Synthesis and anti-influenza activity of aminoalkyl rupestonates

Rupestonic Acid Derivative YZH-106 Promotes Lysosomal Degradation of HBV L- and M-HBsAg via Direct Interaction with PreS2 Domain

Hepatitis B surface antigen (HBsAg) is not only the biomarker of hepatitis B virus (HBV) infection and expression activity in hepatocytes, but it also contributes to viral specific T cell exhaustion and HBV persistent infection. Therefore, anti-HBV therapies targeting HBsAg to achieve HBsAg loss are key approaches for an HBV functional cure. In this study, we found that YZH-106, a rupestonic acid derivative, inhibited HBsAg secretion and viral replication. Further investigation demonstrated that YZH-106 promoted the lysosomal degradation of viral L- and M-HBs proteins. A mechanistic study using Biacore and docking analysis revealed that YZH-106 bound directly to the PreS2 domain of L- and M-HBsAg, thereby blocking their entry into the endoplasmic reticulum (ER) and promoting their degradation in cytoplasm. Our work thereby provides the basis for the design of a novel compound therapy to target HBsAg against HBV infection.

Discovery of phosphonate derivatives containing different substituted 1,2,3-triazole motif as promising tobacco mosaic virus (TMV) helicase inhibitors for controlling plant viral diseases

BACKGROUND

The discovery and identification of targets is of far-reaching significance for developing novel pesticide candidates and increasing the probability of success. To explore and identify highly effective tobacco mosaic virus (TMV) helicase-targeted lead structures, a series of novel phosphonate derivatives containing a 1,2,3-triazole motif were rationally engineered and their antiviral activity was assessed.

RESULTS

Bioassay results showed that the optimized B17 exhibited more potent curative activity (EC50  = 271.5 μg mL-1 ) against TMV in vivo, which was superior to that of commercial Ribavirin (EC50  = 689.3 μg mL-1 ). B17 presented a stronger binding capacity through binding analysis with helicase, affording a corresponding value of 12.7 μM. Enzyme activity assay showed B17 exhibited excellent inhibitory activity on TMV helicase (39.2% at 300 μM). Furthermore, molecular docking simulations demonstrated that B17 displayed strong hydrogen-bond interactions (2.1, 2.1, 2.2, and 3.2 Å) with Ala-33, Gly-10, Gly-8, and Glu-217 of TMV helicase. Encouragingly, transmission electron microscopy analysis revealed that B17 could remarkably disrupt surface morphology and inhibit TMV proliferation. Additionally, these compounds also displayed potential anti-CMV (cucumber mosaic virus) and antipathogens (Xanthomonas oryzae pv. oryzae and Xanthomonas axonopodis pv. citri) by expanding their applications in agriculture.

CONCLUSION

Current research demonstrated that B17 could be considered as a potential antiviral agent alternative though targeting TMV helicase. © 2023 Society of Chemical Industry.

Insight into non-nucleoside triazole-based systems as viral polymerases inhibitors

Viruses have been recognized as the etiological agents responsible for many pathological conditions ranging from asymptomatic infections to serious diseases, even leading to death. For this reason, many efforts have been made to identify selective viral targets with the aim of developing efficient therapeutic strategies, devoid of drug-resistance issues. Considering their crucial role in the viral life cycle, polymerases are very attractive targets. Among the classes of compounds explored as viral polymerases inhibitors, here we present an overview of non-nucleoside triazole-based compounds identified in the last fifteen years. Furthermore, the structure-activity relationships (SAR) of the different chemical entities are described in order to highlight the key chemical features required for the development of effective antiviral agents.

Synthesis and Molecular Docking of New 1,2,3-triazole Carbohydrates with COVID-19 Proteins

AIMS

We have established this paper to recommend a novel way for the preparation of carbohydrates encompassing a 1,2,3-triazole motif that was prepared using an efficient click chemistry synthesis.

BACKGROUND

The SARS-CoV-2 coronavirus epidemic continues to spread at a fast rate worldwide. The main protease (Mpro) is useful target for anti-COVID-19 agents. Triazoles are frequently found in many bioactive products, such as coronavirus inhibitors.

OBJECTIVE

Click reactions are facilitated via the activation of copper nanoparticles, different substrates have been tested using this adopted procedure given in all cases, in high yields and purity. Other interesting comparative docking analyses will be the focus of this article. Calculations of quantitative structure-activity relationships will be studied.

METHODS

Copper nanoparticles were produced by the reaction of cupric acetate monohydrate with oleylamine and oleic acid. To a solution, 5-(azidomethyl)-2,2,7,7-tetramethyltetrahydro-5Hbis([ 1,3]dioxolo)[4,5-b:4',5'-d]pyran 2 (200 mg, 0.72 mmol, 1 eq.) in toluene (15 mL) was added into a mixture of N-(prop-2-yn-1-yl)benzamide derivatives 1a-d (1.5 eq.) and copper nanoparticles (0.57 mg, 0.036 mmol, 0.05 eq.).

RESULTS

A novel series of 1,2,3-triazole carbohydrate skeletons were modeled and efficiently synthesized. Based on the observations, virtual screening using molecular docking was performed to identify novel compounds that can bind with the protein structures of COVID-19 (PDB ID: 6LU7 and 6W41). We believed that the 1,2,3-triazole carbohydrate derivatives could aid in COVID-19 drug discovery.

CONCLUSION

The formations of targeted triazoles were confirmed by different spectroscopic techniques (FT-IR, 1H NMR, 13C NMR, and CHN analyses). The docking scores of the newly synthesized triazole are attributed to the presence of hydrogen bonds together with many interactions between the ligands and the active amino acid residue of the receptor. The comparison of the interactions of the drugs, remdesivir and triazole, in the largest pocket of 6W41 and 6LU7 is also presented.

Traditional Use, Phytochemical Profiles and Pharmacological Properties of Artemisia Genus from Central Asia

The flora of Kazakhstan is characterized by its wide variety of different types of medicinal plants, many of which can be used on an industrial scale. The Traditional Kazakh Medicine (TKM) was developed during centuries based on the six elements of ancient Kazakh theory, associating different fields such as pharmacology, anatomy, pathology, immunology and food nursing as well as disease prevention. The endemic Artemisia L. species are potential sources of unique and new natural products and new chemical structures, displaying diverse bioactivities and leading to the development of safe and effective phytomedicines against prevailing diseases in Kazakhstan and the Central Asia region. This review provides an overview of Artemisia species from Central Asia, particularly traditional uses in folk medicine and the recent numerous phytochemical and pharmacological studies. The review is done by the methods of literature searches in well-known scientific websites (Scifinder and Pubmed) and data collection in university libraries. Furthermore, our aim is to search for promising and potentially active Artemisia species candidates, encouraging us to analyze Protein Tyrosine Phosphatase 1B (PTP1B), α-glucosidase and bacterial neuraminidase (BNA) inhibition as well as the antioxidant potentials of Artemisia plant extracts, in which endemic species have not been explored for their secondary metabolites and biological activities so far. The main result of the study was that, for the first time, the species Artemisia scopiformis Ledeb. Artemisia albicerata Krasch., Artemisia transiliensis Poljakov, Artemisia schrenkiana Ledeb., Artemisia nitrosa Weber and Artemisia albida Willd. ex Ledeb. due to their special metabolites, showed a high potential for α-glucosidase, PTP1B and BNA inhibition, which is associated with diabetes, obesity and bacterial infections. In addition, we revealed that the methanol extracts of Artemisia were a potent source of polyphenolic compounds. The total polyphenolic contents of Artemisia extracts were correlated with antioxidant potential and varied according to plant origin, the solvent of extraction and the analytical method used. Consequently, oxidative stress caused by reactive oxygen species (ROS) may be managed by the dietary intake of current Artemisia species. The antioxidant potentials of the species A. schrenkiana, A. scopaeformis, A. transiliensis and Artemisia scoparia Waldst. & Kitam. were also promising. In conclusion, the examination of details between different Artemisia species in our research has shown that plant materials are good as an antioxidant and eznyme inhibitory functional natural source.

Isatis indigotica: from (ethno) botany, biochemistry to synthetic biology

Isatis indigotica Fort. (Chinese woad) is a species with an ancient and well-documented history as an indigo dye and medicinal plant. It is often confused with Isatis tinctoria L. (European woad), a medicinal plant in Europe. Here, the differences between I. indigotica and I. tinctoria are systematically described. The usage development history, clinical applications and pharmacological activities, and chemical components of I. indigotica are also summarized. Lignans, indole alkaloids, and their corresponding derivatives have been identified as the major active ingredients of I. indigotica and are associated with anti-viral, anti-inflammatory, anti-cancer, and other health-promoting activities. Notable progress has been made in understanding the biosynthetic pathway and regulation mechanism of lignans and indole alkaloids in I. indigotica, the results from which should facilitate the process of targeted metabolic engineering or synthetic biology. Moreover, multiple biotechnology methods such as polyploid breeding and genetic engineering have been used with I. indigotica to result in, for example, greater yields, higher levels of bioactive component accumulation, and enhanced stress tolerance to salt, drought, and insects. Some issues require additional analyses, and suggestions for future research on I. indigotica are also discussed.

Triazole, imidazole, and thiazole-based compounds as potential agents against coronavirus

The expansion of the novel coronavirus known as SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), COVID-19 (coronavirus disease 2019), or 2019-nCoV (2019 novel coronavirus) is a global concern over its pandemic potential. The need for therapeutic alternatives to stop this new pandemic is urgent. Nowadays, no efficacious therapy is available, and vaccines and drugs are underdeveloped to cure or prevent SARS-CoV-2 infections in many countries. Some vaccines candidates have been approved; however, a number of people are still skeptical of this coronavirus vaccines. Probably because of issues related to the quantity of the vaccine and a possible long-term side effects which are still being studied. The previous pandemics of infections caused by coronavirus, such as SARS-CoV in 2003, the Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012, HCoV-229E, and HCoV-OC43 were described in the 1960 s, -HCoV-NL63 isolated in 2004, and HCoV-HKU1identified in 2005 prompted researchers to characterize many compounds against these viruses. Most of them could be potentially active against the currently emerging novel coronavirus. Five membered nitrogen heterocycles with a triazole, imidazole, and thiazole moiety are often found in many bioactive molecules such as coronavirus inhibitors. This present work summarizes to review the biological and structural studies of these compound types as coronavirus inhibitors.

Design, synthesis and molecular docking of novel triazole derivatives as potential CoV helicase inhibitors

Middle East respiratory syndrome coronavirus (MERS-CoV) had emerged and spread because of the worldwide travel and inefficient healthcare provided for the infected patients in several countries. Herein we investigated the anti-MERS-CoV activity of newly synthesized sixteen halogenated triazole compounds through the inhibition of helicase activity using the FRET assay. All new compounds underwent justification for their target structures via microanalytical and spectral data. SAR studies were performed. Biological results revealed that the most potent compounds were 4-(cyclopent-1-en-3-ylamino)-5-(2-(4-iodophenyl)hydrazinyl)-4H-1,2,4-triazole-3-thiol (16) and 4-(cyclopent-1-en-3-ylamino)-5-[2-(4-chlorophenyl)hydrazinyl]-4H-1,2,4-triazole-3-thiol (12). In silico molecular docking of the most potent compounds was performed to the active binding site of MERS-CoV helicase nsp13. Molecular docking results are in agreement with experimental findings.

Novel amides modified rupestonic acid derivatives as anti-influenza virus reagents

In spired by the important role of amide groups of anti-influenza drugs oseltamivir, zanamivir and peramivir in bioactivity, a series of novel amides modified rupestonic acid derivatives were designed and synthesized. The absolute configuration of critical intermediate bearing chloride with newly formed stereocenter was confirmed by X-ray crystallographic analysis. And all new compounds were evaluated for their in vitro inhibitory activities against influenza A (H1N1 and H3N2) and influenza B viruses. The bioassay results showed that 5h with 4-fluorbenzylsulfonyl modified to 2 position of methyl rupestonate displayed the highest activity against influenza A (H1N1 and H3N2) viruses, even stronger than reference drugs oseltamivir and ribavirin (RVB), and might be recommended as a lead compound to further develop the new anti-influenza reagent.

Asymmetric Synthesis of Rupestonic Acid and Pechueloic Acid

In this report, the originally proposed rupestonic acid (5) and pechueloic acid (3) were efficiently synthesized. The chiral lactone 13, recycled from the degradation of saponin glycosides, was utilized to prepare the key chiral fragment 11. During the exploration of this convergent assembly strategy, the ring-closing metathesis (RCM), SmI₂-prompted intermolecular addition, and [2,3]-Wittig rearrangement proved to be effective transformations for the synthesis of subunits.

Synthesis of camphecene derivatives using click chemistry methodology and study of their antiviral activity

A series of seventeen tetrazole derivatives of 1,7,7-trimethyl-[2.2.1]bicycloheptane were synthesized using click chemistry methodology and characterized by spectral data. Studies of cytotoxicity and in vitro antiviral activity against influenza virus A/Puerto Rico/8/34 (H1N1) in MDCK cells of the compounds obtained were performed. The structure-activity relationship analysis suggests that to possess virus-inhibiting activity, the compounds of this group should bear oxygen atom with a short linker (C2-C4), either as a hydroxyl group (18, 19, 29), keto-group (21) or as a part of a heterocycle (24). These compounds demonstrated low cytotoxicity along with high anti-viral activity.

Structure-activity relationship studies of 1-(1'-hydroxyalkyl)rupestonic acid methyl esters against influenza viruses

A series of 1-(1'-hydroxyalkyl)rupestonic acid methyl esters were synthesized via the condensation of methyl rupestonate with various aldehydes in the presence of LDA. This mixed aldol reaction was highly stereoselective and all the new compounds were elucidated by detailed NMR and MS analyses. The absolute configurations of the newly formed stereocenters were further confirmed by X-ray crystallographic analysis of 3d, the results of which were found to be opposite to the prediction based on Zimmerman-Traxler's and Houk's models. All the compounds synthesized were then evaluated for their in vitro inhibitory activities against influenza A (H1N1 and H3N2) and B viruses. The data showed that 3p displayed the highest activity against influenza A H1N1 (IC₅₀=0.69μg/mL) and H3N2 (IC₅₀=0.69μg/mL) viruses, which were even better than Ribavirin and Oseltmivir. On the other hand, both 3c and 3o were found to show comparable activities with the reference drugs in inhibiting both influenza A and B viruses. Further studies will focus on reducing the cytotoxicity of the hits reported in this work.

Synthesis and in vitro biological evaluation of novel diaminothiophene scaffolds as antitumor and anti-influenza virus agents. Part 2

Herein, we report the synthesis and biological evaluation of a novel series of diethyl 2,5-diaminothiophene-3,4-dicarboxylate (DDTD) derivatives as antitumor and anti-influenza virus agents.

Nitric Oxide Inhibitory Dimeric Sesquiterpenoids from Artemisia rupestris

Twelve new dimeric sesquiterpenoids (1-12) were isolated from the dried whole plants of Artemisia rupestris. Their structures were determined using MS and NMR data, and the absolute configurations were elucidated on the basis of experimental and calculated ECD spectra. Compounds 1-9 are presumably formed via biocatalyzed [2+2] or [4+2] cycloaddition reactions. Stereoselectivity of the [4+2] Diels-Alder reaction dictated the formation of endo-products. The dimeric sesquiterpenoids exhibited moderate inhibition on NO production stimulated by lipopolysaccharide in BV-2 microglial cells, with IC50 values in the range 17.0-71.8 μM.

1,2,3-Triazole-containing derivatives of rupestonic acid: click-chemical synthesis and antiviral activities against influenza viruses

Two series of rupestonic acid derivatives, (1-substituted-1H-1,2,3-triazol-4-yl)methyl 2-((5R,8S,8aS)-3,8-dimethyl-2-oxo-1,2,4,5,6,7,8,8a-octahydroazulen-5-yl)acrylate and N-(1-substituted-1H-1,2,3-triazol-4-yl)methyl 2-((5R,8S,8aS)-3,8-dimethyl-2-oxo-1,2,4,5,6,7,8,8a-octahydroazulen-5-yl)acrylamide were easily and efficiently synthesized via click chemistry. These compounds were tested for their in vitro activities against various strains of influenza A virus (H1N1, oseltamivir resistant H1N1, H3N2) and influenza B virus. The results showed that nine compounds were active against the H1N1 strain of influenza A virus and among them the best one 14a, was as active as the reference drugs, Oseltamivir and Ribavirin. Some of them were also active on the Oseltamivir resistant H1N1 strain. In regards to influenza B virus, twenty-one compounds over thirty were active and seven of them 7b, 8b, 9b, 10a, 11b, 12b, 13b showed better activity than Ribavirin. The structure-activity relationship of these compounds is discussed on the basis of each type of the viruses studied. Furthermore, four best representative compounds 7b, 10a, 12b and 14a were evaluated in a plaque assay experiment using MDCK cells and RBV as control compound and the results showed that 7b, 10a and 12b were better than RBV in inhibiting plaque formation, in good accordance with their anti-influenza B activities.

Anti-influenza active and low toxic N-phenyl-substituted β-amidoamidines structurally related to natural antibiotic amidinomycin

A set of racemic N-phenyl-substituted β-amidoamidines hydrochlorides 4, which are structurally related to natural antiviral agent amidinomycin (1), was synthesized in four steps starting from methacryloyl anilide (5). In the final step of the synthetic route, an uncommon monoacylation of β-aminoamidine 8 at the less reactive β-phenylamino-group took place. To rationalize this result, a mechanism which involves initial acylation at the more active amidine-function followed by intramolecular acyl-group transfer to β-phenylamino-group was suggested. All three β-amidoamidines 4d-f bearing long linear aliphatic chain (from n-C8H17 to n-C12H25) revealed significant in vitro activity against influenza A virus (H3N2) and modest cytotoxicity. The in vitro antiviral potency of 4d,e is 6-20 times greater than that of commercial rimantadine with lower EC50 values and higher therapeutic index. The non-toxic in vivo compounds 4d-f showed a beneficial protective effect in influenza A (H3N2) infected mice.

Human viral diseases: what is next for antiviral drug discovery?

For the treatment of human immunodeficiency virus (HIV) infections for which there are ample drugs available, the immediate future lies in a once-daily combination pill containing three or four active ingredients. This strategy may also be envisaged for the treatment of hepatitis C virus (HCV) infections as soon as we have at hand the appropriate direct-acting antiviral agents (DAAs) to be combined. A combination drug therapy is generally not entertained for other viruses. Yet, new drugs are at the horizon for the treatment of herpes simplex virus (HSV), varicella-zoster virus (VZV), poxvirus, hepatitis B virus (HBV), influenza and enveloped viruses-at-large.