Production of a new terpenoid from biotransformation of (-)-isolongifolanol by Aspergillus niger and suppression of SOS-inducing activity

The stereoselective oxidation of (-)-isolongifolanol (1) with a longifolene skeleton by Aspergillus niger (NBRC 4414) as a biocatalyst and suppressive effect on umuC gene expression by chemical mutagens furylfuramid and AFB1 of the SOS response in Salmonella typhimurium TA1535/pSK1002 were investigated. Compound 1 was converted to a new terpenoid, (-)-(2S,8R)-8,12-dihydroxy-isolongifolanol (2). Its structure was determined by NMR, IR, specific rotation and mass spectrometry. The metabolites suppressed the SOS-inducing activity of furylfuramid and AFB(1) in the umu test. Compound 1 suppressed 51% of the SOS-inducing activity against furylfuramid at <1.0 mM. Compound 2 suppressed 15% and 24% of the SOS-inducing activity against furylfuramid and AFB1 at <1.0 mM respectively.