Two new pyrrolizidine alkaloids from Crotalaria albida

Abstract Two new pyrrolizidine alkaloids, namely, neocroalbidine and neocroalbidinone, were isolated from the herbs of Crotalaria albida . Their structures were established using a combination of NMR spectroscopy and mass spectrometry techniques. The absolute stereochemistry of the two alkaloids presented herein was determined by single-crystal X-ray diffraction analysis.