COMPOSITION OF SICKLEPOD (CASSIA-OBTUSIFOLIA) TOXIC WEED SEEDS

Bulk commercial grain, such as soybeans and wheat, may be contaminated with nongrain impurities, including sicklepod seeds (Cassia obtusifolia), that coexist with the crop to be harvested. The present study was undertaken to determine the content of the major anthraquinone constituents of sicklepod seeds, as well as carbohydrate, fat, mineral, and amino acid (protein) content. Thin-layer chromatography, ultraviolet spectroscopy, and combined gas chromatography-mass spectrometry revealed the presence of known and unknown anthroquinone derivatives. Known compounds include chrysophanic acid, physcion, obtusofolin, emodin, questin, obtusin, chrysoobtusin, aurantioobtusin, and others. Rapid thin-layer chromatographic procedures were developed to screen sicklepod seeds for anthraquinone derivatives. These procedures also revealed the presence of beta-sitosterol and of flavonids, UV-quenching compounds, and fluorescent blue compounds of unknown structure. The described methodology should facilitate screening large numbers of samples both in the laboratory and under practical field conditions. The data provide a rational basis for relating seed composition to reported muscle-damaging and other toxicological effects of sicklepod, for assessing the significance of low levels of the seeds in diets of foot-producing animals and humans, and for setting grain standards.