Highlights Lycorine inhibited MERS-CoV, SARS-CoV, and SARS-CoV-2 infections. Lycorine directly inhibited MERS-CoV RdRp activity. Lycorine interacts with SARS-CoV-2 RdRp through hydrogen bonding. Lycorine is a non-nucleoside direct-acting antiviral against emerging coronavirus.

We evaluated the anti-inflammatory effects of SNAH in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages by performing nitric oxide (NO) assays, cytokine enzyme-linked immunosorbent assays, Western blotting, and real-time reverse transcription-polymerase chain reaction analysis. SNAH inhibited the production of NO (nitric oxide), reactive oxygen species (ROS), tumor necrosis factor (TNF)-α, and interleukin (IL)-6. Additionally, 100 μM SNAH significantly inhibited total NO and ROS inhibitory activity by 93% (p < 0.001) and 34% (p < 0.05), respectively. Protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) stimulated by LPS were also decreased by SNAH. Moreover, SNAH significantly (p < 0.001) downregulated the TNF-α, IL-6, and iNOS mRNA expression upon LPS stimulation. In addition, 3–100 µM SNAH was not cytotoxic. Docking simulations and enzyme inhibitory assays with COX-2 revealed binding scores of −6.4 kcal/mol (IC50 = 47.8 μM) with SNAH compared to −11.1 kcal/mol (IC50 = 0.45 μM) with celecoxib, a known selective COX-2 inhibitor. Our results demonstrate that SNAH exerts anti-inflammatory effects via suppression of ROS and NO by COX-2 inhibition. Thus, SNAH may be useful as a pharmacological agent for treating inflammation-related diseases.

23Coronavirus disease 2019 (COVID-19) is a new emerging human infectious disease caused by Severe Acute 24 Respiratory Syndrome Coronavirus 2 (SARS-CoV-2, also previously known as 2019-nCoV), originated in 25 Wuhan seafood and animal market, China. Since December 2019, more than 69,000 cases of COVID-19 have 26 been confirmed in China and quickly spreads to other counties. Currently, researchers put their best efforts to 27 identify effective drugs for COVID-19. The neutralizing antibody, which binds to viral capsid in a manner that 28 inhibits cellular entry of virus and uncoating of the genome, is the specific defense against viral invaders. In this 29 study, we investigate to identify neutralizing antibodies that can bind to SARS-CoV-2 Sipke (S) protein and 30 interfere with the interaction between viral S protein and a host receptor by bioinformatic methods. The 31 sequence analysis of S protein showed two major differences in the RBD region of the SARS-CoV-2 S protein 32 compared to SARS-CoV and SARS-CoV related bat viruses (btSARS-CoV). The insertion regions were close to 33 interacting residues with the human ACE2 receptor. Epitope analysis of neutralizing antibodies revealed that 34 SARS-CoV neutralizing antibodies used conformational epitopes, whereas MERS-CoV neutralizing antibodies 35 used a common linear epitope region, which contributes to form the β-sheet structure in MERS-CoV S protein 36 and deleted in SARS-CoV-2 S protein. To identify effective neutralizing antibodies for SARS-CoV-2, the 37 binding affinities of neutralizing antibodies with SARS-CoV-2 S protein were predicted and compared by 38 antibody-antigen docking simulation. The result showed that CR3022 neutralizing antibody from human may 39 have higher binding affinity with SARS-CoV-2 S protein than SARS-CoV S protein. We also found that 40 F26G19 and D12 mouse antibodies could bind to SARS-CoV S protein with high affinity. Our findings provide 41 crucial clues towards the development of antigen diagnosis, therapeutic antibody, and the vaccine against SARS-42 CoV-2. 43 44 45