Enhancing Structural Diversity of Lathyrane Derivatives through Biotransformation by the Marine-Derived Actinomycete Streptomyces puniceus BC-5GB.11.

Lathyrane-type diterpenes have a wide range of biological activities. Among them, euphoboetirane A ( 1 ) exerts neurogenesis-promoting activity. In order to increase the structural diversity of this type of lathyrane and explore its potential use in neurodegenerative disorders, the biotransformation of 1 by Streptomyces puniceus BC-5GB.11 has been investigated. The strain BC-5GB.11, isolated from surface sediments collected from the intertidal zone of the inner Bay of Cadiz, was identified as Streptomyces puniceus , as determined by phylogenetic analysis using 16S rRNA gene sequence. Biotransformation of 1 by BC-5GB.11 afforded five products ( 3 - 7 ), all of which were reported here for the first time. The main biotransformation pathways involved regioselective oxidation at non-activated carbons ( 3 - 5 ) and isomerization of the ∆ ^12,13 double bond ( 6 ). In addition, a cyclopropane-rearranged compound was found ( 7 ). The structures of all compounds were elucidated on the basis of extensive NMR and HRESIMS spectroscopic studies.