Screening for Non-Protein Amino Acids in Seeds of the Guam Cycad,Cycas circinalis, by an Improved GC-MS Method

Abstract

The non-protein amino acid, beta-N-methyl-amino-L-alanine (L-BMAA) from Cycas circinalis seeds, has been implicated as a causative agent of amyotrophic lateral sclerosis-Parkinsonism dementia complex (ALS-PDC), a disease known from Guam and other areas in the western Pacific. We analyzed C. circinalis seeds for additional free non-protein amino acids by a recently developed GC-MS method. The samples were prepared by water extraction of seed flour. The amino acids present in the extract were derivatized by N(O,S)-isobutyloxycarbonylation of the amine functional groups and then tert-butyldimethylsilylation of the carboxyl functional groups. Peaks for a total of seventeen derivatives of non-protein amino acids were detected by GC-MS. In addition to L-BMAA, four other non-protein amino acids were identified as beta-alanine, gamma-amino-butyric acid, pyroglutamic acid, and alpha-aminoadipic acid.

The putative glutamate receptor 1.1 (AtGLR1.1) functions as a regulator of carbon and nitrogen metabolism in Arabidopsis thaliana

“…Probable explanations for this finding include the possibilities that (i) Glu uptake and͞or distribution is limited in the antiAtGLR1.1 plants, or (ii) Glu is not the natural ligand and perhaps a BMAA-like molecule is the endogenous AtGLR1.1 ligand. The latter explanation is credible because BMAA is a plant-derived compound, found mainly in the cicads (28). Results from another laboratory demonstrated that the effects of an iGLR agonist are reversed only with high concentrations (10 mM) of Glu (8).…”

Analysis of neurological disease in four dimensions: insight from ALS-PDC epidemiology and animal models

“…Various amino acids able to activate subclasses of the ionotropic glutamate receptor family are also present, including b-N-oxalylamino-Lalanine (BOAA) and b-N-methylamino-L-alanine (BMAA), agonists for AMPA and NMDA receptors, respectively. A number of other compounds have also been detected in cycad, some still not well characterized [30,31]. Investigators in the 1960s seized on the toxicity of MAM, using either cycad or the isolated toxin in a series of experiments designed to demonstrate both the neuronal effects as well as the mechanisms of action.…”

Cycad Seeds and Chronic Neurologic Disease (CycasSpecies)

“…Analytical methods to detect the presence of BMAA in plant and animal tissue in the subpicomole range include gas chromatography mass spectrometry (GC/MS) 17 and reversed phase HPLC method with precolumn derivatization by 9 -fl uorenylmethyl chloroformate. 26 Based on an electrophysiology study of 29 Chamorro patients with neurodegenerative diseases, a peripheral neuropathy can occur in these patients.…”