Flavonoids, alkaloids from the seeds of Crotalaria pallida and their cytotoxicity and anti-inflammatory activities.

Three flavonoids, cropalliflavones A-C, including two homoisoflavonoids with rare skeletons; three previously undescribed alkaloids, usaramine-N-oxide and cropallins A-B; and sixteen known compounds, were isolated from the seeds of Crotalaria pallida Ait. The absolute configurations of cropalliflavone A and usaramine-N-oxide were established by an ECD calculation and X-ray crystallography, respectively. Additionally, cropalliflavone B showed anti-proliferative activity against the MCF-7 cell line with an IC50 value of 6.77 μM, and cropalliflavone C showed anti-inflammatory activity, with an IC50 value of 16.07 μM.