Antifungal properties of terpenoids in P icea abies against H eterobasidion parviporum

The antifungal properties of 14 major oleoresin‐constitutive terpenoids of N orway spruce ( P icea abies ) against H eterobasidion parviporum were evaluated in vitro at three gradient concentrations, 0.1, 0.2 and 0.4 μ mol/cm 2 , on potato dextrose agar medium. Eight monoterpene hydrocarbons (+)‐ and (−)‐α‐pinene, (−)‐β‐pinene, (+)‐3‐carene, myrcene, (+)‐ and (−)‐limonene, terpinolene; four oxygenated monoterpenes α‐terpineol, terpinen‐4‐ol, 1,8‐cineole, bornyl acetate; and two resin acids abietic acid and dehydroabietic acid were selected. Abietic and dehydroabietic acids showed the highest antifungal activities at all concentrations. Among oxygenated monoterpenes, bornyl acetate and α‐terpineol showed antifungal activity at the highest concentration. Among monoterpene hydrocarbons, (+)‐α‐pinene showed similar activity to terpinen‐4‐ol and 1,8‐cineole at the highest concentration; however, it was lower than α‐terpineol and bornyl acetate. Other monoterpene hydrocarbons inhibited mycelial growth by