The global coronavirus disease 2019 (COVID-19) pandemic originating from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has exerted profound damage to millions of lives. Baicalein is a flavonoid that has gotten a lot of attention as a possible SARS-CoV-2 main protease (Mpro) inhibitor because it can fight off many different viruses. We prepared and screened three sets of databases, each containing 2563 baicalein analogues, against Mpro using molecular docking simulation. The data showed that several baicalein analogues exhibited stable binding energies relative to standard baicalein, indicating that they have some selectivity against Mpro. The binding properties of the top three stable analogues from each database were further analyzed with respect to their binding properties, such as binding mode, binding energy, and binding interaction of putative stable ligand confirmations at the target binding site region.
Natural products possess a significant role in anticancer therapy and many currently-used anticancer drugs are of natural origin. Cerberin (CR), a cardenolide isolated from the fruit kernel of Cerbera odollam, was found to potently inhibit cancer cell growth (GI50 values 60% bioavailability and rapid absorption; doses of 1-10 mg/kg CR were predicted to maintain efficacious unbound plasma concentrations (>GI50 value). CR's potent and selective anti-tumour activity, and its targeting of key signalling mechanisms pertinent to tumourigenesis support further preclinical evaluation of this cardiac glycoside.
Seven new tropane alkaloids, including five monomeric (1-5), one dimeric (6), and one trimeric (7) 3α-nortropane ester, along with two known monomeric nortropane alkaloids (8 and 9), were isolated from the leaves and bark of Pellacalyx saccardianus. Their structures, including the absolute configuration of the enantiomeric pair of (±)-6, were elucidated by comprehensive spectroscopic analyses. Alkaloids 6 and 7 showed cytotoxicity toward human pancreatic cancer cell lines (AsPC-1, BxPC3, PANC-1, and SW1990). Alkaloids 1, 4, and 9 induced a smooth muscle relaxation effect comparable to that of atropine (Emax 106.1 ± 7.5%, 97.0 ± 5.2%, 100.9 ± 1.4%, 111.7 ± 1.7%, respectively) on isolated rat tracheal rings.