Cinanserin (hydrochloride)

Cinanserin hydrochloride (SQ 10643) is a potent, selective and highly affinity 5-HT₂ receptor antagonist with a K_i of 41 nM. Cinanserin hydrochloride has a much higher binding affinity for the 5-HT₂ than for the 5-HT₁ receptor (K_i of 3500 nM). Cinanserin is also an inhibitor of 3C-like proteinase of severe acute respiratory syndrome coronavirus and strongly reduces virus replication in vitro^[1][2][3]. IC50 & Target:Ki: 41 nM (5-HT₂ receptor)^[3];
3C-like proteinase^[1] In Vitro:Cinanserin/Cinanserin hydrochloride have binding affinity to SARS-CoV 3CL^pro, HCoV-229E 3CL^pro, with the K_D values of 49.4 μM/78.0 μM for SARS-associated coronavirus (SARS-CoV) 3CL^pro and 18.2 μM/36.6 μM for human coronavirus 229E (HCoV-229E) 3CL^pro[1].
The IC₅₀ values of Cinanserin and Cinanserin hydrochloride for inhibiting the catalytic activity of SARS-CoV 3CL^pro are calculated as 4.92 μM and 5.05 μM, respectively, The corresponding IC₅₀ values for HCoV-229E 3CL^pro are 4.68 μM and 5.68 μM. None of the compounds have inhibitory activity against HRV-14 3C^pro at concentrations up to 200 μM^[1]. In Vivo:Cinanserin (5 mg/kg; intravenous injection; for 2 hours; male Wistar rats) treatment significantly reduces systemic burn edema to shamburn levels. Leukocyte-endothelial interactions are significantly reduced by administration of Cinanserin^[2].