Design, Synthesis, and Anti-PVY Biological Activity of 1,3,5-Triazine Derivatives Containing Piperazine Structure

Carbene-Catalyzed Phthalide Ether Functionalization for Discovering Chiral Phytovirucide that Specifically Targets Viral Nia Protein to Inhibit Proliferation

Plant diseases caused by vegetable viruses are an important threat to global food security, presenting a major challenge for the development of antiviral agrochemicals. Functional proteins of plant viruses play a crucial role in the viral life cycle, and targeted inhibition of these proteins has emerged as a promising strategy. However, the current discovery of antiviral small molecules is hampered by the limitations of synthetic approaches and the narrow range of targets. Herein, we report a practical application of organocatalysis for serving pesticide discovery that bears a unique molecular basis. An N-heterocyclic carbene-modulated reaction is first designed to asymmetrically functionalize diverse natural phenols with phthalides. Our designed method is capable of producing a series of new phthalidyl ethers under mild conditions with good yields, enantioselectivity, and functional group tolerance. Among these, compound (R)-3w exhibits excellent and enantioselectivity-preferred curative activity against potato virus Y (PVY). Mechanistically, it is proposed that (R)-3w interacts with the nuclear inclusion body A (Nia) protein of PVY at the His150 residue. This binding impairs Nia's function to cleavage polyprotein, thereby inhibiting formation of viral replication complex. The study provides insights into advancing synthetic protocol to facilitate agrochemical discovery, and our identified (R)-3w may serve as a potential lead for future research and development PVY-Nia inhibitors.

A benzo[b]thiophene-derived inhibitor of virus particle assembly via targeting capsid protein residue Arg157

As a biological macromolecule, the coat protein (CP) of potato virus Y (PVY) mediates the virus' primary pathogenic behaviors. It has been gradually realized that certain residues on the CP are crucial for functions such as virus particle movement and assembly. However, there are few reports of potential drugs successfully targeting these key residues with unique mechanisms of action. Here, we disclose the first new phytovirucide that acts on the key site Arg157 (R157) on the PVY CP. In this investigation, we developed a series of benzo[b]thiophene-based compounds, strategically introducing sulfonamide functionalities to enhance their antiviral performance. Through bio-screening, derivative C54 (EC50 = 69.2 μg/mL for inactive activity) emerged as notably more effective against PVY than the established antiviral agent ningnanmycin (EC50 = 79.6 μg/mL). Mechanistic studies revealed that C54 is an inhibitor of viral particle assembly by specifically binding to the CP residue R157, thereby disrupting its interaction with RNA. These results underscore the promise of C54 as a potent antiviral lead and provide a fresh perspective on the strategic design of inhibitors focusing on viral assembly processes.

Nanoenabled Antiviral Pesticide for Tobacco Mosaic Virus: Excellent Adhesion Performance and Strong Inhibitory Effect to Alleviate the Damage on Photosynthetic System

Tobacco mosaic virus (TMV) is a major agricultural threat. Here, a cationic star polymer (SPc) was designed to construct an efficient nanodelivery system for moroxydine hydrochloride (ABOB). ABOB could self-assemble with SPc via a hydrogen bond and van der Waals force, and this complexation reduced the particle size of ABOB from 2406 to 45 nm. With the aid of SPc, the contact angle of ABOB decreased from 100.8 to 79.0°, and its retention increased from 6.3 to 13.8 mg/cm2. Furthermore, the complexation with SPc could attenuate the degradation of ABOB in plants, and the bioactivity of SPc-loaded ABOB significantly improved with a reduction in relative viral expression from 0.57 to 0.17. The RNA-seq analysis revealed that the ABOB/SPc complex could up-regulate the expression of growth- and photosynthesis-related genes in tobacco seedlings, and the chlorophyll content increased by 2.5 times. The current study introduced an efficient nanodelivery system to improve the bioactivity of traditional antiviral agents.

Innovative Arylimidazole-Fused Phytovirucides via Carbene-Catalyzed [3+4] Cycloaddition: Locking Viral Cell-To-Cell Movement by Out-Competing Virus Capsid-Host Interactions

The control of potato virus Y (PVY) induced crop failure is a challengeable issue in agricultural chemistry. Although many anti-PVY agents are designed to focus on the functionally important coat protein (CP) of virus, how these drugs act on CP to inactivate viral pathogenicity, remains largely unknown. Herein, a PVY CP inhibitor -3j (S) is disclosed, which is accessed by developing unusually efficient (up to 99% yield) and chemo-selective (> 99:1 er in most cases) carbene-catalyzed [3+4] cycloaddition reactions. Compound -3j bears a unique arylimidazole-fused diazepine skeleton and shows chirality-preferred performance against PVY. In addition, -3j (S) as a mediator allows ARG191 (R191) of CP to be identified as a key amino acid site responsible for intercellular movement of virions. R191 is further demonstrated to be critical for the interaction between PVY CP and the plant functional protein NtCPIP, enabling virions to cross plasmodesmata. This key step can be significantly inhibited through bonding with the -3j (S) to further impair pathogenic behaviors involving systemic infection and particle assembly. The study reveals the in-depth mechanism of action of antiviral agents targeting PVY CP, and contributes to new drug structures and synthetic strategies for PVY management.

Antiviral Mechanisms of Anisomycin Produced by Streptomyces albulus SN40 on Potato Virus Y

Microbial secondary metabolites produced by Streptomyces have diverse application prospects in the control of plant diseases. Herein, the fermentation filtrate of Streptomyces SN40 effectively inhibited the infection of tobacco mosaic virus (TMV) in Nicotiana glutinosa and systemic infection of potato virus Y (PVY) in Nicotiana benthamiana. Additionally, metabolomic analysis indicated that anisomycin (C14H19NO4) and trans-3-indoleacrylic acid (C11H9NO2) were highly abundant in the crude extract and that anisomycin effectively suppressed the infection of TMV as well as PVY. Subsequently, transcriptomic analysis was conducted to elucidate its mechanisms on the induction of host defense responses. Furthermore, the results of molecular docking suggested that anisomycin can potentially bind with the helicase domain (Hel) of TMV replicase, TMV coat protein (CP), and PVY helper component proteinase (HC-Pro). This study demonstrates new functions of anisomycin in virus inhibition and provides important theoretical significance for the development of new biological pesticides to control diverse plant viruses.

Medicinal chemistry perspectives on the development of piperazine-containing HIV-1 inhibitors

The Human immunodeficiency virus (HIV) is the causative agent of acquired immunodeficiency syndrome (AIDS), one of the most perilous diseases known to humankind. A 2023 estimate put the number of people living with HIV around 40 million worldwide, with the majority benefiting from various antiretroviral therapies. Consequently, the urgent need for the development of effective drugs to combat this virus cannot be overstated. In the realm of medicinal and organic chemistry, the synthesis and identification of novel compounds capable of inhibiting HIV enzymes at different stages of their life cycle are of paramount importance. Notably, the spotlight is on the progress made in enhancing the potency of HIV inhibitors through the use of piperazine-based compounds. Multiple studies have revealed that the incorporation of a piperazine moiety results in a noteworthy enhancement of anti-HIV activity. The piperazine ring assumes a pivotal role in shaping the pharmacophore responsible for inhibiting HIV-1 at critical stage, including attachment, reverse transcription, integration, and protease activity. This review also sheds light on the various opportunities that can be exploited to develop effective antiretroviral targets and eliminate latent HIV reservoirs. The advancement of highly potent analogues in HIV inhibitor research has been greatly facilitated by contemporary medicinal strategies, including molecular/fragment hybridization, structure-based drug design, and bioisosterism. These techniques have opened up new avenues for the development of compounds with enhanced efficacy in combating the virus.