Saikosaponin A for COVID-19

The continuous emergence of SARS-CoV-2 variants, especially the Omicron strain with its heightened transmissibility, has posed ongoing challenges to the efficacy of existing vaccine and drug regimens. This situation highlights the pressing demand for antiviral drugs employing novel mechanisms of action. Pentacyclic triterpenoids (PTs), a structurally varied group of compounds derived from plants, exhibit both antiviral and anti-inflammatory activities, making them attractive candidates for further therapeutic development. These natural products, along with their saponin derivatives, show broad-spectrum inhibitory effects against multiple SARS-CoV-2 variants (from Alpha to Omicron) via interactions with multiple targets, such as the spike protein, main protease (Mpro), RNA-dependent RNA polymerase (RdRp), and inflammatory signaling pathways. This review consolidates recent findings on PTs and their saponins, emphasizing their influence on the key structural features required for inhibiting viral attachment, membrane fusion, reverse transcription, and protease function. We systematically summarized the structure–activity relationships and their antiviral results of PTs based on different target proteins in existing studies. Furthermore, this work points toward new strategies for designing multi-target PT-based inhibitors with improved efficacy against Omicron and future variants.

Several human diseases are caused by viruses, including cancer, Type I diabetes, Alzheimer’s disease, and hepatocellular carcinoma. In the past, people have suffered greatly from viral diseases such as polio, mumps, measles, dengue fever, SARS, MERS, AIDS, chikungunya fever, encephalitis, and influenza. Recently, COVID-19 has become a pandemic in most parts of the world. Although vaccines are available to fight the infection, their safety and clinical trial data are still questionable. Social distancing, isolation, the use of sanitizer, and personal productive strategies have been implemented to prevent the spread of the virus. Moreover, the search for a potential therapeutic molecule is ongoing. Based on experiences with outbreaks of SARS and MERS, many research studies reveal the potential of medicinal herbs/plants or chemical compounds extracted from them to counteract the effects of these viral diseases. COVID-19′s current status includes a decrease in infection rates as a result of large-scale vaccination program implementation by several countries. But it is still very close and needs to boost people’s natural immunity in a cost-effective way through phytomedicines because many underdeveloped countries do not have their own vaccination facilities. In this article, phytomedicines as plant parts or plant-derived metabolites that can affect the entry of a virus or its infectiousness inside hosts are described. Finally, it is concluded that the therapeutic potential of medicinal plants must be analyzed and evaluated entirely in the control of COVID-19 in cases of uncontrollable SARS infection.

The outbreak of the new coronavirus (COVID-19) has been transferred exponentially. There are many articles that have found the inhibitory effect of plant extracts or plant compounds on the coronavirus family. In this study, we want to use systematic review and meta-analysis to answer the question of which herbal compound can be more effective against the coronavirus. The present study is based on the guidelines for conducting meta-analyzes. An extensive search was conducted in the electronic database, and based on the inclusion and exclusion criteria, articles were selected and data screening was performed. Quality control of articles was performed. Data analysis was carried out in STATA software. The results showed that alkaloid compounds had a good effect in controlling the coronavirus and reducing viral titer. Trypthantrin, Sambucus extract, S. cusia extract, Boceprevir and Indigole B, dioica agglutinin urtica had a good effect on reducing the virus titer but their selectivity index has not been reported and it is recommended to determine for these compounds. Also among the compounds that had the greatest effect on virus inhibition, including Saikosaponins B2, SaikosaponinsD, SaikosaponinsA and Phillyrin, had an acceptable selectivity index greater than 10. Andrographolide showed the highest selectivity index on SARS-COV2, while virus titration and virus inhibition were not reported. The small number of studies that used alkaloid compounds was one of the limitations and it is suggested to investigate the effect of more alkaloid compounds against the coronavirus for verifying its effect.