Isolation of paspaline B, an indole-diterpenoid from Penicillium paxilli

The known indole-diterpenoids paspaline and 13-desoxypaxilline were isolated from Penicillium paxilli Bainier for the first time. In addition, paspaline B, a new indole-diterpenoid, was isolated and identified as paspalin-30-al by a combination of mass spectral and 1D and 2D NMR techniques. Full assignments for the C-13 NMR chemical shifts of paspaline and paspaline B were obtained, resulting in a major revision of the published C-13 NMR chemical shifts for paspaline. The structure of paspaline B suggests that it may closely follow paspaline in the biosynthesis of the tremorgenic indole-diterpenoid paxilline.