The antiviral activity of arctigenin in traditional Chinese medicine on porcine circovirus type 2

Harnessing the power of Arctium lappa root: a review of its pharmacological properties and therapeutic applications

Arctium lappa, widely recognized as burdock, is a perennial plant that is employed in the realm of traditional Chinese medicine for a wide range of medicinal applications. The herb is rich in bioactive metabolites with therapeutic potential, encompassing polyphenolic antioxidants in its leaves, and flavonoids and fructo-oligosaccharides in its underground parts. Nutraceuticals originating from botanical sources such as Arctium lappa provide supplementary health advantages alongside their nutritional content and have demonstrated effectiveness in the prevention and management of specific ailments. The utilization of Arctium lappa root extract has exhibited encouraging outcomes in addressing hepatotoxicity induced by cadmium, lead, chromium, and acetaminophen, ameliorating liver damage and oxidative stress. Additionally, the root extract displays properties such as antidiabetic, hypolipidemic, aphrodisiac, anti-rheumatic, anti-Alzheimer, and various other pharmacological actions.

An integrated network pharmacology and molecular docking approach to reveal the role of Arctigenin against Cutibacterium acnes-induced skin inflammation by targeting the CYP19A1

Acne caused by inflammation of hair follicles and sebaceous glands is a common chronic skin disease. Arctigenin (ATG) is an extract of Arctium lappa L., which has significant anti-inflammatory effects. However, the effect and mechanism of ATG in cutaneous inflammation mediated by Cutibacterium acnes (C. acnes) has not been fully evaluated. The purpose of this study was to explore the effect and potential mechanism of ATG in the treatment of acne through network pharmacology and experimental confirmation. An acne model was established by injected live C. acnes into living mice and treated with ATG. Our data showed that ATG effectively improved acne induced by live C. acnes, which was confirmed by determining ear swelling rate, estradiol concentration and hematoxylin and eosin (H&E) staining. In addition, ATG inhibited the NLRP3 inflammasome signaling pathway in mice ear tissues and reduced the secretion of pro-inflammatory cytokines IL-1β to relieve inflammation. The results of network pharmacology and molecular docking confirmed that ATG can regulate 17β-Estradiol (E2) levels through targeted to CYP19A1, and finally inhibited skin inflammation. Taken together, our results confirmed that ATG regulated E2 secretion by targeting CYP19A1, thereby inhibiting the NLRP3 inflammasome signaling pathway and improving inflammation levels in acne mice. This study provides a basis for the feasibility of ATG in treating acne in clinical practice.

Arctigenin from Arctium lappa L. inhibits chikungunya virus by affecting its entry and replication

BACKGROUND

Dengue and chikungunya, caused by dengue virus (DENV) and chikungunya virus (CHIKV) respectively, are the most common arthropod-borne viral diseases worldwide, for which there are no FDA-approved antivirals or effective vaccines. Arctigenin, a phenylpropanoid lignan from the seeds of Arctium lappa L. is known for its anti-inflammatory, anti-cancer, antibacterial, and immunomodulatory properties. Arctigenin's antimicrobial and immunomodulatory capabilities make it a promising candidate for investigating its potential as an anti-DENV and anti-CHIKV agent.

PURPOSE

The aim of the study was to explore the anti-DENV and anti-CHIKV effects of arctigenin and identify the possible mechanisms of action.

METHODS

The anti-DENV or anti-CHIKV effects of arctigenin was assessed using various in vitro and in silico approaches. Vero CCL-81 cells were infected with DENV or CHIKV and treated with arctigenin at different concentrations, temperature, and time points to ascertain the effect of the compound on virus entry or replication. In silico molecular docking was performed to identify the interactions of the compound with viral proteins.

RESULTS

Arctigenin had no effects on DENV. Various time- and temperature-dependent assays revealed that arctigenin significantly reduced CHIKV RNA copy number and infectious virus particles and affected viral entry. Entry bypass assay revealed that arctigenin inhibited the initial steps of viral replication. In silico docking results revealed the high binding affinity of the compound with the E1 protein and the nsp3 macrodomain of CHIKV.

CONCLUSION

This study demonstrates the in-vitro anti-CHIKV potential of arctigenin and suggests that the compound might affect CHIKV entry and replication. Further preclinical and clinical studies are needed to identify its safety and efficacy as an anti-CHIKV drug.

Burdock miR8175 in diet improves insulin resistance induced by obesity in mice through food absorption

The incidence of type 2 diabetes mellitus (T2DM) induced by obesity is rapidly increasing. Although there are many synthetic drugs for treating T2DM, they have various side effects. Here, we report that miR8175, a plant miRNA from burdock root, has effective antidiabetic activity. After administration of burdock decoction or synthetic miR8175 by gavage, both burdock decoction and miR8175 can significantly improve the impaired glucose metabolism of diabetic mice induced by a high-fat diet (HFD). Our results demonstrate that burdock decoction and miR8175 enhance the insulin sensitivity of the hepatic insulin signaling pathway by targeting Ptprf and Ptp1b, which may be the reason for the improvement in metabolism. This study provides a theoretical basis for the main active component and molecular mechanism of burdock to improve insulin resistance. And the study also suggests that plant miRNA may be an indispensable nutrient for maintaining human health.

Revisiting Porcine Circovirus Infection: Recent Insights and Its Significance in the Piggery Sector

Porcine circovirus (PCV), a member of the Circoviridae family within the genus Circovirus, poses a significant economic risk to the global swine industry. PCV2, which has nine identified genotypes (a-i), has emerged as the predominant genotype worldwide, particularly PCV2d. PCV2 has been commonly found in both domestic pigs and wild boars, and sporadically in non-porcine animals. The virus spreads among swine populations through horizontal and vertical transmission routes. Despite the availability of commercial vaccines for controlling porcine circovirus infections and associated diseases, the continuous genotypic shifts from a to b, and subsequently from b to d, have maintained PCV2 as a significant pathogen with substantial economic implications. This review aims to provide an updated understanding of the biology, genetic variation, distribution, and preventive strategies concerning porcine circoviruses and their associated diseases in swine.

A systematic review on botany, ethnopharmacology, quality control, phytochemistry, pharmacology and toxicity of Arctium lappa L. fruit

ETHNOPHARMACOLOGICAL RELEVANCE

Arctium lappa L., is a biennial plant that grows around the Eurasia. Many parts of Arctium lappa L. (roots, leaves and fruits, etc.) are medically used in different countries. Arctium lappa L. fruit, also called Arctii Fructus, is traditionally applied to dispel wind-heat, ventilate lung to promote eruption, remove toxicity substance and relieve sore throat.

THE AIM OF THE REVIEW

The review aims to integrate the botany, ethnopharmacology, quality control, phytochemistry, pharmacology, derivatives and toxicity information of Arctii Fructus, so as to facilitate future research and explore the potential of Arctii Fructus as an agent for treating diseases.

MATERIALS AND METHODS

Related knowledge about Arctii Fructus were acquired from Science Direct, GeenMedical, PubMed, China National Knowledge Infrastructure (CNKI), Web of Science, Pharmacopoeia of the People's Republic of China, Doctoral and Master's thesis, ancient books, etc. RESULTS: Arctii Fructus as an herb used for medicine and food was pervasively distributed and applicated around the world. It was traditionally used to treat anemopyretic cold, dyspnea and cough, sore throat, etc. To date, more than 200 compounds have been isolated and identified from Arctii Fructus. It contained lignans, phenolic acids and fatty acids, terpenoids, volatile oils and others. Lignans, especially arctigenin and arctiin, had the extensive pharmacological effects such as anti-cancer, antiviral, anti-inflammatory activities. The ester derivatives of arctigenin had the anti-cancer, anti-Alzheimer's disease and immunity enhancing effects. Although Arctii Fructus extract had no toxicity, arctigenin was toxic at a certain dose. The alleviating effects of Arctii Fructus on chronic inflammation and ageing have been demonstrated by clinical studies.

CONCLUSION

Arctii Fructus is regarded as a worthy herb with many chemical components and various pharmacological effects. Several traditional applications have been supported by modern pharmacological research. However, their action mechanisms need to be further studied. Although many chemical components were isolated from Arctii Fructus, the current research mainly focused on lignans, especially arctiin and arctigenin. Therefore, it is very important to deeply clarify the pharmacological activities and action mechanism of the compounds and make full medicinal use of the resources of Arctii Fructus.

Chemoproteomics reveals arctigenin as a phagophore-closure blocker via targeting ESCRT-I subunit VPS28

Arctigenin is the active ingredient of the traditional medicines Arctium lappa and Fructus Arctii and has been extensively investigated for its diverse pharmacological functions, including its novel anti-austerity activity. Although several mechanisms have been proposed, the direct target of arctigenin to induce anti-austerity activity remains unclear. In this study, we designed and synthesized photo-crosslinkable arctigenin probes and utilized them in the chemoproteomic profiling of potential target proteins directly in living cells. Vacuolar protein sorting-associated protein 28 (VPS28), a key subunit of the ESCRT-I complex implicated in phagophore closure, was successfully identified. Unexpectedly, we found that arctigenin degraded VPS28 via the ubiquitin-proteasome pathway. We also demonstrated that arctigenin induces a prominent phagophore closure-blockade phenotype in PANC-1 cells. To the best of our knowledge, this is the first report of a small molecule acting as a phagophore-closure blocker and a VPS28 degrader. The arctigenin-modulating phagophore closure provides a new druggable target for cancers that rely heavily on autophagy activation and may also be used for other diseases associated with the ESCRT system.

Arctium lappa (Burdock): Insights from ethnopharmacology potential, chemical constituents, clinical studies, pharmacological utility and nanomedicine

Arctium lappa L. is a medicinal edible homologous plant, commonly known as burdock or bardana, which belongs to the Asteraceae family. It is widely distributed throughout Northern Asia, Europe, and North America and has been utilized for hundreds of years. The roots, fruits, seeds, and leaves of A. lappa have been extensively used in traditional Chinese Medicine (TCM). A. lappa has attracted a great deal of attention due to its possession of highly recognized bioactive metabolites with significant therapeutic potential. Numerous pharmacological effects have been demonstrated in vitro and in vivo by A. lappa and its bioactive metabolites, including antimicrobial, anti-obesity, antioxidant, anticancer, anti-inflammatory, anti-diabetic, anti-allergic, antiviral, gastroprotective, hepatoprotective, and neuroprotective activities. Additionally, A. lappa has demonstrated considerable clinical efficacies and valuable applications in nanomedicine. Collectively, this review covers the properties of A. lappa and its bioactive metabolites, ethnopharmacology aspects, pharmacological effects, clinical trials, and applications in the field of nanomedicine. Hence, a significant attention should be paid to clinical trials and industrial applications of this plant with particular emphasis, on drug discovery and nanotechnology.

Arctigenin: pharmacology, total synthesis, and progress in structure modification

Arctium lappa L. is a prevalent medicinal herb and a health supplement that is commonly used in Asia. Over the last few decades, the bioactive component arctigenin has attracted the attention of researchers because of its anti-inflammatory, antioxidant, immunomodulatory, multiple sclerosis fighting, antitumor, and anti-leukemia properties. After summarising the research and literature on arctigenin, this study outlines the current status of research on pharmacological activity, total synthesis, and structural modification of arctigenin. The purpose of this study is to assist academics in obtaining a more comprehensive understanding of the research progress on arctigenin and to provide constructive suggestions for further investigation of this useful molecule.

In vitro and in vivo inhibition of a novel arctigenin derivative on aquatic rhabdovirus

Spring viraemia of carp virus (SVCV) poses a serious threat to aquaculture industry due to the lack of approved antiviral treatments. Therefore, a novel arctigenin derivative, 4-(2-methylimidazole) octanoxy-arctigenin (MON), was synthesized to assess the antiviral activity against SVCV in vitro and in vivo. The results indicated MON decreased the SVCV glycoprotein (G) gene expression in vitro by a maximum inhibitory rate of > 99% at 3.5 μM. Furthermore, MON showed the protective effect on epithelioma papulosum cyprinid (EPC) cells and considerably decreased the cytopathic effect (CPE). More importantly, MON inhibited SVCV G gene expression levels in vitro at the half-maximal activity (IC₅₀) of 0.18 μM at 48 h. For in vivo studies, MON demonstrated anti-SVCV activity by enhancing the survival rate of zebrafish (Danio rerio) after infection via pelvic fin base injection. These results tended to be consistent with MON decreasing the SVCV titer of infected zebrafish. During this time, viral loads of the spleen and kidney have declined in SVSV-infected zebrafish. Based on the histopathological assay, MON exhibited the high protective effect in the spleen and kidney of SVCV-infected fish. Combined, MON is on track to become a novel agent to address SVCV infection in aquaculture.

Anti-inflammatory activity of arctigenin against PCV2 infection in a mouse model

Arctigenin (ACT) is a novel anti-inflammatory lignan extracted from Arctium lappa L, a herb commonly used in traditional Chinese herbal medicine. In this study, we investigated the molecular mechanism whereby ACT inhibits PCV2 infection-induced proinflammatory cytokine production in vitro and in vivo. We observed that in PCV2 infection+ACT treated PK-15 cells, proinflammatory cytokine production was significantly reduced, compared to the PCV2-infected cells. The transfection and luciferase reporter assay confirmed that ACT suppressed NF-κB signalling pathway activation following PCV2 infection in PK-15 cells. Furthermore, western blotting demonstrated that ACT suppressed the NF-κB signal pathway in PCV2 infection-stimulated PK-15 cells by inhibiting the translocation of p65 from the cytoplasm to the nucleus and IκBα phosphorylation. BALB/c mice were used as a model to evaluate the anti-inflammatory effect of ACT in vivo. We found that the BALB/c mice inoculated with PCV2 infection + ACT treated showed a significant reduction of proinflammatory cytokine production in serum, lung and spleen tissue, compared to the PCV2-infected mice. Western blotting confirmed that ACT suppressed the NF-κB signal pathway in PCV2-infected mice by inhibiting the translocation of p65 from the cytoplasm to the nucleus and IκBα phosphorylation in lung tissue. Our studies first demonstrate that ACT inhibits PCV2 infection-induced proinflammatory cytokine production by suppressing the phosphorylation and nuclear translocation of NF-κB in vitro and in vivo. These results will help further develop ACT as a Traditional Chinese herbal medicine remedy in the treatment of porcine circovirus-associated diseases.

Arctiin suppresses H9N2 avian influenza virus-mediated inflammation via activation of Nrf2/HO-1 signaling

BACKGROUND

H9N2 avian influenza viruses (AIVs) infect avian and mammalian hosts and provide internal genes for new emerging highly pathogenic avian viruses that cause severe pneumonia with high mortality, for which few medications are available. Arctiin, a bioactive lignan glycoside, has been reported to possess multiple pharmacological properties. However, the effect of arctiin on H9N2 virus infection is unclear. In the current study, we analyzed the effect of arctiin on H9N2 virus infection and the underlying molecular mechanism in vitro.

METHODS

The antiviral effect against H9N2 virus was determined by plaque reduction assay (PRA) and progeny virus reduction assay. We employed MTT assay, qRT-PCR, ELISA, immunofluorescence and Western blotting to better understand the anti-inflammatory effect and corresponding mechanism of arctiin on H9N2 virus-infected cells.

RESULTS

The results showed that arctiin had antiviral activity against H9N2 virus. Arctiin treatment reduced H9N2 virus-triggered proinflammatory cytokines, such as IL-6, and TNF-α. Moreover, arctiin significantly suppressed H9N2 virus-mediated expression of COX-2 and PGE₂. Furthermore, we found that arctiin inhibited H9N2 virus-mediated activation of RIG-I/JNK MAPK signaling. Interestingly, arctiin treatment obviously reversed H9N2 virus-induced reduction of Nrf2, increased the nuclear translocation of Nrf2, and upregulated Nrf2 signaling target genes (HO-1 and SOD2). Zinc protoporphyrin (Znpp)-an HO-1 inhibitor-weakened the inhibitory effect of arctiin on H9N2 virus-induced RIG-I/JNK MAPK and proinflammatory mediators.

CONCLUSION

Taken together, these results suggested that the anti-inflammatory effects of arctiin on H9N2 virus infection may be due to the activation of Nrf2/HO-1 and blocked RIG-I/JNK MAPK signaling; thus, arctiin may be a promising agent for prevention and treatment of H9N2 virus infections.

Fructus arctii: an overview on its traditional uses, pharmacology and phytochemistry

OBJECTIVES

Fructus arctii (F. arctii) is the dried ripe fruit of Arctium lappa Willd (Asteraceae). It is being used as a traditional medicine in China, Japan, Iran, Europe, Afghanistan, India, etc. for cough, inflammation, clearing the heat, detoxification, cancer and diabetes. This review summarized the botanical description, distribution, ethnopharmacology, bioactive constituents and pharmacological actions of F. arctii including methods to assess its quality. In addition, this review also provides insights into future research directions on F. arctii to further explore its bioactive constituents, mechanism involved in pharmacological activity, and clinical use including the development of new analytical methods for assessing the quality.

KEY FINDINGS

The comprehensive analysis of the literature revealed that F. arctii contains lignans, volatile oil, flavonoids, sesquiterpenoids, triterpenes, phenolic acids, etc. Experimental studies on various extracts and drug formulations showed that it has antioxidant, antimicrobial, hypoglycaemic, lipid-lowering, anti-inflammatory, analgesic, antiviral, anti-tumour activity, etc.

SUMMARY

The pharmacological activity of a few major constituents in F. arctii have been identified. However, there are still need more studies and more new technologies to prove the pharmacological activity and the effective mechanism of the other constituents that undergoing uncertain. Except for the animal experiments, clinical studies should be carried out to provide the evidence for clinical application.

Chinese herbal injections for coronavirus disease 2019 (COVID-19): A narrative review

Background

The outbreak of Coronavirus disease 2019 (COVID-19) has caused more than 180 million infections and 3.9 million deaths. To date, emerging clinical evidence has shown the synergetic benefits of Chinese herbal injections in treating this contagious respiratory disease. This review aims to summarize and analyze the efficacy and safety of Chinese herbal injections in the therapy of COVID-19.

Methods

The literature from 3 electronic databases, PubMed, CNKI, and Web of Science, were searched using the search terms “COVID-19”, “SARS-CoV-2”, “traditional Chinese medicine”, “herb”, “herbal”, and “injection”. Then the identified articles were comprehensively evaluated.

Results

Limited data demonstrated that Chinese herbal injections could significantly improve the clinical outcomes of COVID-19 patients, especially in combination with conventional treatment strategies. The benefits of which were mainly associated with the relief of symptoms, prevention of secondary infection, regulation of inflammation and immune function. There was also evidence showing the inhibitory effects on SARS-CoV-2 replication in vitro. Nevertheless, available real-world data suggested the increased risk of adverse event. Furthermore, the defects of existing researches and the insights for discovering novel antiviral drugs were prospectively discussed.

Conclusion

Evidence-based advances revealed that Chinese herbal injections such as XueBiJing injection and ShenMai injection, exerted potent effects against COVID-19. Further laboratory researches and clinical evaluation are needed to gather scientific evidence on the efficacy and safety.

Development of Broad-Spectrum Antiviral Agents-Inspiration from Immunomodulatory Natural Products

Developing broad-spectrum antiviral drugs remains an important issue as viral infections continue to threaten public health. Host-directed therapy is a method that focuses on potential targets in host cells or the body, instead of viral proteins. Its antiviral effects are achieved by disturbing the life cycles of pathogens or modulating immunity. In this review, we focus on the development of broad-spectrum antiviral drugs that enhance the immune response. Some natural products present antiviral effects mediated by enhancing immunity, and their structures and mechanisms are summarized here. Natural products with immunomodulatory effects are also discussed, although their antiviral effects remain unknown. Given the power of immunity and the feasibility of host-directed therapy, we argue that both of these categories of natural products provide clues that may be beneficial for the discovery of broad-spectrum antiviral drugs.

Simultaneous quantification of arctigenin and its glucuronide conjugate in mouse plasma using ultra-high performance liquid chromatography coupled to tandem mass spectrometry

Arctigenin is a natural lignin and a main active component of Fructus arctii, the dried fruit of Arctium lappa. This compound was reported to have some biological activities such as anti-inflammatory, antioxidant, antiviral, renoprotective, and antitumor effects. Arctigenin is mainly metabolized to arctigenin-4'-O-glucuronide by UDP-glucuronosyltransferase. In this study, a simultaneous quantification method was established and validated for measuring arctigenin and arctigenin-4'-O-glucuronide in mouse plasma using ultra-high performance liquid chromatography with tandem mass spectrometry. The assay fulfilled the requirements of the United States Food and Drug Administration guideline for assay validation, with a lower limit of quantification of 2.00 ng/mL for arctigenin and 50.0 ng/mL for arctigenin-4'-O-glucuronide. The recovery rate and matrix effect ranged from 78.4 to 102.8% and 92.5 to 106.3%, respectively, for arctigenin, and 74.3 to 109.2% and 94.9 to 110.2% for arctigenin-4'-O-glucuronide. The method was applied to the measurement of plasma concentrations of arctigenin and arctigenin-4'-O-glucuronide in the plasma of mice after administration of arctigenin. All measured concentrations were within the calibration ranges. Our novel method may be useful to measure plasma arctigenin and arctigenin-4'-O-glucuronide concentrations, and contribute to evaluate the pharmacokinetics of arctigenin and arctigenin-4'-O-glucuronide in mice.

Arctigenin suppresses cell proliferation via autophagy inhibition in hepatocellular carcinoma cells

Autophagy is a catabolic process that degrades dysfunctional proteins and organelles and plays critical roles in cancer development. Our preliminary screening identified that extracts of the fruits of Arctium lappa and the fruits of Forsythia suspensa notably suppressed the proliferation of hepatocellular carcinoma HepG2 cells and downregulated the autophagy. In this study, we explored the effect of arctigenin (ARG), a bioactive lignan in both extracts, on cell proliferation and autophagy-related proteins in HepG2 cells. ARG inhibited the proliferation of HepG2 cells. Analysis of autophagy-related proteins demonstrated that ARG might block the autophagy that leads to sequestosome 1/p62 (p62) accumulation. The stage of inhibition in autophagy by ARG differed from those by the autophagy inhibitors 3-methyladenine (3-MA) or chloroquine (CQ). ARG could also inhibit starvation-induced autophagy. Further analysis of apoptosis-related proteins indicated that ARG did not affect caspase-3 activation and PARP cleavage, suggesting that the antiproliferative effect of ARG can occur independently of apoptosis. In summary, our study showed that ARG suppresses cell proliferation and inhibits autophagy, and might lead to the development of agents for autophagy research and cancer chemoprevention.

Anti‑metastatic effects of arctigenin are regulated by MAPK/AP‑1 signaling in 4T‑1 mouse breast cancer cells

Arctigenin is a natural lignan that is found in burdock with anti‑viral, ‑oxidative, ‑inflammatory and anti‑tumor activities. In the current study, the effect of arctigenin on metastatic potential was examined in 4T‑1 mouse triple‑negative breast cancer cells. The results indicated that arctigenin inhibited cell motility and invasiveness, which was determined using wound healing and transwell invasion assays. Arctigenin suppressed matrix metalloprotease‑9 (MMP‑9) activity via gelatin zymography, and protein expression of cyclooxygenase‑2 (COX‑2) and MMP‑3. Furthermore, arctigenin attenuated the mRNA expression of metastatic factors, including MMP‑9, MMP‑3 and COX‑2. Based on these results, the effect of arctigenin on the mitogen‑activated protein kinase (MAPK)/activating protein‑1 (AP‑1) signaling pathway was assessed in an attempt to identify the regulatory mechanism responsible for its anti‑metastatic effects. Arctigenin was demonstrated to inhibit the phosphorylation of extracellular signal‑regulated protein kinase (ERK) and c‑Jun N‑terminal kinase (JNK), and the nuclear translocations of the AP‑1 subunits, c‑Jun and c‑Fos. In summary, the present study demonstrated that in 4T‑1 mouse triple‑negative breast cancer cells the anti‑metastatic effect of arctigenin is mediated by the inhibition of MMP‑9 activity and by the inhibition of the metastasis‑enhancing factors MMP‑9, MMP‑3 and COX‑2, due to the suppression of the MAPK/AP‑1 signaling pathway. The results of the current study demonstrated that arctigenin exhibits a potential for preventing cell migration and invasion in triple negative breast cancer.

Toxicity Study of 28-Day Subcutaneous Injection of Arctigenin in Beagle Dogs

Our previous studies have investigated the systematic pharmacokinetic characteristics, biological activities, and toxicity of arctigenin. In this research, the potential toxicities of arctigenin in beagle dogs were investigated via repeated 28-day subcutaneous injections. Beagle dogs were randomly divided into control, vehicle [polyethylene glycol (PEG)], and arctigenin 6, 20, 60 mg/kg treated groups. The whole experimental period lasted 77 days, including adaptive period (35 days), drug exposure period (animals were treated with saline, PEG, or arctigenin for 28 consecutive days), and recovery period (14 days). Arctigenin injection (60 mg/kg) affected the lymphatic hematopoietic, digestive, urinary, and cardiovascular systems, and all the impact on these tissues resulted in death in five dogs (three female and two male dogs); 20 mg/kg arctigenin injection resulted in toxic reactions of the lymphatic hematopoietic and digestive systems; and 6 mg/kg arctigenin and PEG injection did not lead to significant toxic reactions. Meanwhile, there were no sexual differences of drug exposure and accumulation when dogs underwent different dosages. As stated previously, the toxic target organs of arctigenin administration include lymphatic hematopoietic, digestive (liver and gallbladder), urinary (kidney), and cardiovascular (heart) systems, and the no observed adverse effect level (NOAEL) of arctigenin is less than 6 mg/kg.

Synthesis and antiviral activity of a new arctigenin derivative against IHNV in vitro and in vivo

Viral diseases in aquaculture were challenging because there are few preventative measures and/or treatments. Our previous study indicated that imidazole arctigenin derivatives possessed antiviral activities against infectious hematopoietic necrosis virus (IHNV). Based on the structure-activity relationship in that study, a new imidazole arctigenin derivative, 4-(8-(2-ethylimidazole)octyloxy)-arctigenin (EOA), was designed, synthesized and its anti-IHNV activity was evaluated. By comparing inhibitory concentration at half-maximal activity (IC₅₀), we found that EOA (IC₅₀ = 0.56 mg/L) possessed a higher antiviral activity than those imidazole arctigenin derivatives in our previous study. Besides, EOA could significantly decrease cytopathic effect (CPE) and viral titer induced by IHNV in epithelioma papulosum cyprinid (EPC) cells. In addition, EOA significantly inhibited apoptosis induced by IHNV in EPC cells. Further data verified that EOA inhibited IHNV replication in rainbow trout, with reducing 32.0% mortality of IHNV-infected fish. The results suggested that EOA was more stable with a prolonged inhibitory half-life in the early stage of virus infection (1-4 days). Consistent with above results, EOA repressed IHNV glycoprotein gene expression in virus sensitive tissues (kidney and spleen) in the early stage of virus infection. Moreover, histopathological evaluation showed that tissues from the spleen and kidney of fish infected with IHNV exhibited pathological changes. But there were no lesions in any of the tissues from the control group and EOA-treaten group. In accordance with the histopathological assay, EOA could elicited anti-inflammation response in non-viral infected rainbow trout by down-regulating the expression of cytokine genes (IL-8, IL-12p40, and TNF-α). Altogether, EOA was expected to be a therapeutic agent against IHNV infection in the field of aquaculture.

Pharmacokinetics of Arctigenin and Fructus Arctii Powder in Piglets

Fructus arctii, also known as great power seed, is the dried fruit of Arctium lappa of the family Compositae. It is a commonly used veterinary herbal medicine, and arctigenin is the main active ingredient. The aim of this study was to characterize the absorption, distribution, metabolism, and excretion of arctigenin and Fructus arctii powder in piglets. These data were used to provide a theoretical reference for the development and clinical use of new veterinary drugs. Sixteen healthy piglets (mean weight 30.0 ± 5.0 kg) were divided into two groups. One group was administered 2.0 mg/kg body weight (bw) arctigenin intravenously, and the other was administered 1.0 g/kg^.bw Fructus arctii powder by gavage. Blood samples were collected from the anterior vena cava at different time points, and the concentration of arctigenin in the plasma of the piglets was determined using high-performance liquid chromatography (HPLC). Arctigenin conformed to a two-compartment model with no absorption, and the main pharmacokinetic parameters were as follows: distribution half-life (t_1/2α)−0.166 ± 0.022 h; elimination half-life (t_1/2β)−3.161 ± 0.296 h; apparent volume of distribution (V_d)−0.231 ± 0.033 L/kg; clearance rate (CL_b)−0.057 ± 0.003 L/(h.kg); and area under the curve (AUC)−1.189 ± 0.057 g^.h/mL. The pharmacokinetic parameters of arctigenin following oral administration of the Fructus arctii powder were as follows: absorption half-life (t_1/2ka)−0.274 ± 0.102 h, t_1/2α−1.435 ± 0.725 h, t_1/2β−63.467 ± 29.115 h, V_d−1.680 ± 0.402 L/kg, CL_b−0.076 ± 0.028 L/(h kg), peak time (t_max)−0.853 ± 0.211 h, peak concentration (C_max)−0.430 ± 0.035 g/mL, and AUC−14.672 ± 4.813 g/mL. These results indicated that intravenous arctigenin was sparingly distributed in tissues. In contrast, orally administered Fructus arctii powder was rapidly absorbed, more widely distributed, and more slowly eliminated than the intravenous arctigenin, which may indicate its sustained pharmacological effects.

Lignans and Neolignans: Plant secondary metabolites as a reservoir of biologically active substances

Lignans and neolignans are plant secondary metabolites derived from the oxidative coupling of phenylpropanoids. Biological activity of these phenolic compounds ranges from antioxidant, antitumor (terminaloside P, IC₅₀ = 10 nM), anti-inflammatory, anti-neurodegenerative (schibitubin B, IC₅₀ = 3.2 nM) and antiviral (patentiflorin A, IC₅₀ = 14-23 nM) to antimicrobial. In addition, it was observed that several members of this group, namely enterolactone and its biochemical precursors also known as phytoestrogens, possess important protective properties. Most of these lignans and neolignans are presented in reasonable amounts in one's diet and thus the protection they provide against the colon and breast cancer, to name a few, is even more important to note. Similarly, neuroprotective properties were observed (schisanwilsonin G, IC₅₀ = 3.2 nM) These structural motives also serve as an important starting point in the development of anticancer drugs. Presumably the most famous members of this family, etoposide and teniposide, synthetic derivatives of podophyllotoxin, are used in the clinical treatment of lymphocytic leukemia, certain brain tumors, and lung tumors already for nearly 20 years. This review describes 413 lignans and neolignans which have been isolated between 2016 and mid-2018 being reported in more than 300 peer-reviewed articles. It covers their source, structure elucidation, and bioactivity. Within the review, the structure-based overview of compounds as well as the bioactivity-based overview of compounds are described.

Synthesis of arctigenin derivatives against infectious hematopoietic necrosis virus

Infectious hematopoietic necrosis virus (IHNV) is a common pathogen that causes severe disease and huge economic losses in the salmonid aquaculture industry. Herein, a series of arctigenin derivatives are synthesized to evaluate their antiviral activity against IHNV. The results indicate that the length of linker and imidazole substituent groups play an important role in decreasing IHNV replication. In this study, the arctigenin-imidazole hybrid derivative 15 with an eight carbon atoms length of the linker reduces IHNV replication with an IC₅₀ value of 1.3 μM. In addition, derivative 15 significantly inhibits apoptosis and cellular morphological damage induced by IHNV. Mechanistically, derivative 15 can not damage the viral particle directly. While time-of-addition and viral binding assays reveal that derivative 15 mainly affect the early replication of IHNV but do not interfere with IHNV adsorption. Overall, derivative 15 could be considered to develop as a promising agent to treat IHNV infection.

Arctigenin Induces an Activation Response in Porcine Alveolar Macrophage Through TLR6-NOX2-MAPKs Signaling Pathway

Arctigenin (ARG), one of the most active ingredients abstracted from seeds of Arctium lappa L., has been proved to exert promising biological activities such as immunomodulatory, anti-viral, and anti-cancer etc. However, the mechanism behind its immunomodulatory function still remains elusive to be further investigated. In this study, we found that ARG had no significant effects on the cell proliferation in both porcine alveolar macrophage cell line (3D4/21) and primary porcine derived alveolar macrophage. It remarkably increased the expression and secretion of the two cytokines including tumor necrosis factor-alpha (TNF-α) and transforming growth factor beta1 (TGF-β1) in a dose-dependent manner with the concomitant enhancement of phagocytosis, which are the indicators of macrophage activation. ARG also elevated the intracellular reactive oxygen species (ROS) production by activating NOX2-based NADPH oxidase. Furthermore, inhibition of ROS generation by diphenyliodonium and apocynin significantly suppressed ARG-induced cytokine secretion and phagocytosis increase, indicating the requirement of ROS for the porcine alveolar macrophage activation. In addition, TLR6-My88 excitation, p38 MAPK and ERK1/2 phosphorylation were all involved in the process. As blocking TLR6 receptor dramatically attenuated the NOX2 oxidase activation, cytokine secretion and phagocytosis increase. Inhibiting ROS generation almost abolished p38 and ERK1/2 phosphorylation, and the cytokine secretion could also be remarkably reduced by p38 and ERK1/2 inhibitors (SB203580 and UO126). Our finding gave a new insight of understanding that ARG could improve the immune-function of porcine alveolar macrophages through TLR6-NOX2 oxidase-MAPKs signaling pathway.

Overview of the anti-inflammatory effects, pharmacokinetic properties and clinical efficacies of arctigenin and arctiin from Arctium lappa L

Arctigenin (AR) and its glycoside, arctiin, are two major active ingredients of Arctium lappa L (A lappa), a popular medicinal herb and health supplement frequently used in Asia. In the past several decades, bioactive components from A lappa have attracted the attention of researchers due to their promising therapeutic effects. In the current article, we aimed to provide an overview of the pharmacology of AR and arctiin, focusing on their anti-inflammatory effects, pharmacokinetics properties and clinical efficacies. Compared to acrtiin, AR was reported as the most potent bioactive component of A lappa in the majority of studies. AR exhibits potent anti-inflammatory activities by inhibiting inducible nitric oxide synthase (iNOS) via modulation of several cytokines. Due to its potent anti-inflammatory effects, AR may serve as a potential therapeutic compound against both acute inflammation and various chronic diseases. However, pharmacokinetic studies demonstrated the extensive glucuronidation and hydrolysis of AR in liver, intestine and plasma, which might hinder its in vivo and clinical efficacy after oral administration. Based on the reviewed pharmacological and pharmacokinetic characteristics of AR, further pharmacokinetic and pharmacodynamic studies of AR via alternative administration routes are suggested to promote its ability to serve as a therapeutic agent as well as an ideal bioactive marker for A lappa.

Mouse models of porcine circovirus 2 infection

PCV2 is considered the main pathogen of porcine circovirus diseases and porcine circovirus-associated diseases (PCVD/PCVAD). However, the exact mechanism underlying PCVD/PCVAD is currently unknown. Mouse models of PCV2 are valuable experimental tools that can shed light on the pathogenesis of infection and will enable the evaluation of antiviral agents and vaccine candidates. In this review, we discuss the current state of knowledge of mouse models used in PCV2 research that has been performed to date, highlighting their strengths and limitations, as well as prospects for future PCV2 studies.

Evaluation on the antiviral activity of arctigenin against spring viraemia of carp virus

Spring viraemia of carp virus (SVCV) causes high morality in several economically important cyprinid fishes, but there is no approved therapy up to now. To address the urgent need for therapeutics to combat SVCV infection, we investigated the anti-SVCV activities of 12 natural compounds and 7 common antiviral agents using epithelioma papulosum cyprini (EPC) cells in this study. From the 19 compounds, we identified arctigenin (ARG) has the highest inhibition on SVCV replication, with maximum inhibitory percentage on SVCV > 90%. And the 48 h half maximal inhibitory concentrations (IC₅₀) of ARG on SVCV glycoprotein and nucleoprotein were 0.29 (0.22-0.39) and 0.35 (0.29-0.41) mg/L respectively. In addition, ARG significantly reduced SVCV-induced apoptosis and recovered SVCV-activated caspase-3/8/9 activity. Further, cellular morphological damage induced by SVCV was blocked by ARG treatment. Mechanistically, ARG did not affect SVCV infectivity. Moreover, ARG could not induce reactive oxygen species (ROS) generation, which plays an antiviral role on SVCV. Interestingly, SVCV-induced autophagy which is necessary for virus replication was inhibited by ARG treatment. These results indicated that the inhibition of ARG on SVCV replication was, at least in part, via blocking SVCV-induced autophagy. Taken together, ARG has the potential to work as an agent for protecting economically important fishes against SVCV.

In vitro schistosomicidal and antiviral activities of Arctium lappa L. (Asteraceae) against Schistosoma mansoni and Herpes simplex virus-1

Schistosomiasis and herpes diseases represent serious issues to the healthcare systems, infecting a large number of people worldwide, mainly in developing countries. Arctium lappa L. (Asteraceae), known as "bardana" and "burdock", is a medicinal plant popularly used for several purposes, including as antiseptic. In this study, we evaluated the in vitro schistosomicidal and antiherpes activities of the crude extract of A. lappa, which have not yet been described. Fruits of A. lappa L. were extracted by maceration with ethanol: H₂O (96:4 v/v) in order to obtain the hydroalcoholic extract of A. lappa (AL). In vitro schistosomicidal assays were assessed against adult worms of Schistosoma mansoni, while the in vitro antiviral activity of AL was evaluated on replication of Herpes simplex virus type-1 (HSV-1). Cell viability was measured by MTT assay, using Vero cells and chemical composition of AL was determined by qualitative UPLC-ESI-QTOF-MS analysis. UPLC-ESI-QTOF-MS analysis of AL revealed the presence of dibenzylbutyrolactone lignans, such as arctiin and arctigenin. Results showed that AL was not cytotoxic to Vero cells even when tested at 400μg/mL. qPCR results indicated a significant viral load decreased for all tested concentrations of AL (400, 50, and 3.125μg/mL), which showed similar antiviral effect to acyclovir (50μg/mL) when tested at 400μg/mL. Also, AL (400, 200, and 100μg/mL) caused 100% mortality and significantly reduction on motor activity of all adult worms of S. mansoni. Confocal laser scanning microscopy showed tegumental morphological alterations and changes on the numbers of tubercles of S. mansoni worms in a dose-dependent manner after treatment with AL. This report provides the first evidence for the in vitro schistosomicidal and antiherpes activities of AL, opening the route to further schistosomicidal and antiviral studies with AL and their compounds, especially lignans.

Global Status of Porcine circovirus Type 2 and Its Associated Diseases in Sub-Saharan Africa

Globally, Porcine circovirus type 2 (PCV2) is a recognized viral pathogen of great economic value in pig farming. It is the major cause of ravaging postweaning multisystemic wasting syndrome (PMWS) and many other disease syndromes generally regarded as Porcine circovirus associated diseases (PCVAD) in Europe. PCV2 infections, specifically PMWS, had impacted huge economic loss on swine production at different regions of the world. It has been studied and reported at different parts of the globe including: North and South America, Europe, Asia, Oceania, Middle East, and the Caribbean. However, till date, this virus and its associated diseases have been grossly understudied in sub-Sahara African region and the entire continent at large. Two out of forty-nine, representing just about 4% of countries that make up sub-Sahara Africa presently, have limited records on reported cases and occurrence of the viral pathogen despite the ubiquitous nature of the virus. This review presents an overview of the discovery of Porcine circovirus and its associated diseases in global pig herds and emphasizes the latest trends in PCV2 vaccines and antiviral drugs development and the information gaps that exist on the occurrence of this important viral pathogen in swine herds of sub-Saharan Africa countries. This will serve as wake-up call for immediate and relevant actions by stakeholders in the region.