Inhibition of the replication of hepatitis B virus in vitro by pu-erh tea extracts

Effect of EGCG Extracted from Green Tea against Largemouth Bass Virus Infection

(1) Background: Largemouth bass virus (LMBV) is a major viral pathogen in largemouth bass (Micropterus salmoides) aquaculture that often causes high mortality and heavy economic losses, thus developing treatments to combat this pathogen is of great commercial importance. Green tea is a well-known medicinal plant that contains active ingredients with antiviral, antibacterial, and other biological activities. The goals of this study were to explore the effect and mechanism of green tea source compounds on LMBV and provide data to serve as the basis for the screening of targeted drugs in the future. In this study, we evaluated the effects of the main component of green tea, epigallocatechin-3-gallate (EGCG), against LMBV infection. (2) Methods: The safe working concentration of EGCG was identified by cell viability detection and light microscopy. The antiviral activity and mechanism of action of EGCG against LMBV infection were evaluated with light microscopy, an aptamer 6-carboxy-fluorescein-based fluorescent molecular probe, and reverse transcription quantitative PCR. (3) Results: The safe working concentration of EGCG was ≤10 μg/mL. EGCG showed significant anti-LMBV infection activity in a concentration-dependent manner, and it also destroyed the structure of virus particles. EGCG impacted the binding of virus particles to cell receptors and virus invasion into the host cells. Inhibitory effects of EGCG on LMBV particles, LMBV binding to the host-cell membrane, and LMBV invasion were 84.89%, 98.99%, and 95.23%, respectively. Meanwhile, the effects of EGCG subsequently were verified in vivo. The fatality rate of the LMBV + EGCG group was significantly lower than that of the LMBV group. (4) Conclusions: Our results suggest that EGCG has effective antiviral properties against LMBV and may be a candidate for the effective treatment and control of LMBV infections in largemouth bass aquaculture.

Anti-hepatitis B activities of Myanmar medicinal plants: a narrative review of current evidence

Hepatitis B is one of the major burdens for health services and is the leading cause of morbidity and mortality from cirrhosis of liver and hepatocellular carcinoma. Current treatment strategies using nucleos(t)ide analogue reverse-transcriptase inhibitors or interferons are targeted for the long-term suppression of hepatitis B DNA. However, functional cure of hepatitis B infection (HBsAg clearance) was difficult to attain with such treatments. Therefore, new treatment strategies or innovative treatments are urgently needed. The new treatments should focus on the potential therapeutic targets such as covalently closed circular DNA which may be important for the HBsAg clearance. Plant based medicines have been used in different traditional medicine practices and these natural products/compounds serve as a good source of information or clues for use in drug discovery and design. Many natural products were found to be effective against hepatitis B virus and some even have better therapeutic activities than currently used compounds. This review summarizes the current evidence of Myanmar medicinal plants in basic and clinical research which shows promising potential for the development of novel therapeutic agents for the treatment of hepatitis B.

Chronic liver disease and oxidative stress - a narrative review

Introduction: Oxidative stress underlies the pathophysiology of various etiologies of chronic liver disease and contributes to the development of hepatocarcinogenesis.Areas covered: This review focuses on the impact of oxidative stress in various etiologies of chronic liver disease such as alcoholic liver disease (ALD), nonalcoholic steatohepatitis (NASH), hepatitis B virus (HBV), and hepatitis C virus (HCV) infection. The efficacy of antioxidants in laboratory, animal, and clinical studies in chronic liver disease is also reviewed.Expert opinion: Currently, there are limited targeted pharmacotherapeutics for NASH and no pharmacotherapeutics for ALD and antioxidant supplementation may be useful in these conditions to improve liver function and reverse fibrosis. Antioxidants may also be used in patients with HBV or HCV infection to supplement antiviral therapies. Specific genotypes of antioxidant and prooxidant genes render patients more susceptible to liver cirrhosis and hepatocellular carcinoma while other individual characteristics like age, genotype, and metabolomic profiling can influence the efficacy of antioxidants on CLD. More research needs to be done to establish the safety, efficacy, and dosage of antioxidants and to establish the ideal patient profile that will benefit the most from antioxidant treatment.

Tea bioactive components prevent carcinogenesis via anti-pathogen, anti-inflammation, and cell survival pathways

Cancer seriously impairs human health and survival. Many perturbations, such as increased oxidative stress, pathogen infection, and inflammation, promote the accumulation of DNA mutations, and ultimately lead to carcinogenesis. Tea is one of the most highly consumed beverages worldwide and has been linked to improvements in human health. Tea contains many active components, including tea polyphenols, tea polysaccharides, L-theanine, tea pigments, and caffeine among other common components. Several studies have identified components in tea that can directly or indirectly reduce carcinogenesis with some being used in a clinical setting. Many previous studies, in vitro and in vivo, have focused on the mechanisms that functional components of tea utilized to protect against cancer. One particular mechanism that has been well described is an improvement in antioxidant capacity seen with tea consumption. However, other mechanisms, including anti-pathogen, anti-inflammation and alterations in cell survival pathways, are also involved. The current review focuses on these anti-cancer mechanisms. This will be beneficial for clinical utilization of tea components in preventing and treating cancer in the future.

Pu-erh Tea Ameliorates Atherosclerosis Associated with Promoting Macrophage Apoptosis by Reducing NF-κB Activation in ApoE Knockout Mice

We explored whether pu-erh tea consumption ameliorates atherosclerosis and the possible mechanism for its effects in apolipoprotein E-deficient (ApoE^−/−) mice. Our data showed that pu-erh tea consumption markedly reduced early fatty streak formation and the advanced fibrofatty plaque sizes. Additionally, the mean proportion of inflammatory macrophages in the plaque decreased, and the number of apoptotic macrophages increased significantly. NF-κB activity in peritoneal macrophages decreased by 75.6% compared to the controls, similar with the levels of IL-6, IL-12, and TNF-α expression. The tea extract increased the apoptosis of RAW264.7 cells by decreasing NF-κB activation and reducing the inflammatory cytokine expression. In conclusion, pu-erh tea ameliorates atherosclerosis progress by alleviating the chronic inflammatory state by reducing NF-κB activation and promoting macrophage apoptosis in atherosclerotic plaques.

Protective effect of Pu-erh tea extracts against ethanol-induced gastric mucosal damage in rats

Pu-erh tea has become a focus of research due to its reported biological activities, including anti-oxidation, anti-inflammation and anti-immunosenescence. The present study was performed to evaluate the potential gastroprotective function of Pu-erh tea extracts against ethanol-induced gastric mucosal damage in rats. Sprague Dawley rats were randomly divided into seven groups: A normal control, a model control, a cimetidine (0.08 g/kg) group, three Pu-erh tea extracts groups (low, moderate and high-dose; 0.50, 1.00 and 1.50 g/kg, respectively, and a green tea powder (1.00 g/kg) group. The normal and model groups were pre-treated with distilled water while the other groups were respectively administered cimetidine, Pu-erh tea extracts and green tea powder for 14 days. Then, absolute ethanol was orally administered to the rats of all groups excluding the normal controls. The effects of the pretreatments on gastric mucosal injury were evaluated by gross assessment of gastric lesions, examination of histopathology and determination of myeloperoxidase (MPO) activity and asymmetric arginine (ADMA) concentration in gastric mucosal homogenate. Pre-treatment with cimetidine or Pu-erh tea extracts markedly suppressed the formation of ethanol-induced gastric lesions. Furthermore, clear decreases in MPO activity and ADMA concentration in the gastric mucosal homogenate were observed following pretreatment with cimetidine or Pu-erh tea extracts. The anti-gastric ulcer activity of green tea was less than that of Pu-erh tea. Overall, these effects of Pu-erh tea extracts may be due to potential functions in protecting the gastric mucus layer and suppressing inflammation.

Luteolin-7-O-Glucoside Present in Lettuce Extracts Inhibits Hepatitis B Surface Antigen Production and Viral Replication by Human Hepatoma Cells in Vitro

Hepatitis B virus (HBV) infection is endemic in Asia and chronic hepatitis B (CHB) is a major public health issue worldwide. Current treatment strategies for CHB are not satisfactory as they induce a low rate of hepatitis B surface antigen (HBsAg) loss. Extracts were prepared from lettuce hydroponically cultivated in solutions containing glycine or nitrate as nitrogen sources. The lettuce extracts exerted potent anti-HBV effects in HepG2 cell lines in vitro, including significant HBsAg inhibition, HBV replication and transcription inhibition, without exerting cytotoxic effects. When used in combination interferon-alpha 2b (IFNα-2b) or lamivudine (3TC), the lettuce extracts synergistically inhibited HBsAg expression and HBV replication. By using differential metabolomics analysis, Luteolin-7-O-glucoside was identified and confirmed as a functional component of the lettuce extracts and exhibited similar anti-HBV activity as the lettuce extracts in vitro. The inhibition rate on HBsAg was up to 77.4%. Moreover, both the lettuce extracts and luteolin-7-O-glucoside functioned as organic antioxidants and, significantly attenuated HBV-induced intracellular reactive oxygen species (ROS) accumulation. Luteolin-7-O-glucoside also normalized ROS-induced mitochondrial membrane potential damage, which suggests luteolin-7-O-glucoside inhibits HBsAg and HBV replication via a mechanism involving the mitochondria. Our findings suggest luteolin-7-O-glucoside may have potential value for clinical application in CHB and may enhance HBsAg and HBV clearance when used as a combination therapy.

Peroxisome Proliferators Activated Receptor (PPAR) agonists activate hepatitis B virus replication in vivo

Background

PPAR agonists are often used in HBV infected patients with metabolic disorders. However, as liver-enriched transcriptional factors, PPARs would activate HBV replication. Risks exsit in such patients. This study aimed to assess the influence of commonly used synthetic PPAR agonists on hepatitis B virus (HBV) transcription, replication and expression through HBV replicative mouse models, providing information for physicians to make necessary monitoring and therapeutic adjustment when HBV infected patients receive PPAR agonists treatment.

Methods

The HBV replicative mouse model was established by hydrodynamic injection of HBV replicative plasmid and the mice were divided into four groups and treated daily for 3 days with saline, PPAR pan-agonist (bezafibrate), PPARα agonist (fenofibrate) and PPARγ agonist (rosiglitazone) respectively. Their serum samples were collected for ECLIA analysis of HBsAg and HBeAg and real-time PCR analysis of Serum HBV DNA. The liver samples were collected for DNA (Southern) filter hybridization of HBV replication intermediates, real-time PCR analysis of HBV mRNA and immunohistochemistry (IHC) analysis of hepatic HBcAg. The alternation of viral transcription, replication and expression were compared in these groups.

Result

Serum HBsAg, HBeAg and HBV DNA were significantly elevated after PPAR agonist treatment. So did the viral replication intermediates in mouse livers. HBV mRNA was also significantly increased by these PPAR agonists, implying that PPAR agonists activate HBV replication at transcription level. Moreover, hepatic HBcAg expression in mouse livers with PPAR agonist treatment was elevated as well.

Conclusion

Our in vivo study proved that synthetic PPAR agonists bezafibrate, fenofibrate and rosiglitazone would increase HBV replication. It suggested that when HBV infected patients were treated with PPARs agonists because of metabolic diseases, HBV viral load should be monitored and regimens may need to be adjusted, an antiviral therapy may be added.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-017-0765-x) contains supplementary material, which is available to authorized users.

TAGLN2, a novel regulator involved in Hepatitis B virus transcription and replication

Hepatitis B virus (HBV) infection is one of the major health problems in the world. Transgelin-2 (TAGLN2) expression has been revealed to be significantly altered in previous studies concerning HBV-host interaction. The present study investigated TAGLN2 expression patterns in HBV related hepatocellular carcinoma (HCC) tissues and its role in HBV transcription and replication. We collected 59 HBV related HCC tissue samples, their adjacent non-tumoral tissues and 16 normal livers to make the tissue microarray. TAGLN2 protein was detected by immunohistochemistry and the transcriptional levels of TAGLN2, HBc, HBs and HBx were detected by qRT-PCR. Then we investigated the function of TAGLN2 on HBV transcription and replication in vitro by ectopic expressing or knocking down TAGLN2 in HepG2 and HepG2.2.15 cell lines. We further studied the effect of HBx on TAGLN2 expression with a Tet-on HBx expressing cell line. TAGLN2 protein expression was lower in normal livers and HBV-HCC tissues comparing to adjacent non-tumoral tissues. The transcriptional levels of TAGLN2 in HBV-HCC tissues and their adjacent tissues were positively related to that of HBc, HBs and HBx (P < 0.05). Ectopic expression of TAGLN2 in vitro could enhance HBV transcription and replication while suppressing TAGLN2 had the contrary effect. TAGLN2 could be induced by HBx in a dose-dependent manner. Our data demonstrated that TAGLN2 might be an HBx induced positive host factor involved in HBV transcription and replication and HBx related liver fibrosis and tumorigenesis.

Antibacterial and laxative activities of strictinin isolated from Pu'er tea (Camellia sinensis)

Strictinin, the major phenolic compound in Pu'er teas produced from young leaves and buds of wild trees, was isolated to evaluate its antibacterial and laxative activities. The minimum inhibitory concentrations of strictinin against Propionibacterium acnes and Staphylococcus epidermidis were determined as 250 μM and 2000 μM, respectively, apparently higher than those of several antibiotics commonly used for bacterial infections. The additive and synergistic effects on the inhibitory activities of strictinin combined with other commercial antibiotics were observed in two bacteria tested in this study via the analysis of fractional inhibitory concentrations. Laxative activity was observed on defecation of the rats fed with strictinin. Further analysis showed that the laxative effect of strictinin was presumably caused by accelerating small intestinal transit, instead of enhancing gastric emptying, increasing food intake, or inducing diarrhea in the rats. Taken together with the antiviral activities demonstrated previously, it is suggested that strictinin is one of the active ingredients responsible for the antiviral, antibacterial, and laxative effects of wild Pu'er tea, and has the potential to be developed as a mild natural substitute for antibiotics and laxatives.

Betaine Inhibits Hepatitis B Virus with an Advantage of Decreasing Resistance to Lamivudine and Interferon α

Betaine (BET) is a native compound known for its ability to protect the liver from toxicants. However, few studies have examined the effects of BET on the most common cause of liver disease, hepatitis B virus (HBV). In this study, the anti-HBV activity of BET was assessed in vitro and in vivo using enzyme-linked immunosorbent assay, quantitative polymerase chain reaction, and Southern blotting. The resistance of HBV to lamivudine and interferon α is challenging in the clinical treatment of HBV. The effect of BET on resistance was also investigated. The results showed that the secretion of HBsAg (HBV surface antigen), HbeAg (HBV e antigen), and HBV DNA in HepG2.2.15 cells was significantly decreased by BET via suppression of GRP78 expression. In duck HBV (DHBV)-infected ducklings, 1.0 or 2.0 g/kg BET significantly reduced serum DHBV DNA, and DHBV DNA did not rebound after the 5 day withdrawal period. BET suppressed HBV DNA rebound produced by the resistance of HBV to lamivudine and decreased the resistance mutation (rtM204V/I) of HBV DNA. Supplementation of BET may improve the anti-HBV effect of interferon α by increasing the expression of antiviral dsRNA-dependent protein kinase induced by the JAK-STAT (JAK = Janus kinase; STAT = signal transducer and activator of transcription) signaling pathway. These results may provide useful information for the clinical application of BET and solution of HBV drug resistance in anti-HBV therapy.

Characterization of thermophilic fungal community associated with pile fermentation of Pu-erh tea

This study aimed to characterize the thermophilic fungi in pile-fermentation process of Pu-erh tea. Physicochemical analyses showed that the high temperature and low pH provided optimal conditions for propagation of fungi. A number of fungi, including Blastobotrys adeninivorans, Thermomyces lanuginosus, Rasamsonia emersonii, Aspergillus fumigatus, Rhizomucor pusillus, Rasamsonia byssochlamydoides, Rasamsonia cylindrospora, Aspergillus tubingensis, Aspergillus niger, Candida tropicalis and Fusarium graminearum were isolated as thermophilic fungi under combination of high temperature and acid culture conditions from Pu-erh tea pile-fermentation. The fungal communities were analyzed by PCR-DGGE. Results revealed that those fungi are closely related to Debaryomyces hansenii, Cladosporium cladosporioides, A. tubingensis, R. emersonii, R. pusillus, A. fumigatus and A. niger, and the last four presented as dominant species in the pile process. These four preponderant thermophilic fungi reached the order of magnitude of 10(7), 10(7), 10(7) and 10(6)copies/g dry tea, respectively, measured by real-time quantitative PCR (q-PCR). The results indicate that the thermophilic fungi play an important role in Pu-erh tea pile fermentation.

(-)-Epigallocatechin-3-gallate inhibits entry of hepatitis B virus into hepatocytes

Hepatitis B virus (HBV) is a major cause of liver disease and hepatocellular carcinoma. Chronic HBV infection is currently managed with either nucleoside/nucleotide-based or interferon-based therapies, but fails to clear infection in a substantial proportion of cases, and antiviral strategies targeting the early stages of infection are therefore required for the prevention of HBV infection. In this study, we examined some common phytochemicals and identified epigallocatechin-3-gallate (EGCG) as a new inhibitor of HBV entry. EGCG, a flavonoid present in green tea extract, belongs to the subclass of catechins. We demonstrated that EGCG at a concentration of 50μM inhibited HBV entry into immortalized human primary hepatocytes by more than 80%, whereas the other four catechins tested had much weaker inhibitory effects. DMSO-differentiated HuS-E/2 cells expressed sodium taurocholate cotransporting polypeptide (NTCP), which is a receptor for HBV. Application of EGCG during HBV inoculation markedly inhibited infection in both DMSO-differentiated HuS-E/2 cells and HA-NTCP-expressing Huh7 cells. Interestingly, EGCG induced clathrin-dependent endocytosis of NTCP from the plasma membrane followed by protein degradation. In addition, EGCG inhibited the clathrin-mediated endocytosis of transferrin. Treatment of cells with EGCG had no effect on HBV genome replication or virion secretion. Moreover, the characteristic of HBV virion and the expression of known HBV entry factors were unaltered by EGCG. Finally, the antiviral activity of EGCG on HBV entry was observed using four different genotypes, A to D. These results show that the green tea-derived molecule EGCG potently inhibits HBV entry and could be used in prevention of HBV reinfection.

miR-125b inhibits hepatitis B virus expression in vitro through targeting of the SCNN1A gene

microRNAs (miRNAs) are small noncoding RNAs that modulate gene expression at the posttranscriptional level, playing an important role in many diseases. However, reports concerning the role of miRNA in hepatitis B virus (HBV) infection are limited. miRNA chips were used to investigate miRNA changes during HBV infection in vitro. Bioinformatics analysis was used to explore possible miRNA and target genes during HBV infection. The expression of miR-125b and its potential target gene, sodium channel, non-voltage-gated 1 alpha (SCNN1A), was further analyzed. A total of 136 miRNAs were analyzed in an HBV transient transfection model (HepG2-HBV1.3), and 78 miRNAs were differentially expressed in HepG2.2.15 cells compared with HepG2 cells. miR-125b expression was decreased in both HepG2-HBV1.3 and HepG2.2.15 cells, and ectopic expression of miR-125b inhibited HBV DNA intermediates and secretion of HBsAg and HBeAg. miR-125b also inhibited the mRNA and protein levels of SCNN1A. Using a dual luciferase reporter system, we found that SCNN1A was one of the targets of miR-125b. In this study, we found that miR-125b inhibits HBV expression in vitro by regulating SCNN1A expression.

New Phenylpropanoid-Substituted Flavan-3-ols from Pu-er Ripe Tea

Pu-er ripe tea is a special microbial post-fermented tea made from Pu-er raw tea, a kind of green tea produced from the leaves of Camellia sinensis var. assamica. It is one of the most consumed teas in the past two decades in China, due to its special flavor, taste, and beneficial effects. This work aimed to obtain diverse catechin structures from Pu-er ripe tea, which led to the isolation of four new phenylpropanoid-substituted flavan-3-ols, puerins C-F (1-4), together with four known flavan-3-ols, (+)-catechin (5), (-)-epicatechin (6), (±)-gallocatechin (7), and (-)-epigallocatechin (8). Their structures were elucidated on the basis of detailed spectroscopic analysis, including 1D and 2D NMR, mass and CD spectra. Compounds 1-4, which could be formed in the post-fermentative process of Pu-er tea, were isolated for the first time from tea and Theaceae plant.

Tea: A native source of antimicrobial agents

Tea (Camellia sinensis) is one of the most popular nonalcoholic beverages, consumed by over two-thirds of the world's population because of its refreshing, mild stimulant and medicinal properties. It is processed in different ways in different parts of the world to give green, black, oolong, and pu-erh tea. Among all tea polyphenols, epigallocatechin-3-gallate has been responsible for much of the health promoting abilities of tea including anti-inflammatory, antimicrobial, antitumour, anti-oxidative, protection from cardiovascular disease, anti-obesity, and anti-aging properties. In the present review, the antibacterial, antiviral, and antifungal activities of different types of tea and their polyphenols are reported, highlighting their mechanisms of action and structure–activity relationship. Moreover, considering that the changing patterns of infectious diseases and the emergence of microbial strains resistant to current antibiotics, there is an urgent need to find out new potent antimicrobial agents as adjuvants to antibiotic therapy. The synergistic effect of tea polyphenols in combination with conventional antimicrobial agents against clinical multidrug-resistant microorganisms has also been discussed in this review.

Hypoglycemic effect of the water extract of Pu-erh tea

The water extraction and composition of pu-erh tea, as well as the hypoglycemic effect of the water extract of pu-erh tea (WEPT) in vivo and in vitro, are reported to investigate its hypoglycemic effect on diabetes. High-performance liquid chromatography and colorimetric methods are used to analyze the tea catechins, caffeine, polyphenols, amino acids, and polysaccharides of the WEPT. The effect of the WEPT on glucose uptake by cultured HepG2 cells and the inhibition effect of rat intestinal sucrase, maltase, and porcine pancreatic amylase are determined in vitro. Then, the blood glucose and insulin levels of intragastrically administered WEPT on fasting and oral glucose tolerance test (OGTT) using type 2 diabetic db/db (BKS.Cg-m +/+ Lepr(db)/J) mice are determined in vivo. The results showed that the WEPT dose-dependently and significantly increased glucose uptake by HepG2 cells and inhibited rat intestinal sucrase, maltase, and porcine pancreatic amylase activity. The WEPT intragastrically given for 4 weeks suppressed the increase in blood insulin and glucose levels of db/db mice fasted overnight. In OGTT, the WEPT improved impaired glucose tolerance and ameliorated retarded insulin response at 60 and 120 min in db/db mice. These results suggest that the WEPT has beneficial effects on glucose homeostasis in type 2 diabetes and in amendment of insulin resistance.