Oxidation and glucose conjugation of synthetic abietane diterpenes by Cunninghamella sp. II. Novel routes to the family of diterpenes from Tripterygium wilfordii.

Abietane diterpenes from the perennial herb, Tripterygium wilfordii, have been shown to possess antiinflammatory activity. To obtain novel analogues of these diterpenes, two synthetic diterpenes, isotriptophenolide [1] (12,19-dihydroxy-18(4-->3)abeo-abieta-3,8,11,13-tetraen++ +-18-oic acid lactone) and triptophenolide [3] (14,19-dihydroxy-18(4-->3)abeo-abieta-3,8,11,13-tetraen++ +-18-oic acid lactone) were incubated with the filamentous fungi, Cunningbamella echinulata and C. elegans. The structures of the metabolites were then determined by spectroscopic methods. Both species of Cunninghamella glucosidated 1 at C-12 to yield 2. When incubated with triptophenolide [3], C. elegans and C. echinulata produced hydroxylated [6] and glucosylated [7] metabolites. In addition to B-ring hydroxylation, aromatic hydroxylation at ring C was also observed. Both species hydroxylated 3 to yield the dihydrodiol 4 which autooxidized to the quinone 5.