Biotransformation of (-)-ambrox by cell suspension cultures of Actinidia deliciosa.

Biotransformation of (-)-ambrox (1) with cell suspension cultures of Actinidia deliciosa (Kiwifruit) yielded the regio- and stereospecific oxygenated products 3-oxoambrox (2), 3beta-hydroxyambrox (3), 1alpha-hydroxyambrox (4), 3beta,6beta-dihydroxyambrox (5), 1alpha,6beta-dihydroxyambrox (6), and 1alpha,3beta-dihydroxyambrox (7). Metabolites 6 and 7 were found to be new compounds. These metabolites were structurally characterized on the basis of spectroscopic studies. The structure of compound 6 was unambiguously deduced by single-crystal X-ray diffraction techniques. Metabolites 2-7 were evaluated for in vitro inhibitory activity against the thymidine phosphorylase enzyme.