Natural compounds as inhibitors of SARS-CoV-2 endocytosis: A promising approach against COVID-19

Screening and evaluation of cytotoxicity and antiviral effects of secondary metabolites from water extracts of Bersama abyssinica against SARS-CoV-2 Delta

Background

Bersama abyssinica is a common herb in Africa, with diverse medical uses in different areas. The plant is well-known in Tanzania for treating respiratory disorders such as TB, tonsillitis, bronchitis, and asthma, and it has lately been utilized to treat COVID-19 symptoms. Water extract of leaf and stem bark has been registered as an herbal medication known as 'Coviba Dawa' in Tanzania for the relief of bacterial respiratory infections. The extracts, however, have not been scientifically tested for their anti-viral activities. The aim of this work was to test for the cytotoxicity and antiviral effects of bioactive ingredients from B. abyssinica extracts against the Delta variant of the SARS-CoV-2 coronavirus.

Methods

B. abyssinica leaves and stem bark were dried under shade in room temperature and then pulverized to obtain small pieces before soaking into different solvents. One hundred grams of each, leaves and stem bark, were extracted in petroleum ether, dichloromethane, ethyl acetate and methanol. Water extract was obtained by decoction of stem bark and leaves into water. Phenols, flavonoids, tannins, and antioxidants were confirmed as components of the extracts. Analysis of polar extracts of bark stem bark and leaves was done. Antiviral screening and cytotoxicity experiments were conducted in a Biosafety Level 3 (BSL-3) Laboratory facility according to International Standard Operating Procedures (SOPs).

Results

By the use of LC–MS/MS analysis, this study confirmed the existence of four phenolic compounds in B. abyssinica water extract; 2,4-di-tert-butylphenol, 4-formyl-2-methoxyphenyl propionate, 7,8-Dihydroxy-4-methylcoumarin, and 2,3, 6-trimethoxyflavone with antioxidant activity. This study showed that, while the water extracts of B. abyssinica had significant antiviral activity against SARS Cov2 virus, it showed no cytotoxicity effect on Vero E6 cells. In particular, the water extract (Coviba dawa) showed 75% while ethylacetate fraction of B. abyssinica leaves showed a 50% in vitro viral inhibition, indicating that these substances may be useful for the development of future anti-viral agents.

Conclusion

We therefore recommend isolation of compounds for further profiling and development with a broader concentration range. We further recommend studies that determine the antiviral activity of extracts of B.abyssinica on other viral pathogens of clinical concern.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03754-3.

Early Outpatient Treatment of COVID-19: A Retrospective Analysis of 392 Cases in Italy

COVID-19 was declared a pandemic in March 2020. The knowledge of COVID-19 pathophysiology soon provided a strong rationale for the early use of both anti-inflammatory and antithrombotic drugs; however, its evidence was slowly and partially incorporated into institutional guidelines. The unmet needs of COVID-19 outpatients were taken care of by networks of physicians and researchers. We analyse the characteristics, management and outcomes in COVID-19 outpatients who were taken care of by physicians within the IppocrateOrg Association. In this observational retrospective study, volunteering doctors provided data on 392 COVID-19 patients. The mean age of patients was 48.5 years (range: 0.5–97), and patients were taken care of in COVID-19 stage 0 (15.6%), stage 1 (50.0%), stage 2a (28.8%) and stage 2b (5.6%). Many patients were overweight (26%) or obese (11.5%), with chronic comorbidities (34.9%), mainly cardiovascular (23%) and metabolic (13.3%). The most frequently prescribed drugs included: vitamins and supplements (98.7%), aspirin (66.1%), antibiotics (62%), glucocorticoids (41.8%), hydroxychloroquine (29.6%), enoxaparin (28.6%), colchicine (8.9%), oxygen therapy (6.9%), and ivermectin (2.8%). Hospitalization occurred in 5.8% of cases, mainly in stage 2b (27.3%). A total of 390 patients (99.6%) recovered; one patient was lost at follow up, and one patient died after hospitalization. This is the first real-world study describing the behaviours of physicians caring for COVID-19 outpatients, and the outcomes of COVID-19 early treatment. The lethality in this cohort was 0.2%, while overall, and over the same period, the COVID-19 lethality in Italy was over 3%. The drug use described in this study appears effective and safe. The present evidence should be carefully considered by physicians and political decision makers.

Dietary supplements for the management of COVID-19 symptoms

SARS-CoV-2, the etiological agent of COVID-19, caused a pandemic in 2020, which is only recently slowing down. The symptoms of COVID-19 range from cough to fever and pneumonia and may persist beyond the active state of the infection, in a condition called post-COVID syndrome. The aim of this paper is to review the relationship between COVID-19 and nutrition and to discuss to most up-to-date dietary supplements proposed for COVID-19 treatment and prevention. Nutrition and nutritional dysregulations, such as obesity and malnutrition, are prominent risk factors for severe COVID-19. These factors exert anti-inflammatory and proinflammatory effects on the immune system, thus exacerbating or reducing the immunological response against the virus. As for the nutritional habits, the Western diet induces a chronic inflammatory state, whereas the Mediterranean diet exerts anti-inflammatory effects and has been proposed for ameliorating COVID-19 evolution and symptoms. Several vaccines have been researched and commercialized for COVID-19 prevention, whereas several drugs, although clinically tested, have not shown promising effects. To compensate for the lack of treatment, several supplements have been recommended for preventing or ameliorating COVID-19 symptoms. Thus, it is critical to review the dietary supplements proposed for COVID-19 treatment. Supplements containing α-cyclodextrin and hydroxytyrosol exhibited promising effects in several clinical trials and reduced the severity of the outcomes and the duration of the infection. Moreover, a supplement containing hydroxytyrosol, acetyl L-carnitine, and vitamins B, C, and D improved the symptoms of patients with post-COVID syndrome.

Foods of the Mediterranean diet: citrus, cucumber and grape

Fruit and vegetables are excellent sources of health-promoting bioactive compounds and nutraceuticals. Regular consumption of fruit and vegetables helps prevent the onset and progression of many non-communicable diseases. The Mediterranean diet envisages consumption of healthy vegetables and fruit on a daily basis for maximum health benefits. Traditional use envisages vegetable-based and fruit-based diets, and many studies scientifically proved the beneficial effects of Mediterranean vegetables and fruits. Rich in bioactive phytochemicals, citrus, cucumbers and grapes have antioxidant, anti-inflammatory, antimicrobial, cardioprotective, anti-ageing and anti-cancer properties. Studies indicate that intake of citrus, cucumbers and grapes reduces hypertension, hyperlipidemia, skin problems and infections and improves the health of the cardiovascular and nervous systems. These beneficial effects are mediated by several bioactive molecules present in Mediterranean diet vegetables and fruits, such as citrus, cucumbers and grapes. Indeed, they contains flavones, isoflavones, tannins, polyphenols and many beneficial natural molecules. This review focuses on the bioactive ingredients in citrus fruit, cucumbers and grapes, all components of the Mediterranean diet, and their health effects. A deep understanding of Mediterranean diet's components, as well as clinical trials to test natural molecules beneficial effects, will permit to further explore the therapeutic potential of the Mediterranean diet in several pathological conditions.

Antioxidant, Anti-inflammatory, and Immunomodulatory Roles of Nonvitamin Antioxidants in Anti-SARS-CoV-2 Therapy

Viral pathologies encompass activation of pro-oxidative pathways and inflammatory burst. Alleviating overproduction of reactive oxygen species and cytokine storm in COVID-19 is essential to counteract the immunogenic damage in endothelium and alveolar membranes. Antioxidants alleviate oxidative stress, cytokine storm, hyperinflammation, and diminish the risk of organ failure. Direct antiviral roles imply: impact on viral spike protein, interference with the ACE2 receptor, inhibition of dipeptidyl peptidase 4, transmembrane protease serine 2 or furin, and impact on of helicase, papain-like protease, 3-chyomotrypsin like protease, and RNA-dependent RNA polymerase. Prooxidative environment favors conformational changes in the receptor binding domain, promoting the affinity of the spike protein for the host receptor. Viral pathologies imply a vicious cycle, oxidative stress promoting inflammatory responses, and vice versa. The same was noticed with respect to the relationship antioxidant impairment-viral replication. Timing, dosage, pro-oxidative activities, mutual influences, and interference with other antioxidants should be carefully regarded. Deficiency is linked to illness severity.

In Silico Study towards Repositioning of FDA-Approved Drug Candidates for Anticoronaviral Therapy: Molecular Docking, Molecular Dynamics and Binding Free Energy Calculations

The SARS-CoV-2 targets were evaluated for a set of FDA-approved drugs using a combination of drug repositioning and rigorous computational modeling methodologies such as molecular docking and molecular dynamics (MD) simulations followed by binding free energy calculations. Six FDA-approved drugs including, Ouabain, Digitoxin, Digoxin, Proscillaridin, Salinomycin and Niclosamide with promising anti-SARS-CoV-2 activity were screened in silico against four SARS-CoV-2 proteins—papain-like protease (PLpro), RNA-dependent RNA polymerase (RdRp), SARS-CoV-2 main protease (Mpro), and adaptor-associated kinase 1 (AAK1)—in an attempt to define their promising targets. The applied computational techniques suggest that all the tested drugs exhibited excellent binding patterns with higher scores and stable complexes compared to the native protein cocrystallized inhibitors. Ouabain was suggested to act as a dual inhibitor for both PLpro and Mpro enzymes, while Digitoxin bonded perfectly to RdRp. In addition, Salinomycin targeted PLpro. Particularly, Niclosamide was found to target AAK1 with greater affinity compared to the reference drug. Our study provides comprehensive molecular-level insights for identifying or designing novel anti-COVID-19 drugs.

Nanoscale Technologies in the Fight against COVID-19: From Innovative Nanomaterials to Computer-Aided Discovery of Potential Antiviral Plant-Derived Drugs

The last few years have increasingly emphasized the need to develop new active antiviral products obtained from artificial synthesis processes using nanomaterials, but also derived from natural matrices. At the same time, advanced computational approaches have found themselves fundamental in the repurposing of active therapeutics or for reducing the very long developing phases of new drugs discovery, which represents a real limitation, especially in the case of pandemics. The first part of the review is focused on the most innovative nanomaterials promising both in the field of therapeutic agents, as well as measures to control virus spread (i.e., innovative antiviral textiles). The second part of the review aims to show how computer-aided technologies can allow us to identify, in a rapid and therefore constantly updated way, plant-derived molecules (i.e., those included in terpenoids) potentially able to efficiently interact with SARS-CoV-2 cell penetration pathways.

Role of Diet and Nutrients in SARS-CoV-2 Infection: Incidence on Oxidative Stress, Inflammatory Status and Viral Production

Coronavirus illness (COVID-19) is an infectious pathology generated by intense severe respiratory syndrome coronavirus 2 (SARS-CoV-2). This infectious disease has emerged in 2019. The COVID-19-associated pandemic has considerably affected the way of life and the economy in the world. It is consequently crucial to find solutions allowing remedying or alleviating the effects of this infectious disease. Natural products have been in perpetual application from immemorial time given that they are attested to be efficient towards several illnesses without major side effects. Various studies have shown that plant extracts or purified molecules have a promising inhibiting impact towards coronavirus. In addition, it is substantial to understand the characteristics, susceptibility and impact of diet on patients infected with COVID-19. In this review, we recapitulate the influence of extracts or pure molecules from medicinal plants on COVID-19. We approach the possibilities of plant treatment/co-treatment and feeding applied to COVID-19. We also show coronavirus susceptibility and complications associated with nutrient deficiencies and then discuss the major food groups efficient on COVID-19 pathogenesis. Then, we covered emerging technologies using plant-based SARS-CoV-2 vaccine. We conclude by giving nutrient and plants curative therapy recommendations which are of potential interest in the COVID-19 infection and could pave the way for pharmacological treatments or co-treatments of COVID-19.

COVID-19 vaccine candidates and vaccine development platforms available worldwide

The pandemic caused by the worldwide spread of the coronavirus, which first appeared in 2019, has been named coronavirus disease 19 (COVID-19). More than 4.5 million deaths have been recorded due to the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), according to the World Health Organization. COVID-19 Dashboard in September 2021. Apart from the wildtype, other variations have been successfully transmitted early in the outbreak although they were not discovered until March 2020. Modifications in the SARS-CoV-2 genetic material, such as mutation and recombination, have the ability to modify the viral life span, along with transitivity, cellular tropism, and symptom severity. Several processes are involved in introducing novel vaccines to the population, including vaccine manufacturing, preclinical studies, Food and Drug Administration permission or certification, processing, and marketing. COVID-19 vaccine candidates have been developed by a number of public and private groups employing a variety of strategies, such as RNA, DNA, protein, and viral vectored vaccines. This comprehensive review, which included the most subsequent evidence on unique features of SARS-CoV-2 and the associated morbidity and mortality, was carried out using a systematic search of recent online databases in order to generate useful knowledge about the COVID-19 updated versions and their consequences on the disease symptoms and vaccine development.

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The ongoing vaccine studies all over the world against the COVID-19 epidemic have been reviewed.

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The effects of different vaccine platforms and new variants on vaccine studies were discussed.

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The effect of vaccines on existing and novel variants was evaluated.

The Commonly Utilized Natural Products during the COVID-19 Pandemic in Saudi Arabia: A Cross-Sectional Online Survey

Objectives: The utilization rate of herbal and dietary supplements among the Saudi population is reported to be high. However, the utilization rate and types of herbal and dietary supplements during the COVID-19 pandemic are largely unknown. Methods: This was an online questionnaire-based cross-sectional study that used convenience sampling and social media platforms (Telegram^®, Twitter^®, and WhatsApp^®) to disseminate a 12-item questionnaire across the Saudi general public aged 18 years and above. The questionnaire inquired about the sociodemographic characteristics (e.g., age, gender, education, geographical location), presence of chronic health conditions and the use of prescription medications, awareness of the viral nature of COVID-19 infection and its common symptoms, and the commonly utilized herbal and/or dietary supplements. Results: Sixty-four percent of the 1473 participants reported using herbal and/or dietary supplements for the purpose of boosting their immune system to prevent COVID-19 infection. In addition, 88.2% of the respondents were misinformed about the manifestation of COVID-19 symptoms. Most of the participants were Saudi (91.9%), aged 49 years and younger (83%), female (52%), and healthy (81%). Honey (46%), lemon (45%), ginger (36%), vitamin C (32%), black seed (26%), garlic (26%), and turmeric (19%) were the most commonly used herbal and/or dietary supplements by the participants. Saudi nationals (OR = 1.67, 95% CI: 1.08 to 2.6, p = 0.02), older adults (OR = 1.30, 95% CI:1.10 to 1.55, p = 0.002), and those taking prescription medications had higher odds of using dietary and/or herbal supplements (OR = 3.31, 95% CI: 2.61 to 4.18, p < 0.0001). Conclusion: The utilization rate of herbal and dietary supplements among the Saudi public during the COVID-19 pandemic is high. Future studies should examine the impact of different public awareness campaigns aimed at improving the public knowledge of the risk and benefits associated with the use of different commonly utilized herbal and dietary products identified in this study.

Potential detrimental role of soluble ACE2 in severe COVID-19 comorbid patients

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters the host cell by binding to angiotensin-converting enzyme 2 (ACE2) receptor. Other important proteins involved in this process include disintegrin and metalloproteinase domain-containing protein 17 (ADAM17) also known as tumour necrosis factor-α-converting enzyme and transmembrane serine protease 2. ACE2 converts angiotensin II (Ang II) to angiotensin (1-7), to balance the renin angiotensin system. Membrane-bound ACE2 ectodomain shedding is mediated by ADAM17 upon viral spike binding, Ang II overproduction and in several diseases. The shed soluble ACE2 (sACE2) retains its catalytic activity, but its precise role in viral entry is still unclear. Therapeutic sACE2 is claimed to exert dual effects; reduction of excess Ang II and blocking viral entry by masking the spike protein. Nevertheless, the paradox is why SARS-CoV-2 comorbid patients struggle to attain such benefit in viral infection despite having a high amount of sACE2. In this review, we discuss the possible detrimental role of sACE2 and speculate on a series of events where protease primed or non-primed virus-sACE2 complex might enter the host cell. As extracellular virus can bind many sACE2 molecules, sACE2 level could be reduced drastically upon endocytosis by the host cell. A consequential rapid rise in Ang II level could potentially aggravate disease severity through Ang II-angiotensin II receptor type 1 (AT1R) axis in comorbid patients. Hence, monitoring sACE2 and Ang II level in coronavirus disease 2019 comorbid patients are crucial to ensure safe and efficient intervention using therapeutic sACE2 and vaccines.