Antifungal activity of hinokitiol-related compounds on wood-rotting fungi and their insecticidal activities

Hinokitiol (beta-thujaplicin), beta-dolabrin and gamma-thujaplicin isolated from Thujopsis dolobrata SIEB, et ZUCC, var hondai MAE;INO showed antifung al activities against all of the wood-rotting fungi examined. The antifunga l activity of three compounds on Daedalea dickinsii IFO-4979 was especially strong, their minimum inhibitory concentration (MIC) values being 0.2 mu g /ml. Their antifungal activities on D, dickinsii IFO-4979 were as high as t hat of amphotericin B used as a positive control. Three compounds had stron g insecticidal activities on Tyrophagus putrescentiae [50%-lethal concentra tion (LC50: g/m(2)) 0.25 in hinokitiol, 0.02 in beta-dolabrin and gamma-thu japlicin]. Their insecticidal activities were higher than that of N,N-dieth yl-m-toluamide (DEET, LC50: 1.46 g/m(2)) used as a positive control. Three compounds also showed strong insecticidal activity on Coptotermes formosanu s [LC,50 (g/m(2)) 0.07 in hinokitiol, 0.05 in beta-dolabrin and gamma-thuja plicin], although their insecticidal activities were much lower than that o f commercial chloropyrifos (LC,50: 0.00016 g/m(2)).