This study aimed to screen the anticancer and antioxidant potential and antimicrobial activity of methanol, petroleum ether, chloroform, ethyl acetate, butanol of Euphorbia hirta Linn. extracts (EH-Me, EH-PE, EH-Ch, EH-EA and EH-Bu, respectively). The results of 2,2-diphenyl-1-pycrylhydrazyl (DPPH) radical scavenging assay and lipid peroxidation inhibition assay showed that EH-EA was the strongest antioxidant (IC50 = 10.33 ± 0.01 µg/mL; IC50 = 1.48 ± 0.12 µg/mL, respectively) compared to all other extracts. In the antimicrobial activity of the extracts against eight strains of Gram-positive and Gram-negative bacteria using the agar disc diffusion method, we found the EH-EA to be the best antimicrobial agent. Anticancer activities of those extracts were examined by sulforhodamine B (SRB) in vitro cytotoxicity assay on two cancer cell lines, including lung cancer cells NCI-H460 and liver cancer cells Hep G2. EH-EA at concentration of 100 μg/mL has significant inhibitory activity the growth of lung cancer cells NCI-H460 and liver cancer cells Hep G2 compared to all other extracts. Our results suggest that E. hirta Linn. extracts possess significant biological activities, including antimicrobial, antioxidant, and moderate anticancer properties. Our results show that this plant could be a good source for natural antioxidants and a possible pharmaceutical supplement. Among five analyzed extracts, EH-EA extract has the strongest activities, and should be used to determine phytochemicals and mechanisms of these activities.

Coptis chinensis has been long used as the potential herbal remedy for the treatment of influenza A infection. The six isoquinolone alkaloids extracted from C. chinensis rhizomes are reported to have good inhibition activity on neuraminidase (NA) of Clostridium perfringens, A/H1N1/1918, and recombinant NA-1; however, the study of the effect of these candidates on other NAs of threatening influenza A causing pandemic and seasonal flu recently has not considered yet. The purpose of this study is to investigate the interaction between these compounds and NAs of different wild and mutant subtypes of influenza A. This process involved the molecular docking of 3D structures of those compounds (ligand) into target proteins NA of A/H1N1/1918, A/H1N1/2009pdm, H3N2/2010 wild type, H3N2/2010 D151G mutant, H5N1 wild type, and H5N1 H274Y mutant. Then, the Protein-Ligand Interaction Profiler (PLIP) was utilized to demonstrate the bond formed between the ligand and the binding pocket of receptors of interest. The results showed that six candidates including palmatine, berberine, jatrorrhizine, epiberberine, columbamine, and coptisine have a higher affinity to all six selected proteins than commercial drugs such as oseltamivir, zanamivir, and natural binding ligand sialic acid. The results could be explained via the 2D picture, which showed the hydrophobic interaction and hydrogen bonding forming between the oxygen molecules of the ligand with the free residue of proteins.

Influenza A has caused several deadly pandemics throughout human history. The virus is often resistant to developed treatments because of its genetic drift or shift property. Broad-spectrum antibodies show a promising potential to overcome the resistance of influenza viruses. In silico studies on broad-reactive antibodies and their interactions with hemagglutinins might shed light on the rational design of a universal vaccine. In this study, 11 broad-spectrum antibodies (or antigen-binding fragments) and 14 hemagglutinins of H3N2 and H5N1 strains were docked and analyzed to provide information about the construction of the scaffold for using universal antibodies against the influenza A virus. Antigen-binding fragments that have high number of appearances in the top 3 within each H3 and H5 subtypes were chosen for protein-protein interaction analysis. The results show that while the hydrogen bond is important for Ab/Fab binding to H3, the H5-Ab/Fab system may need cation-pi interaction for a strong interaction.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the confirmed viral pathogen of COVID-19, a pandemic originated from Wuhan, China at the end of 2019. Since then, SARS-CoV-2 has rapidly spread across the globe with over 8 million confirmed cases and more than 430.000 deaths worldwide as of mid-June 2020. Similar to other strains of coronavirus, the envelope of SARS-CoV-2 comprises of three structural proteins: S protein (spike), E protein (envelope) and M glycoprotein (membrane). SARS-CoV-2 capsids are spherical or pleomorphic. Each capsid contains a positive-sense single-stranded RNA (+ssRNA-Class IV-Baltimore) associated with nucleoprotein N. The viral RNA genome is approximately 30 kb in length and contains 14 open reading frames (ORFs). The binding affinity of the viral S protein to the ACE2 (angiotensin-converting enzyme 2) receptor facilitates the attachment of SARS-CoV-2 to human epithelial cells. Upon binding, SARS-CoV-2 spike protein is cleaved and activated by TMPRSS2 (transmembrane protease, serine 2) or by cathepsin L at the cleavage site S2', and also by furin at the cleavage site S1/S2. The furin cleavage motif RR_R is a notable feature, firstly found in SARS-CoV-2 S protein, which may increase virus transmission rate. This feature and many others might result from several evolution events in SARS-CoV-2 genome. These events could occur when coronaviruses, including SARS-CoV-2, spread from one host to another. They can be causative to high virulence and transmission rate of future coronavirus strains, which may require the development of newer vaccine generations. To understand of SARS-CoV-2’s structure, infection mechanism, diagnosis, treatment, and vaccine development strategies, a review of current literature is of highly importance to disease control in Vietnam.