Isolation of diterpenoids from sugi wood-drying byproducts and their bioactivities

Diterpenoids are the main components of the byproducts discharged from sugi wood-drying process (BWP), making BWP a source of these useful compounds. Since there is no method for purifying these compounds from BWP, we sought to develop one. In this study, seven diterpenoids compounds were isolated: abietatriene (I), phyllocladenes (II-i and II-ii; a complex of isophyllocladene and phyllocladene), abietadiene (III), sandaracopimarinal (IV), 6,7-dehydroferruginol (V), ferruginol (VI), and sandaracopimarinol (VII) using medium-pressure liquid chromatography (MPLC) and high-performance liquid chromatography (HPLC). We tested the biological activities of these diterpenoids. Compounds V and VI showed antioxidant activity in the DPPH radical scavenging method, β-carotene bleaching method, and linoleic acid method. Furthermore, compounds V–VII showed antimicrobial activity against Propionibacterium acnes , and III, VI, and VII showed antifungal activity against Trichophyton mentagrophytes and Trichophyton rubrum . These results contribute to the accumulation of knowledge on diterpenoids and will help in developing new ways of utilizing BWP, a currently unused woody biomass.