Metabolites from traditional Chinese botanical drugs with anti-hepatitis B virus activity - a review

Hepatitis B virus (HBV)-related liver disease poses a major threat to human health worldwide. Although interferon and nucleoside analogues are commonly administered for treating chronic HBV infection, their use is limited by considerable side effects, drug resistance and incapacity for HBV elimination. Hence, novel HBV therapeutics are urgently required. For numerous years, traditional Chinese botanical drugs have been widely used to treat HBV-related diseases. The natural metabolites derived from these traditional drugs exhibit significant anti-HBV effects and serve as potential novel drugs for treating HBV. For overall understanding the therapeutic potential of these metabolites, the anti-HBV effects and mechanisms of action of 107 natural metabolites are summarized in this article. Mechanistically, these natural metabolites exert their anti-HBV effects by influencing the expression and function of host and/or viral genes, which differs from the mechanism of action of nucleoside analogues. Indeed, combining natural metabolites with nucleoside analogues can exert synergistic effects. Accordingly, natural metabolites or their chemically modified derivatives represent potential novel drugs and adjuvants for anti-HBV treatment.

Bushen Formula promotes the decrease of HBsAg levels in patients with CHB by regulating Tfh cells and B-cell subsets

ETHNOPHARMACOLOGICAL RELEVANCE

Bushen Formula (BSF) is the effective traditional Chinese medicine (TCM) for chronic hepatitis B (CHB) according to our previous researches. However, the special effectiveness of BSF treating CHB patients in different stages and the immunoregulatory mechanisms remain to be explored.

AIM OF THE STUDY

To compare the therapeutic effects of BSF in both treatment-naive patients and Peg-IFN-α-treated patients, and explore the potential mechanism of immunomodulation.

MATERIALS AND METHODS

Ultra-high performance liquid chromatography-quadrupole electrostatic field-orbital trap high resolution mass spectrometry and the TCMSP database were used to determine the main components of BSF. Two hundred and sixty-six patients were enrolled in the retrospective study, and they were divided into the treatment group (T-Group, BSF plus Peg-IFN-α) and the control group (C-Group, Peg-IFN-α monotherapy). Within each group, patients were further grouped into subgroups, namely T1/C1 groups (treatment-naive patients, T1 = 34, C1 = 94) and T2/C2 groups (Peg-IFN-α-treated patients, T2 = 56, C2 = 82). Serum HBV markers, serum HBV DNA levels, serum ALT/AST and TCM symptoms were obtained from the record. Bioinformatics analysis was employed to obtain the potential immunoregulatory mechanisms of BSF treating CHB patients. Among patients in T2 and C2 group, peripheral mononuclear cells from 36 patients were used to analyze the characteristics of peripheral follicular helper T (Tfh) cells and B-cell subtypes by flow cytometry. Preparation of BSF-containing serum in rats. In vitro, the co-culture system of CXCR5+ cells and HepG2.2.15 cells was built to investigate the immunoregulatory effects of BSF.

RESULTS

A total of 14 main active compounds were detected in BSF, which were deemed critical for the treatment of CHB. Our findings indicated that the T2-Group exhibited the higher percentage of HBsAg decline ≥ 1-log10 IU/ml and rate of HBeAg seroclearance compared to the C2-Group (35.7% vs. 15.9%, P = 0.033; 33.9% vs. 11.0%, P = 0.002). Additionally, the T2-Group demonstrated the higher percentage of HBsAg decline ≥ 1-log10 IU/ml and rate of HBeAg seroclearance compared to the T1-Group (35.7% vs. 14.7%, P = 0.031; 33.9% vs. 2.9%, P = 0.000). The total effective rate based on TCM clinical syndrome in T1-Group and T2-Group were significantly greater than those in C1-Group and C2-Group (85.3% vs. 61.7%, P = 0.012; 89.1% vs. 63.4%, P = 0.000). Bioinformatics analysis indicated that the immunoregulatory mechanisms of BSF treating CHB patients were mainly linked to the growth and stimulation of B-cell, T-cell differentiation, and the signaling pathway of the B-cell receptor. Furthermore, the frequencies of Tfh cells and its IL-21 level, and the IL-21R expressed by B-cell were all increased after BSF treatment. Additionally, in the co-culture system of CXCR5+ cells and HepG2.2.15 cells, HBsAg and HBeAg levels were decreased after BSF-containing serum treatment，as well as the up-regulating of Tfh cell frequencies and down-regulating of B-cell frequencies.

CONCLUSIONS

BSF have the higher percentage of HBsAg decline and HBeAg seroclearance in Peg-IFN-α-treated patients compared with treatment-naive patients. The potential immunoregulatory mechanism may correlate with promoting the interaction between Tfh cells and B-cell through IL-21/IL-21R signaling pathway.

Elaeocarpus sylvestris var. ellipticus Extract and Its Major Component, Geraniin, Inhibit Herpes Simplex Virus-1 Replication

Elaeocarpus sylvestris var. ellipticus (ES), which our research group had confirmed inhibits influenza A and SARS-CoV-2 viruses, was investigated to identify new potent and selective inhibitors of herpes simplex virus-1 (HSV-1) replication. To clarify the optimal condition for ES extract (ESE), ES was extracted at different concentrations of 0, 30, 50, 70, and 100%, to screen for its anti-HSV-1 effect. Among these ESE samples, ESE50 (50% concentration) exhibited the strongest inhibition of HSV-1 replication (EC50 23.2 μg/mL) while showing low cytotoxicity on host cells (IC50 342.8 μg/mL). The treatment of ESE50 clearly demonstrated a decrease in the expression of ICP0 in the lungs of HSV-1-infected BALB/c nude mice, compared to the MOCK group. Geraniin, which was isolated from ESE50 and analyzed using ESI-MS and 1D-(1H- and 13C-) and 2D-NMR, showed greater potency in inhibiting HSV-1 replication, as determined by the plaque reduction assay (EC50 8.3 μg/mL) and luciferase inhibition (EC50 36.9 μg/mL). The results demonstrate that ESE50 and geraniin show great potential as candidates for new drug discovery in the treatment of HSV-1 and related diseases.

Hyperoside inhibits EHV-8 infection via alleviating oxidative stress and IFN production through activating JNK/Keap1/Nrf2/HO-1 signaling pathways

Equine herpesvirus type 8 (EHV-8) causes abortion and respiratory disease in horses and donkeys, leading to serious economic losses in the global equine industry. Currently, there is no effective vaccine or drug against EHV-8 infection, underscoring the need for a novel antiviral drug to prevent EHV-8-induced latent infection and decrease the pathogenicity of this virus. The present study demonstrated that hyperoside can exert antiviral effects against EHV-8 infection in RK-13 (rabbit kidney cells), MDBK (Madin-Darby bovine kidney), and NBL-6 cells (E. Derm cells). Mechanistic investigations revealed that hyperoside induces heme oxygenase-1 expression by activating the c-Jun N-terminal kinase/nuclear factor erythroid-2-related factor 2/Kelch-like ECH-associated protein 1 axis, alleviating oxidative stress and triggering a downstream antiviral interferon response. Accordingly, hyperoside inhibits EHV-8 infection. Meanwhile, hyperoside can also mitigate EHV-8-induced injury in the lungs of infected mice. These results indicate that hyperoside may serve as a novel antiviral agent against EHV-8 infection.IMPORTANCEHyperoside has been reported to suppress viral infections, including herpesvirus, hepatitis B virus, infectious bronchitis virus, and severe acute respiratory syndrome coronavirus 2 infection. However, its mechanism of action against equine herpesvirus type 8 (EHV-8) is currently unknown. Here, we demonstrated that hyperoside significantly inhibits EHV-8 adsorption and internalization in susceptible cells. This process induces HO-1 expression via c-Jun N-terminal kinase/nuclear factor erythroid-2-related factor 2/Kelch-like ECH-associated protein 1 axis activation, alleviating oxidative stress and triggering an antiviral interferon response. These findings indicate that hyperoside could be very effective as a drug against EHV-8.

Repurposing immune boosting and anti-viral efficacy of Parkia bioactive entities as multi-target directed therapeutic approach for SARS-CoV-2: exploration of lead drugs by drug likeness, molecular docking and molecular dynamics simulation methods

The COVID-19 pandemic has caused adverse health (severe respiratory, enteric and systemic infections) and environmental impacts that have threatened public health and the economy worldwide. Drug repurposing and small molecule multi-target directed herbal medicine therapeutic approaches are the most appropriate exploration strategies for SARS-CoV-2 drug discovery. This study identified potential multi-target-directed Parkia bioactive entities against SARS-CoV-2 receptors (S-protein, ACE2, TMPRSS2, RBD/ACE2, RdRp, MPro, and PLPro) using ADMET, drug-likeness, molecular docking (AutoDock, FireDock and HDOCK), molecular dynamics simulation and MM-PBSA tools. One thousand Parkia bioactive entities were screened out by virtual screening and forty-five bioactive phytomolecules were selected based on favorable binding affinity and acceptable pharmacokinetic and pharmacodynamics properties. The binding affinity values of Parkia phyto-ligands (AutoDock: -6.00--10.40 kcal/mol; FireDock: -31.00--62.02 kcal/mol; and HDOCK: -150.0--294.93 kcal/mol) were observed to be higher than the reference antiviral drugs (AutoDock: -5.90--9.10 kcal/mol; FireDock: -35.64--59.35 kcal/mol; and HDOCK: -132.82--211.87 kcal/mol), suggesting a potent modulatory action of Parkia bioactive entities against the SARS-CoV-2. Didymin, rutin, epigallocatechin gallate, epicatechin-3-0-gallate, hyperin, ursolic acid, lupeol, stigmasta-5,24(28)-diene-3-ol, ellagic acid, apigenin, stigmasterol, and campesterol strongly bound with the multiple targets of the SARS-CoV-2 receptors, inhibiting viral entry, attachment, binding, replication, transcription, maturation, packaging and spread. Furthermore, ACE2, TMPRSS2, and MPro receptors possess significant molecular dynamic properties, including stability, compactness, flexibility and total binding energy. Residues GLU-589, and LEU-95 of ACE2, GLN-350, HIS-186, and ASP-257 of TMPRSS2, and GLU-14, MET-49, and GLN-189 of MPro receptors contributed to the formation of hydrogen bonds and binding interactions, playing vital roles in inhibiting the activity of the receptors. Promising results were achieved by developing multi-targeted antiviral Parkia bioactive entities as lead and prospective candidates under a small molecule strategy against SARS-CoV-2 pathogenesis. The antiviral activity of Parkia bioactive entities needs to be further validated by pre-clinical and clinical trials.

Potential Implications of Hyperoside on Oxidative Stress-Induced Human Diseases: A Comprehensive Review

Hyperoside is a flavonol glycoside mainly found in plants of the genera Hypericum and Crataegus, and also detected in many plant species such as Abelmoschus manihot, Ribes nigrum, Rosa rugosa, Agrostis stolonifera, Apocynum venetum and Nelumbo nucifera. This compound exhibits a multitude of biological functions including anti-inflammatory, antidepressant, antioxidative, vascular protective effects and neuroprotective effects, etc. This review summarizes the quantification, original plant, chemical structure and property, structure-activity relationship, pharmacologic effect, pharmacokinetics, toxicity and clinical application of hyperoside, which will be significant for the exploitation for new drug and full utilization of this compound.

Herb Robert's Gift against Human Diseases: Anticancer and Antimicrobial Activity of Geranium robertianum L

Geranium robertianum L. is a widely distributed plant used as a traditional herbal medicine, but the knowledge of its biological properties still needs to be improved. Thus, the purpose of this presented research was to assess the phytochemical profile of extracts from aerial parts of G. robertianum, commercially available in Poland and to study their anticancer potential and antimicrobial properties, including the antiviral, antibacterial, and antifungal effects. Additionally, the bioactivity of fractions obtained from the hexane and ethyl acetate extract was analyzed. The phytochemical analysis revealed the presence of organic and phenolic acids, hydrolysable tannins (gallo- and ellagitannins), and flavonoids. Significant anticancer activity was found for G. robertianum hexane extract (GrH) and ethyl acetate extract (GrEA) with an SI (selectivity index) between 2.02 and 4.39. GrH and GrEA inhibited the development of HHV-1-induced cytopathic effect (CPE) in virus-infected cells and decreased the viral load by 0.52 log and 1.42 log, respectively. Among the analyzed fractions, only those obtained from GrEA showed the ability to decrease the CPE and reduce the viral load. The extracts and fractions from G. robertianum showed a versatile effect on the panel of bacteria and fungi. The highest activity was observed for fraction GrEA4 against Gram-positive bacteria, including Micrococcus luteus ATCC 10240 (MIC 8 μg/mL), Staphylococcus epidermidis ATCC 12228 (MIC 16 μg/mL), Staphylococcus aureus ATCC 43300 (MIC 125 μg/mL), Enterococcus faecalis ATCC 29212 (MIC 125 μg/mL), and Bacillus subtilis ATCC 6633 (MIC 125 μg/mL). The observed antibacterial effect may justify the traditional use of G. robertianum to treat hard-to-heal wounds.

Botany, ethnopharmacology, phytochemistry and pharmacology of Erodii Herba Geranii Herba-An review

ETHNOPHARMACOLOGICAL RELEVANCE

As a commonly used traditional Chinese herbal medicine, Erodii Herba Geranii Herba (Geranium wilfordii Maxim., Geranium carolinianum L. and Erodium stephanianum Willd.), which was known as Laoguancao (Chinese:), has high medicinal value. It has been used to dispel rheumatism, dredge the meridians, activate blood circulation, remove blood stasis, clear heat and detoxify, and stop diarrhea and dysentery. It's also used to treat eczema, sores, carbuncles, boils caused by accumulation of damp toxin.

AIM OF THE REVIEW

This review aimed to provide a systematic and comprehensive analysis of the current research progress in terms of the botany, ethnopharmacology, phytochemistry and pharmacological activities of Erodii Herba Geranii Herba, and discuss expectations for prospective research and implementation about this herb.

MATERIALS AND METHODS

Information on Erodii Herba Geranii Herba was gathered via the Internet (using Google Scholar, Baidu Scholar, Pubmed, Elsevier, ACS, Medline Plus, CNKI and Web of Science) and libraries. Additionally, information was also obtained from local books and brilliant scholars in ethnopharmacology.

RESULTS

More than isolated 240 chemical compounds were recorded, and main compositions are tannins, flavones, organic acids and volatile oil. The pharmacoactives of Erodii Herba Geranii Herba and its active constituents are diverse, including antibacterial, antiviral, antioxidant, liver and kidney protection, anti-inflammatory and analgesic, other activities. Among them, the antibacterial, antiviral, anti-inflammatory, analgesic, antidiarrheal and other pharmacological activities of it are consistent with traditional applications.

CONCLUSIONS

All kinds of research conducted on Erodii Herba Geranii Herba, especially in field of ethnopharmacological use, phytochemicals and pharmacology have been reviewed. There are plenty of active compounds with varied effects in Erodii Herba Geranii Herba. However, some traditional applications and pharmacological activities of Erodii Herba Geranii Herba have not been scientifically evaluated or convincing due to incomplete methods and ambiguous results, as well as the lack of clinical data. In order to verify the pharmacological activity, clinical efficacy and safety of it, a systematic and comprehensive research evaluation is also required. As an important traditional Chinese medicine, Erodii Herba Geranii Herba should be further explored to promote the development of new drugs and therapeutics for various diseases. How to make better use of it should be paid more attention to.

Kaempferol: Antimicrobial Properties, Sources, Clinical, and Traditional Applications

Flavonoids are a category of plant-derived compounds which exhibit a large number of health-related effects. One of the most well-known and studied flavonoids is kaempferol, which can be found in a wide variety of herbs and plant families. Apart from their anticarcinogenic and anti-inflammatory effects, kaempferol and its associated compounds also exhibit antibacterial, antifungal, and antiprotozoal activities. The development of drugs and treatment schemes based on these compounds is becoming increasingly important in the face of emerging resistance of numerous pathogens as well as complex molecular interactions between various drug therapies. In addition, many of the kaempferol-containing plants are used in traditional systems all over the world for centuries to treat numerous conditions. Due to its variety of sources and associated compounds, some molecular mechanisms of kaempferol antimicrobial activity are well known while others are still under analysis. This paper thoroughly documents the vegetal and food sources of kaempferol as well as the most recent and significant studies regarding its antimicrobial applications.

Repurposing antiviral phytochemicals from the leaf extracts of Spondias mombin (Linn) towards the identification of potential SARSCOV-2 inhibitors

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), a pneumonia-like disease with a pattern of acute respiratory symptoms, currently remains a significant public health concern causing tremendous human suffering. Although several approved vaccines exist, vaccine hesitancy, limited vaccine availability, high rate of viral mutation, and the absence of approved drugs account for the persistence of SARS-CoV-2 infections. The investigation of possibly repurposing of phytochemical compounds as therapeutic alternatives has gained momentum due to their reported affordability and minimal toxicity. This study investigated anti-viral phytochemical compounds from ethanolic leaf extracts of Spondias mombin L as potential inhibitor candidates against SARS-CoV-2. We identified Geraniin and 2-O-Caffeoyl-(+)-allohydroxycitric acid as potential SARS-CoV-2 inhibitor candidates targeting the SARS-CoV-2 RNA-dependent polymerase receptor-binding domain (RBD) of SARS-CoV-2 viral S-protein and the 3C-like main protease (3CLpro). Geraniin exhibited binding free energy (ΔGbind) of - 25.87 kcal/mol and - 21.74 kcal/mol towards SARS-CoV-2 RNA-dependent polymerase and receptor-binding domain (RBD) of SARS-CoV-2 viral S-protein respectively, whereas 2-O-Caffeoyl-(+)-allohydroxycitric acid exhibited a ΔGbind of - 32 kcal/mol towards 3CLpro. Molecular Dynamics simulations indicated a possible interference to the functioning of SARS-CoV-2 targets by the two identified inhibitors. However, further in vitro and in vivo evaluation of these potential SARS-CoV-2 therapeutic inhibitor candidates is needed.

Potent antiviral activity of the extract of Elaeocarpus sylvestris against influenza A virus in vitro and in vivo

BACKGROUND

Elaeocarpus sylvestris (Lour.) Poir. (Elaeocarpaceae) belongs to a genus of tropical and semitropical evergreen trees, which has known biological activities such as antiviral and immunomodulatory activities. However, its antiviral potential against influenza virus infection remains unknown.

PURPOSE

In this study, we investigated the antiviral activity of the 50% aqueous ethanolic extract of E. sylvestris (ESE) against influenza A virus (IAV) infection, which could lead to the development of novel phytomedicine to treat influenza virus infection.

METHODS

To investigate the in vitro antiviral activity of ESE and its main ingredients, 1,​2,​3,​4,​6-​penta-​O-​galloyl-β-d-glucose (PGG) and geraniin (GE), the levels of viral RNAs, proteins, and infectious viral particles in IAV-infected MDCK cells were analyzed. Molecular docking analysis was performed to determine the binding energy of PGG and GE for IAV proteins. To investigate in vivo antiviral activity, IAV-infected mice were treated intranasally or intragastrically with ESE, PGG, or GE.

RESULTS

ESE and its gallate main ingredients (PGG and GE) strongly inhibited the production of viral RNAs, viral proteins, and infectious viral particles in vitro. Also through the viral attachment on cells, polymerase activity, signaling pathway, we revealed the ESE, PGG, and GE inhibit multiple steps of IAV replication. Molecular docking analysis revealed that PGG and GE could interact with 12 key viral proteins (M1, NP, NS1 effector domain (ED), NS1 RNA-binding domain (RBD), HA pocket A, HA receptor-binding domain (RBD), NA, PA, PB1, PB2 C-terminal domain, PB2 middle domain, and PB2 cap-binding domain) of IAV proteins with stable binding energy. Furthermore, intranasal administration of ESE, PGG, or GE protected mice from IAV-induced mortality and morbidity. Importantly, oral administration of ESE suppressed IAV replication and the expression of inflammatory cytokines such as IFN-γ, TNF-α, and IL-6 in the lungs to a large extent.

CONCLUSION

ESE and its major components (PGG and PE) exhibited strong antiviral activity in multiple steps against IAV infection in silico, in vivo, and in vitro. Therefore, ESE could be used as a novel natural product derived therapeutic agent to treat influenza virus infection.

Geraniin inhibits cell growth and promoted autophagy-mediated cell death in the nasopharyngeal cancer C666-1 cells

Background

Nasopharyngeal carcinoma (NPC) is a rare malignant tumor developing from epithelial linings of nasopharynx, and 10–50 out of 100,000 NPC cases were recorded globally particularly in the Asian countries.

Methodology

The cytotoxicity of geraniin against the NPC C666-1 cells were analyzed using MTT assay. The influences of geraniin on the C666-1 cell viability with the presence of ROS and apoptosis inhibitors were also studied. The expressions of PI3K, Akt, mTOR, and autophagic markers LC3, ATG7, P62/SQSTM1 expressions in the C666-1 cells were studied by western blotting analysis. The ROS production was assayed using DCFH-DA staining. The immunofluorescence assay was performed to detect the NF-κB and β-catenin expressions in the C666-1 cells.

Results

The cell viability of C666-1 cells were appreciably prevented by the geraniin. The geraniin treatment also inhibited the C666-1 cell growth with the presence of apoptotic inhibitor Z-VAD-FMK. The geraniin-treatment effectively improved the ROS production and inhibited the NF-κB and β-catenin expressions in the C666-1 cells. Geraniin appreciably modulated the PI3K/Akt/mTOR signaling axis and improved the autophagy-mediated cell death via improving the autophagic markers LC3 and ATG7 expressions in the C666-1 cells.

Conclusion

In conclusion, our results proved that geraniin inhibits C666-1 cell growth and initiated autophagy-mediated cell death via modulating PI3K/Akt/mTOR cascade and improving LC3 and ATG7 expressions in the C666-1. Geraniin and it could be a hopeful and efficient candidate to treat the human NPC in the future.

Old wine in new bottles: Kaempferol is a promising agent for treating the trilogy of liver diseases

As a source of various compounds, natural products have long been important and valuable for drug development. Kaempferol (KP) is the most common flavonol with bioactive activity and has been extracted from many edible plants and traditional Chinese medicines. It has a wide range of pharmacological effects on inflammation, oxidation, and tumour and virus regulation. The liver is an important organ and is involved in metabolism and activity. Because the pathological process of liver diseases is extremely complicated, liver diseases involving ALD, NASH, liver fibrosis, and HCC are often complicated and difficult to treat. Fortunately, there have been many reports that KP has a good pharmacological effect on a series of complex liver diseases. To fully understand the mechanism of KP and provide new ideas for its clinical application in the treatment of liver diseases, this article reviews the pharmacological mechanism and potential value of KP in different studies involving various liver diseases. In the trilogy of liver disease, high concentrations of ROS stimulate peroxidation and activate the inflammatory signal cascade, which involves signalling pathways such as MAPK/JAK-STAT/PERK/Wnt/Hipp, leading to varying degrees of cell degradation and liver damage. The development of liver disease is promoted in an inflammatory environment, which is conducive to the activation of TGF-β1, leading to increased expression of pro-fibrosis and pro-inflammatory genes. Inflammation and oxidative stress promote the formation of tumour microenvironments, and uncontrolled autophagy of cancer cells further leads to the development of liver cancer. The main pathway in this process is AMPK/PTEN/PI3K-Akt/TOR. KP can not only protect liver parenchymal cells through a variety of antioxidant and anti-apoptotic mechanisms but also reduces the immune inflammatory response in the liver microenvironment, thereby preventing cell apoptosis; it can also inhibit the ER stress response, prevent inflammation and inhibit tumour growth. KP exerts multiple therapeutic effects on liver disease by regulating precise signalling targets and is expected to become an emerging therapeutic opportunity to treat liver disease in the future.

Novel Anti-Hepatitis B Virus Activity of Euphorbia schimperi and Its Quercetin and Kaempferol Derivatives

Natural or plant products, because of their structural diversity, are a potential source for identifying new anti-hepatitis B virus (HBV) agents. Here, we report the anti-HBV activity of Euphorbia schimperi and its quercetin (QRC) and kaempferol derivatives. The anti-HBV-active methanol fraction of E. schimperi was subjected to chromatographic techniques, leading to isolation of three flavonols, following their structure determination by ¹H and ¹³C NMR spectroscopies. Their cytotoxicity and anti-HBV potential were assessed using HBV reporter HepG2.2.15 cells, and their modes of action were delineated by molecular docking. The isolated compounds identified as quercetin-3-O-glucuronide (Q3G), quercetin-3-O-rhamnoside (Q3R), and kaempferol-3-O-glucuronide (K3G) were non-cytotoxic to HepG2.2.15 cells. The viral HBsAg/HBeAg production on day 5 was significantly inhibited by K3G (∼70.2/∼73.4%), Q3G (∼67.8/∼72.1%), and Q3R (∼63.2%/∼68.2%) as compared to QRC (∼70.3/∼74.8%) and lamivudine (∼76.5/∼84.5%) used as standards. The observed in vitro anti-HBV potential was strongly supported by in silico analysis, which suggested their structure-based activity via interfering with viral Pol/RT and core proteins. In conclusion, this is the first report on the anti-HBV activity of E. schimperi-derived quercitrin-3-O-glucuronide, quercitrin-3-O-rhamnoside, and kaempferol-3-O-glucuronide, most likely through interfering with HBV proteins.

Geraniin Inhibits the Entry of SARS-CoV-2 by Blocking the Interaction between Spike Protein RBD and Human ACE2 Receptor

The coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite the development of vaccines, the emergence of SARS-CoV-2 variants and the absence of effective therapeutics demand the continual investigation of COVID-19. Natural products containing active ingredients may be good therapeutic candidates. Here, we investigated the effectiveness of geraniin, the main ingredient in medical plants Elaeocarpus sylvestris var. ellipticus and Nephelium lappaceum, for treating COVID-19. The SARS-CoV-2 spike protein binds to the human angiotensin-converting enzyme 2 (hACE2) receptor to initiate virus entry into cells; viral entry may be an important target of COVID-19 therapeutics. Geraniin was found to effectively block the binding between the SARS-CoV-2 spike protein and hACE2 receptor in competitive enzyme-linked immunosorbent assay, suggesting that geraniin might inhibit the entry of SARS-CoV-2 into human epithelial cells. Geraniin also demonstrated a high affinity to both proteins despite a relatively lower equilibrium dissociation constant (K_D) for the spike protein (0.63 μM) than hACE2 receptor (1.12 μM), according to biolayer interferometry-based analysis. In silico analysis indicated geraniin’s interaction with the residues functionally important in the binding between the two proteins. Thus, geraniin is a promising therapeutic agent for COVID-19 by blocking SARS-CoV-2’s entry into human cells.

LC-ESI-QTOF-MS/MS Analysis, Cytotoxic, Antiviral, Antioxidant, and Enzyme Inhibitory Properties of Four Extracts of Geranium pyrenaicum Burm. f.: A Good Gift from the Natural Treasure

This study focused on the biological evaluation and chemical characterization of Geranium pyrenaicum Burm. f. Different solvent extracts (hexane, ethyl acetate, methanol, and water extracts) were prepared. The phytochemical profile, antioxidant, and enzyme inhibitory activity were investigated. Cytotoxicity was assessed using VERO, FaDu, HeLa and RKO cells. The antiviral activity was carried out against HSV-1 (Herpes simplex virus 1) propagated in VERO cell line. The aqueous extract, possessing high phenolic content (170.50 mg gallic acid equivalent/g extract), showed the highest reducing capacity (613.27 and 364.10 mg Trolox equivalent/g extract, for cupric reducing antioxidant capacity and ferric reducing antioxidant power, respectively), radical scavenging potential (469.82 mg Trolox equivalent/g extract, against 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), metal chelating ability (52.39 mg ethylenediaminetetraacetic acid equivalent/g extract) and total antioxidant capacity (3.15 mmol Trolox equivalent/g extract). Liquid chromatography-electrospray ionization-quadrupole time-of-flight-mass spectrometry (LC-ESI-QTOF-MS/MS) alloved to tentatively identify a total of 56 compounds in the extracts, including ellagitannins, gallic acid and galloyl derivatives amongst others. The ethyl acetate extracts substantially depressed cholinesterase enzymes (4.49 and 12.26 mg galantamine equivalent/g extract against AChE and BChE, respectively) and α-amylase enzyme (1.04 mmol acarbose equivalent/g extract). On the other hand, the methanolic extract inhibited tyrosinase (121.42 mg kojic acid equivalent/g extract) and α-glucosidase (2.39 mmol acarbose equivalent/g extract) activities. The highest selectivity towards all cancer cell lines (SI 4.5-10.8) was observed with aqueous extract with the FaDu cells being the most sensitive (CC50 40.22 µg/mL). It can be concluded that the presence of certain bioactive antiviral molecules may be related to the high anti HSV-1 activity of the methanolic extract. This work has generated vital scientific data on this medicinal plant, which is a prospective candidate for the creation of innovative phyto-pharmaceuticals.

Comparative studies of two vegetal extracts from Stokesia laevis and Geranium pratense: polyphenol profile, cytotoxic effect and antiproliferative activity

In this study, two ethanolic extracts, from Stokesia aster (Slae26) and Geranium pratense (Gpre36) respectively, were evaluated in order to assess the cytotoxic activity and potential antiproliferative activity upon the nontumorigenic human epithelial cell line derived from the mammary gland (MCF-12A) and the human breast tumor cell line (BT-20). The selection of the plant species was done on the basis of their chemical composition, specifically combinations of luteolin derivatives with caffeic and gallic acid derivatives. Therefore, the S. laevis ethanolic extract proved its capacity to inhibit the viability of both normal and tumor breast cell lines (i.e., up to 90% cell viability inhibition, IC50 = 42 µg/mL). On the contrary, the G. pratense ethanolic extract proved weak stimulatory effects on the viability of the two human breast cell lines studied. The obtained results were discussed in the contexts of computational studies and drug-likeness bioactivity of seven common luteolin derivatives: luteolin, luteolin-7-O-glucoside/cynaroside, luteolin-5-O-glucoside/galuteolin, luteolin-6-C-glucoside/isoorientin, luteolin-8-C-glucoside/orientin, luteolin-3′,4′-di-O-glucoside and luteolin-7,3′-di-O-glucoside. Computational studies have revealed that the hydrophilic behavior of luteolin derivatives (log P values) does not follow other tested parameters (e.g., polar surface area values), possibly explaining different efficacy concerning the biological properties in vitro. These predictions could be a starting point for studies on the biochemical mechanism by which luteolin derivatives induce biological effects.

Bioassay-guided isolation of anti-hepatitis B virus flavonoid myricetin-3-O-rhamnoside along with quercetin from Guiera senegalensis leaves

Recently, we have shown in vitro anti-hepatitis B virus (HBV) activity of G. senegalensis J.F. Gmel leaves, and Identified quercetin and other flavonoids by HPTLC. Here we report bioassay-directed fractionation of G. senegalensis leaves using column chromatography and isolation of two flavonoinds from the n-butanol fraction, their structure determination (1H NMR, 13C NMR and 2D-NMR) and assessment of antiviral activities (HBsAg and HBeAg assay) in HBV-reporter HepG2.2.2.15 cells. Further molecular docking was performed against HBV polymerase (Pol/RT) and capsid (Core) proteins as well as host-receptor sodium taurocholate co-transporting polypeptide (NTCP). The two isolated bioactive compounds were identified as quercetin and myricetin-3-O-rhamnoside. Quercetin significantly inhibited synthesis of HBsAg and HBeAg by about 60% and 62%, respectively as compared to myricetin-3-O-rhamnoside by 44% and 35%, respectively. Molecular docking of the two anti-HBV flavonoids revealed their higher binding affinities towards Pol/RT than Core and NTCP. In conclusion, this is the first report on anti-HBV active myricetin-3-O-rhamnoside along with quercetin isolated from G. senegalensis leaves. Their possible mode of anti-HBV activities are suggested through binding with viral Pol/RT and Core as well as host NTCP proteins.

Bioactivity of the Geranium Genus: A Comprehensive Review

BACKGROUND

Plants from the Geranium genus, which comprises about 400 species, have been used since ancient times in the practice of traditional medicines throughout the world. Therefore, herbal preparations based on Geranium species have found wide usage for the treatment of a variety of ailments. The aim of this work is to present a review, as comprehensive as possible, of the studies concerning different biological activities of Geranium species.

METHODS

Relevant data were obtained through systematic computer searches from major reputed scientific databases, particularly Web of Science and Scopus. Occasionally, information issued in primary sources not covered by these databases was also included provided published as peer-reviewed literature. This review covers the literature disclosed till the end of 2018.

RESULTS

Accompanying the increasing interest in herbal medicines in general, the evaluation of the biological properties of medicinal plants from the Geranium genus has been addressed thoroughly, mostly over the last two decades. Geranium species are endowed with a number of different biological activities. Herein, we present a survey of the results of the studies concerning these different biological activities.

CONCLUSION

Most studies found in the literature effectively contribute to scientifically validate the beneficial properties of Geranium plants claimed by traditional medicines and medical herbalism and demonstrate that many of them possess evident therapeutic properties.

Probing the effect of quercetin 3-glucoside from Dianthus superbus L against influenza virus infection- In vitro and in silico biochemical and toxicological screening

Investigation of antiviral and cytotoxic effect of quercetin 3-glucoside (Q3G) from Dianthus superbus L over influenza virus infection and replication were studied. Moreover, anti-influenza mechanism was screened by time-dependent antiviral assay, virus-induced symptoms and related gene expressions. The blockade of cap-binding domain of polymerase basic protein subunit were analysed by molecular docking study. The Q3G demonstrated potent antiviral activity showing 4.93, 6.43, 9.94, 8.3, and 7.1 μg/mL of IC₅₀ for A/PR/8/34, A/Victoria/3/75, A/WS/33, B/Maryland/1/59, and B/Lee/40, respectively. The cellular toxicity of Q3G and oseltamivir (control) were tested and >100 μg/mL of CC₅₀ value considered as nontoxic. Influenza A virus infection induced a higher ROS production, however potentially reduced by Q3G treatment and significantly blocked virus infection induced acidic vesicular organelles (AVO). Moreover, Q3G has no inhibitory effect for neuraminidase activity but blocked virus replication through time dependent assay and showed more competitive binding affinity (-8.0 kcal/mal) than GTP (-7.0 kcal/mol) to block polymerase basic protein-2 subunit of influenza virus. Q3G from D. superbus showed potent antiviral activity against influenza A and B viruses with suppressive effect on virus-induced cellular ROS generation and AVO formation. Thus, this study provided a new line of research for Q3G to develop possible natural anti-influenza drug.

Acute oral toxicity of the ellagitannin geraniin and a geraniin-enriched extract from Nephelium lappaceum L rind in Sprague Dawley rats

Despite the lack of its toxicity evaluation, traditional herbal products are being widely used for various health indications. Geraniin, an ellagitannin, is a bioactive compound found in many traditional herbal medicines. In spite its numerous health benefits ranging from anti-inflammatory, anti-hyperglycaemic, hepatoprotective, anti-cancer and anti-microbial, no toxicity data on geraniin is available. The objective of this study is to evaluate the acute oral toxicity of geraniin and an enriched geraniin-extract of Nephelium lappaceum L rind. This study followed the guidelines of the OECD 423 acute oral toxicity test. Subsequent to a single oral administration of the test compounds, the rats were observed for 14 days for signs of toxicity and mortality. Following euthanasia, full blood count, biochemistry of blood and histopathology assessment of organs were carried out. All parameters analysed indicated insignificant difference compared to control. The LD₅₀ cut-off values for both geraniin and geraniin-enriched extract was established to be 2000 mg/kg b. w., following a single oral dose. It was however observed that the hepatocytes of three geraniin-administered rats exhibited a ‘foamy appearance’. As such, the no-observed-adverse-effect level of geraniin is below 2000 mg/kg, while that of geraniin-enriched extract is up to 2000 mg/kg. Further detailed toxicity studies are required to establish geraniin or its enriched extract from Nephelium lappaceum L rind safe for human consumption.

Cytoprotective Effects of Mangiferin and Z-Ligustilide in PAH-Exposed Human Airway Epithelium in Vitro

According to World Health Organisation (WHO) air pollution increases the risk of cardiovascular disorders, respiratory diseases, including COPD, lung cancer and acute respiratory infections, neuro-degenerative and other diseases. It is also known that various phytochemicals may mitigate such risks. This study tested if phytochemicals mangiferin (MNG) and Z-ligustilide (Z-LG) may protect PAH-exposed human lung bronchial epithelial cells (BEAS-2B). Organic PAH extract was obtained from the urban fine PM with high benzo(a)pyrene content collected in Eastern European mid-sized city during winter heating season. Cell proliferation traits and levels of intracellular oxidative stress were examined. Effect of MNG (0.5 µg/mL) alone or in combination with PAH on bronchial epithelium wound healing was evaluated. Both phytochemicals were also evaluated for their antioxidant properties in acellular system. Treatment with MNG produced strong cytoprotective effect on PAH-exposed cells (p < 0.01) while Z-LG (0.5 µg/mL) exhibited strong negative effect on cell proliferation in untreated and PAH-exposed cells (p < 0.001). MNG, being many times stronger antioxidant than Z-LG in chemical in vitro assays (p < 0.0001), was also able to decrease PAH-induced oxidative stress in the cell cultures (p < 0.05). Consequently MNG ameliorates oxidative stress, speeds up wound healing process and restores proliferation rate in PAH-exposed bronchial epithelium. Such protective effects of MNG in air pollution affected airway epithelium stimulate further research on this promising phytochemical.

Molecular structure and spectral characteristics of hyperoside and analysis of its molecular imprinting adsorption properties based on density functional theory

The structure of hyperoside was optimized according to the skeletal types of different galactopyranosides in hyperoside at the DFT/B3LYP/6-31++G(d,p) level, and the frequencies were calculated. The accuracy of the theoretical calculations of the ¹H and ¹³C NMR signals was evaluated by linear correlation. The excited state was calculated via time-dependent density functional theory (TD-DFT). The stable conformation, NMR, UV-vis, natural bond orbital (NBO), molecular electrostatic potential (MEP) and thermodynamic information were obtained. In the most stable conformation of hyperoside, seven intramolecular hydrogen bonds are formed, which affect the imprinting efficiency. The theoretical ¹H and ¹³C NMR results are in good agreement with the experimental results. The B3PW91 function is more suitable than B3LYP for TD-DFT calculations. Combining the UV-vis and NBO analyses, the HOMO→LUMO transition mainly results from the n→π^∗ transition of the phenolic hydroxyl groups and the π→π^∗ transition of the benzene ring on the B ring in ethanol. The HOMO-1→LUMO+1 transition mainly results from the n→π^∗ and π→π^∗ transition on the A ring. The MEP and NBO calculations indicate that the imprinted active sites are mainly located on the carbonyl oxygen atom and the hydroxyl hydrogen atoms. As the temperature increases, the molecular heat capacity, entropy, enthalpy, and activity of the imprinting sites increase. The obtained results provide strong theoretical guidance for hyperoside in the synthesis of molecularly imprinted polymers and separation techniques.

In Vitro Antiviral Activity of Sakuranetin against Human Rhinovirus 3

Objectives

Rhinoviruses (RVs) cause common cold and are associated with exacerbation of chronic inflammatory respiratory diseases. Until now, no clinically effective antiviral chemotherapeutic agents to treat diseases caused by human rhinoviruses (HRVs) have been reported. We assessed the anti-HRV3 activity of sakuranetin isolated from Sorbus commixta Hedl. in human epithelioid carcinoma cervix (HeLa) cells, to evaluate its anti-rhinoviral potential in the clinical setting.

Methods

Antiviral activity and cytotoxicity as well as the effect of sakuranetin on HRV3-induced cytopathic effects (CPEs) were evaluated using the sulforhodamine B (SRB) method using CPE reduction. The morphology of HRV3-infected cells was studied using a light microscope.

Results

Sakuranetin actively inhibited HRV3 replication and exhibited antiviral activity of more than 67% without cytotoxicity in HeLa cells, at 100 μg/mL. Ribavirin showed anti-HRV3 activity similar to that of sakuranetin. Treatment of HRV-infected HeLa cells with sakuranetin visibly reduced CPEs.

Conclusion

The inhibition of HRV production by sakuranetin is mainly due to its general antioxidant activity through inhibition of viral adsorption. Therefore, the antiviral activity of sakuranetin should be further investigated to elucidate its mode of action and prevent HRV3-mediated diseases in pathological conditions.

In vitro evaluation of novel antiviral activities of 60 medicinal plants extracts against hepatitis B virus

Currently, >35 Saudi Arabian medicinal plants are traditionally used for various liver disorders without a scientific rationale. This is the first experimental evaluation of the anti-hepatitis B virus (HBV) potential of the total ethanolic and sequential organic extracts of 60 candidate medicinal plants. The extracts were tested for toxicity on HepG2.2.15 cells and cytotoxicity concentration (CC₅₀) values were determined. The extracts were further investigated on HepG2.2.15 cells for anti-HBV activities by analyzing the inhibition of HBsAg and HBeAg production in the culture supernatants, and their half maximal inhibitory concentration (IC₅₀) and therapeutic index (TI) values were determined. Of the screened plants, Guiera senegalensis (dichloromethane extract, IC₅₀=10.65), Pulicaria crispa (ethyl acetate extract, IC₅₀=14.45), Coccinea grandis (total ethanol extract, IC₅₀=31.57), Fumaria parviflora (hexane extract, IC₅₀=35.44), Capparis decidua (aqueous extract, IC₅₀=66.82), Corallocarpus epigeus (total ethanol extract, IC₅₀=71.9), Indigofera caerulea (methanol extract, IC₅₀=73.21), Abutilon figarianum (dichloromethane extract, IC₅₀=99.76) and Acacia oerfota (total ethanol extract, IC₅₀=101.46) demonstrated novel anti-HBV activities in a time- and dose-dependent manner. Further qualitative phytochemical analysis of the active extracts revealed the presence of alkaloids, tannins, flavonoids and saponins, which are attributed to antiviral efficacies. In conclusion, P. crispa, G. senegalensis and F. parviflora had the most promising anti-HBV potentials, including those of C. decidua, C. epigeus, A. figarianum, A. oerfota and I. caerulea with marked activities. However, a detailed phytochemical study of these extracts is essential to isolate the active principle(s) responsible for their novel anti-HBV potential.

Phytochemistry and Pharmacology of Phyllanthus niruri L.: A Review

Phyllanthus niruri, a typical member of family Euphorbiaceae, is a small annual herb found throughout the tropical and subtropical regions of both hemispheres. The genus Phyllanthus has been used in traditional medicine for its wide range of pharmacological activities like antimicrobial, antioxidant, anticancer, antiinflammatory, antiplasmodial, antiviral, diuretic and hepatoprotective. This review summarizes the information about morphological, biochemical, ethanobotanical, pharmacological, biological and toxicological activities with special emphasis on mechanism of anticancer activity of P. niruri. Gaps in previous studies such as taxonomic inconsistency of P. niruri, novel phytochemicals and their therapeutic properties, especially mechanisms of anticancerous activity and market products available, have been looked into and addressed. Scientific information related to 83 phytochemicals (including many novel compounds detected recently by the authors) has been provided in a very comprehensive manner. Copyright © 2017 John Wiley & Sons, Ltd.

Anti-influenza (H1N1) potential of leaf and stem bark extracts of selected medicinal plants of South India

Variations in antioxidant and anti-viral activities (against Influenza AP/R/8 (H1N1) virus) between the leaves and stem bark of selected medicinal plants were studied. Malin Darby canine kidney (MDCK) cells were used for the viral infection and the antiviral activity of the extracts was studied using sulphorhodamine B (SRB) assay. The stem bark of the plants including Strychnos minor, Diotacanthus albiflorus, Strychnos nux-vomica and Chloroxylon swietenia showed higher flavonoid contents as well as 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging activity when compared with their leaves. In case of 1,1-diphenyl-2-picrylhydrazyl (DPPH) activity, the stem bark of S. nux-vomica and leaf extract of C. swietenia showed the highest activity. Based on the IC₅₀ values, the stem bark extracts of Cayratia pedata (20.5 μg/mL) and S. minor (22.4 μg/mL) showed high antiviral activity. In the mean-time S. nux-vomica, C. swietenia and C. swietenia bark extracts showed cytotoxicity to the MDCK cells. When comparing the stem bark and leaves the content of gallic acid, ferulic acid, o-coumaric acid, total flavonoids (TFC) and total phenols (TPC) was higher in stem bark and hence their anti-viral activity was high. Further study based on the metabolites against H1N1 can reveal the potential of therapeutic compounds against the viral disease.

A review of non-nucleoside anti-hepatitis B virus agents

Hepatitis B Virus is the most common cause of chronic liver disease worldwide. Currently approved agents of chronic HBV infection treatment include interferon and nucleoside analogues. However, the side effects of interferon and the viral resistance of nucleoside analogues make the current treatment far from satisfactory. Therefore, new drugs with novel structures and mechanisms are needed. Recently, a number of non-nucleoside HBV inhibitors have been obtained from natural sources or prepared by synthesis/semi-synthesis. Some of them exhibited potent anti-HBV activity with novel mechanisms. These compounds provide useful information for the medicinal chemist to develop novel non-nucleoside compounds as anti-HBV agents.

Geraniin down regulates gamma radiation-induced apoptosis by suppressing DNA damage

Gamma ray irradiation triggers DNA damage and apoptosis of proliferating stem cells and peripheral immune cells, resulting in the destruction of intestinal crypts and lymphoid system. Geraniin is a natural compound extracts from an aquatic plant Nymphaea tetragona and possesses good antioxidant property. In this study, we demonstrate that geraniin rescues radiosensitive splenocytes and jejunal crypt cells from radiation-induced DNA damage and apoptosis. Isolated splenocytes from C57BL/6 mice treated with geraniin were protected against radiation injury of 2 Gy irradiation through the enhancement of the proliferation and attenuation of DNA damage. Also, geraniin inhibited apoptosis in radiosensitive splenocytes by reducing the expression level and immunoreactivity of proapoptotic p53 and Bax and increasing those of anti-apoptotic Bcl-2. In mice exposed to radiation, geraniin treatment protected splenocytes and intestinal crypt cells from radiation-induced cell death. Our results suggest that geraniin presents radioprotective effects by regulating DNA damage on splenocytes, exerting immunostimulatory capacities and inhibiting apoptosis of radiosensitive immune cells and jejunal crypt cells. Therefore, geraniin can be a radioprotective agent against γ-irradiation exposure.

Application of microdialysis for elucidating the existing form of hyperoside in rat brain: comparison between intragastric and intraperitoneal administration

ETHNOPHARMACOLOGICAL RELEVANCE

Hypericum perforatum (St. John's wort) is an important anti-depressant herb used in clinic and commonly prescribed for mild depression. Hyperoside is one of the major components of H. perforatum and is also detected in many plant species such as Abelmoschus manihot, Black Currant, Rosa agrestis, Apocynum venetum and Nelumbo nucifera.

AIM OF THE STUDY

As the hyperoside showed CNS (central nervous system) protective activity (e.g. anti-depressant-like effect), the possibility of hyperoside or its metabolites to reach CNS should be investigated. Moreover, the pharmacokinetics profile of hyperoside or its metabolites in rat brain should be studied for further elucidating the mechanism of hyperoside action on CNS.

MATERIAL AND METHODS

A simple method for simultaneous determination of unbound hyperoside and its metabolite 3'-O-methyl-hyperoside in rat brain was developed by using ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) and microdialysis technique. This method was applied for pharmacokinetics study of hyperoside and 3'-O-methyl-hyperoside in rat brain after intragastric (i.g.) and intraperitoneally (i.p.) administration of hyperoside in vivo.

RESULTS

Results showed that neither hyperoside nor its metabolites were detected in rat brain after i.g. administration but both compounds could be detected after i.p. administration. Considering the activity of hyperoside through both i.g. and i.p. administration, our results imply that the active components of hyperoside in vivo might be different. Therefore, further studies are needed to identify the active components of hyperoside in vivo through these two different routes. Moreover, non-oral administration route (e.g., i.p.) should be further investigated and be explored to obtain higher bioavailability and better activity for hyperoside. Our results also showed that the real existing form of hyperoside in rat brain were hyperoside and its methylated metabolite with maximum concentration to be 63.78 ng/mL and 24.66 ng/mL after 20mg/kg i.p. administration, respectively. Therefore, a more reasonable concentration of hyperoside should be considered in in vitro assay to reflect the real situation of hyperoside concentration in vivo.

CONCLUSION

Due to the wide use of herbal remedies containing hyperoside, our investigation will contribute to further clarifying the action of this substance. Moreover, this method will be applied for clinical pharmacokinetics study of hyperoside and its metabolite as well as herbs that contain hyperoside.

Anti-HBV agents derived from botanical origin

There are 350,000 hepatitis B virus (HBV) carriers all over the world. Chronic HBV infection is at a high risk of developing liver cirrhosis and hepatocelluar carcinoma (HCC), and heavily threatened people's health. Two kinds of drugs approved by FDA for anti-HBV therapy are immunomodulators (interferon α, pegylated-interferon α) and nucleos(t)ide analogues (lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate). These drugs have been proved to be far from being satisfactory due to their low specificity, side effects, and high rate of drug resistance. There is an urgent need to discover and develop novel effective anti-HBV drugs. With vast resources, various structures, diverse biological activities and action mechanisms, as well as abundant clinical experiences, botanical agents become a promising source of finding new anti-HBV drugs. This review summarizes the recent research and development of anti-HBV agents derived from botanical origin on their sources and active components, inhibitory effects and possible toxicities, as well as action targets and mechanisms, and also addresses the advantages and the existing shortcomings in the development of botanical inhibitors. This information may not only broaden the knowledge of anti-HBV therapy, and offer possible alternative or substitutive drugs for CHB patients, but also provides considerable information for developing new safe and effective anti-HBV drugs.

Herbal products: benefits, limits, and applications in chronic liver disease

Complementary and alternative medicine soughts and encompasses a wide range of approaches; its use begun in ancient China at the time of Xia dynasty and in India during the Vedic period, but thanks to its long-lasting curative effect, easy availability, natural way of healing, and poor side-effects it is gaining importance throughout the world in clinical practice. We conducted a review describing the effects and the limits of using herbal products in chronic liver disease, focusing our attention on those most known, such as quercetin or curcumin. We tried to describe their pharmacokinetics, biological properties, and their beneficial effects (as antioxidant role) in metabolic, alcoholic, and viral hepatitis (considering that oxidative stress is the common pathway of chronic liver diseases of different etiology). The main limit of applicability of CAM comes from the lacking of randomized, placebo-controlled clinical trials giving a real proof of efficacy of those products, so that anecdotal success and personal experience are frequently the driving force for acceptance of CAM in the population.

Anti-hepatitis B virus activity of chickweed [Stellaria media (L.) Vill.] extracts in HepG2.2.15 cells

Stellaria media (Linn.) Villars is a traditional Chinese medicine that has been used for over 200 years, mainly for the treatment of dermatitis and other skin diseases. It has also been used as an anti-viral agent. All the fresh chickweed juice samples used in this study were prepared using macroporous resin and ultrafiltration technology. The anti-hepatitis B virus (HBV) activity of S. media was evaluated in vitro using the human HBV-transfected liver cell line HepG2.2.15. The concentrations of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) in HepG2.2.15 cell culture medium were determined by enzyme-linked immunosorbent assay (ELISA) after S. media-n (SM-n) treatment for 6 or 9 days. HBV DNA was quantified using transcription-mediated amplification and real-time polymerase chain reaction. In HepG2.2.15 cells, 30 μg/mL SM-3 effectively suppressed the secretion of HBsAg and HBeAg with inhibition rates of 27.92% and 25.35% after 6 days of treatment, respectively. Consistent with the reduction in HBV antigens, SM-3 also reduced the level of HBV DNA in a dose-dependent manner. The characterization and quantitation of the chemical composition of SM-3 showed the presence of flavonoid C-glycosides, polysaccharides, and protein, which exhibited diverse antiviral activities. In conclusion, our results demonstrate that SM-3 possesses potential anti-HBV activity in vitro. This is the first report demonstrating the anti-HBV effects of S. media, which is currently under early development as a potential anti-HBV drug candidate.

Antiviral effect of geraniin on human enterovirus 71 in vitro and in vivo

Human enterovirus 71 infection causes hand, foot and mouth disease in children under 6 years of age and has caused mortalities in large-scale outbreaks in the Asia-Pacific region. No effective vaccine or antiviral drugs currently exist against enterovirus 71 in the clinic. In this study, we investigated the antiviral effect of geraniin on enterovirus 71 both in vitro and in vivo. The results showed that geraniin effectively inhibited virus replication in rhabdomyosarcoma cells with an IC(50) of 10 μg/ml. Moreover, geraniin treatment of mice that were challenged with a lethal dose of enterovirus 71 resulted in a reduction of mortality, relieved clinical symptoms, and inhibited virus replication in muscle tissues. The results suggest that geraniin may be used as a potential drug for anti-enterovirus 71.

Anti-Japanese-encephalitis-viral effects of kaempferol and daidzin and their RNA-binding characteristics

BACKGROUND

New therapeutic tools and molecular targets are needed for treatment of Japanese encephalitis virus (JEV) infections. JEV requires an α-1 translational frameshift to synthesize the NS1' protein required for viral neuroinvasiveness. Several flavonoids have been shown to possess antiviral activity in vitro against a wide spectrum of viruses. To date, the antiviral activities of flavonol kaempferol (Kae) and isoflavonoid daidzin (Dai) against JEV have not been described.

METHODOLOGY/PRINCIPAL FINDINGS

The 50% cytotoxic concentration (CC(50)) and 50% effective concentration (EC(50)) against JEV were investigated in BHK21 cells by MTS reduction. Activity against viral genomic RNA and proteins was measured by real-time RT-PCR and western blotting. The frameshift site RNA-binding characterization was also determined by electrospray ionization mass spectrometry, isothermal titration calorimetry and autodocking analysis. EC(50) values of Kae and Dai were 12.6 and 25.9 µM against JEV in cells pretreated before infection, whereas in cells infected before treatment, EC(50) was 21.5 and 40.4 µM, respectively. Kae exhibited more potent activity against JEV and RNA binding in cells following internalization through direct inhibition of viral replication and protein expression, indicating that its antiviral activity was principally due to direct virucidal effects. The JEV frameshift site RNA (fsRNA) was selected as a target for assaying Kae and Dai. ITC of fsRNA revealed an apparent K(b) value for Kae that was nine fold stronger than that for Dai. This binding was confirmed and localized to the RNA using ESI-MS and autodock analysis. Kae could form non-covalent complexes with fsRNA more easily than Dai could.

CONCLUSIONS/SIGNIFICANCE

Kae demonstrates more potent antiviral activity against JEV than does Dai. The mode of action of Kae as an anti-JEV agent seems to be related to its ability to inactivate virus by binding with JEV fsRNA.

Chromatographic fingerprint and the simultaneous determination of five bioactive components of geranium carolinianum L. water extract by high performance liquid chromatography

A simple and sensitive HPLC method has been developed in combination with fingerprint analysis and simultaneous determination of five markers, namely gallic acid, corilagin, methyl brevifolincarboxylate, ellagic acid and rutin for evaluation and quality control of Geranium carolinianum L. water extract. Extraction methods were optimized by comparing the hydrolysis efficiency of geraniin, a major tannin of the herb, resulting in the method of extraction with water under reflux. Water extracts were analyzed by HPLC, with a mobile phase of 0.1% aqueous phosphoric acid (v/v) and acetonitrile in a gradient program within 65 min. Compounds were detected at 274 nm UV wavelength. For fingerprint analysis, 17 peaks were selected as the characteristic peaks to evaluate the similarities of different samples collected from the suburb of Nanjing. The correlation coefficients of similarity were greater than 0.993. In quantitative analysis, the five selected markers showed good regression (R > 0.9991) within test ranges, and the average recoveries were between 97.2-101.7% and their RSD values were less than 4.50%. The total contents of the five markers varied from 44.28 to 71.84 mg/g. The method can be very useful for further development of G. carolinianum L. extracts and preparations.

Ellagitannins from Phyllanthus muellerianus (Kuntze) Exell.: Geraniin and furosin stimulate cellular activity, differentiation and collagen synthesis of human skin keratinocytes and dermal fibroblasts

Leaves from Phyllanthus muellerianus (Kuntze) Exell. are traditionally used for wound healing in Western Africa. Aqueous extracts of dried leaves recently have been shown to stimulate proliferation of human keratinocytes and dermal fibroblasts. Within bioassay-guided fractionation the ellagitannins geraniin (1), corilagin (2), furosin (3), the flavonoids quercetin-3-O-β-D-glucoside (isoquercitrin), kaempferol-3-O-β-D-glucoside (astragalin), quercetin-3-O-D-rutinoside (rutin), gallic acid, methyl gallate, caffeic acid, chlorogenic acid, 3,5-dicaffeoylquinic acid and caffeoylmalic acid (phaselic acid) have been identified in P. muellerianus for the first time. Geraniin was shown to be the dominant component of an aqueous extract. Suitable analytical methods for quality control of geraniin in P. muellerianus extract (methanol/water, 70/30) have been developed and validated based on ICH guidelines (ICH-compliant protocol). Geraniin and furosin increased the cellular energy status of human skin cells (dermal fibroblasts NHDF, HaCaT keratinocytes), triggering the cells towards higher proliferation rates, with fibroblasts being more sensitive than keratinocytes. Highest stimulation of NHDF by geraniin was found at 5 μM, and of keratinocytes at 50-100 μM. Furosin stimulated NHDF at about 50 μM, keratinocytes at about 150-200 μM. Necrotic cytotoxicity of geraniin, as measured by LDH release, was observed at 20 μM for NHDF and 150 μM for keratinocytes. Toxicity of furosin--less than that of geraniin--was observed at > 400 μM. Furosin and geraniin stimulated the biosynthesis of collagen from NHDF at 50 μM and 5-10 μM respectively. Geraniin at 105 μM significantly stimulated the differentiation in NHEK while furosin had a minor influence on the expression of involucrin and cytokeratins K1 and K10. The study proves clearly that hydrophilic extracts from P. muellerianus and especially the lead compound geraniin exhibit stimulating activity on dermal fibroblasts and keratinocytes, leading to increased cell proliferation, barrier formation and formation of extracellular matrix proteins. From these findings the traditional clinical use of such extracts for wound healing seems to be justified.