Chemical properties of the natural neurotoxin of Lathyrus sativus 3-N-oxalyl-2,3-diamino-propanoic acid (beta-ODAP), its nontoxic 2-N-oxalyl isomer, and its hydrolysis product 2,3-diamino-propanoic acid (DAPRO) by 1H- and 13C-NMR spectroscopy

Hydrophilic interaction liquid chromatography with tandem mass spectrometry for the determination of underivatized dencichine (beta-N-oxalyl-L-alpha,beta-diaminopropionic acid) in Panax medicinal plant species

Dencichine (beta-N-oxalyl-L-alpha,beta-diaminopropionic acid) is a haemostatic agent present in important Chinese medicinal herbs such as Panax notoginseng, as well as other Panax species. It is also a reported neurotoxic agent found in Lathyrus sativus (grass pea seed). A selective analytical method incorporating hydrophilic interaction chromatography with positive electrospray ionization tandem mass spectrometry (HILIC/ESI-MS/MS), for the analysis of dencichine in Panax plant species, was developed. Using multiple reaction monitoring (MRM) mode, underivatized dencichine, a small and highly polar compound, was selectively detected and quantified. The contents of dencichine in raw and steamed Panax notoginseng roots, 11 pairs of raw and steamed P. notoginseng herbal products, Panax ginseng roots, and Panax quinquefolium roots, were analyzed and compared. Optimal sensitivity of 0.3 ppm (detection limit) and 1.5 ppm (quantification limit) was achieved. The method was rapid (< or =5 min), with the HILIC peak eluting at about 1 min. Steamed P. notoginseng samples were found to contain less dencichine than the corresponding raw samples, and there were also differences among the three Panax species; raw P. ginseng and P. quinquefolium contained less dencichine than the raw P. notoginseng species. This rapid and specific method may be applied to the quantification of dencichine in complex medicinal plants and their products.

In vivo metabolism of beta-N-oxalyl-L-alpha,beta-diaminopropionic acid: the Lathyrus sativus neurotoxin in experimental animals

A comparative study of the metabolism of 1,2,3 (14)C-ODAP and 4,5 (14)C-ODAP in mice, rats and chicks has been carried out. Following oral administration of 1,2,3 (14)C-ODAP to either black or white mice, nearly 16% of the radioactivity appeared in the expired CO2 within 8 h, while in the rat only 3% of it appeared and in chicks it was less than 2%. No 14CO2 appeared in the expired air in mice given 4,5 (14)C-ODAP. Electrophoregrams of the spot urine samples from the animals given 1,2,3 (14)C-ODAP showed the presence of one radioactive metabolite (metabolite-1) in addition to ODAP. While the urine from rats and mice given 4,5 (14)C-ODAP indicated the presence of metabolite-1 as well as 14C-oxalate, in chicks, however, no 14C-oxalate was present and only metabolite-1 could be detected. The results indicate that ODAP can to some extent undergo oxidation in vivo in mice (and to a lesser extent in rats) leading to the formation of CO2 and oxalate and a similar pathway might be more prominent in humans leading to a near complete oxidation of ODAP.