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The widespread nature of several viruses is greatly credited to their rapidly altering RNA genomes that enable the infection to persist despite challenges presented by host cells. Within the RNA genome of infections is RNA-dependent RNA polymerase (RdRp), which is an essential enzyme that helps in RNA synthesis by catalysing the RNA template-dependent development of phosphodiester bonds. Therefore, RdRp is an important therapeutic target in RNA virus-caused diseases, including SARS-CoV-2. In this review, we describe the promising RdRp inhibitors that have been launched or are currently in clinical studies for the treatment of RNA virus infections. Structurally, nucleoside inhibitors (NIs) bind to the RdRp protein at the enzyme active site, and nonnucleoside inhibitors (NNIs) bind to the RdRp protein at allosteric sites. By reviewing these inhibitors, more precise guidelines for the development of more promising anti-RNA virus drugs should be set, and due to the current health emergency, they will eventually be used for COVID-19 treatment., Graphical abstract Image 1, Highlights • This article provides an overview of RdRp inhibitors that have been launched or are in clinical studies for the treatment of RNA virus infections, including COVID-19. • Nucleoside inhibitors (NIs) exhibit broad-spectrum antiviral activity but pose a more serious toxicity risk than non-nucleoside inhibitors (NNIs) because high dosages of NIs result in accumulation in plasma. • Structurally diverse NNIs are endowed with high potential activities but tend to induce drug resistance due to the RdRp allosteric site.

Bioactive film from sturgeon skin gelatine incorporated with esculine at various concentrations (0.3%, 0.6% and 0.9% w/v) was developed. The physical, mechanical and antioxidant properties of esculine sturgeon gelatine biocomposite films were investigated. The results indicated that the incorporation of esculine into gelatine films significantly increased the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging activity and reducing power in a concentration-dependent manner (p 0.05). Water vapour permeability (WVP) and solubility of esculine-containing films decreased as the amount of esculine increased (p

Fourteen bergenin/cinnamic acid hybrids were synthesized, characterized and evaluated for their antitumour activity both in vitro and in vivo. The most potent compound, 5c, arrested HepG2 cells (IC50 = 4.23 ± 0.79 μM) in the G2/M phase and induced cellular apoptosis. Moreover, compound 5c was also found to suppress the tumour growth in Heps xenograft-bearing mice with low toxicity. In the mechanistic study, 5c administration ignited a mitochondria-mediated apoptosis pathway of HepG2 cell death. Furthermore, 5c activated Akt-dependent pathways and further decreased the expression of the Bcl-2 family of proteins. The downstream mitochondrial p53 translocation was also significantly activated, accompanied by an increase of the caspase-9, caspase-3 activation. These data imply that bergenin/cinnamic acid hybrids could serve as novel Akt/Bcl-2 inhibitors for further preclinical studies.