Kynapcin-28

Two new benzofurans, 5,6-dihydroxybenzofuran-2,3-dicarboxylic acid dimethyl ester (kynapcin-13) and 5,6,5',6'-tetrahydroxy[3,3']bibenzofuranyl-2,2'-dicarboxylic acid 2'-methyl ester (kynapcin-28) were isolated from Polyozellus multiplex, and shown to non-competitively inhibit prolyl endopeptidase (PEP), with the IC50 values of 76.80 and 0.98 microM, respectively. Kynapcin-13 and -28 were less inhibitory to other serine proteases such as chymotrypsin, trypsin, and elastase.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is highly pathogenic to humans and has created health care threats worldwide. This urgent situation has focused the researchers worldwide towards the development of novel vaccine or small molecule therapeutics for SARS-CoV-2. Although several vaccines have already been discovered and are in use for the masses, no therapeutic medication has yet been approved by FDA for the treatment of COVID-19. Keeping this in view, in the present study, we have identified promising hits against the main protease (Mpro) of SARS-CoV-2 from edible mushrooms. Structure-based virtual screening (VS) of 2433 compounds derived from mushrooms was performed with Mpro protein (6LU7). Four promising hits, namely, Kynapcin-12 (M_78), Kynapcin-28 (M_82), Kynapcin-24 (M_83), and Neonambiterphenyls-A (M_366) were identified based on the result of docking, Lipinski's rule, 100 ns molecular dynamics (MD) simulation and MM/PBSA binding free energy calculations. Finally, the inhibitory properties of these hits were compared with three known inhibitors, baicalein (1), baicalin (2), and biflavonoid (3). Data indicated that M_78, M_82 and M_83 compounds present in edible mushroom Polyozellus multiplex were potent inhibitors of Mproprotein (6LU7). It could be concluded that edible mushroom Polyozellus multiplex has potential activity against SARS-CoV-2 infection and identified molecules could be further explored as therapeutic inhibitors against SARS-CoV-2.