Synthesis and anthelmintic activity of arctigenin derivatives against Dactylogyrus intermedius in goldfish

Synthesis and anti-parasites efficacy of coumarin derivatives against Dactylogyrus intermedius

Dactylogyrus is one of the most common parasitic diseases in fish and causes huge losses to the aquaculture industry. With the advantages of safety, low toxicity and easy degradation, plant-derived drugs are ideal for the creation of green aquatic ingredients. The use of plant-derived drugs in aquaculture is limited by their low content and high processing costs, which is a challenge that can be solved by the chemical synthesis of plant-derived drugs. Eleven new coumarin derivatives were synthesized and assessed for their anthelmintic activity in this study. Among them, the derivative 7-((1-tosyl-1H-1,2,3-triazol-4-yl)methoxy)-2H-chromen-2-one (N11) has good anthelmintic activity and its mean anthelmintic efficacy against D. intermedius at a concentration of 10 μM reached 99.84%, which is even better than the anthelmintic activity of the positive control mebendazole. Further studies showed that N11 had concentration values of 3.31 and 1.94 μM for 50% maximal effect (EC50 ) against D. intermedius at 24 and 48 h, respectively. Furthermore, scanning electron microscopy revealed that N11 caused damage to D. intermedius. What is more noteworthy is that a substantial reduction in the ATP content of the parasite was observed following in vitro and in vivo administration of N11. Moreover, it was also found that N11 was able to inhibit the horizontal transmission of D. intermedius. Furthermore, real-time quantitative PCR analysis was utilized to determine the expression profile of genes associated with anti-inflammatory cytokines (IL-10, TGF-β and IL-4) in goldfish. In all examined organs, it was observed that the expression of anti-inflammatory cytokines increased subsequent to treatment with N11, according to the results. Thus, these results all suggest that N11 possesses good anthelmintic activity and is a potentially effective agent for the control of D. intermedius.

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.

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 Studies of the Antiparasitic Effect of Aspirin Against Dactylogyrus Extensus (Monogenea) Invasion in Carp (Cyprinus carpio)

Aspirin is one of the most widely used medications globally as an analgesic and antipyretic drug. Aspirin use as an antiparasitic against fish parasites has never been tested. The parasite Dactylogyrus is considered a serious threat to freshwater aquaculture in relation to considerable losses. The present study is aimed to evaluate the antiparasitic effect of aspirin against Dactylogyrus extensus on Cyprinus carpio and alteration in gill histopathology. In vitro, aspirin exhibited antiparasitic activity with median effective concentration (EC50) values at one and six minutes of 8.137 g/L−1 and 1.629 g/L−1, were assessed for the first time. In vivo antiparasitic efficacy of aspirin to D. extensus was found to be 46.49%. Severe lesion profile was observed in histopathological evaluations of the gills.

Synthesis and biological evaluation of novel coumarin derivatives in rhabdoviral clearance

Diseases caused by rhabdoviruses have had a huge impact on the productive lives of the entire human population. The main problem is the lack of drugs for the treatment of this family of viruses. Infectious hematopoietic necrosis virus (IHNV), the causative agent of IHN, is a typical rhabdovirus which has caused huge losses to the salmonid industry. Therefore, in this study, IHNV was studied as a model to evaluate the antiviral activity of 35 novel coumarin derivatives. Coumarin A9 was specifically selected for further validation studies upon comparing the half maximum inhibitory concentration (IC₅₀) of four screened candidate derivatives in epithelioma papulosum cyprinid (EPC) cells, as it exhibited an IC₅₀ value of 2.96 μM against IHNV. The data revealed that A9 treatment significantly suppressed the virus-induced cytopathic effect (CPE) in EPC cells. In addition, A9 showed IC₅₀ values of 1.68 and 2.12 μM for two other rhabdoviruses, spring viremia of carp virus and micropterus salmoides rhabdovirus, respectively. Furthermore, our results suggest that A9 exerts antiviral activity, but not by destroying the virus particles and interfering with the adsorption of IHNV. Moreover, we found that A9 had an inhibitory effect on IHNV-induced apoptosis in EPC cells, as reflected by the protection against cell swelling, formation of apoptotic bodies, and loss of cell morphology and nuclear division. There was a 19.05 % reduction in the number of apoptotic cells in the A9 treatment group compared with that in the IHNV group. In addition, enzyme activity assays proved that A9 suppressed the expression of caspase 3, 8 and 9. These results suggested that A9 inhibit viral replication, to some extent, by blocking IHNV-induced apoptosis. In an in vivo study, A9 exhibited an anti-rhabdovirus effect in virus-infected fish by substantially enhancing the survival rate. Consistent with the above results, A9 repressed IHNV gene expression in virus-sensitive tissues (brain, kidney and spleen) in the early stages of virus infection. Importantly, the data showed that horizontal transmission of IHNV was reduced by A9 in a static cohabitation challenge model, especially in fish that underwent bath treatment, suggesting that A9 might be a suitable therapeutic agent for IHNV in aquaculture. Therefore, coumarin derivatives can be developed as antiviral agents against rhabdoviruses.

Discovery of stereospecific cytotoxicity of (8R,8'R)-trans-arctigenin against insect cells and structure-activity relationship on aromatic ring

One of the arctigenin stereoisomers, (8R,8'R)-trans-form 1, showed stereospecific cytotoxicity against insect cells, Sf9 and NIAS-AeAl-2 cells. By the comparison with other stereoisomers, the most importance of the 8'R stereochemistry for the higher activities was clarified. On the other hand, the wider range of activity level among stereoisomers against cancer cells, HL-60, was not observed. The structure-activity relationship research using derivatives bearing (8R,8'R)-trans-form was performed to show the same level of activities of 3-iodo, 4-iodo, and 3,4-methylenedioxy derivatives 28, 29, and 36 as (8R,8'R)-trans-arctigenin 1. In the examination of thiono derivatives, 4-iodo thiono and 3,4-methylenedioxy thiono derivatives 66, 67 showed similar level of activities to that of (8R,8'R)-trans-arctigenin 1. The expression of ribosomal 28S rRNA gene of Sf9 cells was increased by (8R,8'R)-trans-arctigenin 1, whereas a degradation of DNA was not observed.

Proteome interrogation using gold nanoprobes to identify targets of arctigenin in fish parasites

Gold nanoparticles (GNPs) are one of the most widely used nanomaterials in various fields. Especially, the unique chemical and physical properties make them as the promising candidates in drug target identification, unfortunately, little is known about their application in parasites. In this paper, GNPs were employed as new solid support to identify drug targets of natural bioactive compound arctigenin (ARG) against fish monogenean parasite Gyrodactylus kobayashi. Before target identification, GNPs with ARG on the surface showed the ability to enter the live parasites even the nucleus or mitochondria, which made the bound compounds capable of contacting directly with target proteins located anywhere of the parasites. At the same time, chemically modified compound remained the anthelminthic efficacy against G. kobayashii. The above results both provide assurance on the reliability of using GNPs for drug target-binding specificity. Subsequently, by interrogating the cellular proteome in parasite lysate, myosin-2 and UNC-89 were identified as the potential direct target proteins of ARG in G. kobayashii. Moreover, results of RNA-seq transcriptomics and iTRAQ proteomics indicated that myosin-2 expressions were down-regulated after ARG bath treatment both in transcript and protein levels, but for UNC-89, only in mRNA level. Myosin-2 is an important structural muscle protein expressed in helminth tegument and its identification as our target will enable further inhibitor optimization towards future drug discovery. Furthermore, our findings demonstrate the power of GNPs to be readily applied to other parasite drugs of unknown targets, facilitating more broadly therapeutic drug design in any pathogen or disease model.

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.

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.

Synthesis and in vitro activities evaluation of arctigenin derivatives against spring viraemia of carp virus

Spring viraemia of carp virus (SVCV) is a viral fish pathogen causing high mortality in several carp species and other cultivated fish. However, robust anti-SVCV drugs currently are extremely scarce. For the purpose of seeking out anti-SVCV drugs, here a total of 35 arctigenin derivatives were designed, synthesized and evaluated for their anti-viral activities. By comparing the inhibitory concentration at half-maximal activity (IC₅₀) of the 15 screened candidate drugs (max inhibitory response surpassing 90%) in epithelioma papulosum cyprini (EPC) cells infected with SVCV, 2Q and 6 A were chosen for additional validation studies, with an IC₅₀ of 0.077 μg/mL and 0.095 μg/mL, respectively. Further experiments revealed that 2Q and 6 A could significantly decrease SVCV-induced apoptosis and have a protective effect on cell morphology at 48 and 72 h post-infection. Moreover, the reactive oxygen species (ROS) induced upon SVCV infection could be obviously inhibited by 2Q and 6 A, while SVCV-infected cells were clearly observed. On account of these findings, 2Q and 6 A could have a promising application for the treatment of infection of SVCV and provide a considerable reference for novel antivirals in aquaculture.

Synthesis and evaluation of novel arctigenin derivatives as potential anti-Toxoplasma gondii agents

Four new series of arctigenin derivatives were designed, synthesised, and evaluated for their anti-Toxoplasma gondii activity in vitro and in vivo. Among the synthesised compounds, 4-(3,4-dimethoxybenzyl)-3-(4-((1-(2-fluorobenzyl)-1H- 1,2,3-triazol-4-yl)methoxy)-3-methoxybenzyl)dihydrofuran-2(3H)-one (D4) exhibited the most potent anti-T. gondii activity and low cytotoxicity (IC₅₀ in T. gondii: 17.1 μM; IC₅₀ in HeLa cells: ≥ 600.0 μM; Selectivity: 35.09), demonstrating better results than the lead compound arctigenin (IC₅₀ in T. gondii: 586.4 μM; IC₅₀ in HeLa cells: 572.7 μM; Selectivity: 0.98) and the clinically applied positive-control drug spiramycin (IC₅₀ in T. gondi: 262.2 μM; IC₅₀ in HeLa cells: 189.0 μM; Selectivity: 0.72) in vitro. Furthermore, 2-(4-((4-(3,4-dimethoxybenzyl)-2-oxotetrahydrofuran-3-yl)methyl)-2- methoxyphenoxy)N-phenylacetamide (E5) had better inhibitory effects on T. gondii in vivo than spiramycin did. Compound D4 and E5 not only significantly reduced the number of tachyzoites in the peritoneal cavity of mice, but also resulted in their partial malformation (P < 0.05) in vivo. The determination of liver and spleen index and biochemical parameters, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutathione (GSH) and malondialdehyde (MDA), were comprehensively evaluated for compound D4 and E5's anti-T. gondii activity and some damage to the liver. In addition, the results of a docking study of D4 into the T. gondii calcium-dependent protein kinase 1 (TgCDPK1) receptor protein-binding site revealed that its mode of action was possibly as a TgCDPK1 inhibitor. Overall, the results revealed that D4 and E5 are promising lead compounds for the further development and identification of arctigenin derivatives as anti-T. gondii agents.