Two novel oxetane containing lignans and a new megastigmane from and analysis of them as prospective SARS-CoV-2 inhibitors.

The chemical characterization of the extract of the aerial parts of afforded two oxetane containing lignans, paronychiarabicine A (1) and B (2), and one new megastigmane, paronychiarabicastigmane A (3), alongside a known lignan (4), eight known phenolic compounds (5-12), one known elemene sesquiterpene (13) and one steroid glycoside (14). The chemical structures of the isolated compounds were constructed based upon the HRMS, 1D, and 2D-NMR results. The absolute configurations were established NOESY experiments as well as experimental and TDDFT-calculated electronic circular dichroism (ECD).

Sarcoehrenbergilides D-F: cytotoxic cembrene diterpenoids from the soft coral .

A solvent extract of the soft coral afforded cembrene diterpenoids, sarcoehrenbergilid D-F (1-3). Chemical structures were established by modern spectroscopic techniques with absolute stereochemistries determined by circular dichroism (CD) and time-dependent density functional theory electronic CD calculations (TDDFT-ECD). Cytotoxicity activities for 1-3 were evaluated against three human cancer cell lines: lung (A549), colon (Caco-2) and liver (HepG2).