Isolation and structures of indoloditerpenes, possible biosynthetic intermediates to the tremorgenic mycotoxin, paxilline, from Emericella striata

Together with paspaline (7), two indoloditerpenes designated dehydroxypaxilline (5), C27H23NO3, and emindole SB (6), C28H39NO, were isolated from the mycelium of Emericella striata. The structures of dehydroxypaxilline (5) and emindole SB (6) were determined on the basis of spectroscopic investigation of these compounds. It is very interesting that emindole SB (6), paspaline (7), and dehyroxypaxilline (5) were isolated from the same fungus, E. striata, on consideration of the biogenesis of paxilline (1) which had also been isolated from the same fungus as one of the main components.