Inhibitory effects against SARS-COV-2 main protease of terpenic substances and selenated naphthoquinones

Clinical studies on COVID-19 patients revealed among multiple symptoms, uncontrolled production of inflammatory mediators. The current study presents the inhibitory effects of eleven terpenoid derivatives (1–11) and two naphthoquinones (12 and 13) on the main protease (Mpro) of SARS-CoV-2. All the terpenoids and compound 13 displayed weak inhibitory effects while compound 12 showed moderate inhibitory effects of Mpro with IC50 of 50.2 µM. Anti-inflammatory effects against pro-inflammatory mediators produced in LPS-induced lung injury and the cytotoxicity against Vero and THP-1 cell lines of molecules 12 and 13 were also evaluated. Molecules 12 and 13 presented promising anti-inflammatory activity by attenuating the exudation and neutrophil and leukocyte migration.