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, -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.