Berberine inhibits hepatitis C virus entry by targeting the viral E2 glycoprotein.

BACKGROUND: Despite the advent of direct-acting antivirals (DAAs), HCV remains an important public health problem globally. There is at present no effective vaccine against the virus, and the DAAs in current use cannot prevent de novo infection, including in liver transplant setting wherein donor livers inevitably become re-infected. Developing inhibitors to HCV entry using nature-derived small molecules may help to expand/complement the current treatment options. PURPOSE: In this study, we explored the effect of the plant alkaloid berberine (BBR) on HCV early viral entry. METHODS: Cell culture-derived HCV (HCVcc), viral pseudoparticles bearing HCV glycoproteins (HCVpp), and entry-related assays were employed to assess BBR's bioactivity. Molecular docking was used to predict BBR-HCV glycoproteins interaction, and the compound's antiviral activity was confirmed against HCVcc infection of primary human hepatocytes (PHHs). RESULTS: BBR specifically impeded HCVcc attachment and entry/fusion steps without inactivating the free virus particles or affecting the expression of host cell entry factors and post-entry viral replication. BBR also effectively inhibited infection by viral pseudoparticles expressing HCV E1/E2 glycoproteins and molecular docking analysis pointed at potential interaction with HCV E2. Finally, BBR could suppress HCVcc infection of PHHs. CONCLUSIONS: We identified BBR as a potent HCV entry inhibitor, which merits further evaluation particularly for use in transplant setting against graft re-infection by HCV.

Methanolic Extract of Rhizoma Coptidis Inhibits the Early Viral Entry Steps of Hepatitis C Virus Infection.

Hepatitis C Virus (HCV) remains an important public health threat with approximately 170 million carriers worldwide who are at risk of developing hepatitis C-associated end-stage liver diseases. Despite improvement of HCV treatment using the novel direct-acting antivirals (DAAs) targeting viral replication, there is a lack of prophylactic measures for protection against HCV infection. Identifying novel antivirals such as those that target viral entry could help broaden the therapeutic arsenal against HCV. Herein, we investigated the anti-HCV activity of the methanolic extract from Rhizoma coptidis (RC), a widely used traditional Chinese medicine documented by the WHO and experimentally reported to possess several pharmacological functions including antiviral effects. Using the cell culture-derived HCV system, we demonstrated that RC dose-dependently inhibited HCV infection of Huh-7.5 cells at non-cytotoxic concentrations. In particular, RC blocked HCV attachment and entry/fusion into the host cells without exerting any significant effect on the cell-free viral particles or modulating key host cell entry factors to HCV. Moreover, RC robustly suppressed HCV pseudoparticles infection of Huh-7.5 cells and impeded infection by several HCV genotypes. Collectively, our results identified RC as a potent antagonist to HCV entry with potential pan-genotypic properties, which deserves further evaluation for use as an anti-HCV agent.

Small molecules targeting coxsackievirus A16 capsid inactivate viral particles and prevent viral binding.

Coxsackievirus A16 (CVA16) is an etiologic agent of hand, foot, and mouth disease (HFMD) that affects young children, and although typically self-limited, severe complications, and fatal cases have been reported. Due to the lack of specific medication and vaccines against CVA16, there is currently a need to develop effective antivirals to better control CVA16 infections in epidemic areas. In this study, we identified the tannins chebulagic acid (CHLA) and punicalagin (PUG) as small molecules that can efficiently disrupt the CVA16 infection of human rhabdomyosarcoma cells. Both compounds significantly reduced CVA16 infectivity at micromolar concentrations without apparent cytotoxicity. A mechanistic analysis revealed that the tannins particularly targeted the CVA16 entry phase by inactivating cell-free viral particles and inhibiting viral binding. Further examination by molecular docking analysis pinpointed the targets of the tannins in the fivefold axis canyon region of the CVA16 capsid near the pocket entrance that functions in cell surface receptor binding. We suggest that CHLA and PUG are efficient antagonists of CVA16 entry and could be of value as antiviral candidates or as starting points for developing molecules to treat CVA16 infections.

Highly bioavailable silibinin nanoparticles inhibit HCV infection.

OBJECTIVE: Silibinin is a flavonolignan that is well established for its robust antiviral activity against HCV infection and has undergone several clinical trials for the management of hepatitis C. Despite its potency, silibinin suffers from poor solubility and bioavailability, restricting its clinical use. To overcome this limitation, we developed highly bioavailable silibinin nanoparticles (SB-NPs) and evaluated their efficiency against HCV infection. DESIGN: SB-NPs were prepared using a nanoemulsification technique and were physicochemically characterised. Infectious HCV culture systems were used to evaluate the influence of SB-NP on the virus life cycle and examine their antioxidant activity against HCV-induced oxidative stress. The safety profiles of SB-NP, in vivo pharmacokinetic studies and antiviral activity against infection of primary human hepatocytes were also assessed. RESULTS: SB-NP consisted of nanoscale spherical particles (<200 nm) encapsulating amorphous silibinin at >97% efficiency and increasing the compound's solubility by >75%. Treatment with SB-NP efficiently restricted HCV cell-to-cell transmission, suggesting that they retained silibinin's robust anti-HCV activity. In addition, SB-NP exerted an antioxidant effect via their free radical scavenging function. Oral administration of SB-NP in rodents produced no apparent in vivo toxicity, and pharmacokinetic studies revealed an enhanced serum level and superior biodistribution to the liver compared with non-modified silibinin. Finally, SB-NP efficiently reduced HCV infection of primary human hepatocytes. CONCLUSIONS: Due to SB-NP's enhanced bioavailability, effective anti-HCV activity and an overall hepatoprotective effect, we suggest that SB-NP may be a cost-effective anti-HCV agent that merits further evaluation for the treatment of hepatitis C.

(4R,6S)-2-Dihydromenisdaurilide is a Butenolide that Efficiently Inhibits Hepatitis C Virus Entry.

Without a vaccine, hepatitis C virus (HCV) remains a significant threat, putting 170-300 million carriers worldwide at risk of cirrhosis and hepatocellular carcinoma. Although the direct-acting antivirals targeting HCV replication have revolutionized the treatment of hepatitis C, several obstacles persist, including resistance development, potential side-effects, and the prohibitive cost that limits their availability. Furthermore, treatment of HCV re-infection in liver transplantation remains a significant challenge. Developing novel antivirals that target viral entry could help expand the scope of HCV therapeutics and treatment strategies. Herein, we report (4R,6S)-2-dihydromenisdaurilide (DHMD), a natural butenolide, as an efficient inhibitor of HCV entry. Specifically, DHMD potently inhibited HCV infection at non-cytotoxic concentration. Examination on the viral life cycle demonstrated that DHMD selectively targeted the early steps of infection while leaving viral replication/translation and assembly/release unaffected. Furthermore, DHMD did not induce an antiviral interferon response. Mechanistic dissection of HCV entry revealed that DHMD could inactivate cell-free virus, abrogate viral attachment, and inhibit viral entry/fusion, with the most pronounced effect observed against the viral adsorption phase as validated using ELISA and confocal microscopy. Due to its potency, DHMD may be of value for further development as an entry inhibitor against HCV, particularly for application in transplant setting.

Enhanced autophagic activity of artocarpin in human hepatocellular carcinoma cells through improving its solubility by a nanoparticle system.

BACKGROUND: Hepatocellular carcinoma (HCC) is the most common liver cancer worldwide, with poor prognosis and resistance to chemotherapy. This gives novel cancer treatment methods an overwhelming significance. Natural products offer great resources of developing new and effective chemopreventive or chemotherapeutic agents. Artocarpus communis extracts and its active constituent, prenylated flavonoid artocarpin induce human hepatocellular carcinoma cell death. However, the poor water solubility drawbacks of artocarpin restrict its clinical application and bioavailability. PURPOSE: This study developed the artocarpin nanoparticle system to overcome the poor water solubility drawbacks and investigated the improvement of therapeutic efficacy of artocarpin by adopting novel nanoparticle delivery strategy. METHODS: Antiproliferative activity of artocarpin was evaluated by MTT assay. Cell morphology observation by microscope, DNA fragmentation assay, cell cycle analysis, Annexin V apoptosis cell staining, monodansylcadaverine and acridine orange staining and immunoblot analysis were used to evaluate the induction of autophagy by artocarpin. The determination of particle size, amorphous transformation, hydrogen-bond formation, yield, encapsulation efficiency and the solubility study were used to investigate the solubility enhancement mechanism of artocarpin. RESULTS: The present study demonstrates that the anticancer effect of artocarpin in HepG2 and PLC/PRF/5 hepatoma cells is mediated through the autophagic cell death mechanism. Results also demonstrated that artocarpin nanoparticles enhanced the solubility of artocarpin by reducing particle size, transforming high energy amorphous state, and forming hydrogen bond with excipients. Additionally, ArtN exhibited better autophagic cytotoxicity compared to free artocarpin. CONCLUSION: This work reveals the antihepatoma activity of artocarpin by inducing autophagic cell death and the improvement of therapeutic efficacy of artocarpin by adopting novel nanoparticle delivery strategy. The research provided a basis of ArtN could be explored as a low-dose alternative of artocarpin in anticancer treatment and research applications.

Activity-based and fraction-guided analysis of Phyllanthus urinaria identifies loliolide as a potent inhibitor of hepatitis C virus entry.

Without a vaccine, hepatitis C virus (HCV) remains a global medical and socio-economic burden, predisposing about 170 million carriers worldwide to end-stage liver diseases including cirrhosis and hepatocellular carcinoma. Although the recently developed direct-acting antivirals (DAAs) have revolutionized hepatitis C treatment, most of them are unsuitable for monotherapy due to risks of resistance, thus necessitating combination with interferon (IFN)-alpha, ribavirin, or additional DAAs. More importantly, the high cost associated with the DAAs restricts their accessibility to most parts of the world. Developing novel cost-effective anti-HCV therapeutics may help expand the scope of antivirals and treatment strategies against hepatitis C. Herein, we applied an activity-based and fraction-guided analysis of extracts from the medicinal plant Phyllanthus urinaria (P. urinaria), which yielded fraction 13 (F13) as possessing the most potent inhibitory activity against early viral entry of cell-culture HCV infection. Chemical analysis (silica gel chromatography followed by ESI LC-MS plus (1)H and (13)C NMR) of F13 identified loliolide (LOD), a monoterpenoid lactone, as a novel inhibitor of HCV entry. Specifically, LOD could efficiently inactivate HCV free virus particles, abrogate viral attachment, and impede viral entry/fusion, with minimal effect on viral replication/translation, particle production, and induction of type I IFN host antiviral immune response. ELISA-based binding analysis confirmed the monoterpenoid's ability in efficiently blocking HCV particle attachment to the host cell surface. Furthermore, LOD could inhibit infection by several genotypic strains of HCV. This is the first report characterizing P. urinaria and its bioactive compound LOD as potent HCV entry inhibitors, which merit further evaluation for development as candidate antiviral agents against hepatitis C.

Anti-melanoma activity of Bupleurum chinense, Bupleurum kaoi and nanoparticle formulation of their major bioactive compound saikosaponin-d.

ETHNOPHARMACOLOGICAL RELEVANCE: Bupleurum chinense is a traditional Chinese medicinal herb which has been used to treat various inflammatory and infectious diseases, while Bupleurum kaoi is an endemic plant in Taiwan. We determined whether B. chinense and B. kaoi and their biologically active saikosaponin compounds possess anti-melanoma activity. In addition, we developed a novel saikosaponin-d nanoparticle system to improve its solubility, and evaluated its antiproliferative effects and molecular mechanisms in melanoma cells. MATERIALS AND METHODS: Ethanolic extracts from B. chinense and B. kaoi were prepared, and their saikosaponin contents were determined by high performance liquid chromatography analysis. Saikosaponin-d nanoparticles were synthesized, and their physicochemical properties were evaluated by particle size analyzer, transmission electron microscopy, differential scanning calorimetry, X-ray diffractometry, and Fourier transform infrared spectroscopy. Human A375.S2 melanoma cells were cultured, and cell viability determined by the MTT assay. Apoptosis was evaluated by determination of mitochondrial membrane potential, and signal transduction pathways investigated by Western blotting. RESULTS: Ethanolic extracts from B. kaoi showed more potent antiproliferative effect on human A375.S2 melanoma cells compared to B. chinense. The saikosaponin-a, -c and -d contents were higher in B. kaoi compared to B. chinense. Saikosaponin-d was the most potent compound in terms of anti-melanoma activity, and saikosaponin-d nanoparticles exhibited increased water solubility due to lowered particle size, amorphous transformation and intermolecular hydrogen bond formation with the excipient. Furthermore, saikosaponin-d nanoparticles showed enhanced antiproliferative activity against melanoma cells, and induced apoptosis through the mitochondrial pathway. The anti-melanoma activity was mediated by phosphorylation of JNK and p38, phosphorylation of p53, increased level of cytochrome c, and activation of caspase 9. CONCLUSIONS: B. kaoi contains higher saikosaponin content and shows greater anti-melanoma activity than B. chinense. Saikosaponin-d nanoparticles have improved solubility, and may have potential use in the future as a form of treatment for melanoma.

Artocarpus communis Induces Autophagic Instead of Apoptotic Cell Death in Human Hepatocellular Carcinoma Cells.

For centuries, natural plant extracts have played an important role in traditional medicine for curing and preventing diseases. Studies have revealed that Artocarpus communis possess various bioactivities, such as anti-inflammation, anti-oxidant, and anticancer activities. A. communis offers economic value as a source of edible fruit, yields timber, and is widely used in folk medicines. However, little is known about its molecular mechanisms of anticancer activity. Here, we demonstrate the antiproliferative activity of A. communis methanol extract (AM) and its dichloromethane fraction (AD) in two human hepatocellular carcinoma (HCC) cell lines, HepG2 and PLC/PRF/5. Colony assay showed the long-term inhibitory effect of both extracts on cell growth. DNA laddering and immunoblotting analyses revealed that both extracts did not induce apoptosis in the hepatoma cell lines. AM and AD-treated cells demonstrated different cell cycle distribution compared to UV-treated cells, which presented apoptotic cell death with high sub-G1 ratio. Instead, acridine orange staining revealed that AM and AD triggered autophagosome accumulation. Immunoblotting showed a significant expression of autophagy-related proteins, which indicated the autophagic cell death (ACD) of hepatoma cell lines. This study therefore demonstrates that A. communis AM and its dichloromethane fraction can induce ACD in HCC cells and elucidates the potential of A. communis extracts for development as anti tumor therapeutic agents that utilize autophagy as mechanism in mediating cancer cell death.

Limonium sinense and gallic acid suppress hepatitis C virus infection by blocking early viral entry.

A preventive vaccine against hepatitis C virus (HCV) infection remains unavailable and newly developed drugs against viral replication are complicated by potential drug-resistance and high cost. These issues justify the need to develop alternative antiviral agents and expand the scope of strategies for the treatment of hepatitis C, such as targeting viral entry. In this study, we explore the bioactivity of Limonium sinense (L. sinense) and its purified constituents against HCV life cycle using subgenomic replicon and infectious HCV culture systems. Data indicated that the water extract from the underground part of L. sinense (LS-UW) exhibited potent inhibitory activity against HCV at non-cytotoxic concentrations. LS-UW targeted early HCV infection without affecting viral replication, translation, and cell-to-cell transmission, and blocked viral attachment and post-attachment entry/fusion steps. Bioactivity analysis of major constituents from LS-UW through viral infectivity/entry assays revealed that gallic acid (GA) also inhibits HCV entry. Furthermore, both LS-UW and GA could suppress HCV infection of primary human hepatocytes. Due to their potency and ability to target HCV early viral entry, LS-UW and GA may be of value for further development as prospective antivirals against HCV.

TnBP/Triton X-45 treatment of plasma for transfusion efficiently inactivates hepatitis C virus.

Risk of transmission of hepatitis C virus (HCV) by clinical plasma remains high in countries with a high prevalence of hepatitis C, justifying the implementation of viral inactivation treatments. In this study, we assessed the extent of inactivation of HCV during minipool solvent/detergent (SD; 1% TnBP / 1% Triton X-45) treatment of human plasma. Luciferase-tagged infectious cell culture-derived HCV (HCVcc) particles were used to spike human plasma prior to treatment by SD at 31 ± 0.5°C for 30 min. Samples were taken before and after SD treatment and filtered on a Sep-Pak Plus C18 cartridge to remove the SD agents. Risk of cytotoxicity was assessed by XTT cell viability assay. Viral infectivity was analyzed based on the luciferase signals, 50% tissue culture infectious dose viral titer, and immunofluorescence staining for HCV NS5A protein. Total protein, cholesterol, and triglyceride contents were determined before and after SD treatment and C18 cartridge filtration. Binding analysis, using patient-derived HCV clinical isolates, was also examined to validate the efficacy of the inactivation by SD. SD treatment effectively inactivated HCVcc within 30 min, as demonstrated by the baseline level of reporter signals, total loss of viral infectivity, and absence of viral protein NS5A. SD specifically targeted HCV particles to render them inactive, with essentially no effect on plasma protein content and hemostatic function. More importantly, the efficacy of the SD inactivation method was confirmed against various genotypes of patient-derived HCV clinical isolates and against HCVcc infection of primary human hepatocytes. Therefore, treatment by 1% TnBP / 1% Triton X-45 at 31°C is highly efficient to inactivate HCV in plasma for transfusion, showing its capacity to enhance the safety of therapeutic plasma products. We propose that the methodology used here to study HCV infectivity can be valuable in the validation of viral inactivation and removal processes of human plasma-derived products.

Saikosaponin b2 is a naturally occurring terpenoid that efficiently inhibits hepatitis C virus entry.

BACKGROUND & AIMS: A vaccine against hepatitis C virus (HCV) is unavailable and cost-effective antivirals that prevent HCV infection and re-infection, such as in the transplant setting, do not exist. In a search for novel and economical prophylactic agents, we examined the antiviral activity of saikosaponins (SSa, SSb2, SSc, and SSd) from Bupleurum kaoi root (BK) as entry inhibitors against HCV infection. METHODS: Infectious HCV culture systems were used to examine the effect of saikosaponins on the complete virus life cycle (entry, RNA replication/translation, and particle production). Antiviral activity against various HCV genotypes, clinical isolates, and infection of primary human hepatocytes were also evaluated. RESULTS: BK and the saikosaponins potently inhibited HCV infection at non-cytotoxic concentrations. These natural agents targeted early steps of the viral life cycle, while leaving replication/translation, egress, and spread relatively unaffected. In particular, we identified SSb2 as an efficient inhibitor of early HCV entry, including neutralization of virus particles, preventing viral attachment, and inhibiting viral entry/fusion. Binding analysis, using soluble viral glycoproteins, demonstrated that SSb2 acted on HCV E2. Moreover, SSb2 inhibited infection by several genotypic strains and prevented binding of serum-derived HCV onto hepatoma cells. Finally, treatment with the compound blocked HCV infection of primary human hepatocytes. CONCLUSIONS: Due to its potency, SSb2 may be of value for development as an antagonist of HCV entry and could be explored as prophylactic treatment during the course of liver transplantation.

Antihepatoma activity of Artocarpus communis is higher in fractions with high artocarpin content.

Extracts from natural plants have been used in traditional medicine for many centuries worldwide. Artocarpus communis is one such plant that has been used to treat liver cirrhosis, hypertension, and diabetes. To our knowledge, this study is the first to investigate the antihepatoma activity of A. communis toward HepG2 and PLC/PRF/5 cells and the first to explore the relationship between antihepatoma activity and the active compound artocarpin content in different fractions of A. communis. A. communis methanol extract and fractions induced dose-dependent reduction of tumor cell viability. DNA laddering analysis revealed that A. communis extract and fractions did not induce apoptosis in HepG2 and PLC/PRF/5 cells. Instead, acridine orange staining revealed that A. communis triggered autophagic cell death in a dose-dependent manner. The antihepatoma activity of A. communis is attributable to artocarpin. The fractions with the highest artocarpin content were also the fractions with the highest antihepatoma activity in the following order: dichloromethane fraction > methanol extract > ethyl acetate fraction > n-butanol fraction > n-hexane fraction. Taken together, A. communis showed antihepatoma activity through autophagic cell death. The effect was related to artocarpin content. Artocarpin could be considered an indicator of the anticancer potential of A. communis extract.

Antiviral natural products and herbal medicines.

Viral infections play an important role in human diseases, and recent outbreaks in the advent of globalization and ease of travel have underscored their prevention as a critical issue in safeguarding public health. Despite the progress made in immunization and drug development, many viruses lack preventive vaccines and efficient antiviral therapies, which are often beset by the generation of viral escape mutants. Thus, identifying novel antiviral drugs is of critical importance and natural products are an excellent source for such discoveries. In this mini-review, we summarize the antiviral effects reported for several natural products and herbal medicines.

Anti-melanogenic effects of δ-tocotrienol are associated with tyrosinase-related proteins and MAPK signaling pathway in B16 melanoma cells.

Tocotrienols are known to possess potent antioxidant, anticancer, and cholesterol lowering activities. Being able to rapidly penetrate the skin, these vitamin E isoforms have been explored for potential treatment against melanoma. This study aimed to elucidate the mechanism involved in the anti-melanogenic effects of δ-tocotrienol (δT3) in B16 melanoma cells. Results showed that at 20 µM of δT3 significantly inhibited melanin formation and ROS generation. Treatment with δT3 also effectively suppressed the expression of melanogenesis-related proteins, including MC1R, MITF, TYRP-1, and TYRP-2. More importantly, we observed that the mitogen-activated protein kinase (MAPK) pathway was involved in mediating δT3's inhibitory effect against melanin production. Specifically, δT3 treatment markedly induced the activation of extracellular signal-regulated kinases (ERK). The use of ERK activation inhibitor (PD98059) abrogated the δT3-mediated downregulation expression melanogenesis-related proteins and restored melanin production. Furthermore, siRNA targeting ERK effectively blocked the δT3-induced repression of tyrosinase and TYRP-1 expression. These results suggest that δT3's inhibitory effect against melanogenesis is mediated by the activation of ERK signaling, thereby resulting in downstream repression of melanogenesis-related proteins and the subsequent melanin production. These data provide insight to δT3's effect and the targeting of ERK signaling for treatment against melanogenesis.

Norartocarpetin from a folk medicine Artocarpus communis plays a melanogenesis inhibitor without cytotoxicity in B16F10 cell and skin irritation in mice.

BACKGROUND: Many natural products used in preventive medicine have also been developed as cosmeceutical ingredients in skin care products, such as Scutellaria baicalensis and Gardenia jasminoides. Norartocarpetin is one of the antioxidant and antityrosinase activity compound in Artocarpus communis; however, the cytotoxicity, skin irritation and antimelanogenesis mechanisms of norartocarpetin have not been investigated yet. METHODS: In the present study, cell viability in vitro and skin irritation in vivo are used to determine the safety of norartocarpetin. The melanogenesis inhibition of norartocarpetin was determined by cellular melanin content and tyrosinase in B16F10 melanoma cell. Moreover, we examined the related-melanogenesis protein by western blot analysis for elucidating the antimelanogenesis mechanism of norartocarpin. RESULTS: The result of the present study demonstrated that norartocarpetin not only present non-cytotoxic in B16F10 and human fibroblast cells but also non-skin irritation in mice. Moreover, our result also first found that norartocarpetin downregulated phospho-cAMP response element-binding (phospho-CREB) and microphthalmia-associated transcription factor (MITF) expression, which in turn decreased both synthesis of tyrosinases (TRP-1 and TRP-2) and cellular melanin content. This process is dependent on norartocarpetin phosphorylation by mitogen-activated protein kinases such as phospho-JNK and phospho-p38, and it results in decreased melanogenesis. CONCLUSION: The present study suggests that norartocarpetin could be used as a whitening agent in medicine and/or cosmetic industry and need further clinical study.

Broad-spectrum antiviral activity of chebulagic acid and punicalagin against viruses that use glycosaminoglycans for entry.

BACKGROUND: We previously identified two hydrolyzable tannins, chebulagic acid (CHLA) and punicalagin (PUG) that blocked herpes simplex virus type 1 (HSV-1) entry and spread. These compounds inhibited viral glycoprotein interactions with cell surface glycosaminoglycans (GAGs). Based on this property, we evaluated their antiviral efficacy against several different viruses known to employ GAGs for host cell entry. RESULTS: Extensive analysis of the tannins' mechanism of action was performed on a panel of viruses during the attachment and entry steps of infection. Virus-specific binding assays and the analysis of viral spread during treatment with these compounds were also conducted. CHLA and PUG were effective in abrogating infection by human cytomegalovirus (HCMV), hepatitis C virus (HCV), dengue virus (DENV), measles virus (MV), and respiratory syncytial virus (RSV), at µM concentrations and in dose-dependent manners without significant cytotoxicity. Moreover, the natural compounds inhibited viral attachment, penetration, and spread, to different degrees for each virus. Specifically, the tannins blocked all these steps of infection for HCMV, HCV, and MV, but had little effect on the post-fusion spread of DENV and RSV, which could suggest intriguing differences in the roles of GAG-interactions for these viruses. CONCLUSIONS: CHLA and PUG may be of value as broad-spectrum antivirals for limiting emerging/recurring viruses known to engage host cell GAGs for entry. Further studies testing the efficacy of these tannins in vivo against certain viruses are justified.

Artocarpin attenuates ultraviolet B-induced skin damage in hairless mice by antioxidant and anti-inflammatory effect.

Artocarpin, a prenylated flavonoid isolated from an agricultural plant Artocarpus communis, has been documented to possess anti-inflammation and anticancer activities. As oxidative stress and inflammation promote the development of ultraviolet B (UVB) irradiation-induced photodamage, the aim of the present study was to evaluate the photoprotective effect of artocarpin on UVB-induced skin damage in hairless mice. Artocarpin at a topical dose of 0.05% and 0.1% showed a significant photoprotective effect by decreasing histopathological changes, such as desquamation, epidermal thicken and sunburn cell formation, but 0.1% of artocarpin administration did not show better effect. Regarding the antioxidant activities, artocarpin exhibited a significant effect (P<0.05) by decreasing levels of reactive species oxygen and lipid peroxidation. In addition, artocarpin can significant decrease the level of tumor necrosis factor-α and interleukin-1ß for downregulating the inflammation protein, including the synthesis of cytosolic phospholipase A2 and cyclooxygenase-2 (P<0.05). In conclusion, these data suggest that artocarpin can prevent skin damage from UVB irradiation-induced photodamage in hairless mice and this is likely mediated through its antioxidant and anti-inflammation mechanisms. Therefore, we suggested that artocarpin could be a useful photoprotective agent in medicine and/or cosmetics.

Anti-viral activity of water extract of Paeonia lactiflora pallas against human respiratory syncytial virus in human respiratory tract cell lines.

Paeonia lactiflora Pallas (P. lactiflora, Ranunculaceae) is a common ingredient of Sheng-Ma-Ge-Gen-Tang (SMGGT; Shoma-kakkon-to) and Ge-Gen-Tang (GGT; kakkon-to). SMGGT and GGT are different prescriptions of traditional Chinese medicine with different ingredients designed for airway symptoms. Both SMGGT and GGT have anti-viral activity against human respiratory syncytial virus (HRSV). Therefore, P. lactiflora was hypothesized to be the effective ingredient of both SMGGT and GGT against HRSV. However, P. lactiflora does not have any proven antiviral activity. This study used both human upper (Human larynx epidermoid carcinoma cell line, HEp-2) and lower (human lung carcinoma cell line, A549) respiratory tract cells to test the hypothesis that a hot water extract of P. lactiflora could effectively inhibit plaque formation induced by HRSV infection. The ability of P. lactiflora to stimulate anti-viral cytokines was evaluated by enzyme-linked immunosorbent assay (ELISA). The results showed that P. lactiflora was time-dependently and dose-dependently effective against HRSV in HEp-2 and A549 cells, particularly supplemented before viral inoculation (p < 0.0001). 10 µg/ml P. lactiflora had a comparable anti-HRSV activity with 10 µg/ml ribavirin, a broad-spectrum antiviral agent. P. lactiflora was dose-dependently effective against viral attachment (p < 0.0001), with a better effect on A549 cells (p < 0.0001). P. lactiflora was time-dependently (p < 0.0001) and dose-dependently (p < 0.0001) effective against viral penetration. Moreover, P. lactiflora stimulated IFN-ß secretion without any effect on TNF-α secretion. Therefore, P. lactiflora could be beneficial at preventing HRSV infection by inhibiting viral attachment, internalization, and stimulating IFN secretion.