Microbial Transformation of a Mixture of Argentatin A and Incanilin

Abstract

The biotransformation of a mixture of argentatin A (20%) 1 and incanilin (80%) 2 by Gibberella suabinetti ATCC 20193 and Septomyxa affinis ATCC 6737 demonstrated the conversion of incanilin to 16beta-hydroxylanosta-2, 8, 23-triene, while argentatin A did not react. The acetate of this triterpenoid mixture was biotransformed by Septomyxa affinis ATCC 6737 to give five metabolites. Argentatin A acetate was transformed to 3beta, 16beta,30-trihydroxycycloart-20, 24-diene, 20R, 24R-epoxy-16beta, 25-dihydroxy-3, 4-seco-cycloart-4(28)-en-3-oic acid acetate and 20R, 24R-epoxy-16beta, 25-dihydroxy-3, 4-seco-cycloart-4(28)-en-3-oic acid. Incanilin acetate was converted to 16beta-hydroxylanosta-2, 8, 23-triene and 20R, 24R-epoxy-16beta, 25-dihydroxy-3, 4-seco-lanost-1, 4(28), 8-trien-3-oic acid acetate. The structural elucidations of these metabolites were achieved by different spectroscopic methods.