Three new alkaloids from the roots of Peganum harmala

Phytochemical investigation of the roots of Peganum harmala resulted in the isolation and characterization of 10 alkaloids, including three new ones (1, 2b, and 3) and seven known ones (2a, 4 - 6, 7a/7b, and 8). Their structures were elucidated by spectroscopic data and quantum mechanical calculations, revealing that these compounds primarily consist of quinazoline-type alkaloids, with one pteridine analogue (4) also identified. Especially, 1 was the first 2-hydroxyl vasicine-type quinazoline, 2b and 3 were two new enantiomers, and 4 was identified for the first time in the genus Peganum. Selected isolates (6 - 8) exhibited pronounced selectivity against the A549 cell line.