Polysaccharides to Combat Viruses (COVID-19) and Microbes: New updates.

COVID-19, which is speedily distributed across the world and presents a significant challenge to public health, is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Following MERS coronavirus (MERS-CoV) and SARS, this is the third severe coronavirus outbreak in less than 20 years. To date, there are no exact agents and vaccines available for the treatment of COVID-19 that are clinically successful. Antimicrobial medications are effective in controlling infectious diseases. However, the extensive use of antibiotics makes microbes more resistant to drugs and demands novel bioactive agents' development. Polysaccharides are currently commonly used in the biomedical and pharmaceutical industries for their remarkable applications. Polysaccharides appear to have a wide range of anti-virus (anti-coronavirus) and antimicrobial applications. Polysaccharides are able to induce bacterial cell membrane disruption as they demonstrate potency in binding onto the surfaces of microbial cells. Here, the antiviral mechanisms of such polysaccharides and their success in the application of antiviral infections are reviewed. Additionally, this report provides a summary of current advancements of well-recognized polysaccharides as antimicrobial and anti-biofilm agents.

A review on triterpenoids from plant sources as potential antiviral agents

Viral infections are considered as leading a health issue globally. Numerous numbers of biologically active anti-viral agents have been identified from plants and other organisms. Particularly, terpenoids are a major component of the plant secondary metabolites and a complexity of these structures is accompanied by the potency of their biological activities. It is believed that most of the terpenoids possess the bioactivity against viral infections and cancer diseases. Hence, affected by the pressing a need elevated by the spreading of seriously life-threaten viruses, this review highlights the importance of terpenoids and their activity as antiviral agents that can be employed to treat current lethal diseases such as HIV, H1N1, SARS-CoV and HSV.

Production of recombinant SARS-CoV-2 3CL-protease: The key for the development of protease inhibitors screening kit in search of potential herb cure for COVID-19

Coronavirus disease-19 (COVID-19) pandemic caused millions of deaths and socio-economics damage worldwide. Corresponding to this, many studies on antiviral drugs exploration are rising to investigate the potential of drug compounds that can repress the replication of the SARS-CoV-2 virus by targeting its main protease named 3-chymotrypsin like protease (3CLpro). Without 3CLpro splicing, polyproteins of SARS-CoV-2 will not function to form new virions. We conducted an in silico thermodynamic study, and found several already known compounds from natural sources such as lovastatin, quinidine, and quinine were potential in inhibiting 3CLpro. However, most of the findings still need further wet-lab experiments to confirm their activity against it. To facilitate rapid screening of protease inhibitors, we aim to develop a screening kit for researchers with focus studies on herbal sources for COVID-19 treatments. Hence, the development of 3CLpro as the target of inhibition screening is essential. Our current work focused on the expression of the SARS-CoV-2 3CL Pro gene harbored by pET-32b(+) in E. coli BL21(DE3) and its purification. The recombinant E.coli were cultivated in LB media at 37 °C with 5 hours IPTG-induced phase followed by crude protein lysate extraction by sonication, and then Ni-NTA purification. A band of recombinant 3CLpro protein (33.8 kDa) detected by SDS PAGE and Western blotting after Ni-NTA purification was specific and clear, showing the right size of our protein interest. A final concentrated protein mixture obtained by 10-kDa membrane filtration displayed >90% purity with a total protein of 2.497 mg mL-1. Further functional assays and inhibitory tests with several natural compounds showed that 3CLpro functioned well as a drug target. © Published under licence by IOP Publishing Ltd.

A comprehensive review on the biological interest of quinoline and its derivatives.

Amongst heterocyclic compounds, quinoline is an advantaged scaffold that appears as a significant assembly motif for the development of new drug entities. Quinoline and its derivatives tested with diverse biological activity constitute an important class of compounds for new drug development. Therefore, many scientific communities have developed these compounds as intent structure and evaluated their biological activities. The present, review provides brief natural sources of quinoline and including a new extent of quinoline-based marketed drugs. This review also confers information about the biological activities of quinoline derivatives such as antibacterial, antifungal, antimycobacterial, antiviral, anti-protozoal, antimalarial, anticancer, cardiovascular, CNS effects, antioxidant, anticonvulsant, analgesic, anti-inflammatory, anthelmintic and miscellaneous activities.

Emerging paradigms of viral diseases and paramount role of natural resources as antiviral agents.

In the current scenario, the increasing prevalence of diverse microbial infections as well as emergence and re-emergence of viral epidemics with high morbidity and mortality rates are major public health threat. Despite the persistent production of antiviral drugs and vaccines in the global market, viruses still remain as one of the leading causes of deadly human diseases. Effective control of viral diseases, particularly Zika virus disease, Nipah virus disease, Severe acute respiratory syndrome, Coronavirus disease, Herpes simplex virus infection, Acquired immunodeficiency syndrome, and Ebola virus disease remain promising goal amidst the mutating viral strains. Current trends in the development of antiviral drugs focus solely on testing novel drugs or repurposing drugs against potential targets of the viruses. Compared to synthetic drugs, medicines from natural resources offer less side-effect to humans and are often cost-effective in the productivity approaches. This review intends not only to emphasize on the major viral disease outbreaks in the past few decades and but also explores the potentialities of natural substances as antiviral traits to combat viral pathogens. Here, we spotlighted a comprehensive overview of antiviral components present in varied natural sources, including plants, fungi, and microorganisms in order to identify potent antiviral agents for developing alternative therapy in future.