Novel ent-Beyeran-19-oic Acids from Biotransformations of Isosteviol Metabolites by Mortierella isabellina

Abstract

Biotransformations of ent-16β-hydroxybeyeran-19-oic acid (1) by Mortierella isabellina produced hydroxylated metabolites. The isolated metabolites included three new compounds, ent-14β,16β-dihydroxybeyeran-19-oic acid (3), ent-12β-hydroxy-16-oxobeyeran-19-oic acid (4), and ent-7α,12β-dihydroxy-16-oxobeyeran-19-oic acid (5), and one known compound, ent-7α,16β-dihydroxybeyeran-19-oic acid (2). The structural elucidation was achieved by detailed analysis of LC-MS chromatograms, and MS and NMR spectroscopic data. In this study, M. isabellina hydroxylated the basic skeleton beyeran-19-oic acid at the 7β-, 12α-, and 14α-positions, and oxidized the skeleton at the 16-position. All compounds were evaluated with the cell viability assay. The results of the bioassay indicated that MTT formazan exocytosis occurs upon treatment of the cells with 1.

ent-16β-Hydroxybeyeran-19-oic acid - Mortierella isabellina - microbial biotransformations - hydroxylation - stevioside - isoteviol - MTT formazan exocytosis

References

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