ABSTRACT
Chemical investigation on a colonial marine tunicate, Didemnum sp. led to the isolation of a series of indole alkaloids including a new (1) and two known metabolites (2-3). Based on the spectroscopic analysis including 1D and 2D NMR along with MS spectra, the structure of 1 (16-epi-18-acetyl herdmanine D) was elucidated as a new amino acid derivative. The absolute configuration of 1 was determined by comparison of specific rotation with the known compound. The structures of compounds 2 and 3 were also identified as bromoindole containing compounds N-(6-bromo-1H-indole-3-carbonyl)-L-arginine and (6-bromo-1H-indol-3-yl) oxoacetamide, respectively, based on 1H and 13C NMR data, MS data and specific rotation value. Their pharmacological potentials as antibacterial agents and FXR antagonists were investigated, but no significant activity was found. However, the structural similarity of compound 1 to compound 4 suggested the antiinflammatory potential of compound 1.
Subject(s)
Anti-Bacterial Agents , Indole Alkaloids , UrochordataABSTRACT
Intensive chemical investigation of Korean marine sponge Spongia sp. has led to the isolation of two new scalaranes. The planar structures of the new compounds 1 and 2 were determined through 1D and 2D NMR spectral data analysis, while the relative stereochemistry of the compounds was determined based on the analysis of 1H-1H coupling constants and NOESY spectroscopic data. Compounds 1 and 2 did not display any significant biological activities on farnesoid X-activated receptor (FXR) in co-transfection assay.