Broad-spectrum antiviral activity of Spatholobus suberectus Dunn against SARS-CoV-2, SARS-CoV-1, H5N1, and other enveloped viruses

Pseudovirus-Based Systems for Screening Natural Antiviral Agents: A Comprehensive Review

Since the outbreak of COVID-19, researchers have been working tirelessly to discover effective ways to combat coronavirus infection. The use of computational drug repurposing methods and molecular docking has been instrumental in identifying compounds that have the potential to disrupt the binding between the spike glycoprotein of SARS-CoV-2 and human ACE2 (hACE2). Moreover, the pseudovirus approach has emerged as a robust technique for investigating the mechanism of virus attachment to cellular receptors and for screening targeted small molecule drugs. Pseudoviruses are viral particles containing envelope proteins, which mediate the virus's entry with the same efficiency as that of live viruses but lacking pathogenic genes. Therefore, they represent a safe alternative to screen potential drugs inhibiting viral entry, especially for highly pathogenic enveloped viruses. In this review, we have compiled a list of antiviral plant extracts and natural products that have been extensively studied against enveloped emerging and re-emerging viruses by pseudovirus technology. The review is organized into three parts: (1) construction of pseudoviruses based on different packaging systems and applications; (2) knowledge of emerging and re-emerging viruses; (3) natural products active against pseudovirus-mediated entry. One of the most crucial stages in the life cycle of a virus is its penetration into host cells. Therefore, the discovery of viral entry inhibitors represents a promising therapeutic option in fighting against emerging viruses.

Spatholobi caulis: A systematic review of its traditional uses, chemical constituents, biological activities and clinical applications

ETHNOPHARMACOLOGICAL RELEVANCE

Spatholobi caulis (SC), the dried vine stem of Spatholobus suberectus Dunn, is known as Ji Xue Teng in China, and has long been used as traditional Chinese medicine (TCM) to treat anaemia, menstrual abnormalities, rheumatoid arthritis, purpura, etc. AIM OF THE REVIEW: The aim of this review is to provide a systematic and updated summary of the traditional uses, chemical constituents, biological activities and clinical applications of SC. In addition, several suggestions for future research on SC are also proposed.

MATERIALS AND METHODS

Extensive information and data on SC were obtained from electronic databases (ScienceDirect, Web of Science, PubMed, CNKI, Baidu Scholar, Google Scholar, ResearchGate, SpringerLink and Wiley Online). Additional information was collected from Ph.D. and MSc dissertations, published books, and classic material medica.

RESULTS

To date, phytochemical studies have revealed that approximately 243 chemical ingredients have been isolated from SC and identified, including flavonoids, glycosides, phenolic acids, phenylpropanoids, volatile oils, sesquiterpenoids and other compounds. Many studies have indicated that extracts and pure constituents from SC possess a wide spectrum of in vitro and in vivo pharmacological effects, such as anti-tumour, haematopoietic, anti-inflammatory, antidiabetic, antioxidant, antiviral and antibacterial effects, as well as other activities. SC could be applied to the treatment of leukopenia, aplastic anemic, endometriosis, etc. according to the clinical reports. The traditional efficacies of SC is due to the biological functions of its chemical compounds, especially flavonoids. However, research investigating the toxicological effects of SC is relatively limited.

CONCLUSIONS

SC is widely used in TCM formulae and its some traditional efficacies has been confirmed by extensive recent pharmacological and clinical studies. Most the biological activities of the SC may be attributed to flavonoids. However, in-depth studies on the molecular mechanisms of the effective ingredients and extracts of SC are limited. Further systematic studies focusing on pharmacokinetics, toxicology and quality control are needed to ensure the effective and safe application of SC.

Spatholobus suberectus inhibits lipogenesis and tumorigenesis in triple-negative breast cancer via activation of AMPK-ACC and K-Ras-ERK signaling pathway

Background and aim

Triple-negative breast cancer (TNBC) is a highly invasive type of breast cancer with a poor prognosis. Currently, there are no effective management strategies for TNBC. Earlier, our lab reported the percolation of Spatholobus suberectus for the treatment of breast cancer. Lipid metabolic reprogramming is a hallmark of cancer. However, the anti-TNBC efficiency of S. suberectus extract and its causal mechanism for preventing lipogenesis have not been fully recognized. Hence, the present study aimed to investigate the inhibitory role of S. suberectus extract on lipogenesis and tumorigenesis in TNBC in vitro and in vivo by activating AMPK-ACC and K-Ras-ERK signaling pathways using lipidomic and metabolomic techniques.

Experimental procedure

Dried stems of S. suberectus extract inhibited lipogenesis and tumorigenesis and promoted fatty acid oxidation as demonstrated by the identification of the metabolites and fatty acid markers using proteomic and metabolomic analysis, qPCR, and Western blot.

Results and conclusion

The results indicated that S. suberectus extract promotes fatty acid oxidation and suppresses lipogenic metabolites and biomarkers, thereby preventing tumorigenesis via the AMPK-ACC and K-Ras-ERK signaling pathways. On the basis of this preclinical evidence, we suggest that this study represents a milestone and complements Chinese medicine. Further studies remain underway in our laboratory to elucidate the active principles of S. suberectus extract. This study suggests that S. suberectus extract could be a promising therapy for TNBC.

Promising role of Vitamin D and plant metabolites against COVID-19: Clinical trials review

Vitamin D possesses immunomodulatory qualities and is protective against respiratory infections. Additionally, it strengthens adaptive and cellular immunity and boosts the expression of genes involved in oxidation. Experts suggested taking vitamin D supplements to avoid and treat viral infection and also COVID-19, on the other hand, since the beginning of time, the use of plants as medicines have been vital to human wellbeing. The WHO estimates that 80 % of people worldwide use plants or herbs for therapeutic purposes. Secondary metabolites from medicinal plants are thought to be useful in lowering infections from pathogenic microorganisms due to their ability to inhibit viral protein and enzyme activity by binding with them. As a result, this manuscript seeks to describe the role of vitamin D and probable plant metabolites that have antiviral activities and may be complementary to the alternative strategy against COVID-19 in a single manuscript through reviewing various case studies.

A comprehensive review: Botany, phytochemistry, traditional uses, pharmacology, and toxicology of Spatholobus suberectus vine stems

ETHNOPHARMACOLOGICAL RELEVANCE

Spatholobus suberectus vine stem (SSVS) is the dried lianoid stem of the leguminous plant, Spatholobus suberectus Dunn, which is mainly distributed in China and some Southeast Asian countries. Due to its notable effects of promoting blood circulation and tonifying blood, regulating menstruation and relieving pain, this phytomedicine has been used in traditional Chinese medicine for hundreds of years.

AIM OF THE STUDY

This review is designed to provide a comprehensive profile of SSVS concerning its botany, traditional uses, phytochemistry, quality control, pharmacology, pharmacokinetics, and toxicology and attempts to provide a scientific basis and future directions for further research and development.

MATERIALS AND METHODS

Related document information was collected with the help of databases such as the Web of Science, Science Direct, PubMed, China National Knowledge Infrastructure (CNKI) and Flora of China.

RESULTS

SSVS is reported to be traditionally used to treat rheumatic arthralgia, numbness and paralysis, blood deficiency, irregular menstruation and other gynecological diseases. Botanical studies have revealed that there are some confusable varieties in some specific locations with a long history. Additionally, 145 chemical constituents have been isolated and identified from SSVS, including flavonoids, organic acids, terpenoids, lignans, and phenolic glycosides. Pharmacological studies have shown that SSVS has a variety of effects, such as nervous system regulation, and antioxidative, antitumor, antiviral, antidiabetic, and anti-inflammatory effects. However, in regard to the absorption-distribution-metabolism-elimination-toxicity (ADMET) of SSVS, few studies have been carried out, and few articles have been published.

CONCLUSION

With a long history of traditional uses, a variety of bioactive phytochemicals and a wide range of definite pharmacological activities, SSVS is believed to have great potential in clinical applications and further research, development and exploitation. The precise action mechanisms, rational quality control and quality markers, and explicit ADMET routes should be highlighted in the future, which might provide effective help to safely, effectively and sustainably use this herbal medicine.

A Comprehensive Update of Various Attempts by Medicinal Chemists to Combat COVID-19 through Natural Products

The ongoing COVID-19 pandemic has resulted in a global panic because of its continual evolution and recurring spikes. This serious malignancy is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the outbreak, millions of people have been affected from December 2019 till now, which has led to a great surge in finding treatments. Despite trying to handle the pandemic with the repurposing of some drugs, such as chloroquine, hydroxychloroquine, remdesivir, lopinavir, ivermectin, etc., against COVID-19, the SARS-CoV-2 virus continues its out-of-control spread. There is a dire need to identify a new regimen of natural products to combat the deadly viral disease. This article deals with the literature reports to date of natural products showing inhibitory activity towards SARS-CoV-2 through different approaches, such as in vivo, in vitro, and in silico studies. Natural compounds targeting the proteins of SARS-CoV-2-the main protease (Mpro), papain-like protease (PLpro), spike proteins, RNA-dependent RNA polymerase (RdRp), endoribonuclease, exoribonuclease, helicase, nucleocapsid, methyltransferase, adeno diphosphate (ADP) phosphatase, other nonstructural proteins, and envelope proteins-were extracted mainly from plants, and some were isolated from bacteria, algae, fungi, and a few marine organisms.

Nutrients, herbal bioactive derivatives and commensal microbiota as tools to lower the risk of SARS-CoV-2 infection

The SARS-CoV-2 outbreak has infected a vast population across the world, causing more than 664 million cases and 6.7 million deaths by January 2023. Vaccination has been effective in reducing the most critical aftermath of this infection, but some issues are still present regarding re-infection prevention, effectiveness against variants, vaccine hesitancy and worldwide accessibility. Moreover, although several old and new antiviral drugs have been tested, we still lack robust and specific treatment modalities. It appears of utmost importance, facing this continuously growing pandemic, to focus on alternative practices grounded on firm scientific bases. In this article, we aim to outline a rigorous scientific background and propose complementary nutritional tools useful toward containment, and ultimately control, of SARS-CoV-2 infection. In particular, we review the mechanisms of viral entry and discuss the role of polyunsaturated fatty acids derived from α-linolenic acid and other nutrients in preventing the interaction of SARS-CoV-2 with its entry gateways. In a similar way, we analyze in detail the role of herbal-derived pharmacological compounds and specific microbial strains or microbial-derived polypeptides in the prevention of SARS-CoV-2 entry. In addition, we highlight the role of probiotics, nutrients and herbal-derived compounds in stimulating the immunity response.

Identification of diphenylurea derivatives as novel endocytosis inhibitors that demonstrate broad-spectrum activity against SARS-CoV-2 and influenza A virus both in vitro and in vivo

Rapid evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus (IAV) poses enormous challenge in the development of broad-spectrum antivirals that are effective against the existing and emerging viral strains. Virus entry through endocytosis represents an attractive target for drug development, as inhibition of this early infection step should block downstream infection processes, and potentially inhibit viruses sharing the same entry route. In this study, we report the identification of 1,3-diphenylurea (DPU) derivatives (DPUDs) as a new class of endocytosis inhibitors, which broadly restricted entry and replication of several SARS-CoV-2 and IAV strains. Importantly, the DPUDs did not induce any significant cytotoxicity at concentrations effective against the viral infections. Examining the uptake of cargoes specific to different endocytic pathways, we found that DPUDs majorly affected clathrin-mediated endocytosis, which both SARS-CoV-2 and IAV utilize for cellular entry. In the DPUD-treated cells, although virus binding on the cell surface was unaffected, internalization of both the viruses was drastically reduced. Since compounds similar to the DPUDs were previously reported to transport anions including chloride (Cl-) across lipid membrane and since intracellular Cl- concentration plays a critical role in regulating vesicular trafficking, we hypothesized that the observed defect in endocytosis by the DPUDs could be due to altered Cl- gradient across the cell membrane. Using in vitro assays we demonstrated that the DPUDs transported Cl- into the cell and led to intracellular Cl- accumulation, which possibly affected the endocytic machinery by perturbing intracellular Cl- homeostasis. Finally, we tested the DPUDs in mice challenged with IAV and mouse-adapted SARS-CoV-2 (MA 10). Treatment of the infected mice with the DPUDs led to remarkable body weight recovery, improved survival and significantly reduced lung viral load, highlighting their potential for development as broad-spectrum antivirals.

Identification of medicinal plant-based phytochemicals as a potential inhibitor for SARS-CoV-2 main protease (Mpro) using molecular docking and deep learning methods

Highly transmissive and rapidly evolving Coronavirus disease-2019 (COVID-19), a viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), triggered a global pandemic, which is one of the most researched viruses in the academia. Effective drugs to treat people with COVID-19 have yet to be developed to reduce mortality and transmission. Studies on the SARS-CoV-2 virus identified that its main protease (Mpro) might be a potential therapeutic target for drug development, as this enzyme plays a key role in viral replication. In search of potential inhibitors of Mpro, we developed a phytochemical library consisting of 2431 phytochemicals from 104 Korean medicinal plants that exhibited medicinal and antioxidant properties. The library was screened by molecular docking, followed by revalidation by re-screening with a deep learning method. Recurrent Neural Networks (RNN) computing system was used to develop an inhibitory predictive model using SARS coronavirus Mpro dataset. It was deployed to screen the top 12 compounds based on their docked binding affinity that ranged from -8.0 to -8.9 kcal/mol. The top two lead compounds, Catechin gallate and Quercetin 3-O-malonylglucoside, were selected depending on inhibitory potency against Mpro. Interactions with the target protein active sites, including His41, Met49, Cys145, Met165, and Thr190 were also examined. Molecular dynamics simulation was performed to analyze root mean square deviation (RMSD), root mean square fluctuation (RMSF), radius of gyration (RG), solvent accessible surface area (SASA), and number of hydrogen bonds. Results confirmed the inflexible nature of the docked complexes. Absorption, distribution, metabolism, excretion, and toxicity (ADMET), as well as bioactivity prediction confirmed the pharmaceutical activities of the lead compound. Findings of this research might help scientists to optimize compatible drugs for the treatment of COVID-19 patients.

Advances in natural product anti-coronavirus research (2002-2022)

COVID-19 is a severe acute respiratory syndrome caused by coronavirus that has triggered acute respiratory infections in countries around the world. In the last 20 years, there have been several outbreaks of coronaviruses, which have had a tremendous impact on productive life and globalization. Since coronaviruses are mutagenic and highly susceptible to mutation, there are no specific drugs against coronaviruses. Medicines made from natural products gains worldwide attention, and the mechanism and effectiveness of natural products for the treatment of coronavirus-related diseases have received much attention after the global pandemic of COVID-19 in 2020. The vitro research results and clinical data from various countries have shown protective effects of good effects against coronaviruses. This review summarizes representative natural products for the treatment of coronavirus-related diseases in the past 20 years, and demonstrates the promising prospects of natural products against coronavirus-related diseases by listing herbal formulas, Chinese patent medicines and natural small molecule compounds and their therapeutic mechanisms, providing references for subsequent related studies.

Ethnopharmacology, Phytochemistry, and Pharmacological Activities of Spatholobus suberectus Vine Stem

Spatholobus suberectus vine stem is an important medicinal material in Chinese, Vietnamese, and Korean traditional medicines. Its decoction has long been used to treat blood disorders, such as anemia and menstrual irregularity, as well as rheumatoid diseases. Previous phytochemical investigations characterized 88 compounds from S suberectus, which mainly belonged to the phenolic class, especially of the flavonoid type. Pharmacological studies showed the beneficial effects of extracts of the plant on the cardiovascular tract, which is ethnopharmacologically relevant to the plant's use in traditional medicine. Besides that, the extracts and isolated compounds also exhibited antimicrobial, anticancer, antiinflammatory, and antioxidant activities. The past study results support the use of S suberectus vine stem in traditional medicine and also revealed new directions of pharmacological effects of this medicinal plant.

A Review of the Pharmacological Potential of Spatholobus suberectus Dunn on Cancer

Spatholobus suberectus Dunn (SSD) has been extensively employed in Traditional Chinese Medicine to treat several ailments. SSD and its active compounds are effective therapeutic agents for treating a variety of diseases with negligible side effects. Therefore, we aimed to investigate its phytochemistry, pharmacology, and potential therapeutic effects exclusively in cancer prevention and treatment. Phytochemical and pharmacological information was collected and arranged in a rational order. SSD has been frequently attributed to having antioxidant, anti-diabetic, anti-inflammatory, hematopoietic, neuroprotective, antimicrobial, and anticancer properties. Evidence has indicated that the bioactive constituents in SSD have attracted increasing scientific attention due to their preventive role in cancers. Further, the present review provides the current information on the health implications of SSD, thus allowing for future clinical trials to explore its restorative benefits. All data of in vitro and animal investigations of SSD, as well as its effect on human health, were obtained from an electronic search and library database. The diverse pharmacological potential of SSD provides an opportunity for preclinical drug discovery, and this comprehensive review strongly indicates that SSD is an excellent anti-tumorigenic agent that modulates or prevents breast cancer.