Ca 2+ -Signal Transduction Inhibitors, Kujiol A and Kujigamberol B, Isolated from Kuji Amber Using a Mutant Yeast

A podocarpatriene and a labdatriene derivative, named kujiol A [13-methyl-8,11,13-podocarpatrien-19-ol (1)] and kujigamberol B [15,20-dinor-5,7,9-labdatrien-13-ol (2)], respectively, were isolated from Kuji amber through detection with the aid of their growth-restoring activity against a mutant yeast strain ( zds1Δ erg3Δ pdr1Δ pdr3Δ), which is known to be hypersensitive with respect to Ca -signal transduction. The structures were elucidated by spectroscopic data analysis. Compounds 1 and 2 are rare organic compounds from Late Cretaceous amber, and the mutant yeast used seems useful for elucidating a variety of new compounds from Kuji amber specimens, produced before the K-Pg boundary.