In this study, we prepared
essential oil (EO) from waste wood chips made from used sake barrels (USBs) of Japanese cedar (i.e., EO-USB) by
steam distillation. We found that EO-USB and three commercially purchased EOs derived from xylem tissue of Japanese woods, such as Japanese cedar (Cryptomeria japonica), Japanese cypress (Chamaecyparis obtusa) and false arborvitae (Thujopsis dolabrata), suppressed fungal growth activity against Trichophyton rubrum, which is the cause of
tinea disease. The magnitude of the suppressive effects of the EOs ranked as follows: T. dolabrata > USB = C. japonica > C. obtusa. These EOs also inhibited the activity of
DNA polymerase in an extract from T. rubrum mycelia with the following ranking: T. dolabrata > USB = C. japonica > C. obtusa. In addition, 50 µg/ml of EO-USB showed antifungal properties, killing T. rubrum mycelia at 27-42˚C in 20 min. By gas chromatography/mass spectrometry analysis, the main
sesquiterpenes in EO-USB were δ-cadinene (25.94%) and epi-
cubenol (11.55%), and the composition of EO-USB was approximately the same as that of EO-C. japonica. Three prepared
sesquiterpenes, δ-cadinene, epi-
cubenol and β-eudesmol, inhibited the fungal growth and
DNA polymerase activities of T. rubrum, and epi-
cubenol showed the strongest inhibition among the compounds tested. These
sesquiterpenes had no inhibitory effects on the activities of other
DNA metabolic
enzymes, such as
DNA topoisomerase II,
IMP dehydrogenase,
polynucleotide kinase and
deoxyribonuclease from T. rubrum. Taken together, these results suggest that EO-USB containing epi-
cubenol may be useful for its anti-
tinea disease properties, which are based on
DNA polymerase inhibition.