Plagranline A, a Novel beta-carboline and the First Alkaloid Isolated from Platycodon grandiflorus

A novel beta-carboline, namely Plagranline A (1), and a known alkaloid (2) were isolated from the roots of Platycodon grandiflorus. Their structure was elucidated using a combination of spectroscopic analyses and computational chemistry, including electronic circular dichroism (ECD) and optical rotatory dispersion (ORD). Alkaloids 1 and 2 exhibited moderate inhibitory effects against NO production. Interestingly, 1 and 2 are the first alkaloid constituents reported from the plant P. grandifloras.