Two New Anti-SARS-CoV-2 Naphthoquinones from Cigar-Tobacco-Derived Endophytic Fusarium oxysporum

In this study, two new naphthoquinones, 6-isopropyl-7-methoxy-2-(2-oxopropyl)naphthalene-1,4-dione (1) and 7-hydroxy-6-isopropyl-2-(2-oxopropyl)naphthalene-1,4-dione (2), together with five known new naphthoquinones (3–7) were isolated from the cigar-tobacco-derived endophytic fungus Fusarium oxysporum. Their structures were determined by means of HR-ESI-MS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1 and 2 were tested for their anti-SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) activity. The results showed that compound 1 exhibited potential anti-SARS-CoV-2 activity with IC50 of 18.2 μM for the Delta strain and 24.6 μM for Omicron BA.1 strain, compound 2 also showed potential anti-SARS-CoV-2 activity with IC50 of 14.6 μM for the Delta strain and 18.0 μM for Omicron BA.1 strain, respectively.