Structure Elucidation of Novel Compounds Bearing a Spiro-β-lactone-γ-lactam Ring Produced by Brevibacillus sp. Isolated from Dung Beetles Excretion

Abstract

A Brevibacillus strain PTH23, which displayed inhibitory activity against bacteria, was isolated from dung beetles (Onthophagus lenzii) excretion. LC/MS analysis of the culture revealed that this bacterial strain produces three new spiro-β-lactone-γ-lactams, brevicillaenes A-C (1-3). The planar structures of these compounds were elucidated by spectroscopic analysis of 1D and 2D NMR, MS, and UV data. The absolute configurations of brevicillaenes A-C (1-3) were determined by the combination of chemical derivatizations, J-based configuration analysis, and quantum mechanics-based computational analysis.