Natural compounds isolated from Brazilian plants are potent inhibitors of hepatitis C virus replication in vitro

Medicinal plant molecules against hepatitis C virus: Current status and future prospect

Hepatitis C virus (HCV), a global malady, causes acute and chronic hepatitis leading to permanent liver damage, hepatocellular carcinoma, and death. Modern anti-HCV therapies are efficient, but mostly inaccessible for residents of underdeveloped regions. To innovate more effective treatments at affordable cost, medicinal plant-based products need to be explored. The aim of this article is to review plant constituents in the light of putative anti-HCV mechanisms of action, and discuss existing problems, challenges, and future directions for their potential application in therapeutic settings. One hundred sixty literatures were collected by using appropriate search strings via scientific search engines: Google Scholar, PubMed, ScienceDirect, and Scopus. Bibliography was prepared using Mendeley desktop software. We found a substantial number of plants that were reported to inhibit different stages of HCV life cycle. Traditional medicinal plants such as Phyllanthus amarus Schumach. and Thonn., Eclipta alba (L.) Hassk., and Acacia nilotica (L.) Delile exhibited strong anti-HCV activities. Again, several phytochemicals such as epigallocatechin-3-gallate, honokilol, punicalagin, and quercetin have shown broad-spectrum anti-HCV effect. We have presented promising phytochemicals like silymarin, curcumin, glycyrrhizin, and camptothecin for nanoparticle-based hepatocyte-targeted drug delivery. Nevertheless, only a few animal studies have been performed to validate the anti-HCV effect of these plant products. Again, insufficient clinical evaluation of the safety and effectiveness of herbal medications remain a problem. Selected plants products could be developed as novel therapeutics for HCV patients only after scrupulous evaluation of their safety and efficacy in a clinical set-up.

Insights into enterovirus a-71 antiviral development: from natural sources to synthetic nanoparticles

Enteroviruses are pathogens responsible for several diseases, being enterovirus A71 (EVA71) the second leading cause of hand, foot, and mouth disease (HFMD), especially in Asia-Pacific countries. HFMD is mostly common in infants and children, with mild symptoms. However, the disease can result in severe nervous system disorders in children as well as in immunosuppressed adults. The virus is highly contagious, and its transmission occurs via fecal-oral, oropharyngeal secretions, and fomites. The EVA71 burdens the healthy systems and economies around the world, however, up to date, there is no antiviral approved to treat infected individuals and the existent vaccines are not available or approved to be used worldwide. In this context, an extensive literature research was conducted to describe and summarize the recent advances in natural and/or synthetic compounds with antiviral activity against EVA71. The summarized data presented here might simply encourage the future studies in EVA71 antiviral development, by encouraging further research encompassing these compounds or even the application of the techniques and technologies to improve or produce new antiviral molecules.

Promising alkaloids and flavonoids compounds as anti-hepatitis c virus agents: a review

Background: Virus infections are presently seen as a major public health problem. Hepatitis C Virus (HCV) is recognized as a “silent killer” because the acute infection has no symptoms, and it develops as a chronic infection that causes hepatocellular carcinoma and liver damage. The World Health Organization (WHO) predicts that between 130-170 million people are estimated to have chronic Hepatitis C. Plants have various phytochemical compounds such as alkaloids and flavonoids that have prominent antiviral effects especially anti-HCV. The current HCV treatment still has limitations related to side effects and can lead to viral resistance. Therefore, it is necessary for the discovery and development of novel anti-HCV drugs for alternative and complementary medicine. Objective: This review intends to evaluate the alkaloids and flavonoids that have the potential to be used against HCV by looking at their classification and their mechanism of action. Methods: Twenty-one articles from 2010 to 2022 obtained from PUBMED database using keywords such as isolated compounds, alkaloids, flavonoids, hepatitis C virus. Results: 21 alkaloids and 37 flavonoids reported active against HCV. Alkaloids include quinoline, quinolizidine and isoquinoline. In addition, flavanone, flavonol, flavone, flavan-3-ol, flavonolignan, anthocyanidin and proanthocyanidin comprise flavonoids. The berberine alkaloids and eriodictyol 7-O-(6′′-caffeoyl)-β-D- glucopyranoside flavonoids had the lowest IC50 with values of 0.49 mM and 0.041 nM. Conclusions: Alkaloids and flavonoids compound had good activity against HCV with various mechanisms. Our results provide information of alkaloids and flavonoids to the researcher for the development of alternative and complementary medicine of hepatitis C.

The long and stumble way to find potential active compounds from plants for defeating hepatitis B and C: review

Hepatitis is a liver illness caused by virus such as hepatitis A virus, hepatitis B virus and hepatitis C virus. Hepatitis B and C are considerably more usual and induce more cirrhosis and dead worldwide than hepatitis A. Although drugs that are currently often used in the medication of hepatitis B and C, the finding of recent drug from various resources including herbal has been intensively developed. Therefore, the purpose of this review is to consider the possibility of plant’s compounds as anti-HBV and anti-HCV. From the results of a review of several articles, several plant’s compound have shown effectiveness againts HBV and HCV by in silico, in vitro and in vivo studies. In conclusion, several plant’s active compounds are possibility to be developed as anti-hepatitis B and C.

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.

An in vitro study of an Artocarpus heterophyllus substance as a hepatitis C antiviral and its combination with current anti-HCV drugs

Background

Current therapy of chronic hepatitis C virus (HCV) with direct-acting antivirals (DAAs) has dramatically improved the sustained virologic response (SVR) of affected patients; however, treatment with DAAs remains expensive, and drug-resistant HCV variants remain a threat. As a result, there is still a need to continue to develop affordable and effective drugs for the treatment of HCV. Previously, we have demonstrated that a crude extract from Artocarpus heterophyllus leaves is a potential anti-HCV candidate. In this study, we have further purified this crude extract, examined which sub-fraction possesses the highest antiviral activity, and then explored its efficacy at different HCV life cycle stages. We also assessed synergistic antiviral effects between the A. heterophyllus extract and commercially available anti-HCV drugs.

Methods

We used vacuum liquid chromatography (VLC) and high-performance liquid chromatography (HPLC) to fractionate a dichloromethane extract of A. heterophyllus leaves. We then examined the anti-HCV activity of the fractions using HCV genotype 2a, JFH1a; the antiviral mode of action was determined by exploring adding the treatments at different times. We examined the antiviral effects on the viral entry stage through a virucidal activity test, viral adsorption examination, and pretreatment of cells with the drug. The effects on the post-viral entry stage were determined by the levels of HCV protein expression and HCV RNA expression in infected cells.

Results

Through activity guided purification, we identified the sub-fraction FR3T3 as possessing the most robust anti-HCV activity with an IC₅₀ value of 4.7 ± 1.0 μg/mL. Mode-of-action analysis revealed that FR3T3 inhibited post-viral entry stages such as HCV NS3 protein expression and HCV RNA replication with marginal effects on the viral entry stage. Thin-layer Chromatography (TLC) indicated that FR3T3 contained terpenoids and chlorophyll-related compounds. We also found a synergistic antiviral activity when the DCM extract of A. heterohyllus was used in combination therapy with commercial anti-HCV drugs; Ribavirin, Simeprevir, Cyclosporin A.

Conclusions

The extract of A. heterophyllus and its sub-fraction, FR3T3, presented here have anti-HCV activities and could be candidate drugs for add-on-therapy for treatment of chronic HCV infections.

Natural Bioactive Compounds as Adjuvant Therapy for Hepatitis C Infection

Background:

Hepatitis C virus infection is a significant global health burden, which causes acute or chronic hepatitis. Acute hepatitis C is generally asymptomatic and progresses to cure, while persistent infection can progress to chronic liver disease and extrahepatic manifestations. Standard treatment is expensive, poorly tolerated, and has variable sustained virologic responses amongst the different viral genotypes. New therapies involve direct acting antivirals; however, it is also very expensive and may not be accessible for all patients worldwide. In order to provide a complementary approach to the already existing therapies, natural bioactive compounds are investigated as to their several biologic activities, such as direct antiviral properties against hepatitis C, and effects on mitigating chronic progression of the disease, which include hepatoprotective, antioxidant, anticarcinogenic and anti-inflammatory activities; additionally, these compounds present advantages, as chemical diversity, low cost of production and milder or inexistent side effects.

Objective:

To present a broad perspective on hepatitis C infection, the chronic disease, and natural compounds with promising anti-HCV activity. Methods: This review consists of a systematic review study about the natural bioactive compounds as a potential therapy for hepatitis C infection.

Results:

The quest for natural products has yielded compounds with biologic activity, including viral replication inhibition in vitro, demonstrating antiviral activity against hepatitis C.

Conclusion:

One of the greatest advantages of using natural molecules from plant extracts is the low cost of production, not requiring chemical synthesis, which can lead to less expensive therapies available to low and middle-income countries.

Alkaloid and benzopyran compounds of Melicope latifolia fruit exhibit anti-hepatitis C virus activities

BACKGROUND

New agents for developing alternative or complementary medicine to treat the hepatitis C virus (HCV) are still needed due to high rates of HCV infection globally and the current limitations of available treatments. Treatment of HCV with a combination of direct acting antivirals have been shown to be approximately 90% effective but will be limited in the future due to the emergence of drug resistance and high cost. The leaves of Melicope latifolia have previously been reported to have anti-HCV activity and are a potential source of bioactive compounds for future novel drug development. This study aimed to evaluate the efficacy of the extract of M. latifolia fruit to treat HCV and to isolate its active compounds.

METHOD

M. latifolia fruit was extracted using methanol and purified using vacuum liquid chromatography (VLC) and Radial Chromatography. The anti-HCV activity was analyzed using cell culture lines Huh7it-1 and JFH1 (genotype 2a). Time-of-addition and immunoblotting studies were performed to identify the mode of action of the isolated active compounds. The structures of the active compounds were determined using nuclear magnetic resonance (NMR) spectra, UV, IR, and Mass Spectra.

RESULTS

Six known compounds were isolated from M. latifolia fruit: O-methyloktadrenolon, alloevodionol, isopimpinellin, alloxanthoxyletin, methylevodionol, and N-methylflindersine. N-methylflidersine was the most active compound with IC50 value of 3.8 μg/ml while methylevodionol, isopimpinellin, and alloevodionol were less active. O-methyloktadrenolon and alloxanthoxyletin were moderately active with IC50 values of 10.9 and 21.72 μg/ml, respectively. N-methylflidersine decreased level of HCV NS3 protein expression in the cells.

CONCLUSION

The alkaloid compound, N-methylflindersine which was isolated from M. latifolia possesses anti-HCV activity through post-entry inhibition and suppressed NS3 protein expression.

Antivirals against Chikungunya Virus: Is the Solution in Nature?

The worldwide outbreaks of the chikungunya virus (CHIKV) in the last years demonstrated the need for studies to screen antivirals against CHIKV. The virus was first isolated in Tanzania in 1952 and was responsible for outbreaks in Africa and Southwest Asia in subsequent years. Between 2007 and 2014, some cases were documented in Europe and America. The infection is associated with low rates of death; however, it can progress to a chronic disease characterized by severe arthralgias in infected patients. This infection is also associated with Guillain–Barré syndrome. There is no specific antivirus against CHIKV. Treatment of infected patients is palliative and based on analgesics and non-steroidal anti-inflammatory drugs to reduce arthralgias. Several natural molecules have been described as antiviruses against viruses such as dengue, yellow fever, hepatitis C, and influenza. This review aims to summarize the natural compounds that have demonstrated antiviral activity against chikungunya virus in vitro.

A diarylamine derived from anthranilic acid inhibits ZIKV replication

Zika virus (ZIKV) is a mosquito-transmitted Flavivirus, originally identified in Uganda in 1947 and recently associated with a large outbreak in South America. Despite extensive efforts there are currently no approved antiviral compounds for treatment of ZIKV infection. Here we describe the antiviral activity of diarylamines derived from anthranilic acid (FAMs) against ZIKV. A synthetic FAM (E3) demonstrated anti-ZIKV potential by reducing viral replication up to 86%. We analyzed the possible mechanisms of action of FAM E3 by evaluating the intercalation of this compound into the viral dsRNA and its interaction with the RNA polymerase of bacteriophage SP6. However, FAM E3 did not act by these mechanisms. In silico results predicted that FAM E3 might bind to the ZIKV NS3 helicase suggesting that this protein could be one possible target of this compound. To test this, the thermal stability and the ATPase activity of the ZIKV NS3 helicase domain (NS3Hel) were investigated in vitro and we demonstrated that FAM E3 could indeed bind to and stabilize NS3Hel.

Ecological Insights to Track Cytotoxic Compounds among Maytenus ilicifolia Living Individuals and Clones of an Ex Situ Collection

Biodiversity is key for maintenance of life and source of richness. Nevertheless, concepts such as phenotype expression are also pivotal to understand how chemical diversity varies in a living organism. Sesquiterpene pyridine alkaloids (SPAs) and quinonemethide triterpenes (QMTs) accumulate in root bark of Celastraceae plants. However, despite their known bioactive traits, there is still a lack of evidence regarding their ecological functions. Our present contribution combines analytical tools to study clones and individuals of Maytenus ilicifolia (Celastraceae) kept alive in an ex situ collection and determine whether or not these two major biosynthetic pathways could be switched on simultaneously. The relative concentration of the QMTs maytenin (1) and pristimerin (2), and the SPA aquifoliunin E1 (3) were tracked in raw extracts by HPLC-DAD and ¹H-NMR. Hierarchical Clustering Analysis (HCA) was used to group individuals according their ability to accumulate these metabolites. Semi-quantitative analysis showed an extensive occurrence of QMT in most individuals, whereas SPA was only detected in minor abundance in five samples. Contrary to QMTs, SPAs did not accumulate extensively, contradicting the hypothesis of two different biosynthetic pathways operating simultaneously. Moreover, the production of QMT varied significantly among samples of the same ex situ collection, suggesting that the terpene contents in root bark extracts were not dependent on abiotic effects. HCA results showed that QMT occurrence was high regardless of the plant age. This data disproves the hypothesis that QMT biosynthesis was age-dependent. Furthermore, clustering analysis did not group clones nor same-age samples together, which might reinforce the hypothesis over gene regulation of the biosynthesis pathways. Indeed, plants from the ex situ collection produced bioactive compounds in a singular manner, which postulates that rhizosphere environment could offer ecological triggers for phenotypical plasticity.

Crude leaf extracts of Piperaceae species downmodulate inflammatory responses by human monocytes

In this study, we aimed to evaluate the immunomodulatory effects of crude leaf extracts from Piper gaudichaudianum Kunth, P. arboreum Aub., P. umbellata L., P. fuligineum Kunth, and Peperomia obtusifolia A. Dietr. on an in vitro model of inflammatory response. The crude extracts were previously obtained by maceration of the leaves. The half-maximal inhibitory concentration was determined by the MTT assay using human peripheral blood mononuclear cells. Human monocytes were simultaneously challenged with each crude extract and lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, to induce a strong inflammatory response. After 24 h of incubation, cell-free supernatants were used for evaluating the mediators involved in inflammation: H₂O₂, TNF-α, IL-8, IL-6, IL-1β, IL-10, IL-12, FGF-b, and TGF-β1. We also compared the results with the effects of ketoprofen, a well-known anti-inflammatory drug. The P. gaudichaudianum crude extract downmodulated the production of H₂O₂, IL-1β, IL-6, IL-8, and TGF-β1 by LPS-stimulated monocytes; P. arboreum, IL-1β, IL-6, IL-8, and TNF-α; P. umbellata and P. fuligineum, H₂O₂, IL-1β, IL-6, IL-8, IL-10, and TNF-α; and P. obtusifolia, H₂O₂, IL-6, IL-8, IL-10, and TNF-α. In general, the crude leaf extracts amplified the anti-inflammatory response when compared with ketoprofen, particularly reducing the production of IL-8, a mediator involved in neutrophil recruitment during tissue damage. Thus, the crude leaf extracts of P. gaudichaudianum, P. arboreum, P. umbellata, P. fuligineum, and Peperomia obtusifolia elicited an anti-inflammatory response against LPS-challenged monocytes. These findings show the anti-inflammatory properties of these crude leaf extracts and offer new perspectives for their use in the treatment of inflammatory diseases.

Plant-derived antivirals against hepatitis c virus infection

Hepatitis C virus (HCV) infection is a worldwide public health burden and it is estimated that 185 million people are or have previously been infected worldwide. There is no effective vaccine for prevention of HCV infection; however, a number of drugs are available for the treatment of infection. The availability of direct-acting antivirals (DAAs) has dramatically improved therapeutic options for HCV genotype 1. However, the high costs and potential for development of resistance presented by existing treatment demonstrate the need for the development of more efficient new antivirals, or combination of therapies that target different stages of the viral lifecycle. Over the past decades, there has been substantial study of compounds extracted from plants that have activity against a range of microorganisms that cause human diseases. An extensive variety of natural compounds has demonstrated antiviral action worldwide, including anti-HCV activity. In this context, plant-derived compounds can provide an alternative approach to new antivirals. In this review, we aim to summarize the most promising plant-derived compounds described to have antiviral activity against HCV.

Flavonoids from Pterogyne nitens Inhibit Hepatitis C Virus Entry

Hepatitis C virus (HCV) is one of the leading causes of liver diseases and transplantation worldwide. The current available therapy for HCV infection is based on interferon-α, ribavirin and the new direct-acting antivirals (DAAs), such as NS3 protease and NS5B polymerase inhibitors. However, the high costs of drug design, severe side effects and HCV resistance presented by the existing treatments demonstrate the need for developing more efficient anti-HCV agents. This study aimed to evaluate the antiviral effects of sorbifolin (1) and pedalitin (2), two flavonoids from Pterogyne nitens on the HCV replication cycle. These compounds were investigated for their anti-HCV activities using genotype 2a JFH-1 subgenomic replicons and infectious virus systems. Flavonoids 1 and 2 inhibited virus entry up to 45.0% and 78.7% respectively at non-cytotoxic concentrations. The mechanism of the flavonoid 2 block to virus entry was demonstrated to be by both the direct action on virus particles and the interference on the host cells. Alternatively, the flavonoid 1 activity was restricted to its virucidal effect. Additionally, no inhibitory effects on HCV replication and release were observed by treating cells with these flavonoids. These data are the first description of 1 and 2 possessing in vitro anti-HCV activity.

Multiple effects of toxins isolated from Crotalus durissus terrificus on the hepatitis C virus life cycle

Hepatitis C virus (HCV) is one of the main causes of liver disease and transplantation worldwide. Current therapy is expensive, presents additional side effects and viral resistance has been described. Therefore, studies for developing more efficient antivirals against HCV are needed. Compounds isolated from animal venoms have shown antiviral activity against some viruses such as Dengue virus, Yellow fever virus and Measles virus. In this study, we evaluated the effect of the complex crotoxin (CX) and its subunits crotapotin (CP) and phospholipase A2 (PLA2-CB) isolated from the venom of Crotalus durissus terrificus on HCV life cycle. Huh 7.5 cells were infected with HCVcc JFH-1 strain in the presence or absence of these toxins and virus was titrated by focus formation units assay or by qPCR. Toxins were added to the cells at different time points depending on the stage of virus life cycle to be evaluated. The results showed that treatment with PLA2-CB inhibited HCV entry and replication but no effect on HCV release was observed. CX reduced virus entry and release but not replication. By treating cells with CP, an antiviral effect was observed on HCV release, the only stage inhibited by this compound. Our data demonstrated the multiple antiviral effects of toxins from animal venoms on HCV life cycle.

In Vitro Study on Anti-Hepatitis C Virus Activity of Spatholobus suberectus Dunn

Hepatitis C virus (HCV) infects 200 million people worldwide, and 75% of HCV cases progress into chronic infections, which consequently cause cirrhosis and hepatocellular carcinoma. HCV infection is treated with currently considered standard drugs, including direct anti-viral agents (DAAs), alone or in combination with peginterferon-α plus ribavirin. However, sustained viral responses vary in different cohorts, and high costs limit the broad use of DAAs. In this study, the ethanol and water extracts of 12 herbs from Lingnan in China were examined in terms of their inhibitory effect on HCV replication. Among the examined extracts, Spatholobus suberectus ethanol extracts suppressed HCV replication. By comparison, Extracts from Fructus lycii, Radix astragali (root), Rubus chingii Hu (fruit), Flos chrysanthemi Indici (flower), Cassia obtusifolia (seed), Lonicera japonica Thunb (flower), Forsythia suspense Thunb (fruit), Poria cocos (sclerotia), Carthamus tinctorius L. (flower), Crataegus pinnatifida Bge. (fruit), and Leonurus japonicas Houtt. (leaf) extracts failed to show a similar activity. Active S. suberectus fractions containing tannins as the major component also inhibited the in vitro translation of HCV RNA. The combination treatments of single compounds, such as epigallocatechin gallate and epicatechin gallate, were not as potent as crude S. suberectus fractions; therefore, crude S. suberectus extract may be a potential alternative treatment against HCV either alone or in combination with other agents.

Promising Anti-Hepatitis C Virus Compounds from Natural Resources

Hepatitis C virus (HCV) infection is a major worldwide problem, which involves approximately 170 million people. High morbidity of patients is caused by chronic infection, which leads to liver cirrhosis, hepatocellular carcinoma and other HCV-related diseases. The sustained virological response (SVR) has been markedly improved to be >90% by the current standard interferon (IFN)-free treatment regimens with a combination of direct-acting antiviral agents (DAAs) targeting the viral NS3 protease, NS5A multi-function protein and NS5B RNA-dependent RNA polymerase, compared with 50–70% of SVR rates achieved by the previous standard IFN-based treatment regimens with or without an NS3 protease inhibitor. However, the emergence of DAA-resistant HCV strains and the limited access to the DAAs due to their high cost could be major concerns. Also, the long-term prognosis of patients treated with DAAs, such as the possible development of hepatocellular carcinoma, still needs to be further evaluated. Natural resources are considered to be good candidates to develop anti-HCV agents. Here, we summarize anti-HCV compounds obtained from natural resources, including medicinal plant extracts, their isolated compounds and some of their derivatives that possess high antiviral potency against HCV.

Hepatitis C virus: Promising discoveries and new treatments

Despite advances in therapy, hepatitis C virus (HCV) infection remains an important global health issue. It is estimated that a significant part of the world population is chronically infected with the virus, and many of those affected may develop cirrhosis or liver cancer. The virus shows considerable variability, a characteristic that directly interferes with disease treatment. The response to treatment varies according to HCV genotype and subtype. The continuous generation of variants (quasispecies) allows the virus to escape control by antivirals. Historically, the combination of ribavirin and interferon therapy has represented the only treatment option for the disease. Currently, several new treatment options are emerging and are available to a large part of the affected population. In addition, the search for new substances with antiviral activity against HCV continues, promising future improvements in treatment. Researchers should consider the mutation capacity of the virus and the other variables that affect treatment success.

Incidence of hepatitis C in Brazil

INTRODUCTION

Hepatitis C is a public health problem of global dimensions, affecting approximately 200 million people worldwide. The main objective of this study was to estimate the incidence rate of hepatitis C in Brazil during the period between 2001 and 2012.

METHODS

An epidemiological, temporal, and descriptive study was performed using data from the Information System for Reportable Diseases.

RESULTS

Between 2001 and 2012, a total of 151,056 hepatitis C cases were recorded, accounting for 30.3% of all hepatitis notifications in Brazil. The average gross coefficient for the analysis period was 6.7 new cases per 100,000 inhabitants. The regions with the highest rates were the Southeast region (8.7 new cases/100,000 inhabitants) and the South (13.9 new cases/100,000 inhabitants). There was a predominance of men with respect to the incidence rate (8.0 new cases/100,000 inhabitants) compared to women (5.5 new cases/100,000 inhabitants). Injection drug use was the most common source of infection, and members of the white race, residents of urban areas, and those aged 60 to 64 years had the highest incidences.

CONCLUSIONS

Over the last 10 years, the incidence of hepatitis C in Brazil has increased, mainly in the South and Southeast. The adoption of fast, accurate diagnostic methods, together with epidemiological awareness, can facilitate early intervention measures for adequate control of the disease.

Anti-Hepatitis C Virus Activity of a Crude Extract from Longan (Dimocarpus longan Lour.) Leaves

Infection with hepatitis C virus (HCV) results in hepatitis C, a disease characterized by chronic infection, cirrhosis, and hepatocellular carcinoma. Currently, the standard therapy is a combination of pegylated interferon-α plus ribavirin with NS3 protease inhibitors. Addition of NS3 protease inhibitors to the standard therapy improves response rates; however, use of NS3 protease inhibitors is also associated with significant adverse effects and an increase in the overall cost of treatment. Therefore, there is a need to develop safe and inexpensive drugs for the treatment of HCV infections. In this study, we examined the antiviral activity of a crude extract from Dimocarpus longan leaves against HCV (genotype 2a strain JFH1). The D. longan crude extract (DL-CE) exhibited anti-HCV activity with a 50% effective concentration (EC50) of 19.4 μg/ml without cytotoxicity. A time-of-addition study demonstrated that DL-CE has anti-HCV activity at both the entry and post-entry steps and markedly blocks the viral entry step through direct virucidal activity with marginal inhibition of virion assembly. Co-treatment of DL-CE with cyclosporine A, an immunosuppressant or telaprevir, an NS3 protease inhibitor, resulted in additive and synergistic antiviral effects, respectively. Our findings suggest that DL-CE may be useful as an add-on therapy candidate for treating HCV infections.