Structural modification on rupestonic acid leads to highly potent inhibitors against influenza virus

Sesquiterpenes and Sesquiterpene Derivatives from Ferula: Their Chemical Structures, Biosynthetic Pathways, and Biological Properties

Ferula is a genus of flowering plants known for its edible and medicinal properties. Since ancient times, many species of Ferula have been used in traditional medicine to treat various health issues across countries, such as digestive disorders, respiratory problems, and even as a remedy for headaches and toothaches. In addition, they are also used as a flavoring agent in various cuisines. As the main active ingredients in Ferula, sesquiterpenes and their derivatives, especially sesquiterpene coumarins, sesquiterpene phenylpropanoids, and sesquiterpene chromones, have attracted the attention of scientists due to the diversity of their chemical structures, as well as their extensive and promising biological properties, such as antioxidative, anti-inflammatory, antibacterial properties. However, there has not been a comprehensive review of sesquiterpenes and their derivatives from this plant. This review aims to provide an overview of the chemical structures, biosynthetic pathways, and biological properties of sesquiterpenes and sesquiterpene derivatives from Ferula, which may help guide future research directions and possible application methods for this valuable edible and medicinal plant.

An Estimation of the Antiviral Activity and Toxicity of Biologically Active Substances Obtained from the Raw Materials of Artemisia cina Berg. In Vitro and In Vivo

Species of the genus Artemisia are well known for their use as ingredients in ancient medicine. The advantage of using plant extracts compared to individual pharmaceutical ingredients is the rate of adaptation of the pathogenic microorganisms to the drug. Due to the rapid development of multidrug-resistance in microorganisms in the field, it is essential to search for novel, effective drugs with low toxicity. Therefore, the purpose of this study was to isolate and study the biologically active substances obtained from various substances in the raw materials of Artemisia cina Berg. The identification of the main biologically active components was performed using the method of chromato-mass spectrometry. Moreover, the antiviral activity of several extracts was studied using the method of measuring limiting dilutions (the Reed-Mench method), with some modifications. For the first time, the biological activity of extracts from the raw material of Artemisia cina Berg. upon the SARS-CoV-2 virus was confirmed. All the obtained extracts exhibited nontoxic effects in animals, with an LD₅₀ greater than 2 g/kg. Comprehensive toxicological analyses are also presented in the study, such as those of the biochemical parameters of urine after one day and one week of the extracts' administration in mice at a dose of 2 g/kg body weight. In all groups of animals that received extracts of Artemisia cina Berg., a slight increase in the presence of red blood cells in their urine was observed one day following the administration of the extracts. This increase decreased somewhat after a week; however, it remained higher than the levels observed in the control animals. In the three groups, there was also a slight increase in the amount of ketones in the urine. Two weeks following the administration of the extracts to these groups, the internal organs of the animals were examined. The examination showed that the internal organs of the animals that received the extracts were not visibly different from those of the control animals in terms of their size or appearance. The weight of the internal organs of the animals that received the extracts was also similar to the weight of the internal organs of the control animals, illustrating the absence of toxicity.

The Effects of Artemisia Plant and Its Components Against Respiratory Viruses Like Influenza and Their Mechanisms of Action

Context: Artemisia genus and its chemical constituents show antiviral activity against different viruses. The aim of this study was to review the effects of selected Artemisia species and their components against respiratory viruses like influenza and coronavirus. Methods: All the articles published in English or Persian related to the effects of Artemisia and its components on viral respiratory infections and relevant mechanisms of action were searched throughout Medline, Science Direct, Scopus, Ebsco, Google Scholar, and Cochrane Library Database from 1966 up to April 2020. Results: A few numbers of Artemisia species such as A. scoparia, A. rupestris, and A. annua and their components showed efficacy against the influenza virus and coronaviruses. Furthermore, some chemical compounds isolated from Artemisia species, like rupestonic acid, showed potent anti-influenza activity. The mechanism of antiviral activity was also determined for some of these compounds. Conclusions: The present study summarized the efficacy of a number of Artemisia species and their components against respiratory viruses like influenza and coronavirus. Future studies on other Artemisia species may lead to the discovery of new antiviral drugs against the influenza virus and coronaviruses.

Fragment tailoring strategy to design novel chemical entities as potential binders of novel corona virus main protease

The recent pandemic of severe acute respiratory syndrome-coronavirus2 (SARS-CoV-2) infection (COVID-19) has put the world on serious alert. The main protease of SARS-CoV-2 (SARS-CoV-2-MPro) cleaves the long polyprotein chains to release functional proteins required for replication of the virus and thus is a potential drug target to design new chemical entities in order to inhibit the viral replication in human cells. The current study employs state of art computational methods to design novel molecules by linking molecular fragments which specifically bind to different constituent sub-pockets of the SARS-CoV-2-MPro binding site. A huge library of 191678 fragments was screened against the binding cavity of SARS-CoV-2-MPro and high affinity fragments binding to adjacent sub-pockets were tailored to generate new molecules. These newly formed molecules were further subjected to molecular docking, ADMET filters and MM-GBSA binding energy calculations to select 17 best molecules (named as MP-In1 to MP-In17), which showed comparable binding affinities and interactions with the key binding site residues as the reference ligand. The complexes of these 17 molecules and the reference molecule with SARS-CoV-2-MPro, were subjected to molecular dynamics simulations, which assessed the stabilities of their binding with SARS-CoV-2-MPro. Fifteen molecules were found to form stable complexes with SARS-CoV-2-MPro. These novel chemical entities designed specifically according to the pharmacophoric requirements of SARS-CoV-2-MPro binding pockets showed good synthetic feasibility and returned no exact match when searched against chemical databases. Considering their interactions, binding efficiencies and novel chemotypes, they can be further evaluated as potential starting points for SARS-CoV-2 drug discovery.

Recent progress in chemical approaches for the development of novel neuraminidase inhibitors

Influenza virus is the main cause of an infectious disease called influenza affecting the respiratory system including the throat, nose and lungs. Neuraminidase inhibitors are reagents used to block the enzyme called neuraminidase to prevent the influenza infection from spreading. Neuraminidase inhibitors are widely used in the treatment of influenza infection, but still there is a need to develop more potent agents for the more effective treatment of influenza. Complications of the influenza disease lead to death, and one of these complications is drug resistance; hence, there is an urgent need to develop more effective agents. This review focuses on the recent advances in chemical synthesis pathways used for the development of new neuraminidase agents along with the medicinal aspects of chemically modified molecules, including the structure-activity relationship, which provides further rational designs of more active small molecules.

Discovery of Multitarget-Directed Ligands Against Influenza A Virus From Compound Yizhihao Through a Predictive System for Compound-Protein Interactions

Influenza A virus (IAV) is a threat to public health due to its high mutation rate and resistance to existing drugs. In this investigation, 15 targets selected from an influenza virus–host interaction network were successfully constructed as a multitarget virtual screening system for new drug discovery against IAV using Naïve Bayesian, recursive partitioning, and CDOCKER methods. The predictive accuracies of the models were evaluated using training sets and test sets. The system was then used to predict active constituents of Compound Yizhihao (CYZH), a Chinese medicinal compound used to treat influenza. Twenty-eight compounds with multitarget activities were selected for subsequent in vitro evaluation. Of the four compounds predicted to be active on neuraminidase (NA), chlorogenic acid, and orientin showed inhibitory activity in vitro. Linarin, sinensetin, cedar acid, isoliquiritigenin, sinigrin, luteolin, chlorogenic acid, orientin, epigoitrin, and rupestonic acid exhibited significant effects on TNF-α expression, which is almost consistent with predicted results. Results from a cytopathic effect (CPE) reduction assay revealed acacetin, indirubin, tryptanthrin, quercetin, luteolin, emodin, and apigenin had protective effects against wild-type strains of IAV. Quercetin, luteolin, and apigenin had good efficacy against resistant IAV strains in CPE reduction assays. Finally, with the aid of Gene Ontology biological process analysis, the potential mechanisms of CYZH action were revealed. In conclusion, a compound-protein interaction-prediction system was an efficient tool for the discovery of novel compounds against influenza, and the findings from CYZH provide important information for its usage and development.