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

Characterisation of the antibody-mediated selective pressure driving intra-host evolution of SARS-CoV-2 in prolonged infection

Neutralising antibodies against the SARS-CoV-2 spike (S) protein are major determinants of protective immunity, though insufficient antibody responses may cause the emergence of escape mutants. We studied the humoral immune response causing intra-host evolution in a B-cell depleted, haemato-oncologic patient experiencing clinically severe, prolonged SARS-CoV-2 infection with a virus of lineage B.1.177.81. Following bamlanivimab treatment at an early stage of infection, the patient developed a bamlanivimab-resistant mutation, S:S494P. After five weeks of apparent genetic stability, the emergence of additional substitutions and deletions within the N-terminal domain (NTD) and the receptor binding domain (RBD) of S was observed. Notably, the composition and frequency of escape mutations changed in a short period with an unprecedented dynamic. The triple mutant S:Delta141-4 E484K S494P became dominant until virus elimination. Routine serology revealed no evidence of an antibody response in the patient. A detailed analysis of the variant-specific immune response by pseudotyped virus neutralisation test, surrogate virus neutralisation test, and immunoglobulin-capture enzyme immunoassay showed that the onset of an IgM-dominated antibody response coincided with the appearance of escape mutations. The formation of neutralising antibodies against S:Delta141-4 E484K S494P correlated with virus elimination. One year later, the patient experienced clinically mild re-infection with Omicron BA.1.18, which was treated with sotrovimab and resulted in an increase in Omicron-reactive antibodies. In conclusion, the onset of an IgM-dominated endogenous immune response in an immunocompromised patient coincided with the appearance of additional mutations in the NTD and RBD of S in a bamlanivimab-resistant virus. Although virus elimination was ultimately achieved, this humoral immune response escaped detection by routine diagnosis and created a situation temporarily favouring the rapid emergence of various antibody escape mutants with known epidemiological relevance.

[The Impact of Antidepressants on COVID-19 and Post-Acute COVID-19 Syndrome: A Scoping-Review Update]

Introduction Preclinically, fluvoxamine and other antidepressants (AD) exerted antiviral and anti-inflammatory properties also against SARS-COV-2. Therfore, It makes sense to test the clinical effect of AD against COVID-19 and Long COVID.

METHODS

On May 20, 2024, this systematic scoping review in PUBMED identified 1016 articles related to AD and COVID-19, Long COVID and SARS-COV-2. These included 10 retrospective "large scale" studies (> 20000 chart reviews), 8 prospective clinical trials (plus 4 regarding Long COVID), 11 placebo-controlled randomized (RCT) (plus 2 regarding Long COVID) and 15 meta-analyses.

RESULTS

COVID-19: Retrospective studies with cohorts taking AD primarily for psychiatric comorbidities or chronic pain conditions directly prior to SARS-COV-2 infection described that this substance class (most studied: Selective Serotonin Re-Uptake Inhibitors (SSRI) and Selective Serotonin Noradrenaline Re-Uptake Inhibitors (SSNRI)) were associated with (i) significantly fewer SARS-COV-2 infections and (ii) a milder course of COVID-19 ("COVID-19 protection"). Ten of the 11 RCTs found regarding COVID-19 tested fluvoxamine, as this old AD appeared suitable as a prophylactic agent against severe COVID-19, taking into account its in vitro potency against the progression of intracellular sepsis cascades. Therefore, most (12 out of 15) meta-analyses also referred to fluvoxamine. They found (iii) a significant (40-70% reduction) in mortality, intubation and hospitalization rates when fluvoxamine was used as an add-on to standard therapy for mild to moderate COVID-19. When this AD was used in the early stages of the disease, it was more successful than when it was given later in advanced, severe COVID-19 (e.g. severe pneumonia, final sepsis stages). A dose dependency was observed: 2x50 mg fluvoxamine over 15 days was less effective than 2x100 or even 3x100 mg with an adverse event profile still at the placebo level. Direct comparisons with drugs approved for COVID-19 do not yet exist. A first indirect meta-analytical comparison showed an advantage of paxlovid or molnupiravir versus fluvoxamine against the development of severe COVID-19: risk reduction of 95% (I2 = N/A, but only one study) or 78% (I2=0) versus 5+-5% (I2=48). However, an add-on of fluvoxamine was still significantly more efficacious than symptom-oriented standard therapy alone. Long COVID: A common Long COVID phenotype with dominant anxiety and depression symptoms, which responds to AD, relaxation therapy and/or psychotherapy, has now been identified. Casuistics report positive effects of AD on fatigue, cognitive and autonomic dysfunctions. A first large prospective open-label RCT has just shown significantly more favourable courses, less viral load and less pro-inflammatory cytokines in the treatment of mild to moderate COVID-19 with fluvoxamine versus standard treatment, also with regard to the subsequent development of neuropsychiatric and pulmonary Long COVID or fatigue.

CONCLUSION

Overall, there is promising evidence of a preventive effect of AD (especially fluvoxamine) against progression to severe COVID-19 and against the development of Long COVID. It is likely, that the entire AD substance class could be effective here. This assumption is based on the results of retrospective large scale studies, but awaits verification by better controlled studies. The potential effectiveness/efficacy (currently low and moderate confidence of the evidence for the entire substance class and specifically fluvoxamine, respectively) of fluvoxamine as an add-on against COVID-19 and possibly also directly against Long COVID could stimulate similar projects in other infectious diseases that also have the potential to pose a lasting threat to the health of those affected. We consider the evidence to date to be sufficient to be able to emphasize a possible positive effect of these substances in the psychoeducation of patients with COVID-19 or Long COVID who are already receiving AD for other conditions - especially also against the symptoms associated with the viral disease or its consequences. In regions where neither vaccines nor antiviral agents currently approved for the prevention or treatment of COVID-19 are available, AD and in particular fluvoxamine would be a cost-effective alternative to protect against a severe course, even if this AD appears to have a smaller effect against COVID-19 than the currently approved antiviral agents, but with presumably better tolerability. A direct comparative clinical trial with approved antiviral agents is still pending and should be positive to further open the door for a guideline-based recommendation of fluvoxamine (or perhaps even AD) for COVID-19 or its aftermath.

Phytochemical and Toxicological Analyses of Herbal Mixtures Containing Hypericum perforatum and Melissa officinalis

Objectives

This study aimed to formulate a novel herbal mixture of Hypericum perforatum (H) and Melissa officinalis (M) and evaluate its toxicity, microbial load, and phytochemical content.

Materials and Methods

Total flavonoids were measured using the AlCl3/NaNO2 complex formation method and colorimetric assay. The quercetin content of the herbal mixture was determined by reverse-phase high-performance liquid chromatography. The in vitro and in vivo safety of the herbal formulations were analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and acute oral toxicity analysis in the rat model, respectively.

Results

The formulated extract (HM), compared with the standard rutin extract, had a total flavonoid content of 15.29 ± 0.64 mg rutin per mL sample. Reverse-phase high-performance liquid chromatography revealed a quercetin content of 0.187 mg/mL. Microbial tests for Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella spp. were negative. Colony counts for total aerobic microbial and yeast and mold counts were 10 in each case. The MTT assay (with up to about 5% v/v HM extract) using the NIH/3T3 cell line revealed no cell toxicity in the range of concentrations tested. Acute oral toxicity was tested in the Wistar rat model, and the LD50 was 695.2 ± 7.5 mg/kg. The dry weight of the HM extract was 38.1 mg/mL.

Conclusion

Preliminary results proved the safety of the HM herbal mixture, with its toxicity and microbial load within the limits of accepted guidelines allowable for use in clinical trials.

Progress in Research on Inhibitors Targeting SARS-CoV-2 Main Protease (Mpro)

Since 2019, the novel coronavirus (SARS-CoV-2) has caused significant morbidity and millions of deaths worldwide. The Coronavirus Disease 2019 (COVID-19), caused by SARS-CoV-2 and its variants, has further highlighted the urgent need for the development of effective therapeutic agents. Currently, the highly conserved and broad-spectrum nature of main proteases (Mpro) renders them of great importance in the field of inhibitor study. In this study, we categorize inhibitors targeting Mpro into three major groups: mimetic, nonmimetic, and natural inhibitors. We then present the research progress of these inhibitors in detail, including their mechanism of action, antiviral activity, pharmacokinetic properties, animal experiments, and clinical studies. This review aims to provide valuable insights and potential avenues for the development of more effective antiviral drugs against SARS-CoV-2.

Cannabigerol and Cannabicyclol Block SARS-CoV-2 Cell Fusion

The search for new active substances against SARS-CoV-2 is still a central challenge after the COVID-19 pandemic. Antiviral agents to complement vaccination are an important pillar in the clinical situation. Selected cannabinoids such as cannabigerol, cannabicyclol, cannabichromene, and cannabicitran from Cannabis sativa and synthetic homologues of cannabigerol and cannabicyclol were evaluated for effects on the cell viability of Vero cells (CC50 of cannabigerol and cannabicyclol 40 resp. 38 µM) and reduced virus entry of vesicular stomatitis pseudotyped viruses with surface-expressed SARS-CoV-2 spike protein at 20 µM. In addition to a reduction of pseudotyped virus entry, a titer reduction assay on Vero cells after preincubation of Wuhan SARS-CoV-2 significantly confirmed antiviral activity. Investigations on the molecular targets addressed by cannabigerol and cannabicyclol indicated that both compounds are inhibitors of SARS-CoV-2 spike protein-mediated membrane fusion, as could be shown by a virus-free reporter fusion inhibition assay (EC50 for cannabigerol 5.5 µM and for cannabicyclol 10.8 µM) and by monitoring syncytia formation in Vero reporter cells. Selectivity indices were calculated as 7.4 for cannabigerol and 3.5 for cannabicyclol. Systematic semisynthetic alterations of cannabigerol and cannabicyclol indicated that the side chains of both compounds do not contribute to the observed anti-membrane fusion activity.

The potential role of Hypericum perforatum in wound healing: A literature review on the phytochemicals, pharmacological approaches, and mechanistic perspectives

St. John's Wort, commonly known as Hypericum perforatum L., is a flowering plant in the Clusiaceae family that traditionally been employed for treating anxiety, depression, wounds, burns, sunburn, irritation, and stomach ailments. This review provides a synopsis of H. perforatum L. phytoconstituents and their biological effects, highlighting its beneficial therapeutic properties for dermatological indications, as well as its antioxidant, antimicrobial, anti-inflammatory, and anti-angiogenic activity in various applications including wound healing and skin conditions such as eczema, sun burn and minor burns also spastic paralysis, stiff neck and mood disorders as anti-depressant and nerve pains such as neuralgia. The data were collected from several databases as Web of Science PubMed, ScienceDirect, Scopus and Google Scholar using the terms: "H. perforatum L.", "H. perforatum L. /phytochemistry," and "H. perforatum extracts/wound healing" collected from 1994 to 2023. The findings suggest H. perforatum L. acts through various mechanisms and plays a role in each phase of the wound healing process, including re-epithelialization, angiogenesis, wound contraction, and connective tissue regeneration. H. perforatum L. enhances collagen deposition, decreases inflammation, inhibits fibroblast migration, and promotes epithelialization by increasing the number of fibroblasts with polygonal shape and the number of collagen fibers within fibroblasts. H. Perforatum L. extracts modulate the immune response and reduce inflammation were found to accelerate the wound healing process via inhibition of inflammatory mediators' production like interleukin-6, tumor necrosis factor-α, cyclooxygenase-2 gene expression, and inducible nitric oxide synthase. Thus, H. perforatum L. represents a potential remedy for a wide range of dermatological problems, owing to its constituents with beneficial therapeutic properties. H. perforatum L. could be utilized in the development of novel wound healing therapies.

Computational and experimental validation of phthalocyanine and hypericin as effective SARS-CoV-2 fusion inhibitors

Phthalocyanine and hypericin have been previously identified as possible SARS-CoV-2 Spike glycoprotein fusion inhibitors through a virtual screening procedure. In this paper, atomistic simulations of metal-free phthalocyanines and atomistic and coarse-grained simulations of hypericins, placed around a complete model of the Spike embedded in a viral membrane, allowed to further explore their multi-target inhibitory potential, uncovering their binding to key protein functional regions and their propensity to insert in the membrane. Following computational results, pre-treatment of a pseudovirus expressing the SARS-CoV-2 Spike protein with low compounds concentrations resulted in a strong inhibition of its entry into cells, suggesting the activity of these molecules should involve the direct targeting of the viral envelope surface. The combination of computational and in vitro results hence supports the role of hypericin and phthalocyanine as promising SARS-CoV-2 entry inhibitors, further endorsed by literature reporting the efficacy of these compounds in inhibiting SARS-CoV-2 activity and in treating hospitalized COVID-19 patients.Communicated by Ramaswamy H. Sarma.

Surrogate Virus Neutralisation Test Based on Nanoluciferase-Tagged Antigens to Quantify Inhibitory Antibodies against SARS-CoV-2 and Characterise Omicron-Specific Reactivity in a Vaccination Cohort

Virus-specific antibodies are crucial for protective immunity against SARS-CoV-2. Assessing functional antibodies through conventional or pseudotyped virus neutralisation tests (pVNT) requires high biosafety levels. Alternatively, the virus-free surrogate virus neutralisation test (sVNT) quantifies antibodies interfering with spike binding to angiotensin-converting enzyme 2. We evaluated secreted nanoluciferase-tagged spike protein fragments as diagnostic antigens in the sVNT in a vaccination cohort. Initially, spike fragments were tested in a capture enzyme immunoassay (EIA), identifying the receptor binding domain (RBD) as the optimal diagnostic antigen. The sensitivity of the in-house sVNT applying the nanoluciferase-labelled RBD equalled or surpassed that of a commercial sVNT (cPass, GenScript Diagnostics) and an in-house pVNT four weeks after the first vaccination (98% vs. 94% and 72%, respectively), reaching 100% in all assays four weeks after the second and third vaccinations. When testing serum reactivity with Omicron BA.1 spike, the sVNT and pVNT displayed superior discrimination between wild-type- and variant-specific serum reactivity compared to a capture EIA. This was most pronounced after the first and second vaccinations, with the third vaccination resulting in robust, cross-reactive BA.1 construct detection. In conclusion, utilising nanoluciferase-labelled antigens permits the quantification of SARS-CoV-2-specific inhibitory antibodies. Designed as flexible modular systems, the assays can be readily adjusted for monitoring vaccine efficacy.

Hypericin as a promising natural bioactive naphthodianthrone: A review of its pharmacology, pharmacokinetics, toxicity, and safety

Hypericin can be derived from St. John's wort, which is widely spread around the world. As a natural product, it has been put into clinical practice such as wound healing and depression for a long time. In this article, we review the pharmacology, pharmacokinetics, and safety of hypericin, aiming to introduce the research advances and provide a full evaluation of it. Turns out hypericin, as a natural photosensitizer, exhibits an excellent capacity for anticancer, neuroprotection, and elimination of microorganisms, especially when activated by light, potent anticancer and antimicrobial effects are obtained after photodynamic therapy. The mechanisms of its therapeutic effects involve the induction of cell death, inhibition of cell cycle progression, inhibition of the reuptake of amines, and inhibition of virus replication. The pharmacokinetics properties indicate that hypericin has poor water solubility and bioavailability. The distribution and excretion are fast, and it is metabolized in bile. The toxicity of hypericin is rarely reported and the conventional use of it rarely causes adverse effects except for photosensitization. Therefore, we may conclude that hypericin can be used safely and effectively against a variety of diseases. We hope to provide researchers with detailed guidance and enlighten the development of it.

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.

Multi-structural molecular docking (MOD) combined with molecular dynamics reveal the structural requirements of designing broad-spectrum inhibitors of SARS-CoV-2 entry to host cells

New variants of SARS-CoV-2 that can escape immune response continue to emerge. Consequently, there is an urgent demand to design small molecule therapeutics inhibiting viral entry to host cells to reduce infectivity rate. Despite numerous in silico and in situ studies, the structural requirement of designing viral-entry inhibitors effective against multiple variants of SARS-CoV-2 has yet to be described. Here we systematically screened the binding of various natural products (NPs) to six different SARS-CoV-2 receptor-binding domain (RBD) structures. We demonstrate that Multi-structural Molecular Docking (MOD) combined with molecular dynamics calculations allowed us to predict a vulnerable site of RBD and the structural requirement of ligands binding to this vulnerable site. We expect that our findings lay the foundation for in silico screening and identification of lead molecules to guide drug discovery into designing new broad-spectrum lead molecules to counter the threat of future variants of SARS-CoV-2.

Recent advances in the discovery of plant-derived antimicrobial natural products to combat antimicrobial resistant pathogens: insights from 2018-2022

Covering: 2018 to 2022Antimicrobial resistance (AMR) poses a significant global health threat. There is a rising demand for innovative drug scaffolds and new targets to combat multidrug-resistant bacteria. Before the advent of antibiotics, infections were treated with plants chosen from traditional medicine practices. Of Earth's 374 000 plant species, approximately 9% have been used medicinally, but most species remain to be investigated. This review illuminates discoveries of antimicrobial natural products from plants covering 2018 to 2022. It highlights plant-derived natural products with antibacterial, antivirulence, and antibiofilm activity documented in lab studies. Additionally, this review examines the development of novel derivatives from well-studied parent natural products, as natural product derivatives have often served as scaffolds for anti-infective agents.

Hypericum perforatum L. and the Underlying Molecular Mechanisms for Its Choleretic, Cholagogue, and Regenerative Properties

Any defects in bile formation, secretion, or flow may give rise to cholestasis, liver fibrosis, cirrhosis, and hepatocellular carcinoma. As the pathogenesis of hepatic disorders is multifactorial, targeting parallel pathways potentially increases the outcome of therapy. Hypericum perforatum has been famed for its anti-depressive effects. However, according to traditional Persian medicine, it helps with jaundice and acts as a choleretic medication. Here, we will discuss the underlying molecular mechanisms of Hypericum for its use in hepatobiliary disorders. Differentially expressed genes retrieved from microarray data analysis upon treatment with safe doses of Hypericum extract and intersection with the genes involved in cholestasis are identified. Target genes are located mainly at the endomembrane system with integrin-binding ability. Activation of α5β1 integrins, as osmo-sensors in the liver, activates a non-receptor tyrosine kinase, c-SRC, which leads to the insertion of bile acid transporters into the canalicular membrane to trigger choleresis. Hypericum upregulates CDK6 that controls cell proliferation, compensating for the bile acid damage to hepatocytes. It induces ICAM1 to stimulate liver regeneration and regulates nischarin, a hepatoprotective receptor. The extract targets the expression of conserved oligomeric Golgi (COG) and facilitates the movement of bile acids toward the canalicular membrane via Golgi-derived vesicles. In addition, Hypericum induces SCP2, an intracellular cholesterol transporter, to maintain cholesterol homeostasis. We have also provided a comprehensive view of the target genes affected by Hypericum's main metabolites, such as hypericin, hyperforin, quercitrin, isoquercitrin, quercetin, kaempferol, rutin, and p-coumaric acid to enlighten a new scope in the management of chronic liver disorders. Altogether, standard trials using Hypericum as a neo-adjuvant or second-line therapy in ursodeoxycholic-acid-non-responder patients define the future trajectories of cholestasis treatment with this product.

Strategies for the Management of Spike Protein-Related Pathology

In the wake of the COVID-19 crisis, a need has arisen to prevent and treat two related conditions, COVID-19 vaccine injury and long COVID-19, both of which can trace at least part of their aetiology to the spike protein, which can cause harm through several mechanisms. One significant mechanism of harm is vascular, and it is mediated by the spike protein, a common element of the COVID-19 illness, and it is related to receiving a COVID-19 vaccine. Given the significant number of people experiencing these two related conditions, it is imperative to develop treatment protocols, as well as to consider the diversity of people experiencing long COVID-19 and vaccine injury. This review summarizes the known treatment options for long COVID-19 and vaccine injury, their mechanisms, and their evidentiary basis.

Investigation of the inhibitory activity of extracts, fractions and secondary metabolites of <i>Silene</i> spp. (<i>Caryophyllaceae</i>) and <i>Serratula cupuliformis</i> (<i>Asteraceae</i>) on the replication of SARS-CoV-2 coronavirus

Aim. In vitro analysis of the inhibitory activity of extracts, fractions and secondary metabolites of plants of the genus Silene [Caryophylaceae] and Serratula cupuliformis [Asteraceae) on the replication of SARS-CoV-2.

Material and Methods. Silene spp. and Serratula cupuliformis of the Siberian Botanical Garden of National Research Tomsk State University were used. Ethanol extracts and butanol fractions of Silene spp. were prepared. The flavonoid shaftoside and the ecdysteroid 20-hydroxyecdysone from Lychnis chalcedonica were isolated. Analysis of BAS was carried out by the HPLC method. In vitro analysis of the inhibitory activity of extracts on SARS-CoV-2 replication was performed in Vero cell culture by direct inactivation [neutralization) of virions. Comparison samples were dry ethanol extracts of chaga [Inonotus obliquus, Basidiomycota), spices of cloves [Syzygium aromaticum, Myrtaceae) and root of licorice [Glycyrrhiza glabra L., Fabaceae).

Results. The inhibitory activity of ethanol extracts and butanol fractions of Silene spp., as well as individual compounds [shaftozide and 20-E) was revealed in the range of 50% effective concentrations [EC50) when dissolved in water from 339.85±83.92 pg/ml to 1.59±0.39 pg/ml and when dissolved in DMSO from 119.34±26.34 pg/ml to 2.22±0.57 pg/ml, respectively. The butanol fraction of Serratula cupuliformis was active with EC50=21.74±4.80 and 27.42±6.05 pg/mL. These results for some samples of Silene spp. and Serratula cupuliformis are comparable to the EC50 values of the comparators.

Conclusion. The results obtained suggest the presence of biologically active substances in the herbal preparations studied that act destructively on virions of SARS-CoV-2 and affect one of the main stages of its "life" cycle - on the attachment to receptors of sensitive cells.

Production, Characterization, and In Vitro and In Vivo Studies of Nanoemulsions Containing St. John’s Wort Plant Constituents and Their Potential for the Treatment of Depression

The current project was designed to prepare an oil-in-water (oil/water) hypericin nanoemulsion using eucalyptus oil for the preparation of an oil phase with chitosan as an emulsion stabilizer. The study might be a novelty in the field of pharmaceutical sciences, especially in the area of formulation development. Tween® 80 (Polysorbate) was used as the nonionic surfactant. The nanoemulsion was prepared by using the homogenization technique, followed by its physicochemical evaluation. The surface morphological studies showed the globular structure has a nano-sized diameter, as confirmed by zeta size analysis. The zeta potential analysis confirmed a positive surface charge that might be caused by the presence of chitosan in the formulation. The pH was in the range of 5.14 to 6.11, which could also be compatible with the range of nasal pH. The viscosity of the formulations was found to be affected by the concentration of chitosan (F1-11.61 to F4-49.28). The drug release studies showed that the presence of chitosan greatly influenced the drug release, as it was noticed that formulations having an elevated concentration of chitosan release lesser amounts of the drug. The persistent stress in the mouse model caused a variety of depressive- and anxiety-like behaviors that can be counteracted by chemicals isolated from plants, such as sulforaphane and tea polyphenols. In the behavioral test and source performance test, hypericin exhibited antidepressant-like effects. The results show that the mice treated for chronic mild stress had a considerably higher preference for sucrose after receiving continuous hypericin for 4 days (p = 0.0001) compared to the animals administered with normal saline (p ≤ 0.0001) as well as the naïve group (p ≤ 0.0001). In conclusion, prepared formulations were found to be stable and can be used as a potential candidate for the treatment of depression.

Hypericin: A natural anthraquinone as promising therapeutic agent

BACKGROUND

Hypericin is a prominent secondary metabolite mainly existing in genus Hypericum. It has become a research focus for a quiet long time owing to its extensively pharmacological activities especially the anti-cancer, anti-bacterial, anti-viral and neuroprotective effects. This review concentrated on summarizing and analyzing the existing studies of hypericin in a comprehensive perspective.

METHODS

The literature with desired information about hypericin published after 2010 was gained from electronic databases including PubMed, SciFinder, Science Direct, Web of Science, China National Knowledge Infrastructure databases and Wan Fang DATA.

RESULTS

According to extensive preclinical and clinical studies conducted on the hypericin, an organized and comprehensive summary of the natural and artificial sources, strategies for improving the bioactivities, pharmacological activities, drug combination of hypericin was presented to explore the future therapeutic potential of this active compound.

CONCLUSIONS

Overall, this review offered a theoretical guidance for the follow-up research of hypericin. However, the pharmacological mechanisms, pharmacokinetics and structure activity relationship of hypericin should be further studied in future research.

Inhibitory activity of dry ethanol extracts of <i>Artemisia</i> spp. on SARS‐CoV‐2 replication <i>in vitro</i>

Aim. In vitro analysis of the inhibitory activity of dry ethanol extracts of some Artemisia spp. growing in the Novosibirsk region for SARS‐CoV‐2 replication.

Materials and Methods. The laboratory strain SARS‐CoV‐2/human/RUS/Nsk‐FRCFTM‐1/2020 was passed on Vero cell culture. Dry ethanol extracts of plant parts (stems, flowers, leaves) of six types of Artemisia were prepared. The types used were: A. vulgaris L.; A. glauca (Pall. Ex Willd.); A. dracunculus L. (from three growth locations); A. absinthium L.; A. frigida Willd.; and A. sieversiana Ehrh. ex Willd. Dry extracts were dissolved in DMSO. In vitro analysis of the inhibitory activity of extracts against SARS‐CoV‐2 (an infectious titer of 103 TCID50/ml) replication was performed in a Vero E6 cell culture. To do this, the method of direct inactivation (neutralization) of virions, as well as schemes of “preventive” and “therapeutic” of cells, were used. Comparison samples were dry ethanol extracts of Inonotus obliquus, Syzygium aromaticum L. and Camellia sinensis L.

Results. Extracts of leaves of Artemisia spp. proved to be most effective in direct inactivation of virions. By equal and decreasing activity these are the species: A. vulgaris; A. dracunculus*; A. absinthium; A. dracunculus***; A. dracunculus**; A. frigidа; A. glauca; and A. sieversiana with a 50% effective concentration of range 1.10±0.24 – 11.72±2.89 μg/ml. Extracts of flowers of A. vulgaris, A.glauca, A. dracunculus*, A. dracunculus**, A. dracunculus***, A. frigida and A. sieversiana also contain biologically active substances which act both destructively on virions and after the virus has entered cells. For extracts of stems consistently high values of EC50 were found for A. glauca (6.84±1.35; 7.81±2.00 and 14.06±3.06 μg/ml) according to the results of three experimental schemes.

Conclusion. The results obtained can become the basis for the development of inexpensive domestic drugs for the treatment and/or prevention of COVID‐19.

Biochemical Analyses of Bioactive Extracts from Plants Native to Lampedusa, Sicily Minor Island

Major threats to the human lifespan include cancer, infectious diseases, diabetes, mental degenerative conditions and also reduced agricultural productivity due to climate changes, together with new and more devastating plant diseases. From all of this, the need arises to find new biopesticides and new medicines. Plants and microorganisms are the most important sources for isolating new metabolites. Lampedusa Island host a rich contingent of endemic species and subspecies. Seven plant species spontaneously growing in Lampedusa, i.e., Atriplex halimus L. (Ap), Daucus lopadusanus Tineo (Dl), Echinops spinosus Fiori (Es) Glaucium flavum Crantz (Gf) Hypericum aegypticum L: (Ha), Periploca angustifolia Labill (Pa), and Prasium majus L. (Pm) were collected, assessed for their metabolite content, and evaluated for potential applications in agriculture and medicine. The HPLC-MS analysis of n-hexane (HE) and CH2Cl2 (MC) extracts and the residual aqueous phases (WR) showed the presence of several metabolites in both organic extracts. Crude HE and MC extracts from Dl and He significantly inhibited butyrylcholinesterase, as did WR from the extraction of Dl and Pa. HE and MC extracts showed a significant toxicity towards hepatocarcinoma Huh7, while Dl, Ha and Er HE extracts were the most potently cytotoxic to ileocecal colorectal adenocarcinoma HCT-8 cell lines. Most extracts showed antiviral activity. At the lowest concentration tested (1.56 μg/mL), Dl, Gf and Ap MC extracts inhibited betacoronavirus HCoV-OC43 infection by> 2 fold, while the n-hexane extract of Pm was the most potent. In addition, at 1.56 μg/mL, potent inhibition (>10 fold) of dengue virus was detected for Dl, Er, and Pm HE extracts, while Pa and Ap MC extracts dampened infections to undetectable levels. Regarding to phytotoxicity, MC extracts from Er, Ap and Pm were more effective in inhibiting tomato rootlet elongation; the same first two extracts also inhibited seed cress germination while its radicle elongation, due to high sensitivity, was affected by all the extracts. Es and Gf MC extracts also inhibited seed germination of Phelipanche ramosa. Thus, we have uncovered that many of these Lampedusa plants displayed promising biopesticide, antiviral, and biological properties.

Broadly Applicable, Virus-Free Dual Reporter Assay to Identify Compounds Interfering with Membrane Fusion: Performance for HSV-1 and SARS-CoV-2

Membrane fusion constitutes an essential step in the replication cycle of numerous viral pathogens, hence it represents an important druggable target. In the present study, we established a virus-free, stable reporter fusion inhibition assay (SRFIA) specifically designed to identify compounds interfering with virus-induced membrane fusion. The dual reporter assay is based on two stable Vero cell lines harboring the third-generation tetracycline (Tet3G) transactivator and a bicistronic reporter gene cassette under the control of the tetracycline responsive element (TRE3G), respectively. Cell–cell fusion by the transient transfection of viral fusogens in the presence of doxycycline results in the expression of the reporter enzyme secreted alkaline phosphatase (SEAP) and the fluorescent nuclear localization marker EYFPNuc. A constitutively expressed, secreted form of nanoluciferase (secNLuc) functioned as the internal control. The performance of the SRFIA was tested for the quantification of SARS-CoV-2- and HSV-1-induced cell–cell fusion, respectively, showing high sensitivity and specificity, as well as the reliable identification of known fusion inhibitors. Parallel quantification of secNLuc enabled the detection of cytotoxic compounds or insufficient transfection efficacy. In conclusion, the SRFIA reported here is well suited for high-throughput screening for new antiviral agents and essentially will be applicable to all viral fusogens causing cell–cell fusion in Vero cells.

Medicinal Herbs in the Relief of Neurological, Cardiovascular, and Respiratory Symptoms after COVID-19 Infection A Literature Review

COVID-19 infection causes complications, even in people who have had a mild course of the disease. The most dangerous seem to be neurological ailments: anxiety, depression, mixed anxiety-depressive (MAD) syndromes, and irreversible dementia. These conditions can negatively affect the respiratory system, circulatory system, and heart functioning. We believe that phytotherapy can be helpful in all of these conditions. Clinical trials confirm this possibility. The work presents plant materials (Valeriana officinalis, Melissa officinalis, Passiflora incarnata, Piper methysticum, Humulus lupulus, Ballota nigra, Hypericum perforatum, Rhodiola rosea, Lavandula officinalis, Paullinia cupana, Ginkgo biloba, Murraya koenigii, Crataegus monogyna and oxyacantha, Hedera helix, Polygala senega, Pelargonium sidoides, Lichen islandicus, Plantago lanceolata) and their dominant compounds (valeranon, valtrate, apigenin, citronellal, isovitexin, isoorientin, methysticin, humulone, farnesene, acteoside, hypericin, hyperforin, biapigenin, rosavidin, salidroside, linalool acetate, linalool, caffeine, ginkgolide, bilobalide, mihanimbine, epicatechin, hederacoside C,α-hederine, presegenin, umckalin, 6,7,8-trixydroxybenzopyranone disulfate, fumaroprotocetric acid, protolichesteric acid, aucubin, acteoside) responsible for their activity. It also shows the possibility of reducing post-COVID-19 neurological, respiratory, and cardiovascular complications, which can affect the functioning of the nervous system.