Identification of potential Indonesian marine invertebrate bioactive compounds as TMPRSS2 and SARS-CoV-2 Omicron spike protein inhibitors through computational screening.

The coronavirus pandemic led to the announcement of a worldwide health emergency. The SARS-CoV-2 Omicron variant, which swiftly spread worldwide, has fueled existing challenges. Appropriate medication is necessary to avoid severe SARS-CoV-2 disease. The human TMPRSS2 and SARS-CoV-2 Omicron spike protein, which are required for viral entry into the host phase, were identified as the target proteins through computational screening. Structure-based virtual screening; molecular docking; absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis; and molecular dynamics simulation were the methods applied for TMPRSS2 and spike protein inhibitors. Bioactive marine invertebrates from Indonesia were employed as test ligands. Camostat and nafamostat (co-crystal) were utilized as reference ligands against TMPRSS2, whereas mefloquine was used as a reference ligand against spike protein. Following a molecular docking and dynamics simulation, we found that acanthomanzamine C has remarkable effectiveness against TMPRSS2 and spike protein. Compared to camostat (-8.25 kcal/mol), nafamostat (-6.52 kcal/mol), and mefloquine (-6.34 kcal/mol), acanthomanzamine C binds to TMPRSS2 and spike protein with binding energies of -9.75 kcal/mol and -9.19 kcal/mol, respectively. Furthermore, slight variances in the MD simulation demonstrated consistent binding to TMPRSS2 and spike protein after the initial 50 ns. These results are highly valuable in the search for a treatment for SARS-CoV-2 infection.

Unique Polyhalogenated Peptides from the Marine Sponge Ircinia sp.

Two new bromopyrrole peptides, haloirciniamide A (1) and seribunamide A (2), have been isolated from an Indonesian marine sponge of the genus Ircinia collected in the Thousand Islands (Indonesia). The planar structure of both compounds was assigned on the basis of extensive 1D and 2D NMR spectroscopy and mass spectrometry. The absolute configuration of the amino acid residues in 1 and 2 was determined by the application of Marfey's method. Compound 1 is the first dibromopyrrole cyclopeptide having a chlorohistidine ring, while compound 2 is a rare peptide possessing a tribromopyrrole ring. Both compounds failed to show significant cytotoxicity against four human tumor cell lines, and neither compound was able to inhibit the enzyme topoisomerase I or impair the interaction between programmed cell death protein PD1 and its ligand, PDL1.