Anti-SARS-CoV-2 Activity of Ampelozizyphus amazonicus (Saracura-Mirá): Focus on the Modulation of the Spike-ACE2 Interaction by Chemically Characterized Bark Extracts by LC-DAD-APCI-MS/MS.

Traditional medicine shows several treatment protocols for COVID-19 based on natural products, revealing its potential as a possible source of anti-SARS-CoV-2 agents. Ampelozizyphus amazonicus is popularly used in the Brazilian Amazon as a fortifier and tonic, and recently, it has been reported to relieve COVID-19 symptoms. This work aimed to investigate the antiviral potential of A. amazonicus, focusing on the inhibition of spike and ACE2 receptor interaction, a key step in successful infection. Although saponins are the major compounds of this plant and often reported as its active principles, a polyphenol-rich extract was the best inhibitor of the spike and ACE2 interaction. Chemical characterization of A. amazonicus bark extracts by LC-DAD-APCI-MS/MS before and after clean-up steps for polyphenol removal showed that the latter play an essential role in maintaining this activity. The effects of the extracts on viral replication were also assessed, and all samples (aqueous and ethanol extracts) demonstrated in vitro activity, inhibiting viral titers in the supernatant of Calu-3 cells after 24 hpi. By acting both in the SARS-CoV-2 cell entry process and its replication, A. amazonicus bark extracts stand out as a multitarget agent, highlighting the species as a promising candidate in the development of anti-SARS-CoV-2 drugs.

Antiviral Potential of the Genus Panax: An updated review on their effects and underlying mechanism of action.

Viral infections are known as one of the major factors causing death. Ginseng is a medicinal plant that demonstrated a wide range of antiviral potential, and saponins are the major bioactive ingredients in the genus Panax with vast therapeutic potential. Studies focusing on the antiviral activity of the genus Panax plant-derived agents (extracts and saponins) and their mechanisms were identified and summarized, including contributions mainly from January 2016 until January 2022. P. ginseng, P. notoginseng, and P. quinquefolius were included in the review as valuable medicinal herbs against infections with 14 types of viruses. Reports from 9 extracts and 12 bioactive saponins were included, with 6 types of protopanaxadiol (PPD) ginsenosides and 6 types of protopanaxatriol (PPT) ginsenosides. The mechanisms mainly involved the inhibition of viral attachment and replication, the modulation of immune response by regulating signaling pathways, including the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, cystathionine γ-lyase (CSE)/hydrogen sulfide (H2S) pathway, phosphoinositide-dependent kinase-1 (PDK1)/ protein kinase B (Akt) signaling pathway, c-Jun N-terminal kinase (JNK)/activator protein-1 (AP-1) pathway, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. This review includes detailed information about the mentioned antiviral effects of the genus Panax extracts and saponins in vitro and in vivo, and in human clinical trials, which provides a scientific basis for ginseng as an adjunctive therapeutic drug or nutraceutical.

Chapter 2 - Saponin and its derivatives (glycyrrhizin) and SARS-CoV-2

Saponins, the glycosidic compounds, are the subclass of terpenoids that are exceedingly diverse and largest group of natural products found in plants. Based on the aglycone structure, saponins can be classified as triterpenoid, steroidal, and alkaloidal saponins. Glycyrrhizin is a triterpenoid saponin from the root and rhizome concentrates of Liquorice (Glycyrrhiza glabra). Saponin triterpene glycyrrhizin plays an important role in various activities and applications, including molluscicidal, anti-inflammatory, anti-allergic, antidiabetic, cytotoxic, antitumor, antifungal, antibacterial, antiparasitic, and antiviral. The traditional glycyrrhizin therapy is effective for treating a variety of clinical conditions. Due to the wide range of pharmacological properties, it is commonly used in COVID-19 patients. It inhibits replication of respiratory viruses, causes cytopathological effects, and could be an auxiliary medication for COVID-19 treatment due to its liver-protective properties. This chapter discusses biological and nutraceutical applications of saponins and glycyrrhizin in detail.

A review on triterpenoids from plant sources as potential antiviral agents

Viral infections are considered as leading a health issue globally. Numerous numbers of biologically active anti-viral agents have been identified from plants and other organisms. Particularly, terpenoids are a major component of the plant secondary metabolites and a complexity of these structures is accompanied by the potency of their biological activities. It is believed that most of the terpenoids possess the bioactivity against viral infections and cancer diseases. Hence, affected by the pressing a need elevated by the spreading of seriously life-threaten viruses, this review highlights the importance of terpenoids and their activity as antiviral agents that can be employed to treat current lethal diseases such as HIV, H1N1, SARS-CoV and HSV.

Saponin-based PAK-1 inhibitors as promising agents for struggle against SARS-CoV-2 infection

The serine/threonine p21-activating PAK kinases which act as important mediators of the Rho family of GTPases (Rho GTPases) Cdc42ĝ€¢GTP and Racĝ€¢GTP. PAK1 is one of the key molecules in the regulation of cytoskeletal actin assembly, phenotypic signaling, gene expression, and directly affects many cellular processes such as cell motility, invasion, metastasis, cell growth, angiogenesis, cell cycle progression. To date, several sulphated steroidal saponins have been reported to block the PAK1-dependent growth of A549 lung cancer. In this study, we investigated molecular interactions of N-triterpene saponins and PAK1 in silico molecular docking, and further evaluated the binding affinities. Molecular docking simulation was performed through AutoDock 4.2.2. an automated docking tool. We found that N-triterpene saponin 2 had the higher binding affinity towards PAK1 targeted protein. To the best of our knowledge, no report on N-triterpene saponins as a PAK1 inhibitor. © 2022 ACM.

Synthesis and structure-activity relationship study of saponin-based membrane fusion inhibitors against SARS-CoV-2.

We previously discovered that triterpenoid saponin platycodin D inhibits the SARS-CoV-2 entry to the host cell. Herein, we synthesized various saponin derivatives and established a structure-activity relationship of saponin-based antiviral agents against SARS-CoV-2. We discovered that the C3-glucose, the C28-oligosaccharide moiety that consist of (→3)-ß-d-Xyl-(1 â†’ 4)-α-l-Rham-(1 â†’ 2)-ß-d-Ara-(1 â†’ ) as the last three sugar units, and the C16-hydroxyl group were critical components of saponin-based coronavirus cell entry inhibitors. These findings enabled us to develop minimal saponin-based antiviral agents that are equipotent to the originally discovered platycodin D. We found that our saponin-based antiviral agents inhibited both the endosomal and transmembrane protease serine 2-mediated cell surface viral entries. Cell fusion assay experiment revealed that our newly developed compounds inhibit the SARS-CoV-2 entry by blocking the fusion between the viral and host cell membranes. The effectiveness of the newly developed antiviral agents over various SARS-CoV-2 variants hints at the broad-spectrum antiviral efficacy of saponin-based therapeutics against future coronavirus variants.

LC-HRMS Based Approach for Identification and Quantification Analysis of Chemical Constituents of Sea Cucumbers from Aegean Sea - Their Cytotoxic and Antiviral Potentials

There are nearly 1200 species of sea cucumber in the world's seas. Among these creatures included in the Holothuroidea class, 37 species show distribution in the Mediterranean and Aegean Sea. The purpose of this study is to determine the chemical content and biological potent of five sea cucumber species, Holothuria tubulosa, Holothuria poli, Holothuria mammata, Holothuria sanctori and Stichopus regalis which were collected from the Aegean Sea. The detailed flavonoid, phenolic and triterpene contents were determined by LCHR/MS. Cytotoxic activities against several cancer cell lines, MDA-MB-231, PC-3, A549, PANC-1, HEPG2 and a healthy cell line CCD-34LU were performed by MTT method. Antiviral activities of the samples were measured as virucidal activity against avian coronavirus by in ovo. According to the results of LC-HRMS analysis, H. sanctori, H. poli and S. regalis had the richest chemical content diversity in terms of examined triterpene compounds. Fumaric acid was detected as the most abundant substance in all sea cucumber species. H. tubulosa had a highly toxic effect on all the tested cells. The best cytotoxic activity on A549 cells was seen in H. mammata, H. sanctori and H. poli. H. sanctori also showed a significant toxic effect against PANC-1, MDA-MB-231, HepG2 and A549 cells, whereas the IC50 value in CCD-34LU cells was above 50 mu g/mL for this sample. The n-butanol extracts of sea cucumber species reduced hemagglutination (HA) virus titer between 1-fold to 4-fold in log2-based at all tested concentrations. The best inhibited virus HA titer results were found in H. tubulosa at 5 mu g/g. According to these results we have obtained, the extracts of sea cucumbers may be used in many fields such as medicine, food, cosmetics in the future. This study is also very important in terms of being a guide for all studies on the use, processing and production of sea cucumbers and detailed isolation and purification studies on sea cucumber species from Turkey.

Phytochemical screening, GCMS profile, and in-silico properties of bioactive compounds in methanolic leaf extracts of Moringa oleifera

Plant Based Natural Products (PBNPs) have been subject of interest since ancient time due to their use in food, industrial and biomedical applications. Research attention has further augmented to explore their phytochemical composition, properties, and potential application in the post-COVID era. In the present study phytochemical screening has been carried out with Methanolic Leaf Extracts of Moringa oleifera (MLEMO) followed by Gas Chromatography-Mass Spectrometry (GCMS) analysis. Phytochemical analysis of MLEMO revealed the presence of Alkaloids, Carbohydrates, Coumarins, Flavonoids, Glycosides, Phenol, Proteins, Quinones, Saponins, Steroids, Tannins and Terpenoids. Further, GCMS analysis revealed the presence of 41 compounds of which Dihydroxyacetone;Monomethyl malonate;4H-Pyran-4-one,2,3-dihydro- 3,5-dihydroxy-6-methyl;1,3-Propanediol, 2-ethyl-2-(hydroxymethyl);Propanoic acid, 2- methyl-, octyl ester;3-Deoxy-d-mannoic lactone;Sorbitol;Inositol;Cyclohexanemethanol, alpha-methyl-4-(1-methylethyl), Hexadecanoic acid, Methyl palmitate;n-Hexadecanoic acid (Palmitic acid);9-Octadecenoic acid, methyl ester;Phytol;9,12,15-Octadecatrienoic acid;Octadecanoic acid;9-Octadecenamide were prominent. Most of the compounds in the list are bioactive and possess medicinal properties that are expected to serve as a baseline lead for the development of therapeutic agents.

The use of phytopreparations in the treatment of bronchopulmonary diseases: evidence base and practical experience

Respiratory diseases take the lead in the infectious pathology pattern of various organs and systems and are the most common. Acute bronchitis is inflammation of the bronchi due to a viral infection and is characterized by a persistent cough that can be productive or dry. The authors consider the use of herbal preparations as an effective symptomatic product for the treatment of cough of various origins. Medicinal herbs are widely used in medicine due to many useful properties and do not have any serious side effects. Ivy leaf (Hedera helix) extract preparations are common cough medicines available over the counter that are approved by the European Medicines Agency (EMA). Ivy (Hedera helix) leaves contain various biologically active components, but saponins are the main substance. Saponins are natural compounds that have a variety of biological effects. According to literature data, the action of saponins is determined not only by their bronchodilator and mucolytic properties: among additional therapeutic options of saponins are high anti-inflammatory activity, as well as antimicrobial, antifungal and antiviral effects. The article shows the potential for use of ivy saponins as carriers of pharmaceutical substances, which can significantly reduce the effective doses of certain drugs. Preparations containing ivy leaf extract are safe and approved for use even in new-borns. Also, herbal preparations with antiviral, immunomodulatory and anti-inflammatory potential become the object of study as a new strategy for treating COVID-19. © 2022, Remedium Group Ltd. All rights reserved.

Identification, optimization, and biological evaluation of 3-O-ß-chacotriosyl ursolic acid derivatives as novel SARS-CoV-2 entry inhibitors by targeting the prefusion state of spike protein.

The COVID-19 pandemic generates a global threat to public health and continuously emerging SARS-CoV-2 variants bring a great challenge to the development of both vaccines and antiviral agents. In this study, we identified UA-18 and its optimized analog UA-30 via the hit-to-lead strategy as novel SARS-CoV-2 fusion inhibitors. The lead compound UA-30 showed potent antiviral activity against infectious SARS-CoV-2 (wuhan-HU-1 variant) in Vero-E6 cells and was also effective against infection of diverse pseudotyped SARS-CoV-2 variants with mutations in the S protein including the Omicron and Delta variants. More importantly, UA-30 might target the cavity between S1 and S2 subunits to stabilize the prefusion state of the SARS-CoV-2 S protein, thus leading to interfering with virus-cell membrane fusion. This study offers a set of novel SARS-CoV-2 fusion inhibitors against SARS-CoV-2 and its variants based on the 3-O-ß-chacotriosyl UA skeleton.

Recent Advances and Applications of Plant-Based Bioactive Saponins in Colloidal Multiphase Food Systems.

The naturally occurring saponins exhibit remarkable interfacial activity and also possess many biological activities linking to human health benefits, which make them particularly attractive as bifunctional building blocks for formulation of colloidal multiphase food systems. This review focuses on two commonly used food-grade saponins, Quillaja saponins (QS) and glycyrrhizic acid (GA), with the aim of clarifying the relationship between the structural features of saponin molecules and their subsequent self-assembly and interfacial properties. The recent applications of these two saponins in various colloidal multiphase systems, including liquid emulsions, gel emulsions, aqueous foams and complex emulsion foams, are then discussed. A particular emphasis is on the unique use of GA and GA nanofibrils as sole stabilizers for fabricating various multiphase food systems with many advanced qualities including simplicity, ultrastability, stimulability, structural viscoelasticity and processability. These natural saponin and saponin-based colloids are expected to be used as sustainable, plant-based ingredients for designing future foods, cosmetics and pharmaceuticals.

The Effect of Plant Metabolites on Coronaviruses: A Comprehensive Review Focusing on their IC50 Values and Molecular Docking Scores.

Coronaviruses have caused worldwide outbreaks in different periods. SARS (severe acute respiratory syndrome) was the first emerged virus from this family, followed by MERS (Middle East respiratory syndrome) and SARS-CoV-2 (2019-nCoV or COVID 19), which is newly emerged. Many studies have been conducted on the application of chemical and natural drugs for treating these coronaviruses and they are mostly focused on inhibiting the proteases of viruses or blocking their protein receptors through binding to amino acid residues. Among many substances which are introduced to have an inhibitory effect against coronaviruses through the mentioned pathways, natural components are of specific interest. Secondary and primary metabolites from plants, are considered as potential drugs to have an inhibitory effect on coronaviruses. IC50 value (the concentration in which there is 50% loss in enzyme activity), molecular docking score and binding energy are parameters to understand the ability of metabolites to inhibit the specific virus. In this study we reviewed 154 papers on the effect of plant metabolites on different coronaviruses and data of their IC50 values, molecular docking scores and inhibition percentages are collected in tables. Secondary plant metabolites such as polyphenol, alkaloids, terpenoids, organosulfur compounds, saponins and saikosaponins, lectins, essential oil, and nicotianamine, and primary metabolites such as vitamins are included in this study.

Checklist of African Soapy Saponin-Rich Plants for Possible Use in Communities' Response to Global Pandemics.

Plants that exhibit foaming properties when agitated in aqueous solutions are commonly referred to as soapy plants, and they are used in different communities for washing, bathing, and hair shampooing. The frothing ability of these plants is attributed to saponins which are also well-documented to possess antimicrobial attributes. In the light of COVID-19, soap and hand hygiene have taken center stage. The pandemic has also revealed the low access to running water and commercial soaps in many marginalized and poor communities to the detriment of global health. Thus, soapy plants, either in their natural form or through incorporation in commercial products, may be a relevant additional weapon to assist communities to improve hand hygiene and contribute to curbing COVID-19 and other communicable infections. This review paper was compiled from a review of literature that was published between 1980 and 2020. We found 68 plant species, including those which are already used as traditional soaps. Our findings support the potential use of extracts from soapy plants because of their putative viricidal, bactericidal, and fungicidal activities for use in crude home-based formulations and possibly for developing natural commercial soap products.

Saponins: Extraction, bio-medicinal properties and way forward to anti-viral representatives.

Medicinal or herbal plants are widely used for their many favourable properties and are generally safe without any side effects. Saponins are sugar conjugated natural compounds which possess a multitude of biological activities such as medicinal properties, antimicrobial activity, antiviral activity, etc. Saponin production is a part of the normal growth and development process in a lot of plants and plant extracts such as liquorice and ginseng which are exploited as potential drug sources. Herbal compounds have shown a great potential against a wide variety of infectious agents, including viruses such as the SARS-CoV; these are all-natural products and do not show any adverse side effects. This article reviews the various aspects of saponin biosynthesis and extraction, the need for their integration into more mainstream medicinal therapies and how they could be potentially useful in treating viral diseases such as COVID-19, HIV, HSV, rotavirus etc. The literature presents a close review on the saponin efficacy in targeting mentioned viral diseases that occupy a high mortality rate worldwide. This manuscript indicates the role of saponins as a source of dynamic plant based anti-viral remedies and their various methods for extraction from different sources.

SARS-CoV-2 main protease inhibition by compounds isolated from Luffa cylindrica using molecular docking.

In this study, chemical investigation of methanol extract of the air-dried fruits of Luffa cylindrica led to the identification of a new δ-valerolactone (1), along with sixteen known compounds (2-17). Their chemical structures including the absolute configuration were elucidated by extensive spectroscopic analysis and electronic circular dichroism analysis, as well as by comparison with those reported in the literature. For the first time in literature, we have examined the binding potential of the isolated compounds to highly conserved protein, Mpro of SARS-CoV-2 using the molecular docking technique. We found that the isolated saponins (14-17) bind to the substrate-binding pocket of SARS-CoV-2 Mpro with docking energy scores of -7.13, -7.29, -7.47, and -7.54 kcal.mol-1, respectively, along with binding abilities equivalent to an already claimed N3 protease inhibitor (-7.51 kcal.mol-1).

Discovery and structural optimization of 3-O-ß-chacotriosyl oleanane-type triterpenoids as potent entry inhibitors of SARS-CoV-2 virus infections.

Currently, SARS-CoV-2 virus is an emerging pathogen that has posed a serious threat to public health worldwide. However, no agents have been approved to treat SARS-CoV-2 infections to date, underscoring the great need for effective and practical therapies for SARS-CoV-2 outbreaks. We reported that a focused screen of OA saponins identified 3-O-ß-chacotriosyl OA benzyl ester 2 as a novel small molecule inhibitor of SARS-CoV-2 virus entry, via binding to SARS-CoV-2 glycoprotein (S). We performed structure-activity relationship profiling of 2 and discovered C-17-COOH of OA was an important modification site that improved both inhibitor potency toward SARS-CoV-2 and selectivity index. Then optimization from hit to lead resulted in a potent fusion inhibitor 12f displaying strong inhibition against infectious SARS-CoV-2 with an IC50 value of 0.97 µM in vitro. Mechanism studies confirmed that inhibition of SARS-CoV-2 viral entry of 12f was mediated by the direct interaction with SARS-CoV-2 S2 subunit to block membrane fusion. These 3-O-ß-chacotriosyl OA amide saponins are suitable for further optimization as SARS-CoV-2 entry inhibitors with the potential to be developed as therapeutic agents for the treatment of SARS-CoV-2 virus infections.

Bioactive Terpenes and Their Derivatives as Potential SARS-CoV-2 Proteases Inhibitors from Molecular Modeling Studies.

The coronavirus disease 2019 (COVID-19) pandemic is caused by a novel coronavirus; the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Millions of cases and deaths to date have resulted in a global challenge for healthcare systems. COVID-19 has a high mortality rate, especially in elderly individuals with pre-existing chronic comorbidities. There are currently no effective therapeutic approaches for the prevention and treatment of COVID-19. Therefore, the identification of effective therapeutics is a necessity. Terpenes are the largest class of natural products that could serve as a source of new drugs or as prototypes for the development of effective pharmacotherapeutic agents. In the present study, we discuss the antiviral activity of these natural products and we perform simulations against the Mpro and PLpro enzymes of SARS-CoV-2. Our results strongly suggest the potential of these compounds against human coronaviruses, including SARS-CoV-2.

In silico investigation of saponins and tannins as potential inhibitors of SARS-CoV-2 main protease (Mpro).

It is no longer news that a novel strain of coronavirus named SARS-CoV-2 is ravaging the health sector worldwide, several attempts have been made to curtail this pandemic via repurposing of old drugs but at the present, available drugs are not adequately effective. Over the years, plant phytochemicals are increasingly becoming alternative sources of antimicrobial agents with novel mechanisms of action and limited side effects compared to synthetic drugs. Isolated saponins and tannins were evaluated for antiviral activity against SARS-CoV-2 (Mpro) via Molecular Docking and it was observed that a handsome number of the phytochemicals had binding affinities much better than Remdesivir, Dexamethasone, and N3 inhibitor which were used as the standards in this study. Further investigation of drug-likeness, ADMET profile, PASS profile, oral bioavailability, bioactivity, binding mode, and molecular interactions of these phytochemicals revealed that binding affinity alone is not enough to justify the potency of a molecule in the drug discovery process, as only 4 among the screened compounds passed all the analyses and are identified as potential inhibitors of SARS-CoV-2 (Mpro). This preliminary study thereby recommends Ellagic acid (- 8.4 kcal/mol), Arjunic Acid (- 8.1 kcal/mol), Theasapogenol B (- 8.1 kcal/mol), and Euscaphic Acid (- 8.0 kcal/mol) as potential inhibitors of SARS-CoV-2 (Mpro) with better pharmacokinetics and bioavailability compared to Remdesivir which is currently used compassionately.