Natural Products: Review for Their Effects of Anti-HBV

Solamargine acts as an antiviral by interacting to MZF1 and targeting the core promoter of the hepatitis B virus gene

BACKGROUND

Hepatitis B virus (HBV) infection is still a serious threat to global health and can lead to a variety of liver diseases, including acute and chronic hepatitis, liver cirrhosis, liver failure, hepatocellular carcinoma (HCC), and so on. At present, there are mainly two kinds of drugs for the treatment of hepatitis B at home and abroad: interferon (IFN) and nucleoside/nucleotide analogs (NAs). In recent years, natural compounds have been considered an important source for the development of new anti-HBV drugs due to their complex structure, diverse components, high efficiency, and low toxicity. Many studies have demonstrated that Solamargine has significant anticancer activity, but the antiviral effect is rarely studied. This study aimed to verify the anti-HBV effect of Solamargine and to explore the specific mechanism.

METHOD

The relative expression of HBV pregenomic RNA (pgRNA) was detected by reverse transcription real-time fluorescence quantitative PCR (RT-qPCR). Northern blot and western blot were used to detect the relative expression of HBV pgRNA and target protein. PCR was used in the construction of HBV pg-promoter, ENII/BCP, and a series of gene deletion mutant fluorescent reporter vectors. The fluorescence relative expression of each mutant was detected by Renilla luciferase assay.

RESULTS

By binding to MZF1 (Myeloid zinc finger protein 1, MZF1), Solamargine inhibits HBV core promoter activity, reduces pregenomic RNA level, and inhibits HBV, achieving antiviral effects.

Discovery and mechanistic study of Imperatorin that inhibits HBsAg expression and cccDNA transcription

Chronic hepatitis B virus (HBV) infection remains a significant global health challenge due to its link to severe conditions like HBV-related cirrhosis and hepatocellular carcinoma (HCC). Although current treatments effectively reduce viral levels, they have limited impact on certain HBV elements, namely hepatitis B surface antigen (HBsAg) and covalently closed circular DNA (cccDNA). This highlights the urgent need for innovative pharmaceutical and biological interventions that can disrupt HBsAg production originating from cccDNA. In this study, we identified a natural furanocoumarin compound, Imperatorin, which markedly inhibited the expression of HBsAg from cccDNA, by screening a library of natural compounds derived from Chinese herbal medicines using ELISA assay and qRT-PCR. The pharmacodynamics study of Imperatorin was explored on HBV infected HepG2-NTCP/PHHs and HBV-infected humanized mouse model. Proteome analysis was performed on HBV infected HepG2-NTCP cells following Imperatorin treatment. Molecular docking and bio-layer interferometry (BLI) were used for finding the target of Imperatorin. Our findings demonstrated Imperatorin remarkably reduced the level of HBsAg, HBV RNAs, HBV DNA and transcriptional activity of cccDNA both in vitro and in vivo. Additionally, Imperatorin effectively restrained the actions of HBV promoters responsible for cccDNA transcription. Mechanistic study revealed that Imperatorin directly binds to ERK and subsequently interfering with the activation of CAMP response element-binding protein (CREB), a crucial transcriptional factor for HBV and has been demonstrated to bind to the PreS2/S and X promoter regions of HBV. Importantly, the absence of ERK could nullify the antiviral impact triggered by Imperatorin. Collectively, the natural compound Imperatorin may be an effective candidate agent for inhibiting HBsAg production and cccDNA transcription by impeding the activities of HBV promoters through ERK-CREB axis.

The role of Traditional Chinese medicine in anti-HBV: background, progress, and challenges

Chronic hepatitis B (CHB) remains a major world's most serious public health issues. Despite the remarkable effect of nucleos(t)ide analogues (NAs) in inhibiting hepatitis B virus (HBV) deoxyribonucleic acid (DNA) as the first-line drug, there are several limitations still, such as poor antigen inhibition, drug resistance, low-level viremia, restricting patients' functional cure. Due to the constraints of NAs, traditional medicines, such as traditional Chinese medicine (TCM), have become more prevalently used and researched in the clinical treatment of CHB as complementary alternative therapies. As a consequence, the review focuses on the background based on HBV's life cycle as well as the NAs' limitations, progress based on direct and indirect pathway of targeting HBV of TCM, and challenges of TCM. We found TCMs play an increasingly important role in anti-HBV. In a direct antiviral way, they regulate HBV infection, replication, assembly, and other aspects of the HBV life cycle. As for indirect way, TCMs can exert anti-HBV effects through targeting the host, including immune regulation, apoptosis, autophagy, oxidative stress, etc. Especially, TCMs have the advantages of strong antigenic inhibition compared to NAs. Specifically, we can combine the benefits of TCMs in strong HBV antigen inhibition with the benefits of NAs in targeted antiviral effects, in order to find a suitable combination of "TCM + NAs" to contribute to Chinese knowledge of the realisation of the "global elimination of HBV by 2030" goal of the World Health Organization.

Anti-hepatitis B virus activities of natural products and their antiviral mechanisms

Chronic hepatitis B (CHB) infections caused by the hepatitis B virus (HBV) continue to pose a significant global public health challenge. Currently, the approved treatments for CHB are limited to interferon and nucleos(t)ide analogs, both of which have their limitations, and achieving a complete cure remains an elusive goal. Therefore, the identification of new therapeutic targets and the development of novel antiviral strategies are of utmost importance. Natural products (NPs) constitute a class of substances known for their diverse chemical structures, wide-ranging biological activities, and low toxicity profiles. They have shown promise as potential candidates for combating various diseases, with a substantial number demonstrating anti-HBV properties. This comprehensive review focuses on the current applications of NPs in the fight against HBV and provides a summary of their antiviral mechanisms, considering their impact on the viral life cycle and host hepatocytes. By offering insights into the world of anti-HBV NPs, this review aims to furnish valuable information to support the future development of antiviral drugs.

Manipulation of fungal cell wall integrity to improve production of fungal natural products

Fungi, as an important industrial microorganism, play an essential role in the production of natural products (NPs) due to their advantages of utilizing cheap raw materials as substrates and strong protein secretion ability. Although many metabolic engineering strategies have been adopted to enhance the biosynthetic pathway of NPs in fungi, the fungal cell wall as a natural barrier tissue is the final and key step that affects the efficiency of NPs synthesis. To date, many important progresses have been achieved in improving the synthesis of NPs by regulating the cell wall structure of fungi. In this review, we systematically summarize and discuss various strategies for modifying the cell wall structure of fungi to improve the synthesis of NPs. At first, the cell wall structure of different types of fungi is systematically described. Then, strategies to disrupt cell wall integrity (CWI) by regulating the synthesis of cell wall polysaccharides and binding proteins are summarized, which have been applied to improve the synthesis of NPs. In addition, we also summarize the studies on the regulation of CWI-related signaling pathway and the addition of exogenous components for regulating CWI to improve the synthesis of NPs. Finally, we propose the current challenges and essential strategies to usher in an era of more extensive manipulation of fungal CWI to improve the production of fungal NPs.

Forthcoming Developments in Models to Study the Hepatitis B Virus Replication Cycle, Pathogenesis, and Pharmacological Advancements

Hepatitis, liver cirrhosis, and hepatocellular carcinoma are all manifestations of chronic hepatitis B. Its pathogenesis and molecular mechanism remain mysterious. As medical science progresses, different models are being used to study the disease from the physiological and molecular levels. Animal models have played an unprecedented role in achieving in-depth knowledge of the disease while posing no risk of harming humans throughout the study. The scarcity of acceptable animal models has slowed progress in hepatitis B virus (HBV) research and preclinical testing of antiviral medicines since HBV has a narrow species tropism and exclusively infects humans and higher primates. The development of human chimeric mice was supported by a better understanding of the obstacles to interspecies transmission, which has substantially opened the way for HBV research in vivo and the evaluation of possible chronic hepatitis B therapeutics. Animal models are cumbersome to handle, not accessible, and expensive. Hence, it is herculean to investigate the HBV replication cycle in animal models. Therefore, it becomes essential to build a splendid in vitro cell culture system to demonstrate the mechanisms attained by the HBV for its multiplication and sustenance. We also addressed the advantages and caveats associated with different models in examining HBV.

The progress of molecules and strategies for the treatment of HBV infection

Hepatitis B virus infections have always been associated with high levels of mortality. In 2019, hepatitis B virus (HBV)-related diseases resulted in approximately 555,000 deaths globally. In view of its high lethality, the treatment of HBV infections has always presented a huge challenge. The World Health Organization (WHO) came up with ambitious targets for the elimination of hepatitis B as a major public health threat by 2030. To accomplish this goal, one of the WHO’s strategies is to develop curative treatments for HBV infections. Current treatments in a clinical setting included 1 year of pegylated interferon alpha (PEG-IFNα) and long-term nucleoside analogues (NAs). Although both treatments have demonstrated outstanding antiviral effects, it has been difficult to develop a cure for HBV. The reason for this is that covalently closed circular DNA (cccDNA), integrated HBV DNA, the high viral burden, and the impaired host immune responses all hinder the development of a cure for HBV. To overcome these problems, there are clinical trials on a number of antiviral molecules being carried out, all -showing promising results so far. In this review, we summarize the functions and mechanisms of action of various synthetic molecules, natural products, traditional Chinese herbal medicines, as clustered regularly interspaced short palindromic repeats and their associated proteins (CRISPR/Cas)-based systems, zinc finger nucleases (ZFNs), and transcription activator-like effector nucleases (TALENs), all of which could destroy the stability of the HBV life cycle. In addition, we discuss the functions of immune modulators, which can enhance or activate the host immune system, as well some representative natural products with anti-HBV effects.

A Novel L-Phenylalanine Dipeptide Inhibits the Growth and Metastasis of Prostate Cancer Cells via Targeting DUSP1 and TNFSF9

Prostate cancer (PCa) is a common malignant cancer of the urinary system. Drug therapy, chemotherapy, and radical prostatectomy are the primary treatment methods, but drug resistance and postoperative recurrence often occur. Therefore, seeking novel anti-tumor compounds with high efficiency and low toxicity from natural products can produce a new tumor treatment method. Matijin-Su [N-(N-benzoyl-L-phenylalanyl)-O-acetyl-L-phenylalanol, MTS] is a phenylalanine dipeptide monomer compound that is isolated from the Chinese ethnic medicine Matijin (Dichondra repens Forst.). Its derivatives exhibit various pharmacological activities, especially anti-tumor. Among them, the novel MTS derivative HXL131 has a significant inhibitory effect against prostate tumor growth and metastasis. This study is designed to investigate the effects of HXL131 on the growth and metastasis of human PCa cell lines PC3 and its molecular mechanism through in vitro experiments combined with proteomics, molecular docking, and gene silencing. The in vitro results showed that HXL131 concentration dependently inhibited PC3 cell proliferation, induced apoptosis, arrested cell cycle at the G2/M phase, and inhibited cell migration capacity. A proteomic analysis and a Western blot showed that HXL131 up-regulated the expression of proliferation, apoptosis, cell cycle, and migration-related proteins CYR61, TIMP1, SOD2, IL6, SERPINE2, DUSP1, TNFSF9, OSMR, TNFRSF10D, and TNFRSF12A. Molecular docking, a cellular thermal shift assay (CETSA), and gene silencing showed that HXL131 had a strong binding affinity with DUSP1 and TNFSF9, which are important target genes for inhibiting the growth and metastasis of PC3 cells. This study demonstrates that HXL131 exhibited excellent anti-prostate cancer activity and inhibited the growth and metastasis of prostate cancer cells by regulating the expression of DUSP1 and TNFSF9.

Phytomedicines to Target Hepatitis B Virus DNA Replication: Current Limitations and Future Approaches

Hepatitis B virus infection (HBV) is one of the most common causes of hepatitis, and may lead to cirrhosis or hepatocellular carcinoma. According to the World Health Organization (WHO), approximately 296 million people worldwide are carriers of the hepatitis B virus. Various nucleos(t)ide analogs, which specifically suppress viral replication, are the main treatment agents for HBV infection. However, the development of drug-resistant HBV strains due to viral genomic mutations in genes encoding the polymerase protein is a major obstacle to HBV treatment. In addition, adverse effects can occur in patients treated with nucleos(t)ide analogs. Thus, alternative anti-HBV drugs of plant origin are being investigated as they exhibit excellent safety profiles and have few or no side effects. In this study, phytomedicines/phytochemicals exerting significant inhibitory effects on HBV by interfering with its replication were reviewed based on different compound groups. In addition, the chemical structures of these compounds were developed. This will facilitate their commercial synthesis and further investigation of the molecular mechanisms underlying their effects. The limitations of compounds previously screened for their anti-HBV effect, as well as future approaches to anti-HBV research, have also been discussed.

A Review of Medicinal Plants with Antiviral Activity Available in Bangladesh and Mechanistic Insight Into Their Bioactive Metabolites on SARS-CoV-2, HIV and HBV

Currently, viral infection is the most serious health issue which causing unexpected higher rate of death globally. Many viruses are not yet curable, such as corona virus-2 (SARS-CoV-2), human immunodeficiency virus (HIV), hepatitis virus, human papilloma virus and so others. Furthermore, the toxicities and ineffective responses to resistant strains of synthetic antiviral drugs have reinforced the search of effective and alternative treatment options, such as plant-derived antiviral drug molecules. Therefore, in the present review, an attempt has been taken to summarize the medicinal plants reported for exhibiting antiviral activities available in Bangladesh along with discussing the mechanistic insights into their bioactive components against three most hazardous viruses, namely SARS-CoV-2, HIV, and HBV. The review covers 46 medicinal plants with antiviral activity from 25 families. Among the reported 79 bioactive compounds having antiviral activities isolated from these plants, about 37 of them have been reported for significant activities against varieties of viruses. Hesperidin, apigenin, luteolin, seselin, 6-gingerol, humulene epoxide, quercetin, kaempferol, curcumin, and epigallocatechin-3-gallate (EGCG) have been reported to inhibit multiple molecular targets of SARS-CoV-2 viral replication in a number of in silico investigations. Besides, numerous in silico, in vitro, and in vivo bioassays have been demonstrated that EGCG, anolignan-A, and B, ajoene, curcumin, and oleanolic acid exhibit anti-HIV activity while piperine, ursolic acid, oleanolic acid, (+)-cycloolivil-4'-O-β-d-glucopyranoside, quercetin, EGCG, kaempferol, aloin, apigenin, rosmarinic acid, andrographolide, and hesperidin possess anti-HBV activity. Thus, the antiviral medicinal plants and the isolated bioactive compounds may be considered for further advanced investigations with the aim of the development of effective and affordable antiviral drugs.

A Review on the Ethnomedicinal Usage, Phytochemistry, and Pharmacological Properties of Gentianeae (Gentianaceae) in Tibetan Medicine

Gentianaceae is a large plant family and is distributed worldwide. As the largest tribe in Gentianaceae, Gentianeae contains 939-968 species, and the Qinghai-Tibet Plateau and adjacent areas are the main centers of diversity for Gentianeae. Species from the Gentianeae are widely used in traditional Tibetan medicine. In this review, a systematic and constructive overview of the information on botany, ethnomedicinal usage, phytochemistry, and pharmacological properties of Gentianeae in Tibetan medicine is provided. The results of this study are based on a literature search, including electronic databases, books, websites, papers, and conference proceedings. Botanical studies showed that Gentianeae includes the subtribe Gentianeae and Swertiinae, and several new genera and taxa have been identified. Approximately 83 species from Gentianeae were used in Tibetan medicine, among which Gentiana and Swertia constituted the largest number of species with 42 and 24 species, respectively. The species from Gentianeae are mainly used as Bangjian (སྤང་རྒྱན།), Jieji (ཀྱི་ལྕེ།), Dida (ཏིག་ཏ།), and Ganggaqiong (གང་གྰཆུང་།) in Tibetan medicine with different clinical applications. More than 240 formulas were found containing Gentianeae species with different attending functions. Phytochemical studies showed that the main active components of Gentianeae species are iridoids, xanthones, flavonoids, and triterpenoids. The bioactivities of plants from Gentianeae include hepatic protection, upper respiratory tract protection, joint and bone protection, glucose regulation, antibacterial, antioxidant, anticancer, and antiviral effects. This review will provide a reference for future research on natural resource protection, plant-based drug development, and further clinical investigation.