MCPA-Gly) and methylenecyclopropylformyl-glycine (MCPF-Gly). These metabolites were processed by isotope dilution, separated by reverse-phase liquid chromatography, and monitored by electrospray ionization tandem mass spectrometry. The analytical response ratio was linearly proportional to the concentration of MCPF-Gly and MCPA-Gly in urine from 0.10 to 20 μg/mL with a correlation coefficient of r > 0.99. The assay demonstrated accuracy ≥80% and precision ≤20% RSD across the calibration range. This method has been applied to assess exposure to hypoglycin A and MCPG as part of a larger public health initiative and was used to provide the first reported identification of MCPF-Gly and MCPA-Gly in human urine.
Oak Ridge Institute for Science and Education Fellow, ‡Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States.
Samantha L
SL
Isenberg
Oak Ridge Institute for Science and Education Fellow, ‡Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States.
Melissa D
MD
Carter
Oak Ridge Institute for Science and Education Fellow, ‡Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States.
Leigh Ann
LA
Graham
Oak Ridge Institute for Science and Education Fellow, ‡Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States.
Thomas P
TP
Mathews
Oak Ridge Institute for Science and Education Fellow, ‡Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States.
Darryl
D
Johnson
Oak Ridge Institute for Science and Education Fellow, ‡Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States.
Jerry D
JD
Thomas
Oak Ridge Institute for Science and Education Fellow, ‡Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States.
James L
JL
Pirkle
Oak Ridge Institute for Science and Education Fellow, ‡Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States.
Rudolph C
RC
Johnson
D000818:Animals; D003521:Cyclopropanes / Q000633:toxicity*; D004781:Environmental Exposure; D005998:Glycine / Q000031:analogs & derivatives* / Q000633:toxicity; D006801:Humans; D007005:Hypoglycins / Q000633:toxicity*; D051381:Rats; D032127:Sapindus / Q000737:chemistry*
D003521:Cyclopropanes; D007005:Hypoglycins; C041757:hypoglycin; C059830:methylenecyclopropylglycine; D005998:Glycine