Synthesis and antiviral activities of novel 1,4-pentadien-3-one derivatives bearing an emodin moiety

Identification of Novel Bisamide-Decorated Benzotriazole Derivatives as Anti-Phytopathogenic Virus Agents: Bioactivity Evaluation and Computational Simulation

As a notorious phytopathogenic virus, the tobacco mosaic virus (TMV) severely reduced the quality of crops worldwide and caused critical constraints on agricultural production. The development of novel virucides is a persuasive strategy to address this predicament. Herein, a series of novel bisamide-decorated benzotriazole derivatives were elaborately prepared and screened. Biological tests implied that the optimized compound 7d possessed the most brilliant antiviral inactive profile (EC50 = 157.6 μg/mL) and apparently surpassed that of commercial ribavirin (EC50 = 442.1 μg/mL) 2.8-fold. The preliminary antiviral mechanism was elaborately investigated via transmission electron microscopy, microscale thermophoresis (MST) determination, RT-qPCR, and Western blot analysis. The results showed that compound 7d blocked the assembly of TMV by binding with coat protein (Kd = 0.7 μM) and suppressed TMV coat protein gene expression and biosynthesis process. Computational simulations indicated that 7d displayed strong H-bonds and pi interactions with TMV coat protein, affording a lower binding energy (ΔGbind = -17.8 kcal/mol) compared with Ribavirin (ΔGbind = -10.7 kcal/mol). Overall, current results present a valuable perception of bisamide decorated benzotriazole derivatives with appreciably virustatic competence and should be profoundly developed as virucidal candidates in agrochemical.

Synthesis and antiviral activity of diverse heterocyclic scaffolds

Heterocyclic moieties form a major part of organic chemistry as they are widely distributed in nature and have wide scale practical applications ranging from extensive clinical use to diverse fields such as medicine, agriculture, photochemistry, biocidal formulations, and polymer science. By virtue of their therapeutic properties, they could be employed in combating many infectious diseases. Among the common infectious diseases, viral infections are of great public health importance worldwide. Thus, there is an urgent need for the discovery and development of antiviral drugs and clinical methods to prevent various viral infections so as to increase the life expectancy. This review presents the comprehensive overview of the synthesis and antiviral activity of different heterocyclic compounds 2015 onwards, which aids in present knowledge and helps the researchers and other stakeholders to explore their field.

Recent Research Progress: Discovery of Anti-Plant Virus Agents Based on Natural Scaffold

Plant virus diseases, also known as “plant cancers”, cause serious harm to the agriculture of the world and huge economic losses every year. Antiviral agents are one of the most effective ways to control plant virus diseases. Ningnanmycin is currently the most successful anti-plant virus agent, but its field control effect is not ideal due to its instability. In recent years, great progress has been made in the research and development of antiviral agents, the mainstream research direction is to obtain antiviral agents or lead compounds based on structural modification of natural products. However, no antiviral agent has been able to completely inhibit plant viruses. Therefore, the development of highly effective antiviral agents still faces enormous challenges. Therefore, we reviewed the recent research progress of anti-plant virus agents based on natural products in the past decade, and discussed their structure-activity relationship (SAR) and mechanism of action. It is hoped that this review can provide new inspiration for the discovery and mechanism of action of novel antiviral agents.

Synthesis and anti-inflammatory effects of novel emodin derivatives bearing azole moieties

Twelve azole derivatives of emodin were designed to possess anti-inflammatory activity and synthesized via a two-step sequence composed of the Williamson ether reaction and N-alkylation. The anti-inflammatory properties of these compounds were evaluated in RAW264.7 cells by measuring lipopolysaccharide (LPS)-induced nitric oxide (NO) production. The introduction of imidazole and four carbons into the scaffold of emodin led to the discovery of the potent compound 7e, which showed the best inhibition of NO production among twelve analogs. In our experiential setting, the IC₅₀ of compound 7e in NO production is 1.35 µM, which is lower than that of indomethacin. Mechanically, compound 7e effectively inhibited the protein and messenger RNA expressions of cyclooxygenase-2 and inducible NO synthase, as well as that of the proinflammatory cytokine interleukin-6, and the cytokines interleukin-1β and tumor necrosis factor-α in the LPS-stimulated RAW 264.7 macrophages. Compound 7e exerted inhibitory effects on the nuclear factor κB pathway by reducing the LPS-induced phosphorylation of the inhibitor of NF-κB and the nuclear translation of p-p65. These results suggest the potential of compound 7e in improving inflammatory conditions and diseases.

Design, synthesis, antiviral bioactivities and interaction mechanisms of penta-1,4-diene-3-one oxime ether derivatives containing a quinazolin-4(3H)-one scaffold

Background

penta-1,4-diene-3-one oxime ether and quinazolin-4(3H)-one derivatives possess favorable agricultural activities. Aiming to discover novel molecules with highly-efficient agricultural activities, a series of penta-1,4-diene-3-one oxime ether derivatives containing a quinazolin-4(3H)-one scaffold were synthesized and evaluated for their antiviral activities.

Result

Antiviral bioassays indicated that some title compounds exhibited significant antiviral activity against tobacco mosaic virus (TMV). In particular, compounds 8c, 8j and 8k possessed appreciable curative activities against TMV in vivo, with half-maximal effective concentration (EC₅₀) values of 138.5, 132.9 and 125.6 μg/mL, respectively, which are better than that of ningnanmycin (207.3 μg/mL). Furthermore, the microscale thermophoresis experiments (MST) on the interaction of compound 8k with TMV coat protein (TMV CP) showed 8k bound to TMV CP with a dissociation constant of 0.97 mmol/L. Docking studies provided further insights into the interaction of 8k with the Arg90 of TMV CP.

Conclusions

Sixteen penta-1,4-diene-3-one oxime ether derivatives containing a quinazolin-4(3H)-one scaffold were designed, synthesized, and their antiviral activities against TMV were evaluated. Antiviral bioassays indicated that some target compounds exhibited remarkable antiviral activities against TMV. Furthermore, through the MST and docking studies, we can speculate that 8k inhibited the virulence of TMV by binding Arg90 in TMV CP. These results indicated that this kind of penta-1,4-diene-3-one oxime ether derivatives containing a quinazolin-4(3H)-one scaffold could be further studied as potential alternative templates in the search for novel antiviral agents.

Electronic supplementary material

The online version of this article (10.1186/s13065-019-0547-1) contains supplementary material, which is available to authorized users.

Synthesis, antiviral and antibacterial activities and action mechanism of penta-1,4-dien-3-one oxime ether derivatives containing a quinoxaline moiety

A series of penta-1,4-dien-3-one oxime ether derivatives containing a quinoxaline moiety were synthesized, and their bioactivities and action mechanism were evaluated.

Design, Synthesis, and Biological Activity of Novel Myricetin Derivatives Containing Amide, Thioether, and 1,3,4-Thiadiazole Moieties

A series of myricetin derivatives containing amide, thioether, and 1,3,4-thiadiazole moieties were designed and synthesized, and their antiviral and antibacterial activities were assessed. The bioassays showed that all the title compounds exhibited potent in vitro antibacterial activities against Xanthomonas citri (Xac), Ralstonia solanacearum (Rs), and Xanthomonas oryzae pv. Oryzae (Xoo). In particular, the compounds 5a, 5f, 5g, 5h, 5i, and 5l, with EC50 values of 11.5⁻27.3 μg/mL, showed potent antibacterial activity against Xac that was better than the commercial bactericides Bismerthiazol (34.7 μg/mL) and Thiodiazole copper (41.1% μg/mL). Moreover, the in vivo antiviral activities against tobacco mosaic virus (TMV) of the target compounds were also tested. Among these compounds, the curative, protection, and inactivation activities of 5g were 49.9, 52.9, and 73.3%, respectively, which were better than that of the commercial antiviral Ribavirin (40.6, 51.1, and 71.1%, respectively). This study demonstrates that myricetin derivatives bearing amide, thioether, and 1,3,4-thiadiazole moieties can serve as potential alternative templates for the development of novel, highly efficient inhibitors against plant pathogenic bacteria and viruses.

Discovery of Topsentin Alkaloids and Their Derivatives as Novel Antiviral and Anti-phytopathogenic Fungus Agents

Topsentin alkaloids and their derivatives were designed, synthesized, and characterized on the basis of NMR and mass spectroscopy. The antiviral activities against tobacco mosaic virus (TMV) and anti-phytopathogenic fungus activities of these alkaloids were evaluated for the first time. Alkaloids 1c, 1e, 2b, and 2d displayed significantly higher antiviral activities against TMV than Ribavirin, emerging as new lead compounds for anti-TMV research. Further fungicidal activity tests against 14 kinds of phytopathogenic fungi revealed that these alkaloids displayed broad-spectrum fungicidal activities. Topsentin derivative 2d with 4-5 mg/kg EC₅₀ values against Sclerotinia sclerotiorum (Lib.), Rhizoctonia solani (Kuhn), and Botrytis cinerea (Pers.) emerged as a new lead compound for fungicidal research. Current studies provide support for the application of topsentin alkaloids as novel agrochemicals.