New Metabolites from the South China Sea Sponge Diacarnus megaspinorhabdosa

Abstract

Chemical investigation on CH₂Cl₂ extract of the marine sponge Diacarnus megaspinorhabdosa resulted in the isolation of two new farnesylacetone derivatives 1–2, a new γ-lactone 3, a known dinorditerpenone 4 and four known norsesterterpene peroxides 5–8. Their structures were elucidated by using one and two dimensional (1D and 2D)-NMR, high resolution-electrospray ionization (HR-ESI)-MS, and comparison with the literature. Compounds 1 and 2 were cis/trans-olefinic isomers and determined through nuclear Overhauser effect spectroscopy (NOESY) experiment. The absolute configuration of 3 was established by comparison of circular dichroism (CD) data with known lactones. The cytotoxic activities of the compounds were evaluated against five cancer cell lines, and compound 3 showed moderate cytotoxicity activities against cancer cell lines HeLa, H446, NCI-H460, SGC-7901 and MCF-7, with IC₅₀ values in the range of 18.5 to 47.1 µM.

Graphical Abstract