In vitro anti-hepatitis B virus effect of Hypericum perforatum L

Specialized metabolites from plants as a source of new multi-target antiviral drugs: a systematic review

Viral infections have always been the main global health challenge, as several potentially lethal viruses, including the hepatitis virus, herpes virus, and influenza virus, have affected human health for decades. Unfortunately, most licensed antiviral drugs are characterized by many adverse reactions and, in the long-term therapy, also develop viral resistance; for these reasons, researchers have focused their attention on investigating potential antiviral molecules from plants. Natural resources indeed offer a variety of specialized therapeutic metabolites that have been demonstrated to inhibit viral entry into the host cells and replication through the regulation of viral absorption, cell receptor binding, and competition for the activation of intracellular signaling pathways. Many active phytochemicals, including flavonoids, lignans, terpenoids, coumarins, saponins, alkaloids, etc., have been identified as potential candidates for preventing and treating viral infections. Using a systematic approach, this review summarises the knowledge obtained to date on the in vivo antiviral activity of specialized metabolites extracted from plant matrices by focusing on their mechanism of action.

Hypericum perforatum and Its Ingredients Hypericin and Pseudohypericin Demonstrate an Antiviral Activity against SARS-CoV-2

For almost two years, the COVID-19 pandemic has constituted a major challenge to human health, particularly due to the lack of efficient antivirals to be used against the virus during routine treatment interventions. Multiple treatment options have been investigated for their potential inhibitory effect on SARS-CoV-2. Natural products, such as plant extracts, may be a promising option, as they have shown an antiviral activity against other viruses in the past. Here, a quantified extract of Hypericum perforatum was tested and found to possess a potent antiviral activity against SARS-CoV-2. The antiviral potency of the extract could be attributed to the naphtodianthrones hypericin and pseudohypericin, in contrast to other tested ingredients of the plant material, which did not show any antiviral activity. Hypericum perforatum and its main active ingredient hypericin were also effective against different SARS-CoV-2 variants (Alpha, Beta, Delta, and Omicron). Concerning its mechanism of action, evidence was obtained that Hypericum perforatum and hypericin may hold a direct virus-blocking effect against SARS-CoV-2 virus particles. Taken together, the presented data clearly emphasize the promising antiviral activity of Hypericum perforatum and its active ingredients against SARS-CoV-2 infections.

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.

Anti-Tumor Activity of Hypericum perforatum L. and Hyperforin through Modulation of Inflammatory Signaling, ROS Generation and Proton Dynamics

In this paper we review the mechanisms of the antitumor effects of Hypericum perforatum L. (St. John's wort, SJW) and its main active component hyperforin (HPF). SJW extract is commonly employed as antidepressant due to its ability to inhibit monoamine neurotransmitters re-uptake. Moreover, further biological properties make this vegetal extract very suitable for both prevention and treatment of several diseases, including cancer. Regular use of SJW reduces colorectal cancer risk in humans and prevents genotoxic effects of carcinogens in animal models. In established cancer, SJW and HPF can still exert therapeutic effects by their ability to downregulate inflammatory mediators and inhibit pro-survival kinases, angiogenic factors and extracellular matrix proteases, thereby counteracting tumor growth and spread. Remarkably, the mechanisms of action of SJW and HPF include their ability to decrease ROS production and restore pH imbalance in tumor cells. The SJW component HPF, due to its high lipophilicity and mild acidity, accumulates in membranes and acts as a protonophore that hinders inner mitochondrial membrane hyperpolarization, inhibiting mitochondrial ROS generation and consequently tumor cell proliferation. At the plasma membrane level, HPF prevents cytosol alkalization and extracellular acidification by allowing protons to re-enter the cells. These effects can revert or at least attenuate cancer cell phenotype, contributing to hamper proliferation, neo-angiogenesis and metastatic dissemination. Furthermore, several studies report that in tumor cells SJW and HPF, mainly at high concentrations, induce the mitochondrial apoptosis pathway, likely by collapsing the mitochondrial membrane potential. Based on these mechanisms, we highlight the SJW/HPF remarkable potentiality in cancer prevention and treatment.

Isolation and identification of an anti-hepatitis B virus compound from Hydrocotyle sibthorpioides Lam

ETHNOPHARMACOLOGICAL RELEVANCE

Hydrocotyle sibthorpioides (Apiaceae) have been used as a folk remedy for the treatment of fever, edema, detoxication, throat pain, psoriasis and hepatitis B virus infections in China. The aim of this study is to isolate and identify an anti-HBV compound from this herb.

MATERIALS AND METHODS

A compound (saponin) was isolated from the active ethanol extract using bioassay-guided screening. The structure of the saponin was elucidated by spectroscopic methods and compared with published data. The anti-HBV activity of the saponin was evaluated by detecting the levels of HBV antigens, extracellular HBV DNA, nuclear covalent closed circular DNA (cccDNA) and five HBV promoters in HepG2.2.15 cells. In addition, the levels of serum HBsAg/HBeAg, DHBV DNA, ALT/AST and hepatic pathological changes were analyzed in DHBV-infected ducks.

RESULTS

The chemical analysis indicated that the saponin isolated from Hydrocotyle sibthorpioides is asiaticoside. The pharmacodynamics experimental studies showed that asiaticoside effectively suppressed the levels of HBsAg/HBeAg, extracellular HBV DNA and intracellular cccDNA in a dose-dependent manner. Furthermore, experiments demonstrated that asiaticoside markedly reduced viral DNA transcription and replication by inhibiting the activities of core, s1, s2, and X gene promoters. In addition, asiaticoside markedly reduced DHBV replication without any obvious signs of toxicity. The levels of serum DHBV DNA, HBsAg/HBeAg were increased 3 days after drug withdrawal, but the levels rebounded slightly in the asiaticoside treatment groups compared with the 3TC treatment group. Moreover, analysis of the serum ALT/AST levels and the liver pathological changes indicated that asiaticoside could alleviate liver damage.

CONCLUSIONS

Our results show that asiaticoside could efficiently inhibit HBV replication both in vitro and in vivo, and asiaticoside may be a major bioactive ingredient in Hydrocotyle sibthorpioides.

Design, synthesis, and biological evaluation of new 2'-deoxy-2'-fluoro-4'-triazole cytidine nucleosides as potent antiviral agents

A series of 4'-[1,2,3]triazole-2'-deoxy-2'-fluoro-β-d-arabinofuranosylcytosines (9-17) were prepared by Cu(I)-mediated [3 + 2] cycloaddition reactions (CuAAC) of 1-(4'-azido-2'-deoxy-2'-fluoro-β-d-arabinofuranosyl)cytosine (1) with appropriate alkynes in good yields. Their structures were fully established by (1)H NMR, (13)C NMR, HRMS, and elemental analysis. Most of these nucleoside analogs exhibited potent anti-HIV-1 activity with no cytotoxicity observed at the highest tested concentration up to 25 μM. Among them, compounds 9, 10 and 13 exhibited extremely potent antiviral activity, thus had a great potential for further development as novel nucleoside reverse transcriptase inhibitors (NRTIs) for the treatment of HIV-1 infection. Besides, the anti-HBV activity of compounds 10, 11 and 17 had been investigated.

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.

Elicitation of secondary metabolism in Hypericum perforatum by rhizosphere bacteria and derived elicitors in seedlings and shoot cultures

CONTEXT

Hypericum perforatum L. (Guttiferae) appears as an alternative treatment to mild and moderate depression and been traditionally used as a health enhancer based on the phytochemicals hyperforin and hypericin. However, field grown medicinal plants show variable levels of phytopharmaceuticals depending on environmental conditions. Elicitation is a good strategy to trigger secondary metabolism.

OBJECTIVE

This study explored the ability of 6 rhizobacterial strains to trigger secondary metabolism in H. perforatum seedlings and molecular elicitors from the most effective strain N5.18 were tested in shoot cultures.

MATERIALS AND METHODS

Hypericin and pseudohypericin were determined on seedlings and shoot cultures by HPLC. Three putative elicitors from bacterial culture media were assayed in three different concentrations.

RESULTS

Strain N5.18 significantly increased hypericin up to 1.2 ppm and pseudohypericin up to 3.4 ppm, over controls (0.3 and 2.5 ppm, respectively) when delivered to seedlings. In shoot cultures, only pseudohypericin was detected (168.9 ppm) and significant increases were observed under the different elicitors, reaching values of 3164.8 ppm with small elicitors in the middle concentration.

DISCUSSION AND CONCLUSION

Secondary metabolism in plants is highly inducible due to its role in plant communication and defense. Our findings demonstrate that some beneficial bacterial strains are able to trigger secondary metabolism in H. perforatum plants when delivered through the roots and bacterial determinants released to culture media are able to reproduce the effect in shoot cultures. Therefore, these elicitors have great potential to enhance phytopharmaceutical production.