Prenylcoumarin with Rev-export inhibitory activity from Cnidii Monnieris Fructus

Prenylcoumarin osthol (1) was disclosed as the new Rev-export inhibitor from Cnidii Monnieris Fructus. Both prenyl residue and carbonyl conjugated double bond were revealed to play an important role in the biological potency of 1. By use of the fission yeast expressing the model fusion protein comprised of GST, SV40 T antigen NLS, GFP, and Rev-NES in the bioassay, the prenylcoumarin osthol (1) was disclosed as the new Rev-export inhibitor from the MeOH extract of Cnidii Monnieris Fructus. Furthermore, 1 was also found to inhibit export the genuine Rev in HeLa cells by indirect fluorescent antibody technique. By the competitive experiment using the biotinylated probe 3, osthol (1) was revealed to inhibit nuclear export of Rev through a NES non-antagonistic mode. Structure–activity relationship analysis of several analogs of 1 clarified that both prenyl side chain and double bond adjacent to the lactone carbonyl residue play an important role in the Rev-export inhibitory potency of 1.