The hydroxylation of the sequiterpenoid valerianol by Mucor plumbeus

The sesquiterpenoid valerianol 2 is a constituent of valerian oil (Jommi, Krepinsky, Herout & Sorm, 1969) and it may be prepared by the oxy-mercuration of commercially available valencene 1 (Fontes Arantes, Hanson & Hitchcock, 1999). Valerianol is identical to kusenol which was obtained (Hikino, Suzuki & Takemoto, 1968) from the higher boiling fraction of camphor blue oil. More highly hydroxylated sesquiterpenoids possessing the eremophilane carbon skeleton are of interest (Fraga, 1998 and previous reports) because of their biological activity as phytoalexins (Katsui, Yagihashi & Murai, 1982) and as toxic fungal metabolites (Moreau et al., 1980). Although there is a report (Paknikar & Dhavlikar, 1975) of the bacterial conversion of valencene to dihydro-a-agarofuran, there have not been any reports (Lamare & Furstoss, 1990) on the microbiological hydroxylation of valerianol. We have therefore examined the biotransformation of valerianol and that of some derivatives by the fungus, Mucor plumbeus.