In vitro Anti-viral Activity of Psoraleae Semen Water Extract against Influenza A Viruses

The potential of Panax notoginseng against COVID-19 infection

The COVID-19 pandemic has changed the world and has presented the scientific community with unprecedented challenges. Infection is associated with overproduction of proinflammatory cytokines secondary to hyperactivation of the innate immune response, inducing a cytokine storm and triggering multiorgan failure and significant morbidity/mortality. No specific treatment is yet available. For thousands of years, Panax notoginseng has been used to treat various infectious diseases. Experimental evidence of P. notoginseng utility in terms of alleviating the cytokine storm, especially the cascade, and improving post-COVID-19 symptoms, suggests that P. notoginseng may serve as a valuable adjunct treatment for COVID-19 infection.

Antiviral Effect of Isoquercitrin against Influenza A Viral Infection via Modulating Hemagglutinin and Neuraminidase

Isoquercitrin (IQC) is a component abundantly present in many plants and is known to have an anti-viral effect against various viruses. In this study, we demonstrate that IQC exhibits strong anti-influenza A virus infection, and its effect is closely related to the suppression of hemagglutinin (HA) and neuraminidase (NA) activities. We used green fluorescent protein-tagged Influenza A/PR/8/34 (H1N1), A/PR/8/34 (H1N1), and HBPV-VR-32 (H3N2) to evaluate the anti-IAV effect of IQC. The fluorescence microscopy and fluorescence-activated cell sorting analysis showed that IQC significantly decreases the levels of GFP expressed by IAV infection, dose-dependently. Consistent with that, IQC inhibited cytopathic effects by H1N1 or H3N2 IAV infection. Immunofluorescence analysis confirmed that IQC represses the IAV protein expression. Time-of-addition assay showed that IQC inhibits viral attachment and entry and exerts a strong virucidal effect during IAV infection. Hemagglutination assay confirmed that IQC affects IAV HA. Further, IQC potently reduced the NA activities of H1N1 and H3N2 IAV. Collectively, IQC prevents IAV infection at multi-stages via virucidal effects, inhibiting attachment, entry and viral release. Our results indicate that IQC could be developed as a potent antiviral drug to protect against influenza viral infection.

Dietary supplementation with nanoparticle CMCS-20a enhances the resistance to GCRV infection in grass carp (Ctenopharyngodon idella)

Combination of antimicrobial proteins and nanomaterials provides a platform for the development of immunopotentiators. Oral administration of immunopotentiators can significantly enhance the immunity of organisms, which provides ideas for disease prevention. In this study, we confirmed that nanoparticles CMCS-20a can efficiently prevent grass carp reovirus (GCRV) infection. Firstly, we verified that CiCXCL20a is involved in the immune responses post GCRV challenge in vivo and alleviates the cell death post GCRV challenge in CIK cells. Then, we prepared nanoparticles CMCS-20a using carboxymethyl chitosan (CMCS) loaded with grass carp (Ctenopharyngodon idella) CXCL20a (CiCXCL20a). Meanwhile, we confirmed nanoparticles CMCS-20a can alleviate the degradation in intestine. Subsequently, we added it to the feed by low temperature vacuum drying method and high temperature spray drying method, respectively. Grass carp were oral administration for 28 days and challenged by GCRV. Low temperature vacuum drying group (LD-CMCS-20a) significantly improve grass carp survival rate, but not high temperature spray drying group (HD-CMCS-20a). To reveal the mechanisms, we investigated the serum biochemical indexes, intestinal mucus barrier, immune gene regulation and tissue damage. The complement component 3 content, lysozyme and total superoxide dismutase activities are highest in LD-CMCS-20a group. LD-CMCS-20a effectively attenuates the damage of GCRV to the number of intestinal villous goblet cells and mucin thickness. LD-CMCS-20a effectively regulates mRNA expressions of immune genes (IFN1, Mx2, Gig1 and IgM) in spleen and head kidney tissues. In addition, LD-CMCS-20a obviously alleviate tissue lesions and viral load in spleen. These results indicated that the nanoparticles CMCS-20a can enhance the disease resistance of fish by improving their immunity, which provides a new perspective for fish to prevent viral infections.

Novel and Alternative Therapeutic Strategies for Controlling Avian Viral Infectious Diseases: Focus on Infectious Bronchitis and Avian Influenza

The growth of poultry farming has enabled higher spread of infectious diseases and their pathogens among different kinds of birds, such as avian infectious bronchitis virus (IBV) and avian influenza virus (AIV). IBV and AIV are a potential source of poultry mortality and economic losses. Furthermore, some pathogens have the ability to cause zoonotic diseases and impart human health problems. Antiviral treatments that are used often lead to virus resistance along with the problems of side effects, recurrence, and latency of viruses. Though target hosts are being vaccinated, the constant emergence and re-emergence of strains of these viruses cause disease outbreaks. The pharmaceutical industry is gradually focusing on plant extracts to develop novel herbal drugs to have proper antiviral capabilities. Natural therapeutic agents developed from herbs, essential oils (EO), and distillation processes deliver a rich source of amalgams to discover and produce new antiviral drugs. The mechanisms involved have elaborated how these natural therapeutics agents play a major role during virus entry and replication in the host and cause inhibition of viral pathogenesis. Nanotechnology is one of the advanced techniques that can be very useful in diagnosing and controlling infectious diseases in poultry. In general, this review covers the issue of the poultry industry situation, current infectious diseases, mainly IB and AI control measures and, in addition, the setup of novel therapeutics using plant extracts and the use of nanotechnology information that may help to control these diseases.

Broccoli Leaves Attenuate Influenza A Virus Infection by Interfering With Hemagglutinin and Inhibiting Viral Attachment

Broccoli (Brassica oleracea L. var. Italica) leaves are a byproduct of broccoli and could be used as a food source. The study aimed to evaluate the effect of broccoli leaves on influenza A virus (IAV) infection. We investigated the effect of ethanol extract of Broccoli leaves (EBL) on IAV infection using green fluorescent protein (GFP)–tagged Influenza A/PR/8/34 virus (PR8-GFP IAV). When EBL and PR8-GFP IAV were cotreated to RAW 264.7 cells, the fluorescence microscopy and fluorescence-activated cell sorting (FACS) analysis showed that EBL significantly reduced the levels of GFP expression by influenza viral infection dose-dependently. Immunofluorescence (IF) analysis confirmed that EBL decreased the expression of IAV proteins. EBL exhibited a strong inhibitory effect of IAV binding on the cells and moderate virucidal impact. Consistently, EBL potently suppressed the hemagglutination by IAV infection. These results indicate that EBL prevents IAV attachment via the inhibition of HA upon viral infection. Finally, EBL as an HA inhibitor of IAV could be used as the natural antiviral source to protect against influenza viral infection.

A Herbal Mixture Formula of OCD20015-V009 Prophylactic Administration to Enhance Interferon-Mediated Antiviral Activity Against Influenza A Virus

OCD20015-V009 is an herbal mix of water-extracted Ginseng Radix, Poria (Hoelen), Rehmanniae Radix, Adenophorae Radix, Platycodi Radix, Crataegii Fructus, and Astragali Radix. In this study, its in vitro and in vivo antiviral activity and mechanisms against the influenza A virus were evaluated using a GFP-tagged influenza A virus (A/PR/8/34-GFP) to infect murine macrophages. We found that OCD20015-V009 pre-treatment substantially reduced A/PR/8/34-GFP replication. Also, OCD20015-V009 pre-treatment increased the phosphorylation of type-I IFN-related proteins TBK-1 and STAT1 and the secretion of pro-inflammatory cytokines TNF-α and IL-6 by murine macrophages. Moreover, OCD20015-V009 prophylactic administration increased IFN-stimulated genes-related 15, 20, and 56 and IFN-β mRNA in vitro. Thus, OCD20015-V009 likely modulates murine innate immune response via macrophages. This finding is potentially useful for developing prophylactics or therapeutics against the influenza A virus. Furthermore, pre-treatment with OCD20015-V009 decreased the mortality of the mice exposed to A/PR/8/34-GFP by 20% compared to that in the untreated animals. Thus, OCD20015-V009 stimulates the antiviral response in murine macrophages and mice to viral infections. Additionally, we identified chlorogenic acid and ginsenoside Rd as the antiviral components in OCD20015-V009. Further investigations are needed to elucidate the protective effects of active components of OCD20015-V009 against influenza A viruses.

Plant-Based Natural Products and Extracts: Potential Source to Develop New Antiviral Drug Candidates

Viral infections are among the most complex medical problems and have been a major threat to the economy and global health. Several epidemics and pandemics have occurred due to viruses, which has led to a significant increase in mortality and morbidity rates. Natural products have always been an inspiration and source for new drug development because of their various uses. Among all-natural sources, plant sources are the most dominant for the discovery of new therapeutic agents due to their chemical and structural diversity. Despite the traditional use and potential source for drug development, natural products have gained little attention from large pharmaceutical industries. Several plant extracts and isolated compounds have been extensively studied and explored for antiviral properties against different strains of viruses. In this review, we have compiled antiviral plant extracts and natural products isolated from plants reported since 2015.

Preliminary study of Yinhuapinggan granule against H1N1 influenza virus infection in mice through inhibition of apoptosis

CONTEXT

Yinhuapinggan granule (YHPG) is frequently used for treating fever, cough, and viral pneumonia in traditional Chinese medicine.

OBJECTIVE

This study investigated the antiviral effects of YHPG in H1N1 influenza virus (IFV)-infected mice and its possible mechanism.

MATERIALS AND METHODS

ICR mice were intranasally infected with 10 LD₅₀ viral dose of IFV and then oral administration of YHPG (6, 12, and 18 g/kg) or oseltamivir (positive control) once a day for 2 or 4 consecutive days, six mice in each group. The lung, spleen and thymus indexes of IFV-infected mice, the expression of viral loads and pathological changes in lung tissues were performed to evaluate the antiviral effects of YHPG. Real-time PCR, immunohistochemistry and western blot assays were used to determine the expression of Bax, Bcl-2 and caspase-3.

RESULTS

LD₅₀ in mice was 10^-3.5/0.02 mL. YHPG (6, 12, and 18 g/kg) dose-dependently decreased the lung index and viral load; the inhibition ratio of lung index was 5.31, 18.22, and 34.06%, respectively. Further detection revealed that YHPG (12 and 18 g/kg) significantly attenuated lung pathological changes, and increased the spleen and thymus indexes. Moreover, YHPG significantly down-regulated the mRNA and protein expression of Bax and caspase-3 in lung tissues of mice infected with IFV, and up-regulated the expression of Bcl-2.

CONCLUSIONS

YHPG has significant antiviral effects in IFV-infected mice, partially by inhibiting influenza virus replication and regulating the occurrence of apoptosis induced by influenza virus infection, suggesting that YHPG may be a promising antiviral agent with potential clinical application prospects.

The extraordinary transformation of traditional Chinese medicine: processing with liquid excipients

Context: The Chinese medicinal materials originate from animals, plants, or minerals must undergo appropriate treatment before use as decoction pieces. Processing of Chinese medicines with liquid excipients is a pharmaceutical technique that transforms medicinal raw materials into decoction pieces which are significantly different from the original form. During processing, significant changes occur in chemical constituents, which inevitably affects clinical efficacy. At present, the liquid materials in processing mainly involve wine, vinegar, honey, saline water, ginger juice, herbal juice, etc.Objective: This review introduces the typical methods of liquid excipients processing, summarizes the influence on chemical composition, pharmacological efficacy, and expounds the ways and mechanisms of liquid excipients to change the properties of drugs, enhance the efficacy, eliminate or reduce toxicity and adverse reaction.Methods: English and Chinese literature from 1986 to 2020 was collected from databases including Web of Science, PubMed, Elsevier, Chinese Pharmacopoeia 2015, and CNKI (Chinese). Liquid excipients, processing, pharmacological effects, synergism, chemical constitution, traditional Chinese medicine (TCM) were used as the key words.Results: Liquid excipients play a key role in the application of TCM. Processing with proper liquid excipients can change the content of toxic or active components by physical or chemical transformation, decrease or increase drug dissolution, alter drug pharmacokinetics, or exert their own pharmacological effects. Thus, processing with liquid excipients is essential to ensure the safety and efficacy of TCM in clinic.Conclusion: This article could be helpful for researchers who are interested in traditional Chinese herbs processed with liquid excipients.

Anti-Influenza Activity of an Ethyl Acetate Fraction of a Rhus verniciflua Ethanol Extract by Neuraminidase Inhibition

Antigenic mismatch can cause influenza vaccines to be ineffective, and influenza viruses resistant to antiviral drugs are rising. Thus, development of antiviral agents against these viruses is an immediate need. Rhus verniciflua (RVS) has long been used in herbal medicine and as a nutritional supplement. The effect of RVS and its components on influenza virus has not, however, been reported. We found that RVS treatment significantly reduced viral replication when evaluated with green fluorescent protein- (GFP-) tagged virus (influenza A virus, A/PR/8/34-GFP) in Madin-Darby canine kidney (MDCK) cells. RVS showed significant inhibition of neuraminidase from A/PR/8/34. Subsequently, three fractions were prepared from an ethanolic crude extract of RVS. In vitro assays indicated that an ethyl acetate fraction (RVSE) was more potent than H₂O and CHCl₃ fractions. RVSE significantly suppressed influenza virus infection in MDCK cells via neuraminidase inhibition. Additionally, RVSE treatment inhibited expression of several virus proteins and decreased mortality of mice exposed to influenza A/PR/8/34 by 50% and reduced weight loss by 11.5%. Active components in RVSE were isolated, and 5-deoxyluteolin (5) and sulfuretin (7) demonstrate the highest neuraminidase inhibitory activity against influenza A virus. RVS, RVSE, and their constituents may be useful for the development of anti-influenza agents.

Irradiation by a Combination of Different Peak-Wavelength Ultraviolet-Light Emitting Diodes Enhances the Inactivation of Influenza A Viruses

Influenza A viruses (IAVs) pose a serious global threat to humans and their livestock. This study aimed to determine the ideal irradiation by ultraviolet-light emitting diodes (UV-LEDs) for IAV disinfection. We irradiated the IAV H1N1 subtype with 4.8 mJ/cm² UV using eight UV-LEDs [peak wavelengths (WL) = 365, 310, 300, 290, 280, 270, and 260 nm)] or a mercury low pressure (LP)-UV lamp (Peak WL = 254 nm). Inactivation was evaluated by the infection ratio of Madin–Darby canine kidney (MDCK) cells or chicken embryonated eggs. Irradiation by the 260 nm UV-LED showed the highest inactivation among all treatments. Because the irradiation-induced inactivation effects strongly correlated with damage to viral RNA, we calculated the correlation coefficient (R_AE) between the irradiant spectrum and absorption of viral RNA. The R_AE scores strongly correlated with the inactivation by the UV-LEDs and LP-UV lamp. To increase the R_AE score, we combined three different peak WL UV-LEDs (hybrid UV-LED). The hybrid UV-LED (R_AE = 86.3) significantly inactivated both H1N1 and H6N2 subtypes to a greater extent than 260 nm (R_AE = 68.6) or 270 nm (R_AE = 42.2) UV-LEDs. The R_AE score is an important factor for increasing the virucidal effects of UV-LED irradiation.

Angelicin-A Furocoumarin Compound With Vast Biological Potential

Angelicin, a member of the furocoumarin group, is related to psoralen which is well known for its effectiveness in phototherapy. The furocoumarins as a group have been studied since the 1950s but only recently has angelicin begun to come into its own as the subject of several biological studies. Angelicin has demonstrated anti-cancer properties against multiple cell lines, exerting effects via both the intrinsic and extrinsic apoptotic pathways, and also demonstrated an ability to inhibit tubulin polymerization to a higher degree than psoralen. Besides that, angelicin too demonstrated anti-inflammatory activity in inflammatory-related respiratory and neurodegenerative ailments via the activation of NF-κB pathway. Angelicin also showed pro-osteogenesis and pro-chondrogenic effects on osteoblasts and pre-chondrocytes respectively. The elevated expression of pro-osteogenic and chondrogenic markers and activation of TGF-β/BMP, Wnt/β-catenin pathway confirms the positive effect of angelicin bone remodeling. Angelicin also increased the expression of estrogen receptor alpha (ERα) in osteogenesis. Other bioactivities, such as anti-viral and erythroid differentiating properties of angelicin, were also reported by several researchers with the latter even displaying an even greater aptitude as compared to the commonly prescribed drug, hydroxyurea, which is currently on the market. Apart from that, recently, a new application for angelicin against periodontitis had been studied, where reduction of bone loss was indirectly caused by its anti-microbial properties. All in all, angelicin appears to be a promising compound for further studies especially on its mechanism and application in therapies for a multitude of common and debilitating ailments such as sickle cell anaemia, osteoporosis, cancer, and neurodegeneration. Future research on the drug delivery of angelicin in cancer, inflammation and erythroid differentiation models would aid in improving the bioproperties of angelicin and efficacy of delivery to the targeted site. More in-depth studies of angelicin on bone remodeling, the pro-osteogenic effect of angelicin in various bone disease models and the anti-viral implications of angelicin in periodontitis should be researched. Finally, studies on the binding of angelicin toward regulatory genes, transcription factors, and receptors can be done through experimental research supplemented with molecular docking and molecular dynamics simulation.

Antiviral Activity Against Infectious Bronchitis Virus and Bioactive Components of Hypericum perforatum L

Hypericum perforatum L., also known as Saint John’s Wort, has been well studied for its chemical composition and pharmacological activity. In this study, the antiviral activities of H. perforatum on infectious bronchitis virus (IBV) were evaluated in vitro and in vivo for the first time. The results of in vitro experiments confirmed that the antiviral component of H. perforatum was ethyl acetate extraction section (HPE), and results showed that treatment with HPE significantly reduced the relative messenger ribonucleic acid (mRNA) expression and virus titer of IBV, and reduced positive green immunofluorescence signal of IBV in chicken embryo kidney (CEK) cells. HPE treatment at doses of 480–120 mg/kg for 5 days, reduced IBV induced injury in the trachea and kidney, moreover, reduced the mRNA expression level of IBV in the trachea and kidney in vivo. The mRNA expression levels of IL-6, tumor necrosis factor alpha (TNF-α), and nuclear factor kappa beta (NF-κB) significantly decreased, but melanoma differentiation-associated protein 5 (MDA5), mitochondrial antiviral signaling gene, interferon alpha (IFN-α), and interferon beta (IFN-β) mRNA levels significantly increased in vitro and in vivo. Our findings demonstrated that HPE had significant anti-IBV effects in vitro and in vivo, respectively. In addition, it is possible owing to up-regulate mRNA expression of type I interferon through the MDA5 signaling pathway and down-regulate mRNA expression of IL-6 and TNF-α via the NF-κB signaling pathway. Moreover, the mainly active compositions of HPE analyzed by high-performance liquid chromatography/electrospray ionization–mass spectroscopy (ESI-MS) are hyperoside, quercitrin, quercetin, pseudohypericin, and hypericin, and a combination of these compounds could mediate the antiviral activities. This might accelerate our understanding of the antiviral effect of H. perforatum and provide new insights into the development of effective therapeutic strategies.

Aloe vera and its Components Inhibit Influenza A Virus-Induced Autophagy and Replication

Aloe vera ethanol extract (AVE) reportedly has significant anti-influenza virus activity, but its underlying mechanisms of action and constituents have not yet been completely elucidated. Previously, we have confirmed that AVE treatment significantly reduces the viral replication of green fluorescent protein-labeled influenza A virus in Madin-Darby canine kidney (MDCK) cells. In addition, post-treatment with AVE inhibited viral matrix protein 1 (M1), matrix protein 2 (M2), and hemagglutinin (HA) mRNA synthesis and viral protein (M1, M2, and HA) expressions. In this study, we demonstrated that AVE inhibited autophagy induced by influenza A virus in MDCK cells and also identified quercetin, catechin hydrate, and kaempferol as the active antiviral components of AVE. We also found that post-treatment with quercetin, catechin hydrate, and kaempferol markedly inhibited M2 viral mRNA synthesis and M2 protein expression. A docking simulation suggested that the binding affinity of quercetin, catechin hydrate, and kaempferol for the M2 protein may be higher than that of known M2 protein inhibitors. Thus, the inhibition of autophagy induced by influenza virus may explain the antiviral activity of AVE against H1N1 or H3N2. Aloe vera extract and its constituents may, therefore, be potentially useful for the development of anti-influenza agents.

Screening of Antiviral Components of Ma Huang Tang and Investigation on the Ephedra Alkaloids Efficacy on Influenza Virus Type A

Although Ma Huang Tang (MHT) has long been considered as a classical formula for respiratory infections like influenza, bronchitis and asthma, its chemical ingredients that really exert the main efficacy are still obscure. In this study we aimed to screen its antiviral components and investigate the potential mechanisms. The MDCK cellular research results showed that, among nine predominant ingredients of MHT, L-methylephedrin (LMEP), L-ephedrine (LEP) and D-pseudo- ephedrine (DPEP) significantly inhibited the proliferation of influenza A virus in vitro, and the inhibitory effect at 24 h after the treatment was more obvious than that at 48 h. They also significantly inhibited the mRNA expression levels of related genes in the TLR3, TLR4 and TLR7 signaling pathways, which were accompanied with the down-regulation of TNF-α level and the up-regulation of IFN-β level in the cell supernatant. Therefore, three Ephedra alkaloids exert an antiviral effect in vitro which may be closely related to the inhibition of viral replication and the modulation of inflammatory response. Animal research further indicated, at the 3rd and 7th days after infection, LEP and DPEP significantly attenuated lung injury, decreased lung index, virus load in the lung and the level of IL-1β in serum, inhibited the mRNA expression levels of TNF-α, TLR3, TLR4, TLR7, MyD88, NF-κB p65 and RIG-1 as well as the protein expression levels of TLR4, TLR7, MyD88 and NF-κB p65 and markedly increased thymus index, the level of IL-10 in serum and the mRNA expression level of IFN-γ. LEP and DPEP have certain protective effects on the influenza virus-infected mice, which may be associated with their abilities of effectively alleviating lung injury, improving the immunologic function of infected mice and adjusting the host's TLRs and RIG-1 pathways. The overall findings demonstrate that, as effective and inexpensive natural substances, Ephedra alkaloids and MHT may have potential utility in clinical management.

Study on the 2-Phenylchroman-4-One Derivatives and their anti-MERS-CoV Activities

Study on the 2-phenylchroman-4-one derivatives and their anti-MERS-CoVactivities.

The Antihistamine Drugs Carbinoxamine Maleate and Chlorpheniramine Maleate Exhibit Potent Antiviral Activity Against a Broad Spectrum of Influenza Viruses

Influenza A viruses (IAV) comprise some of the most common infectious pathogens in humans, and they cause significant mortality and morbidity in immunocompromised people as well as children and the elderly. After screening an FDA-approved drug library containing 1280 compounds by cytopathic effect (CPE) reduction assay using the Cell Counting Kit-8, we found two antihistamines, carbinoxamine maleate (CAM) and S-(+)-chlorpheniramine maleate (SCM) with potent antiviral activity against A/Shanghai/4664T/2013(H7N9) infection with IC₅₀ (half-maximal inhibitory concentration) of 3.56 and 11.84 μM, respectively. Further studies showed that CAM and SCM could also inhibit infection by other influenza A viruses, including A/Shanghai/37T/2009(H1N1), A/Puerto Rico/8/1934(H1N1), A/Guizhou/54/1989(H3N2), and one influenza B virus, B/Shanghai/2017(BY). Mice were challenged intranasally with A/H7N9/4664T/2013 (H7N9) virus and intraperitoneally injected with CAM (10 mg/kg per day) or SCM (1 mg/kg per day) for 5 days. CAM or SCM (10 mg/kg per day) were fully protected against challenge with A/Shanghai/4664T/2013(H7N9). The results from mechanistic studies indicate that both could inhibit influenza virus infection by blocking viral entry into the target cell, the early stage of virus life cycle. However, CAM and SCM neither blocked virus attachment, characteristic of HA activity, nor virus release, characteristic of NA activity. Such data suggest that these two compounds may interfere with the endocytosis process. Thus, we have identified two FDA-approved antihistamine drugs, CAM and SCM, which can be repurposed for inhibiting infection by divergent influenza A strains and one influenza B strain with potential to be used for treatment and prevention of influenza virus infection.

Irradiation by ultraviolet light-emitting diodes inactivates influenza a viruses by inhibiting replication and transcription of viral RNA in host cells

Influenza A viruses (IAVs) pose a serious global threat to humans and their livestock, especially poultry and pigs. This study aimed to investigate how to inactivate IAVs by using different ultraviolet-light-emitting diodes (UV-LEDs). We developed sterilization equipment with light-emitting diodes (LEDs) those peak wavelengths were 365 nm (UVA-LED), 310 nm (UVB-LED), and 280 nm (UVC-LED). These UV-LED irradiations decreased dose fluence-dependent plaque-forming units of IAV H1N1 subtype (A/Puerto Rico/8/1934) infected Madin-Darby canine kidney (MDCK) cells, but the inactivation efficiency of UVA-LED was significantly lower than UVB- and UVC-LED. UV-LED irradiations did not alter hemagglutination titer, but decreased accumulation of intracellular total viral RNA in infected MDCK cells was observed. Additionally, UV-LED irradiations suppressed the accumulation of intracellular mRNA (messenger RNA), vRNA (viral RNA), and cRNA (complementary RNA), as measured by strand-specific RT-PCR. These results suggest that UV-LEDs inhibit host cell replication and transcription of viral RNA. Both UVB- and UVC-LED irradiation decreased focus-forming unit (FFU) of H5N1 subtype (A/Crow/Kyoto/53/2004), a highly pathogenic avian IAV (HPAI), in infected MDCK cells, and the amount of FFU were lower than the H1N1 subtype. From these results, it appears that IAVs may have different sensitivity among the subtypes, and UVB- and UVC-LED may be suitable for HPAI virus inactivation.

Highly efficient inhibition of spring viraemia of carp virus replication in vitro mediated by bavachin, a major constituent of psoralea corlifonia Lynn

As one of nine piscine viruses recognized by the International Office of Epizootics, spring viraemia of carp virus (SVCV) is an important pathogen bringing high mortality to cyprinids. Up to now, there is no approved therapy on SVCV, making them strong public health threat in aquaculture. In this study, the anti-SVCV activities of 12 plant crude extracts were investigated by using epithelioma papulosum cyprini (EPC) cells. Among these plants, Psoralea corylifolia Linn. showed the highest inhibition on SVCV replication, with an inhibitory percentage of 67.98%. Further studies demonstrated that bavachin (BVN), one of the major constituents of Psoralea corylifolia Linn., was also highly effective to SVCV infection. The half maximal inhibitory concentrations (IC₅₀) of BVN on SVCV glycoprotein and nucleoprotein expression were 0.46 (0.29-0.73) and 0.31 (0.13-0.55) mg/L, respectively. In addition, SVCV-induced apoptosis which may be negative to SVCV replication was inhibited by BVN. The apoptotic cells were decreased 21.42% for BVN compared with SVCV group. These results indicated that the inhibition of BVN on SVCV replication was, in some extent, via blocking SVCV induced apoptosis. Furthermore, cellular morphological damage induced by SVCV was also blocked by BVN treatment. Mechanistically, BVN did not affect SVCV infectivity and cannot be used for prevention of SVCV infection. Time-of-addition and viral binding assays revealed that BVN mainly inhibited the early events of SVCV replication but did not interfere with SVCV adsorption. In conclusion, BVN was considered to develop as a promising agent to treat SVCV infection.

Antiviral effects and mechanisms of Yinhuapinggan granule against H1N1 influenza virus infection in RAW264.7 cells

Yinhuapinggan granule (YHPG), a modified prescription based on Ma-Huang-Tang (MHT), is used in traditional Chinese medicine (TCM) to treat influenza, cough, and viral pneumonia. In this study, we investigated the antiviral effects of YHPG by means of pre-, post-, and co-treatment, and its underlying mechanisms on regulating the levels of inflammatory-related cytokines, modulating the mRNA expressions of interferon-stimulated genes in influenza virus-infected murine macrophage cells (RAW264.7), and evaluating the protein expressions of key effectors in the Type I IFN and pattern recognition receptor (PRRs) signaling pathways. The results showed that YHPG markedly inhibited influenza virus (IFV) replication in pre-, post- and co-treatment assay, especially in post-treatment assay. Antiviral mechanisms studies revealed that YHPG (500 and 250 μg/mL) significantly up-regulated levels of IFN-β, IFN-stimulated genes (Mx-1, ISG-15 and ISG-56) compared with the IFV control group, while the levels of IL-6 and TNF-α were significantly down-regulated. Furthermore, western blot analysis results revealed that the protein expressions of the phosphorylated forms of TBK1, IRF3, ERK1/2, P38 MAPK and NF-κB p65 were significantly down-regulated in RAW264.7 cells with the YHPG (500 and 250 μg/mL) treatment, while the expression of the phosphorylated form of STAT1 was significantly enhanced. Based on these results, YHPG had antiviral effects in IFV-infected RAW264.7 cells, which might be associated with regulation of the inflammatory cytokines production, evaluation of the levels of IFN-stimulated genes, and modulation of the protein expressions of key effectors in the Type I IFN and PRRs signaling pathways.

Protective Effect of Panax notoginseng Root Water Extract against Influenza A Virus Infection by Enhancing Antiviral Interferon-Mediated Immune Responses and Natural Killer Cell Activity

Influenza is an acute respiratory illness caused by the influenza A virus, which causes economic losses and social disruption mainly by increasing hospitalization and mortality rates among the elderly and people with chronic diseases. Influenza vaccines are the most effective means of preventing seasonal influenza, but can be completely ineffective if there is an antigenic mismatch between the seasonal vaccine virus and the virus circulating in the community. In addition, influenza viruses resistant to antiviral drugs are emerging worldwide. Thus, there is an urgent need to develop new vaccines and antiviral drugs against these viruses. In this study, we conducted in vitro and in vivo analyses of the antiviral effect of Panax notoginseng root (PNR), which is used as an herbal medicine and nutritional supplement in Korea and China. We confirmed that PNR significantly prevented influenza virus infection in a concentration-dependent manner in mouse macrophages. In addition, PNR pretreatment inhibited viral protein (PB1, PB2, HA, NA, M1, PA, M2, and NP) and viral mRNA (NS1, HA, PB2, PA, NP, M1, and M2) expression. PNR pretreatment also increased the secretion of pro-inflammatory cytokines [tumor necrosis factor alpha and interleukin 6] and interferon (IFN)-beta and the phosphorylation of type-I IFN-related proteins (TANK-binding kinase 1, STAT1, and IRF3) in vitro. In mice exposed to the influenza A H1N1 virus, PNR treatment decreased mortality by 90% and prevented weight loss (by approximately 10%) compared with the findings in untreated animals. In addition, splenocytes from PNR-administered mice displayed significantly enhanced natural killer (NK) cell activity against YAC-1 cells. Taking these findings together, PNR stimulates an antiviral response in murine macrophages and mice that protects against viral infection, which may be attributable to its ability to stimulate NK cell activity. Further investigations are needed to reveal the molecular mechanisms underlying the protective effects of PNR and its components against influenza virus A infection.

Eupatorium fortunei and Its Components Increase Antiviral Immune Responses against RNA Viruses

Eupatorium fortunei (EF) has long been used as herbal medicine in Korea, China, and Asian countries to treat a variety of diseases. Recent studies have reported that EF has anti-metastatic, anti-angiogenic, anti-bacterial, and anti-oxidant activities, as well as activities against malignant metastatic human cancers. The effect of EF and its components on viruses has not been reported. In the present study, the antiviral activity and mechanism of action of an aqueous extract of EF (WEF) and its components were evaluated in vitro. We found that pretreatment with WEF markedly reduced viral replication, as evaluated using a green fluorescent protein (GFP)-tagged virus (influenza A virus, Newcastle disease virus, and vesicular stomatitis virus) in murine RAW 264.7 macrophage cells. We demonstrated that WEF induces the production of type I IFN including pro-inflammatory cytokines. Additionally, we identified the active anti-viral components of WEF as quercetin, psoralen, and quercitrin. Thus, WEF and its active components are immunomodulators of the innate immune response in murine macrophages, a finding that is potentially useful to developing prophylactic or therapeutic treatments against a range of viruses.