Biol. Pharm. Bull. 27(6) 899—902 (2004)

∗ To whom correspondence should be addressed. e-mail: [email protected] © 2004 Pharmaceutical Society of Japan In our previous paper, antimicrobial activity, phytogrowth-inhibitory effect, cytotoxic activity and metalloprotease inhibition have been found as biological activities of athujaplicin (Chart 1), a minor component of Thujopsis dolabrata SIEB. et ZUCC. var. hondai MAKINO. At the same time, as the yield of a-thujaplicin was too small to permit examination of various biological activities, it was also reported to be chemically synthesized. As reported already, in addition to a-thujaplicin, hinokitiol-related compounds such as 4-acetyltropolone, hinokitiol (b-thujaplicin), b-dolabrin and g-thujaplicin have also been isolated from this plant. As regards the biological activities of hinokitiol-related compounds, it has previously been reported by the authors that hinokitiol, b-dolabrin, g-thujaplicin and 4-acetyltropolone have antimicrobial activity, metalloprotease inhibition, cytotoxic effect, phytogrowth-inhibitory activity and an insecticidal effect. However, no work has yet been done on other biological tests, except for the abovementioned activities of a-thujaplicin, because of its low yield. In this work, to determine the range of biological activity of hinokitiol-related compounds, the antifungal activity on plant-pathogenic fungi, antibacterial effect on Legionella species and acaricidal and insecticidal activities against Dermatophagoides farinae and Reticulitermes speratus of a-thujaplicin were investigated. The cytotoxic effect on the murine P388 lymphocytic leukemia cell line in vitro of a-thujaplicin was also examined.