Nitro compounds in Astragalus species from Iran

Leaflets of 460 specimens including 440 species of Astragalus from the Herbarium of the Research Institute of Forests and Rangelands, Tehran, Iran, were analysed for toxic aliphatic nitro compounds. The catabolites of nitro compounds found in species of Astragalus, 3-nitro-1-propanol and 3-nitropropionic acid, are specially toxic to cattle and sheep. Nitro compounds in concentration of 4-25 mg NO2/g of plant, were detected in 37 of 440 (8.4%) species. There is a chemotaxonomic relationship among nitro-bearing species of Astragalus and nitro compounds could be used to predict the presence or absence of these compounds in other taxa, relative concentrations and the probable toxicity of the plant to livestock. The occurrence of nitro-toxins in 16 species of Astragalus is reported for the first time. (C) 1999 Elsevier Science Ltd. All rights reserved.