Hypoglycin A in Acer genus plants.

Hypoglycin A (HGA) is an amino acid occuring in the Sapindaceae family. Ingestion of certain Acer genus plants belonging to this family has been connected with atypical myopathy (AM) or seasonal pasture myopathy (SPM). To date, all cases of AM/SPM have been associated with sycamore (Acer pseudoplatanus) and boxelder maple (Acer negundo). The aim of this work was to determine and compare HGA in sycamore, boxelder and silver maple (Acer saccharinum), the trees known for HGA content, whose occurence is quite common in the Czech Republic. In sycamore and boxelder maple the effect of location, weather condition and sampling season was evaluated. The other aim was screening for presence of HGA in 12 other species of Acer genus which are grown as ornamental trees in Europe. The determination of HGA was conducted using ultra - high performance liquid chromatography - tandem mass spectrometry (LC/MS). HGA was detected in all samples of sycamore, boxelder and silver maple except for eight leave samples of boxelder maple. In the case of sycamore maple, the highest concentrations of HGA (median) were found in seedlings (770 mg/kg) followed by samaras (130 mg/kg) and by leaves (48 mg/kg) and inflorescences (24 mg/kg). In boxelder maple, significantly higher concentrations of HGA (median) were found in seedlings (550 mg/kg) compared with samaras (45 mg/kg), leaves (14 mg/kg) and inflorescences (24 mg/kg). According to the results the seedlings could pose a significant risk of poisoning, although other factors such as accessibility and palatability of other parts, especially samaras, should be considered. No significant differences of HGA concentrations in silver maple (56 mg/kg) were found between samaras, leaves and inflorescences. HGA was also identified in sugar maple (Acer saccharum), Japanese maple (Acer palmatum), trident maple (Acer buergerianum), paperbark maple (Acer griseum) and Himalayan maple (Acer oblongum). Although silver maple and other ornamental maples have not been reported to cause AM/SPM, the possibility of intoxication in animals can not be excluded.