Enzymatic epimerization of monoterpene indole alkaloids in kratom.

ABSTRACT: Monoterpene indole alkaloids (MIAs) are a large, structurally diverse class of bioactive natural products. These compounds are biosynthetically derived from a stereoselective Pictet-Spengler condensation that generates a tetrahydro-β-carboline scaffold characterized by a 3S stereocenter. However, a subset of MIAs contains a noncanonical 3R stereocenter. Here we report the basis for 3R-MIA biosynthesis in Mitragyna speciosa (kratom). We discover the presence of the iminium species (20S)-3-dehydrocorynantheidine, which supports isomerization of 3S to 3R via oxidation and stereoselective reduction downstream of the initial Pictet-Spengler condensation. Isotopologue feeding experiments identify the sites for downstream MIA pathway biosynthesis as well as the oxidase/reductase pair that catalyz

SUBMITTER: McDonald A 

PROVIDER: S-EPMC12441186 | biostudies-literature | 2026 Feb

REPOSITORIES: biostudies-literature