Background: Influenza virus is still at large and seriously affects social welfare and health. Dianthus superbus is a well-known medicinal plant widely used in Mongolian and Chinese traditional medicine for anti-inflammatory purposes.
Purpose: To investigate the influence of this novel herbal medicinal product over virus infection and virus-induced symptoms
Method: Quercetin-7-O-glucoside was isolated by bioassay (anti-influenza)-guided fractionation. The structural elucidation was made with 1H-NMR and 13C-NMR. Influenza A/Vic/3/75 (H3N2), A/PR/8/34 (H1N1), B/Maryland/1/59 and B/Lee/40 viruses were used for the evaluation of the antiviral activity. Virus-induced reactive oxygen species and autophagy formation levels were studied. The antiviral mechanism was elucidated via time-dependent, pre-, post-incubation assay methods. The viral RNA replication inhibition of Q7G was analyzed using quantitative RT-PCR method. The blocking of polymerase basic protein subunits of influenza viral RNA polymerase by Q7G was detected by in silico molecular docking assays using AutoDock Vina program with m(7)GTP. Additionally, Q7G was tested against M-MuLV RNA polymerase.
Results: Q7G was not cytotoxic (CC50>100µg/ml) in MDCK cells and it showed 3.1µg/ml, 6.61µg/ml, 8.19µg/ml and 5.17µg/ml IC50 values against influenza A/PR/8/34, A/Vic/3/75, B/Lee/40 and B/Maryland/1/59 virus strains, respectively. Treatment of Q7G highly reduced ROS and autophagy formation induced by influenza virus infection. Q7G did not reduce NA activity and did not directly interact with the virus particles. Since viral RNA synthesis was blocked by treatment of Q7G. We targeted viral RNA polymerase for further probing. Interestingly, the binding energy of Q7G on viral PB2 protein was -9.1kcal/mol and was higher than m(7)GTP recorded as -7.5kcal/mol. It also was observe to block M-MuLV RNA polymerase.
Conclusion: Isolated compound Q7G showed strong inhibition activity against influenza A and B viruses. It also reduced virus-induced ROS and autophagy formation. Q7G does not directly bind to the virus particles and did not affect NA activity. These results indicated that Q7G inhibits viral RNA polymerase, and that it occupies the binding site of m(7)GTP on viral PB2 protein.
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http://dx.doi.org/10.1016/j.phymed.2016.06.001 | DOI Listing |
Nat Commun
January 2025
Molecular and Cellular Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA.
Coronaviruses evade detection by the host immune system with the help of the endoribonuclease Nsp15, which regulates levels of viral double stranded RNA by cleaving 3' of uridine (U). While prior structural data shows that to cleave double stranded RNA, Nsp15's target U must be flipped out of the helix, it is not yet understood whether Nsp15 initiates flipping or captures spontaneously flipped bases. We address this gap by designing fluorinated double stranded RNA substrates that allow us to directly relate a U's sequence context to both its tendency to spontaneously flip and its susceptibility to cleavage by Nsp15.
View Article and Find Full Text PDFJ Transl Med
January 2025
Evvivax Biotech, Via Castel Romano 100, 00128, Rome, Italy.
In the past decades, Chimeric Antigen Receptor (CAR)-T cell therapy has achieved remarkable success, leading to the approval of six therapeutic products for haematological malignancies. Recently, the therapeutic potential of this therapy has also been demonstrated in non-tumoral diseases. Currently, the manufacturing process to produce clinical-grade CAR-T cells is complex, time-consuming, and highly expensive.
View Article and Find Full Text PDFFood Chem Toxicol
January 2025
Department of Histology and Embryology, Erciyes University, Faculty of Medicine, 38039 Kayseri, Turkey. Electronic address:
Favipiravir, a broad-spectrum RNA-dependent RNA polymerase inhibitor widely used during the COVID-19 pandemic, effectively reduces viral load but has been linked to inflammatory changes in tissues such as the liver and kidneys. High-dose and prolonged use of favipiravir for COVID-19 raises concerns about its potential toxic effects on the lungs, particularly in patients with pre-existing pulmonary conditions. This study investigated favipiravir's effects on lung tissue in healthy rats.
View Article and Find Full Text PDFVet Microbiol
December 2024
Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510462, China; National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou 510642, China. Electronic address:
Since its emergence, porcine reproductive and respiratory syndrome (PRRS) has caused enormous economic losses to the global swine industry. The pathogenesis of PRRS remains under investigation. The porcine reproductive and respiratory syndrome virus (PRRSV) causes reproductive disorders in pigs and respiratory in piglets, which is a 15 kb RNA virus that encodes 16 viral proteins, most of which exhibit multiple functions during the virus lifecycle.
View Article and Find Full Text PDFVirology
December 2024
The Centre for Infection and Immunity Studies, School of Medicine, Sun Yat-sen University, Shenzhen, Guangdong, 518107, China. Electronic address:
The knowledge on the life cycle of flaviviruses is still incomplete, and no direct-acting antivirals against their infections are clinically available. Herein, by screening via a Zika virus (ZIKV) replicon assay, we found that the N-terminus of NS2A exhibited great tolerance to the insertions of different split fluorescent proteins (split-FPs). Furthermore, both ZIKV and dengue virus encoding a split-FP-tagged NS2A propagated efficiently, and the split-FP-tagged ZIKVs had good genetic stability.
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