Quercetin and Vitamin C: An Experimental, Synergistic Therapy for the Prevention and Treatment of SARS-CoV-2 Related Disease (COVID-19)

Curcumin and quercetin co-encapsulated in nanoemulsions for nasal administration: A promising therapeutic and prophylactic treatment for viral respiratory infections

One of the most frequent causes of respiratory infections are viruses. Viruses reaching the airways can be absorbed by the human body through the respiratory mucosa and mainly infect lung cells. Several viral infections are not yet curable, such as coronavirus-2 (SARS-CoV-2). Furthermore, the side effect of synthetic antiviral drugs and reduced efficacy against resistant variants have reinforced the search for alternative and effective treatment options, such as plant-derived antiviral molecules. Curcumin (CUR) and quercetin (QUE) are two natural compounds that have been widely studied for their health benefits, such as antiviral and anti-inflammatory activity. However, poor oral bioavailability limits the clinical applications of these natural compounds. In this work, nanoemulsions (NE) co-encapsulating CUR and QUE designed for nasal administration were developed as promising prophylactic and therapeutic treatments for viral respiratory infections. The NEs were prepared by high-pressure homogenization combined with the phase inversion temperature technique and evaluated for their physical and chemical characteristics. In vitro assays were performed to evaluate the nanoemulsion retention into the porcine nasal mucosa. In addition, the CUR and QUE-loaded NE antiviral activity was tested against a murine β-COV, namely MHV-3. The results evidenced that CUR and QUE loaded NE had a particle size of 400 nm and retention in the porcine nasal mucosa. The antiviral activity of the NEs showed a percentage of inhibition of around 99 %, indicating that the developed NEs has interesting properties as a therapeutic and prophylactic treatment against viral respiratory infections.

Hesperidin, a Potential Antiviral Agent against SARS-CoV-2: The Influence of Citrus Consumption on COVID-19 Incidence and Severity in China

This review examines hesperidin, a citrus bioflavonoid, as a potential antiviral agent against SARS-CoV-2. The COVID-19 pandemic has demanded an urgent need to search for effective antiviral compounds, including those of natural origin, such as hesperidin. The review provides a comprehensive analysis of the chemical properties, bioavailability and antiviral mechanisms of hesperidin, particularly its potential efficacy against SARS-CoV-2. A review of databases, including PubMedPico, Scopus and Web of Science, was conducted using specific keywords and search criteria in accordance with PRISMA (Re-porting Items for Systematic Reviews and Meta-Analysis) guidelines between 2020 and 2024. Of the 207 articles, 37 were selected for the review. A key aspect is the correlation of in vitro, in silico and clinical studies on the antiviral effects of hesperidin with epidemiological data on citrus consumption in China during 2020-2024. The importance of integrating laboratory findings with actual consumption patterns to better understand the role of hesperidin in mitigating COVID-19 was highlighted, and an attempt was made to analyze epidemiological studies to examine the association between citrus juice consumption as a source of hesperidin and the incidence and severity of COVID-19 using China as an example. The review identifies consistencies and discrepancies between experimental and epidemiological data, highlighting the need to correlate the two fields to better understand the potential of hesperidin as an agent against SARS-CoV-2. Challenges and limitations in interpreting the results and future research perspectives in this area are discussed. The aim of this comprehensive review is to bridge the gap between experimental studies and epidemiological evidence and to contribute to the understanding of their correlation.

Antimicrobial Activities of Natural Bioactive Polyphenols

Secondary metabolites, polyphenols, are widespread in the entire kingdom of plants. They contain one or more hydroxyl groups that have a variety of biological functions in the natural environment. These uses include polyphenols in food, beauty products, dietary supplements, and medicinal products and have grown rapidly during the past 20 years. Antimicrobial polyphenols are described together with their sources, classes, and subclasses. Polyphenols are found in different sources, such as dark chocolate, olive oil, red wine, almonds, cashews, walnuts, berries, green tea, apples, artichokes, mushrooms, etc. Examples of benefits are antiallergic, antioxidant, anticancer agents, anti-inflammatory, antihypertensive, and antimicrobe properties. From these sources, different classes of polyphenols are helpful for the growth of internal functional systems of the human body, providing healthy fats, vitamins, and minerals, lowering the risk of cardiovascular diseases, improving brain health, and rebooting our cellular microbiome health by mitochondrial uncoupling. Among the various health benefits of polyphenols (curcumin, naringenin, quercetin, catechin, etc.) primarily different antimicrobial activities are discussed along with possible future applications. For polyphenols and antimicrobial agents to be proven safe, adverse health impacts must be substantiated by reliable scientific research as well as in vitro and in vivo clinical data. Future research may be influenced by this evaluation.

Exploring the Interplay of Food Security, Safety, and Psychological Wellness in the COVID-19 Era: Managing Strategies for Resilience and Adaptation

The global population surge presents a dual challenge and opportunity in the realms of food consumption, safety, and mental well-being. This necessitates a projected 70% increase in food production to meet growing demands. Amid this backdrop, the ongoing COVID-19 pandemic exacerbates these issues, underscoring the need for a deeper understanding of the intricate interplay between food consumption patterns and mental health dynamics during this crisis. Mitigating the spread of COVID-19 hinges upon rigorous adherence to personal hygiene practices and heightened disease awareness. Furthermore, maintaining stringent food quality and safety standards across both public and private sectors is imperative for safeguarding public health and containing viral transmission. Drawing upon existing research, this study delves into the pandemic's impact on mental health, food consumption habits, and food safety protocols. Through a comprehensive analysis, it aims to elucidate the nuanced relationship among food, food safety, and mental well-being amid the COVID-19 pandemic, highlighting synergistic effects and dynamics that underpin holistic human welfare. Our study offers a novel approach by integrating psychological wellness with food security and safety. In conceiving this review, we aimed to comprehensively explore the intricate interplay among food security, safety, and psychological wellness amid the backdrop of the COVID-19 pandemic. Our review is structured to encompass a thorough examination of existing research, synthesizing insights into the multifaceted relationships among food consumption patterns, mental health dynamics, and food safety protocols during the crisis. Our findings provide valuable insights and practical recommendations for enhancing food security and psychological well-being, thus supporting both academic research and real-world applications in crisis management and policy development.

Alterations in Circadian Rhythms, Sleep, and Physical Activity in COVID-19: Mechanisms, Interventions, and Lessons for the Future

Although the world is acquitting from the throes of COVID-19 and returning to the regularity of life, its effects on physical and mental health are prominently evident in the post-pandemic era. The pandemic subjected us to inadequate sleep and physical activities, stress, irregular eating patterns, and work hours beyond the regular rest-activity cycle. Thus, perturbing the synchrony of the regular circadian clock functions led to chronic psychiatric and neurological disorders and poor immunological response in several COVID-19 survivors. Understanding the links between the host immune system and viral replication machinery from a clock-infection biology perspective promises novel avenues of intervention. Behavioral improvements in our daily lifestyle can reduce the severity and expedite the convalescent stage of COVID-19 by maintaining consistent eating, sleep, and physical activity schedules. Including dietary supplements and nutraceuticals with prophylactic value aids in combating COVID-19, as their deficiency can lead to a higher risk of infection, vulnerability, and severity of COVID-19. Thus, besides developing therapeutic measures, perpetual healthy practices could also contribute to combating the upcoming pandemics. This review highlights the impact of the COVID-19 pandemic on biological rhythms, sleep-wake cycles, physical activities, and eating patterns and how those disruptions possibly contribute to the response, severity, and outcome of SARS-CoV-2 infection.

Therapeutic effects and molecular mechanisms of quercetin in gynecological disorders

Quercetin is a representative flavonoid that is widely present in fruits, herbs, and vegetables. It is also an important active core component in traditional Chinese medicines. As an important flavonoid, quercetin has various properties and exerts antioxidant, anti-inflammatory, and cardioprotective effects. The public interest in quercetin is increasing, and quercetin has been used to prevent or treat numerous of diseases, such as polycystic ovary syndrome (PCOS), cancer, autoimmune diseases and chronic cardiovascular diseases, in clinical experiments and animal studies due to its powerful antioxidant properties and minimal side effects. Quercetin exerts marked pharmacological effects on gynecological disorders; however, there have been no reviews about the potential health benefits of quercetin in the context of gynecological disorders, including PCOS, premature ovary failure (POF), endometriosis (EM), ovarian cancer (OC), cervical cancer (CC) and endometrial carcinoma (EC). Thus, this review aimed to summarize the biological effects of quercetin on gynecological disorders and its mechanisms.

Computational identification of natural senotherapeutic compounds that mimic dasatinib based on gene expression data

The major risk factor for chronic disease is chronological age, and age-related chronic diseases account for the majority of deaths worldwide. Targeting senescent cells that accumulate in disease-related tissues presents a strategy to reduce disease burden and to increase healthspan. The senolytic combination of the tyrosine-kinase inhibitor dasatinib and the flavonol quercetin is frequently used in clinical trials aiming to eliminate senescent cells. Here, our goal was to computationally identify natural senotherapeutic repurposing candidates that may substitute dasatinib based on their similarity in gene expression effects. The natural senolytic piperlongumine (a compound found in long pepper), and the natural senomorphics parthenolide, phloretin and curcumin (found in various edible plants) were identified as potential substitutes of dasatinib. The gene expression changes underlying the repositioning highlight apoptosis-related genes and pathways. The four compounds, and in particular the top-runner piperlongumine, may be combined with quercetin to obtain natural formulas emulating the dasatinib + quercetin formula.

Therapeutic detoxification of quercetin for aflatoxin B1-related toxicity: Roles of oxidative stress, inflammation, and metabolic enzymes

Aflatoxins (AFTs), a type of mycotoxin mainly produced by Aspergillus parasiticus and Aspergillus flavus, could be detected in food, feed, Chinese herbal medicine, grain crops and poses a great threat to public health security. Among them, aflatoxin B1 (AFB1) is the most toxic one. Exposure to AFB1 poses various health risks to both humans and animals, including the development of chronic inflammatory diseases, cardiovascular diseases, neurodegenerative diseases, and cancer. The molecular mechanisms underlying these risks are intricate and dependent on specific contexts. This review primarily focuses on summarizing the protective effects of quercetin, a natural phenolic compound, in mitigating the toxic effects induced by AFB1 in both in vitro experiments and animal models. Additionally, the review explores the molecular mechanisms that underlie these protective effects. Quercetin has been demonstrated to not only have the direct inhibitory action on the production of AFTs from Aspergillus, both also possess potent ameliorative effects against AFB1-induced cytotoxicity, hepatotoxicity, and neurotoxicity. These effects are attributed to the inhibition of oxidative stress, mitochondrial dysfunction, mitochondrial apoptotic pathway, and inflammatory response. It could also directly target several metabolic enzymes (i.e., CYP3As and GSTA1) to reduce the production of toxic metabolites of AFB1 within cells, then reduce AFB1-induced cytotoxicity. In conclusion, this review highlights quercetin is a promising detoxification agent for AFB1. By advancing our understanding of the protective mechanisms offered by quercetin, we aim to contribute to the development of effective detoxification agents against AFB1, ultimately promoting better health outcomes.

The Potential of Anti-coronavirus Plant Secondary Metabolites in COVID-19 Drug Discovery as an Alternative to Repurposed Drugs: A Review

In early 2020, a global pandemic was announced due to the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), known to cause COVID-19. Despite worldwide efforts, there are only limited options regarding antiviral drug treatments for COVID-19. Although vaccines are now available, issues such as declining efficacy against different SARS-CoV-2 variants and the aging of vaccine-induced immunity highlight the importance of finding more antiviral drugs as a second line of defense against the disease. Drug repurposing has been used to rapidly find COVID-19 therapeutic options. Due to the lack of clinical evidence for the therapeutic benefits and certain serious side effects of repurposed antivirals, the search for an antiviral drug against SARS-CoV-2 with fewer side effects continues. In recent years, numerous studies have included antiviral chemicals from a variety of plant species. A better knowledge of the possible antiviral natural products and their mechanism against SARS-CoV-2 will help to develop stronger and more targeted direct-acting antiviral agents. The aim of the present study was to compile the current data on potential plant metabolites that can be investigated in COVID-19 drug discovery and development. This review represents a collection of plant secondary metabolites and their mode of action against SARS-CoV and SARS-CoV-2.

Quercetin's antibiofilm effectiveness against drug resistant Staphylococcus aureus and its validation by in silico modeling

Staphylococcus aureus is typically treated with antibiotics, however, due to its widespread and unselective usage, resistant strains of S. aureus have increased to a great extent. Treatment failure and recurring staphylococcal infections are also brought on by biofilm development, which boosts an organism's ability to withstand antibiotics and is thought to be a virulence factor in patients. The present study investigates the antibiofilm activity of naturally available polyphenol Quercetin against drug-resistant S. aureus. Micro dilution plating and tube adhesion methods were performed to evaluate the antibiofilm activity of quercetin against S. aureus. Quercetin treatment resulted in remarkably reduction of biofilm in S. aureus cells. Further we performed a study to investigate binding efficacies of quercetin with genes icaB and icaC from ica locus involved in biofilm formation. 3D structure of icaB, icaC and quercetin were retrieved from Protein data bank and PubChem chemical compound database, respectively. All computational simulation were carried out using AutoDock Vina and AutoDockTools (ADT) v 1.5.4. In silico study demonstrated a strong complex formation, large binding constants (Kb) and low free binding energy (ΔG) between quercetin and icaB (Kb = 1.63 × 10-5, ΔG = -7.2 k cal/mol) and icaC (Kb = 1.98 × 10-6, ΔG = -8.7 kcal/mol). This in silico analysis indicates that quercetin is capable of targeting icaB and icaC proteins which are essential for biofilm formation in S. aureus. Our study highlighted the antibiofilm activity of quercetin against drug resistant pathogen S.aureus.

Treating COVID-19 with Medicinal Plants: Is It Even Conceivable? A Comprehensive Review

In 2020, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) challenged the world with a global outbreak that led to millions of deaths worldwide. Coronavirus disease 2019 (COVID-19) is the symptomatic manifestation of this virus, which can range from flu-like symptoms to utter clinical complications and even death. Since there was no clear medicine that could tackle this infection or lower its complications with minimal adverse effects on the patients' health, the world health organization (WHO) developed awareness programs to lower the infection rate and limit the fast spread of this virus. Although vaccines have been developed as preventative tools, people still prefer going back to traditional herbal medicine, which provides remarkable health benefits that can either prevent the viral infection or limit the progression of severe symptoms through different mechanistic pathways with relatively insignificant side effects. This comprehensive review provides scientific evidence elucidating the effect of 10 different plants against SARS-CoV-2, paving the way for further studies to reconsider plant-based extracts, rich in bioactive compounds, into more advanced clinical assessments in order to identify their impact on patients suffering from COVID-19.

Biological Properties of Recently Described Wild Bramble Rubus oklejewiczii against the Species from Similar Niches

The aim of this study was to compare the biological properties, such as antiviral, antibacterial, and antioxidant, of recently described pentaploid species Rubus oklejewiczii with tetraploid taxa growing in similar habitats including R. plicatus, R. gracilis, and R. wimmerianus. The antiviral potential was analyzed against bacteriophages with different genetic material: phi6 (a surrogate for the SARS-CoV-2 virus), T7, phiX174, and MS2. Antibacterial properties of fruit and leaf extracts were determined against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Salmonella enterica. The total phenolic content, as well as anthocyanins, ascorbic acid, pH, and antioxidant properties (FRAP and DPPH) were determined. R. oklejewiczii leaf extract was characterized by the weakest antibacterial and antiviral properties, which was closely correlated with the lowest content of polyphenolic compounds and antioxidant properties. The strongest biological properties were observed for R. wimmerianus leaves. Fruit extracts were characterized by lower phenolic content and antioxidant activities than leaves, with the lowest values observed for R. oklejewiczii extract. The antibacterial properties of fruit extracts were strongest for R. gracilis. The strongest antiviral potential was observed for R. oklejewiczii and R. wimmerianus fruit extracts against the bacteriophage phi6, which correlated with the lowest pH and the highest ascorbic acid content. The positive effect of the higher ploidy of R. oklejewiczii for most of the analyzed biological properties was not observed except for the antiviral potential of fruit extract. Due to its large and tasty fruits, this species seems to be very promising for cultivation and attractive for consumers, even though most of its biological properties were not any better compared to other examined tetraploid species.

Emerging Therapeutic Potential of Polyphenols from Geranium sanguineum L. in Viral Infections, Including SARS-CoV-2

The existing literature supports the anti-inflammatory, antioxidant, and antiviral capacities of the polyphenol extracts derived from Geranium sanguineum L. These extracts exhibit potential in hindering viral replication by inhibiting enzymes like DNA polymerase and reverse transcriptase. The antiviral properties of G. sanguineum L. seem to complement its immunomodulatory effects, contributing to infection resolution. While preclinical studies on G. sanguineum L. suggest its potential effectiveness against COVID-19, there is still a lack of clinical evidence. Therefore, the polyphenols extracted from this herb warrant further investigation as a potential alternative for preventing and treating COVID-19 infections.

Novel antioxidant protein target therapy to counter the prevalence and severity of SARS-CoV-2

Background

This review analyzed the magnitude of the COVID-19 pandemic globally and in India and the measures to counter its effect using natural and innate immune booster molecules. The study focuses on two phases: the first focuses on the magnitude, and the second on the effect of antioxidants (natural compounds) on SARS-CoV-2.

Methods

The magnitude of the prevalence, mortality, and comorbidities was acquired from the World Health Organization (WHO) report, media, a report from the Ministry of Health and Family Welfare (MoHFW), newspapers, and the National Centre of Disease Control (NCDC). Research articles from PubMed as well as other sites/journals and databases were accessed to gather literature on the effect of antioxidants.

Results

In the elderly and any chronic diseases, the declined level of antioxidant molecules enhanced the reactive oxygen species, which in turn deprived the immune system.

Conclusion

Innate antioxidant proteins like sirtuin and sestrin play a vital role in enhancing immunity. Herbal products and holistic approaches can also be alternative solutions for everyday life to boost the immune system by improving the redox balance in COVID-19 attack. This review analyzed the counteractive effect of alternative therapy to boost the immune system against the magnitude of the COVID-19 pandemic.

Network Pharmacology and Experimental Validation of Qingwen Baidu Decoction Therapeutic Potential in COVID-19-related Lung Injury

BACKGROUND AND PURPOSE

Coronavirus disease 2019 (COVID-19) is a lifethreatening disease worldwide due to its high infection and serious outcomes resulting from acute lung injury. Qingwen Baidu decoction (QBD), a well-known herbal prescription, has shown significant efficacy in patients with Coronavirus disease 2019. Hence, this study aims to uncover the molecular mechanism of QBD in treating COVID-19-related lung injury.

METHODS

Traditional Chinese Medicine Systems Pharmacology database (TCMSP), DrugBanks database, and Chinese Knowledge Infrastructure Project (CNKI) were used to retrieve the active ingredients of QBD. Drug and disease targets were collected using UniProt and Online Mendelian Inheritance in Man databases (OMIM). The core targets of QBD for pneumonia were analyzed by the Protein-Protein Interaction Network (PPI), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) to reveal the underlying molecular mechanisms. The analysis of key targets using molecular docking and animal experiments was also validated.

RESULTS

A compound-direct-acting target network mainly containing 171 compounds and 110 corresponding direct targets was constructed. The key targets included STAT3, c-JUN, TNF-α, MAPK3, MAPK1, FOS, PPARG, MAPK8, IFNG, NFκB1, etc. Moreover, 117 signaling pathways mainly involved in cytokine storm, inflammatory response, immune stress, oxidative stress and glucose metabolism were found by KEGG. The molecular docking results showed that the quercetin, alanine, and kaempferol in QBD demonstrated the strongest affinity to STAT3, c- JUN, and TNF-α. Experimental results displayed that QBD could effectively reduce the pathological damage to lung tissue by LPS and significantly alleviate the expression levels of the three key targets, thus playing a potential therapeutic role in COVID-19.

CONCLUSION

QBD might be a promising therapeutic agent for COVID-19 via ameliorating STAT3-related signals.

Antiviral Flavonoids: A Natural Scaffold with Prospects as Phytomedicines against SARS-CoV2

Flavonoids are vital candidates to fight against a wide range of pathogenic microbial infections. Due to their therapeutic potential, many flavonoids from the herbs of traditional medicine systems are now being evaluated as lead compounds to develop potential antimicrobial hits. The emergence of SARS-CoV-2 caused one of the deadliest pandemics that has ever been known to mankind. To date, more than 600 million confirmed cases of SARS-CoV2 infection have been reported worldwide. Situations are worse due to the unavailability of therapeutics to combat the viral disease. Thus, there is an urgent need to develop drugs against SARS-CoV2 and its emerging variants. Here, we have carried out a detailed mechanistic analysis of the antiviral efficacy of flavonoids in terms of their potential targets and structural feature required for exerting their antiviral activity. A catalog of various promising flavonoid compounds has been shown to elicit inhibitory effects against SARS-CoV and MERS-CoV proteases. However, they act in the high-micromolar regime. Thus a proper leadoptimization against the various proteases of SARS-CoV2 can lead to high-affinity SARS-CoV2 protease inhibitors. To enable lead optimization, a quantitative structure-activity relationship (QSAR) analysis has been developed for the flavonoids that have shown antiviral activity against viral proteases of SARS-CoV and MERS-CoV. High sequence similarities between coronavirus proteases enable the applicability of the developed QSAR to SARS-CoV2 proteases inhibitor screening. The detailed mechanistic analysis of the antiviral flavonoids and the developed QSAR models is a step forward toward the development of flavonoid-based therapeutics or supplements to fight against COVID-19.

Therapeutic Potential and Clinical Effectiveness of Quercetin: A Dietary Supplement

Fruits and vegetables (like apples, citrus, grapes, onions, parsley, etc.) are the primary dietary sources of quercetin. In addition, isolated quercetin is also available on the market as a dietary supplement with a daily dose of up to 1000 mg/d. The objective of the present study is to explore the therapeutic potential and clinical efficacy of quercetin as a dietary supplement. The present paper highlights the safety parameters and clinical trial studies with several targets reviewed from the data available on PubMed, Science Direct, ClinicalTrails. gov, and from many reputed foundations. The results of the studies prove the unique position of quercetin in the treatment of various disorders and the possibility of using phytochemicals such as quercetin for an efficient cure. As evidenced by the numerous published reports on human interventions, it has been concluded that quercetin intake significantly improves disease conditions with minimal adverse effects.

Synthesis of new non-natural L-glycosidic flavonoid derivatives and their evaluation as inhibitors of Trypanosoma cruzi ecto-nucleoside triphosphate diphosphohydrolase 1 (TcNTPDase1)

Trypanosoma cruzi is the pathogen of Chagas disease, a neglected tropical disease that affects more than 6 million people worldwide. There are no vaccines to prevent infection, and the therapeutic arsenal is very minimal and toxic. The unique E-NTPDase of T. cruzi (TcNTPDase1) plays essential roles in adhesion and infection and is a virulence factor. Quercetin is a flavonoid with antimicrobial, antiviral, and antitumor activities. Its potential as a partial inhibitor of NTPDases has also been demonstrated. In this work, we synthesized the non-natural L-glycoside derivatives of quercetin and evaluated them as inhibitors of recombinant TcNTPDase1 (rTcNTPDase1). These compounds, and quercetin and miquelianin, a natural quercetin derivative, were also tested. Compound 16 showed the most significant inhibitory effect (94%). Quercetin, miquelianin, and compound 14 showed inhibition close to 50%. We thoroughly investigated the inhibitory effect of 16. Our data suggested a competitive inhibition with a Ki of 8.39 μM (± 0.90). To better understand the interaction of compound 16 and rTcNTPDase1, we performed molecular dynamics simulations of the enzyme and docking analyses with the compounds. Our predictions show that compound 16 binds to the enzyme's catalytic site and interacts with important residues for NTPDase activity. As an inhibitor of a critical T. cruzi enzyme, (16) could be helpful as a starting point in the developing of a future treatment for Chagas disease. Furthermore, the discovery of (16) as an inhibitor of TcNTPDase1 may open new avenues in the study and development of new inhibitors of E-NTPDases.

Comparative Study of Quercetin and Hyperoside: Antimicrobial Potential towards Food Spoilage Bacteria, Mode of Action and Molecular Docking

The antibacterial activities of quercetin and hyperoside were evaluated towards two major spoilage bacteria in fish, Pseudomonas aeruginosa (PA) and Shewanella putrefaciens (SP). Hyperoside showed a lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) towards both spoilage bacteria, PA and SP, than quercetin. Cell membrane morphology was affected when treated with hyperoside and quercetin. The release of content from the treated cells occurred, as ascertained by the release of potassium and magnesium ions and the increase in conductivity of the culture media. The morphology of cells was significantly changed, in which shrinkage and pores were obtained, when observed using SEM. Both compounds negatively affected the motility, both swimming and swarming, and the formation of extracellular polymeric substance (EPS), thus confirming antibiofilm activities. Agarose gel analysis revealed that both compounds could bind to or degrade the genomic DNA of both bacteria, thereby causing bacterial death. Molecular docking indicated that the compounds interacted with the minor groove of the DNA, favoring the adenine-thymine-rich regions. Thus, both quercetin and hyperoside could serve as potential antimicrobial agents to retard the spoilage of fish or perishable products.

Quercetin and AMPK: A Dynamic Duo in Alleviating MG-Induced Inflammation via the AMPK/SIRT1/NF-κB Pathway

Mycoplasma gallisepticum (MG) is recognized as a principal causative agent of avian chronic respiratory disease, inflicting substantial economic losses upon the poultry industry. However, the extensive use of conventional antibiotics has resulted in the emergence of drug resistance and various challenges in their clinical application. Consequently, there is an urgent need to identify effective therapeutic agents for the prevention and treatment of mycoplasma-induced respiratory disease in avian species. AMP-activated protein kinase (AMPK) holds significant importance as a regulator of cellular energy metabolism and possesses the capacity to exert an anti-inflammatory effect by virtue of its downstream protein, SIRT1. This pathway has shown promise in counteracting the inflammatory responses triggered by pathogenic infections, thus providing a novel target for studying infectious inflammation. Quercetin possesses anti-inflammatory activity and has garnered attention as a potential alternative to antibiotics. However, there exists a gap in knowledge concerning the impact of this activation on MG-induced inflammatory damage. To address this knowledge gap, we employed AlphaFold2 prediction, molecular docking, and kinetic simulation methods to perform a systematic analysis. As expected, we found that both quercetin and the AMPK activator AICAR activate the chicken AMPKγ1 subunit in a similar manner, which was further validated at the cellular level. Our project aims to unravel the underlying mechanisms of quercetin's action as an agonist of AMPK against the inflammatory damage induced by MG infection. Accordingly, we evaluated the effects of quercetin on the prevention and treatment of air sac injury, lung morphology, immunohistochemistry, AMPK/SIRT1/NF-κB pathway activity, and inflammatory factors in MG-infected chickens. The results confirmed that quercetin effectively inhibits the secretion of pro-inflammatory cytokines such as IL-1β, TNF-α, and IL-6, leading to improved respiratory inflammation injury. Furthermore, quercetin was shown to enhance the levels of phosphorylated AMPK and SIRT1 while reducing the levels of phosphorylated P65 and pro-inflammatory factors. In conclusion, our study identifies the AMPK cascade signaling pathway as a novel cellular mediator responsible for quercetin's ability to counter MG-induced inflammatory damage. This finding highlights the potential significance of this pathway as an important target for anti-inflammatory drug research in the context of avian respiratory diseases.

Network pharmacology-based exploration identified the antiviral efficacy of Quercetin isolated from mulberry leaves against enterovirus 71 via the NF-κB signaling pathway

Introduction: Mulberry leaf (ML) is known for its antibacterial and anti-inflammatory properties, historically documented in "Shen Nong's Materia Medica". This study aimed to investigate the effects of ML on enterovirus 71 (EV71) using network pharmacology, molecular docking, and in vitro experiments. Methods: We successfully pinpointed shared targets between mulberry leaves (ML) and the EV71 virus by leveraging online databases. Our investigation delved into the interaction among these identified targets, leading to the identification of pivotal components within ML that possess potent anti-EV71 properties. The ability of these components to bind to the targets was verified by molecular docking. Moreover, bioinformatics predictions were used to identify the signaling pathways involved. Finally, the mechanism behind its anti-EV71 action was confirmed through in vitro experiments. Results: Our investigation uncovered 25 active components in ML that targeted 231 specific genes. Of these genes, 29 correlated with the targets of EV71. Quercetin, a major ingredient in ML, was associated with 25 of these genes. According to the molecular docking results, Quercetin has a high binding affinity to the targets of ML and EV71. According to the KEGG pathway analysis, the antiviral effect of Quercetin against EV71 was found to be closely related to the NF-κB signaling pathway. The results of immunofluorescence and Western blotting showed that Quercetin significantly reduced the expression levels of VP1, TNF-α, and IL-1β in EV71-infected human rhabdomyosarcoma cells. The phosphorylation level of NF-κB p65 was reduced, and the activation of NF-κB signaling pathway was suppressed by Quercetin. Furthermore, our results showed that Quercetin downregulated the expression of JNK, ERK, and p38 and their phosphorylation levels due to EV71 infection. Conclusion: With these findings in mind, we can conclude that inhibiting the NF-κB signaling pathway is a critical mechanism through which Quercetin exerts its anti-EV71 effectiveness.

Investigating the potential mechanism of quercetin against cervical cancer

BACKGROUND

Cervical cancer is emerging as a potential target of increased susceptibility to coronavirus disease-2019 (COVID-19), leading to compromised survival rates. Despite this critical link, efficacious anti-cervical cancer/COVID-19 interventions remain limited. Quercetin, known for its efficacy against both cancer and viral infections, holds promise as a therapeutic agent. This study aims to elucidate quercetin's anti-cervical cancer/COVID-19 mechanisms and potential targets.

METHODS

We initiated our investigation with differential gene expression analysis using cervical cancer transcriptome data from The Cancer Genome Atlas (TCGA) and The Genotype-Tissue Expression (GTEx), focusing on intersections with COVID-19-related genes. Network pharmacology was employed to identify the shared targets between cervical cancer/COVID-19 DEGs and quercetin's targets. Subsequently, Cox proportional hazards analyses were employed to establish a risk score based on these genes. Molecular docking techniques were applied to predict quercetin's therapeutic targets and mechanisms for mitigating cervical cancer and COVID-19.

RESULTS

Our findings unveiled 45 potential quercetin targets with anti-cervical cancer/COVID-19 actions. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses highlighted significant enrichment in immune pathways and COVID-19-related pathways. A refined risk score model, comprising PLA2G7, TNF, TYK2, F2, and NRP1, effectively stratified cervical cancer patients into distinct risk groups. Importantly, molecular docking analyses illuminated quercetin's remarkable binding affinity to the primary protease of the coronavirus.

CONCLUSIONS

In summation, our study suggests that quercetin holds promise as a potential therapeutic agent for mitigating coronavirus function, specifically through its interaction with the primary protease. This research offers novel insights into exploring COVID-19 susceptibility and enhancing survival in cervical cancer patients.

Unwinding the potentials of vitamin C in COVID-19 and other diseases: An updated review

Background: The discovery of vitamin C (ascorbic acid) is related to the ancient history of persistent research on the origins of the haemorrhagic disease scurvy. Vitamin C is an important nutrient that aids in a variety of biological and physiological processes. Scientists have been researching the function of vitamin C in the prevention and ailment of sepsis and pneumonia for decades. This has created a potential platform for applying these results to individuals suffering from severe coronavirus infection (COVID-19). Vitamin C's ability to activate and enhance the immune system makes it a promising treatment in the present COVID-19 pandemic. Vitamin C also aids in the activation of vitamin B, the production of certain neurotransmitters, and the transformation of cholesterol into bile acids. Hence, vitamin C is used for the treatment of many diseases. Aim: This review highlights the Vitamin C investigations that are performed by various researchers on patients with COVID 19 infection, the clinical studies and their observations. The authors have additionally updated information on the significance of vitamin C insufficiency, as well as its relevance and involvement in diseases such as cancer, wound healing, iron deficiency anaemia, atherosclerosis and neurodegenerative disorders. Here, we discuss them with the references. Methods: The method used in order to perform literature search was done using SciFinder, PubMed and ScienceDirect. Results: There is a potential role of vitamin C in various diseases including neurodegenerative disorders, COVID-19 and other diseases and the results are highlighted in the review with the help of clinical and preclinical data. Conclusion: More research on vitamin C and the undergoing clinical trials might prove a potential role of vitamin C in protecting the population from current COVID-19 pandemic.

Effects of the Natural Flavonoid Quercetin on Arenavirus Junín Infection

There is no specific chemotherapy approved for the treatment of pathogenic arenaviruses that cause severe hemorrhagic fever (HF) in the population of endemic regions in America and Africa. The present study reports the effects of the natural flavonoid quercetin (QUER) on the infection of A549 and Vero cells with Junín virus (JUNV), agent of the Argentine HF. By infectivity assays, a very effective dose-dependent reduction of JUNV multiplication was shown by cell pretreatment at 2-6 h prior to the infection at non-cytotoxic concentrations, with 50% effective concentration values in the range of 6.1-7.5 µg/mL. QUER was also active by post-infection treatment but with minor efficacy. Mechanistic studies indicated that QUER mainly affected the early steps of virus adsorption and internalization in the multiplication cycle of JUNV. Treatment with QUER blocked the phosphorylation of Akt without changes in the total protein expression, detected by Western blot, and the consequent perturbation of the PI3K/Akt pathway was also associated with the fluorescence redistribution from membrane to cytoplasm of TfR1, the cell receptor recognized by JUNV. Then, it appears that the cellular antiviral state, induced by QUER treatment, leads to the prevention of JUNV entry into the cell.

Recent Advances in Potential Health Benefits of Quercetin

Quercetin, a flavonoid found in fruits and vegetables, has been a part of human diets for centuries. Its numerous health benefits, including antioxidant, antimicrobial, anti-inflammatory, antiviral, and anticancer properties, have been extensively studied. Its strong antioxidant properties enable it to scavenge free radicals, reduce oxidative stress, and protect against cellular damage. Quercetin's anti-inflammatory properties involve inhibiting the production of inflammatory cytokines and enzymes, making it a potential therapeutic agent for various inflammatory conditions. It also exhibits anticancer effects by inhibiting cancer cell proliferation and inducing apoptosis. Finally, quercetin has cardiovascular benefits such as lowering blood pressure, reducing cholesterol levels, and improving endothelial function, making it a promising candidate for preventing and treating cardiovascular diseases. This review provides an overview of the chemical structure, biological activities, and bioavailability of quercetin, as well as the different delivery systems available for quercetin. Incorporating quercetin-rich foods into the diet or taking quercetin supplements may be beneficial for maintaining good health and preventing chronic diseases. As research progresses, the future perspectives of quercetin appear promising, with potential applications in nutraceuticals, pharmaceuticals, and functional foods to promote overall well-being and disease prevention. However, further studies are needed to elucidate its mechanisms of action, optimize its bioavailability, and assess its long-term safety for widespread utilization.

The effects of functional foods mixture on inflammatory cytokines and biochemical findings in hospitalized patients with COVID-19: a randomized double-blind controlled trial

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has been shown to affect nutritional recommendations. Some functional foods have been demonstrated to be useful in the treatment of people with COVID-19. However, little is known about the impact of combining functional foods on disease control. This study aimed to investigate the effects of functional foods mixture on serum levels of inflammatory cytokines and biochemical findings in patients with COVID-19.

METHODS

A randomized double-blind controlled trial was conducted in Baqiyatallah Al-Azam hospital in Tehran, Iran. Sixty patients were randomly assigned to receive either a soup containing functional foods (n = 30) or a usual soup (control group) (n = 30). Participants' sociodemographic information was gathered using a general questionnaire. Blood levels of inflammatory markers and biochemical findings were assessed using standard protocols.

RESULTS

The results showed that soup containing functional foods was more effective in controlling serum levels of D-dimer, blood urea nitrogen, and creatinine than the control group (P < 0.05). Also, more significant improvement was found in the intervention group vs control group in terms of interleukin (IL)-1β, IL-6, IL-17, IL-10, and tumor necrose factor-α (P < 0.05). In contrast, the control intervention more efficiently controlled potassium levels and reduced quantitative C-reactive protein than the intervention group (P < 0.05).

CONCLUSIONS

This study indicates a soup containing functional foods could alleviate biomarkers of inflammation in patients with COVID-19. However, its effectiveness on biochemical findings remained inconclusive which warranted further research.

TRIAL REGISTRATION

IRCT, IRCT20180201038585N11. Registered 23 August 2021, https://www.irct.ir/trial/57338.

Functional Foods: A Promising Strategy for Restoring Gut Microbiota Diversity Impacted by SARS-CoV-2 Variants

Natural herbs and functional foods contain bioactive molecules capable of augmenting the immune system and mediating anti-viral functions. Functional foods, such as prebiotics, probiotics, and dietary fibers, have been shown to have positive effects on gut microbiota diversity and immune function. The use of functional foods has been linked to enhanced immunity, regeneration, improved cognitive function, maintenance of gut microbiota, and significant improvement in overall health. The gut microbiota plays a critical role in maintaining overall health and immune function, and disruptions to its balance have been linked to various health problems. SARS-CoV-2 infection has been shown to affect gut microbiota diversity, and the emergence of variants poses new challenges to combat the virus. SARS-CoV-2 recognizes and infects human cells through ACE2 receptors prevalent in lung and gut epithelial cells. Humans are prone to SARS-CoV-2 infection because their respiratory and gastrointestinal tracts are rich in microbial diversity and contain high levels of ACE2 and TMPRSS2. This review article explores the potential use of functional foods in mitigating the impact of SARS-CoV-2 variants on gut microbiota diversity, and the potential use of functional foods as a strategy to combat these effects.

Plausibility of natural immunomodulators in the treatment of COVID-19-A comprehensive analysis and future recommendations

The COVID-19 pandemic has inflicted millions of deaths worldwide. Despite the availability of several vaccines and some special drugs approved for emergency use to prevent or treat this disease still, there is a huge concern regarding their effectiveness, adverse effects, and most importantly, their efficacy against the new variants. A cascade of immune-inflammatory responses is involved with the pathogenesis and severe complications with COVID-19. People with dysfunctional and compromised immune systems display severe complications, including acute respiratory distress syndrome, sepsis, multiple organ failure etc., when they get infected with the SARS-CoV-2 virus. Plant-derived natural immune-suppressant compounds, such as resveratrol, quercetin, curcumin, berberine, luteolin, etc., have been reported to inhibit pro-inflammatory cytokines and chemokines. Therefore, natural products with immunomodulatory and anti-inflammatory potential could be plausible targets to treat this contagious disease. This review aims to delineate the clinical trials status and outcomes of natural compounds with immunomodulatory potential in COVID-19 patients along with the outcomes of their in-vivo studies. In clinical trials several natural immunomodulators resulted in significant improvement of COVID-19 patients by diminishing COVID-19 symptoms such as fever, cough, sore throat, and breathlessness. Most importantly, they reduced the duration of hospitalization and the need for supplemental oxygen therapy, improved clinical outcomes in patients with COVID-19, especially weakness, and eliminated acute lung injury and acute respiratory distress syndrome. This paper also discusses many potent natural immunomodulators yet to undergo clinical trials. In-vivo studies with natural immunomodulators demonstrated reduction of a wide range of proinflammatory cytokines. Natural immunomodulators that were found effective, safe, and well tolerated in small-scale clinical trials are warranted to undergo large-scale trials to be used as drugs to treat COVID-19 infections. Alongside, compounds yet to test clinically must undergo clinical trials to find their effectiveness and safety in the treatment of COVID-19 patients.

Evaluation of therapeutic potentials of selected phytochemicals against Nipah virus, a multi-dimensional in silico study

The current study attempted to evaluate the potential of fifty-three (53) natural compounds as Nipah virus attachment glycoprotein (NiV G) inhibitors through in silico molecular docking study. Pharmacophore alignment of the four (4) selected compounds (Naringin, Mulberrofuran B, Rutin and Quercetin 3-galactoside) through Principal Component Analysis (PCA) revealed that common pharmacophores, namely four H bond acceptors, one H bond donor and two aromatic groups were responsible for the residual interaction with the target protein. Out of these four compounds, Naringin was found to have the highest inhibitory potential ( - 9.19 kcal mol^-1) against the target protein NiV G, when compared to the control drug, Ribavirin ( - 6.95 kcal mol^-1). The molecular dynamic simulation revealed that Naringin could make a stable complex with the target protein in the near-native physiological condition. Finally, MM-PBSA (Molecular Mechanics-Poisson-Boltzmann Solvent-Accessible Surface Area) analysis in agreement with our molecular docking result, showed that Naringin ( - 218.664 kJ mol^-1) could strongly bind with the target protein NiV G than the control drug Ribavirin ( - 83.812 kJ mol^-1).

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03595-y.

COVID-19 Therapeutic Potential of Natural Products

Despite the fact that coronavirus disease 2019 (COVID-19) treatment and management are now considerably regulated, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still one of the leading causes of death in 2022. The availability of COVID-19 vaccines, FDA-approved antivirals, and monoclonal antibodies in low-income countries still poses an issue to be addressed. Natural products, particularly traditional Chinese medicines (TCMs) and medicinal plant extracts (or their active component), have challenged the dominance of drug repurposing and synthetic compound libraries in COVID-19 therapeutics. Their abundant resources and excellent antiviral performance make natural products a relatively cheap and readily available alternative for COVID-19 therapeutics. Here, we deliberately review the anti-SARS-CoV-2 mechanisms of the natural products, their potency (pharmacological profiles), and application strategies for COVID-19 intervention. In light of their advantages, this review is intended to acknowledge the potential of natural products as COVID-19 therapeutic candidates.

Protective role of flavonoids quercetin and silymarin in the viral-associated inflammatory bowel disease: an updated review

Inflammatory bowel disease (IBD) is a chronic recurrent inflammation of the gastrointestinal tract (GIT). IBD patients are susceptible to various infections such as viral infections due to the long-term consumption of immunosuppressive drugs and biologics. The antiviral and IBD protective traits of flavonoids have not been entirely investigated. This study objective included an overview of the protective role of flavonoids quercetin and silymarin in viral-associated IBD. Several viral agents such as cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella zoster virus (VZV) and enteric viruses can be reactivated and thus develop or exacerbate the IBD conditions or eventually facilitate the disease remission. Flavonoids such as quercetin and silymarin are non-toxic and safe bioactive compounds with remarkable anti-oxidant, anti-inflammatory and anti-viral effects. Mechanisms of anti-inflammatory and antiviral effects of silymarin and quercetin mainly include immune modulation and inhibition of caspase enzymes, viral binding and replication, RNA synthesis, viral proteases and viral assembly. In the nutraceutical sector, natural flavonoids low bioavailability and solubility necessitate the application of delivery systems to enhance their efficacy. This review study provided an updated understanding of the protective role of quercetin and silymarin against viral-associated IBD.

Comparison study of Beninese and Chinese herbal medicines in treating COVID-19

ETHNOPHARMACOLOGICAL RELEVANCE

The worldwide use of natural remedies is an alternative therapeutic solution to strengthen immunity, fight, and prevent this disease. The rapid spread of the coronavirus disease worldwide has promoted the search for therapeutic solutions following different approaches. China and Benin have seen the use of natural remedies such as Chinese herbal medicine and local endemic plants as alternative solutions in treating COVID-19.

AIM OF THE STUDY

The present study was designed to identify the prevalence of medicinal plant use in four municipalities of Benin most affected by COVID-19 and compare them with traditional Chinese medicine and finally verify the efficacy of the main components of the six plants most frequently used, via in vitro experiments.

MATERIALS AND METHODS

This study targeting market herbalists and traditional healers was conducted in the form of an ethnomedicinal survey in four representative communities (Cotonou, Abomey-Calavi, Zè, and Ouidah) of southern Benin. The chemical compositions of the six most commonly used herbs were investigated using network pharmacology. Network-based global prediction of disease genes and drug, target, function, and pathway enrichment analysis of the top six herbs was conducted using databases including IPA and visualised using Cytoscape software. The natural botanical drugs involved three medicines and three formulas used in the treatment of COVID-19 in China from the published literature were compared with the top six botanical drugs used in Benin to identify similarities between them and guide the clinical medication in both countries. Finally, the efficacy of the common ingredients in six plants was verified by measuring the viability of BEAS-2B cells and the release of inflammatory factors after administration of different ingredients. Binding abilities of six components to COVID-19 related targets were verified by molecular docking.

RESULTS

According to the medication survey investigation, the six most used herbs were Citrus aurantiifolia (13.18%), Momordica charantia (7.75%), Ocimum gratissimum (7.36%), Crateva adansonii (6.59%), Azadirachta indica (5.81%), and Zanthoxylum zanthoxyloides (5.42%). The most represented botanical families were Rutaceae, Lamiaceae, Cucurbitaceae, Meliaceae, and Capparaceae. The network pharmacology of these six herbal plants showed that the flavonoids quercetin, kaempferol, and β-sitosterol were the main active ingredients of the Benin herbal medicine. Chinese and Beninese herbal medicine are similar in that they have the same targets and pathways in inflammation and oxidative stress relief. Mild COVID-19-related targets come from C. aurantiifolia and M. charantia, and severe COVID-19-related targets come from A. indica A. Juss. Cell viability and enzyme-linked immunosorbent assay results confirmed that six major compounds could protect BEAS-2B cells against injury by inhibiting the expression of inflammatory factors, among which quercetin and isoimperatorin were more effective. Docking verified that the six compounds have good binding potential with COVID-19 related targets.

CONCLUSIONS

These results suggest that Benin herbal medicine and Chinese herbal medicine overlap in compounds, targets, and pathways to a certain extent. Among the commonly used plants in Benin, C. aurantiifolia and M. charantia may have a good curative effect on the treatment of mild COVID-19, while for severe COVID-19, A. indica can be added on this basis.

Natural flavonols: actions, mechanisms, and potential therapeutic utility for various diseases

Background

Flavonols are phytoconstituents of biological and medicinal importance. In addition to functioning as antioxidants, flavonols may play a role in antagonizing diabetes, cancer, cardiovascular disease, and viral and bacterial diseases. Quercetin, myricetin, kaempferol, and fisetin are the major dietary flavonols. Quercetin is a potent scavenger of free radicals, providing protection from free radical damage and oxidation-associated diseases.

Main body of the abstract

An extensive literature review of specific databases (e.g., Pubmed, google scholar, science direct) were conducted using the keywords "flavonol," "quercetin," "antidiabetic," "antiviral," "anticancer," and "myricetin." Some studies concluded that quercetin is a promising antioxidant agent while kaempferol could be effective against human gastric cancer. In addition, kaempferol prevents apoptosis of pancreatic beta-cells via boosting the function and survival rate of the beta-cells, leading to increased insulin secretion. Flavonols also show potential as alternatives to conventional antibiotics, restricting viral infection by antagonizing the envelope proteins to block viral entry.

Short conclusion

There is substantial scientific evidence that high consumption of flavonols is associated with reduced risk of cancer and coronary diseases, free radical damage alleviation, tumor growth prevention, and insulin secretion improvement, among other diverse health benefits. Nevertheless, more studies are required to determine the appropriate dietary concentration, dose, and type of flavonol for a particular condition to prevent any adverse side effects.

Structure-based virtual identification of natural inhibitors of SARS-CoV-2 and its Delta and Omicron variant proteins

Aim

Structure-based identification of natural compounds against SARS-CoV-2, Delta and Omicron target proteins.

Materials & methods

Several known antiviral natural compounds were subjected to molecular docking and MD simulation against SARS-CoV-2 Mpro, Helicase and Spike, including Delta and Omicron Spikes.

Results

Of the docked ligands, 20 selected for each complex exhibited overall good binding affinities (-7.79 to -5.06 kcal/mol) with acceptable physiochemistry following Lipinski's rule. Finally, two best ligands from each complex upon simulation showed structural stability and compactness.

Conclusion

Quercetin-3-acetyl-glucoside, Rutin, Kaempferol, Catechin, Orientin, Obetrioside and Neridienone A were identified as potential inhibitors of SARS-CoV-2 Mpro, Helicase and Spike, while Orientin and Obetrioside also showed good binding affinities with Omicron Spike. Catechin and Neridienone A formed stable complexes with Delta Spike.

Antiviral Activity of Quercetin Hydrate against Zika Virus

Zika virus (ZIKV) has re-emerged in recent decades, leading to outbreaks of Zika fever in Africa, Asia, and Central and South America. Despite its drastic re-emergence and clinical impact, no vaccines or antiviral compounds are available to prevent or control ZIKV infection. This study evaluated the potential antiviral activity of quercetin hydrate against ZIKV infection and demonstrated that this substance inhibits virus particle production in A549 and Vero cells under different treatment conditions. In vitro antiviral activity was long-lasting (still observed 72 h post-infection), suggesting that quercetin hydrate affects multiple rounds of ZIKV replication. Molecular docking indicates that quercetin hydrate can efficiently interact with the specific allosteric binding site cavity of the NS2B-NS3 proteases and NS1-dimer. These results identify quercetin as a potential compound to combat ZIKV infection in vitro.

Natural Products as a Potential Source of Promising Therapeutics for COVID-19 and Viral Diseases

Background

A global pandemic has recently been observed due to the new coronavirus disease, caused by SARS-CoV-2. Since there are currently no antiviral medicines to combat the highly contagious and lethal COVID-19 infection, identifying natural sources that can either be viricidal or boost the immune system and aid in the fight against the disease can be an essential therapeutic support.

Methods

This review was conducted based on published papers related to the herbal therapy of COVID-19 by search on databases including PubMed and Scopus with herbal, COVID-19, SARS-CoV-2, and therapy keywords.

Results

To combat this condition, people may benefit from the therapeutic properties of medicinal plants, such as increasing their immune system or providing an antiviral impact. As a result, SARS-CoV-2 infection death rates can be reduced. Various traditional medicinal plants and their bioactive components, such as COVID-19, are summarized in this article to assist in gathering and debating techniques for combating microbial diseases in general and boosting our immune system in particular.

Conclusion

The immune system benefits from natural products and many of these play a role in activating antibody creation, maturation of immune cells, and stimulation of innate and adaptive immune responses. The lack of particular antivirals for SARS-CoV-2 means that apitherapy might be a viable option for reducing the hazards associated with COVID-19 in the absence of specific antivirals.

Can egg yolk antibodies terminate the CSBV infection in apiculture?

Chinese sacbrood virus (CSBV) is the most severe pathogen of Apis cerana, which leads to serious fatal diseases in bee colonies and eventual catastrophe for the Chinese beekeeping industry. Additionally, CSBV can potentially infect Apis mellifera by bridging the species barrier and significantly affect the productivity of the honey industry. Although several approaches, such as feeding royal jelly, traditional Chinese medicine, and double-stranded RNA treatments, have been employed to suppress CSBV infection, their practical applicabilities are constrained due to their poor effectiveness. In recent years, specific egg yolk antibodies (EYA) have been increasingly utilized in passive immunotherapy for infectious diseases without any side effects. According to both laboratory research and practical use, EYA have demonstrated superior protection for bees against CSBV infection. This review provided an in-depth analysis of the issues and drawbacks in this field in addition to provide a thorough summary of current advancements in CSBV studies. Some promising strategies for the synergistic study of EYA against CSBV, including the exploitation of novel antibody drugs, novel TCM monomer/formula determination, and development of nucleotide drugs, are also proposed in this review. Furthermore, the prospects for the future perspectives of EYA research and applications are presented. Collectively, EYA would terminate CSBV infection soon, as well as will provide scientific guidance and references to control and manage other viral infections in apiculture.

Quercetin as a Dietary Supplementary Flavonoid Alleviates the Oxidative Stress Induced by Lead Toxicity in Male Wistar Rats

Quercetin is a naturally existing plant pigment belonging to the flavonoid group; it is contained in a wide range of vegetables and fruits. The accumulated evidence points to the potential uses of quercetin in protection of some disease conditions. Lead is one of the highly toxicant heavy metals that are widely spread in the environment and implicated in a wide spectrum of industries. No previous study has been reported to evaluate the effect of quercetin on lead toxicity. Therefore, the present study was conducted to elucidate some aspects of quercetin bioactivities in regard to its ability to combat the oxidative stress induced by lead toxicity. For this purpose, a total of sixty male Wistar rats were randomly and equally divided into three groups of 20 animals each; untreated control animals (group 1), lead-exposed animals (group 2; exposed to lead daily by oral gavage at the dose of 80 mg/Kg b.w.), and group 3 of animals, which were exposed to lead and daily received quercetin (10 h gap time between lead exposure and the receiving of quercetin) by oral gavage at the dose of 350 mg/Kg b.w. The experiment period was 8 weeks. All the assayed hematological and biochemical parameters of animals exposed to lead were significantly altered compared with the untreated control levels. Animals exposed to lead (group 2) exhibited significant decrements of the erythrocytic and total leucocytic counts, hemoglobin concentration, packed cell volume percent, total proteins, albumin and globulin. These animals also disclosed significantly decreased levels of antioxidant markers including total thiols, catalase and glutathione. On the other hand, these animals demonstrated significant increments in the levels of bilirubin, urea, creatinine, BUN, serum enzymes, H₂O₂ and MDA. Animals exposed to lead and given quercetin (group 3) exhibited improvement of these parameters, which were brought back at varying degrees toward the untreated control levels. Basing on the improvements of the assayed hematological and biochemical parameters, it was concluded that quercetin as a dietary supplement can act efficiently as an antioxidant to counteract the oxidative stress induced by lead toxicity and to maintain the oxidant antioxidant balance.

GPR84 regulates pulmonary inflammation by modulating neutrophil functions

Acute lung injury (ALI) is an acute, progressive hypoxic respiratory failure that could develop into acute respiratory distress syndrome (ARDS) with very high mortality rate. ALI is believed to be caused by uncontrolled inflammation, and multiple types of immune cells, especially neutrophils, are critically involved in the development of ALI. The treatment for ALI/ARDS is very limited, a better understanding of the pathogenesis and new therapies are urgently needed. Here we discover that GPR84, a medium chain fatty acid receptor, plays critical roles in ALI development by regulating neutrophil functions. GPR84 is highly upregulated in the cells isolated from the bronchoalveolar lavage fluid of LPS-induced ALI mice. GPR84 deficiency or blockage significantly ameliorated ALI mice lung inflammation by reducing neutrophils infiltration and oxidative stress. Further studies reveal that activation of GPR84 strongly induced reactive oxygen species production from neutrophils by stimulating Lyn, AKT and ERK1/2 activation and the assembly of the NADPH oxidase. These results reveal an important role of GPR84 in neutrophil functions and lung inflammation and strongly suggest that GPR84 is a potential drug target for ALI.

COVID-19 and cellular senescence

The clinical severity of coronavirus disease 2019 (COVID-19) is largely determined by host factors. Recent advances point to cellular senescence, an ageing-related switch in cellular state, as a critical regulator of SARS-CoV-2-evoked hyperinflammation. SARS-CoV-2, like other viruses, can induce senescence and exacerbates the senescence-associated secretory phenotype (SASP), which is comprised largely of pro-inflammatory, extracellular matrix-degrading, complement-activating and pro-coagulatory factors secreted by senescent cells. These effects are enhanced in elderly individuals who have an increased proportion of pre-existing senescent cells in their tissues. SASP factors can contribute to a 'cytokine storm', tissue-destructive immune cell infiltration, endothelialitis (endotheliitis), fibrosis and microthrombosis. SASP-driven spreading of cellular senescence uncouples tissue injury from direct SARS-CoV-2-inflicted cellular damage in a paracrine fashion and can further amplify the SASP by increasing the burden of senescent cells. Preclinical and early clinical studies indicate that targeted elimination of senescent cells may offer a novel therapeutic opportunity to attenuate clinical deterioration in COVID-19 and improve resilience following infection with SARS-CoV-2 or other pathogens.

Nutritional deficiencies that may predispose to long COVID

Multiple nutritional deficiencies (MND) confound studies designed to assess the role of a single nutrient in contributing to the initiation and progression of disease states. Despite the perception of many healthcare practitioners, up to 25% of Americans are deficient in five-or-more essential nutrients. Stress associated with the COVID-19 pandemic further increases the prevalence of deficiency states. Viral infections compete for crucial nutrients with immune cells. Viral replication and proliferation of immunocompetent cells critical to the host response require these essential nutrients, including zinc. Clinical studies have linked levels of more than 22 different dietary components to the likelihood of COVID-19 infection and the severity of the disease. People at higher risk of infection due to MND are also more likely to have long-term sequelae, known as Long COVID.

Honey and Nigella sativa against COVID-19 in Pakistan (HNS-COVID-PK): A multicenter placebo-controlled randomized clinical trial

Until now, no specific and effective treatment exists for coronavirus disease 2019 (COVID-19). Since honey and Nigella sativa (HNS) have established antiviral, antibacterial, antiinflammatory, antioxidant, and immunomodulatory properties, we tested their efficacy for this disease in a multicenter, placebo-controlled, and randomized clinical trial at four medical care facilities in Pakistan. RT-PCR confirmed COVID-19 adults showing moderate or severe disease were enrolled in the trial. Patients were randomly assigned in a 1:1 ratio to receive either honey (1 g kg^-1  day^-1 ) and Nigella sativa seeds (80 mg kg^-1  day^-1 ) or a placebo for up to 13 days along with standard care. The outcomes included symptoms' alleviation, viral clearance, and 30-day mortality in the intention-to-treat population. Three hundred and thirteen patients, 210 with moderate and 103 with severe disease, underwent randomization from April 30 to July 29, 2020. Among the moderate cases, 107 were assigned to HNS, whereas 103 were assigned to the placebo group. Among the severe cases, 50 were given HNS, and 53 were given the placebo. HNS resulted in ~50% reduction in time taken to alleviate symptoms as compared to placebo (moderate cases: 4 vs. 7 days, Hazard Ratio [HR]: 6.11; 95% Confidence Interval [CI]: 4.23-8.84, p < 0.0001 and for severe cases: 6 vs. 13 days, HR: 4.04; 95% CI: 2.46-6.64; p < 0.0001). HNS also cleared the virus earlier than placebo in both moderate cases (6 vs. 10 days, HR: 5.53; 95% CI: 3.76-8.14, p < 0.0001) and severe cases (8.5 vs. 12 days, HR: 4.32; 95% CI: 2.62-7.13, p < 0.0001). HNS further led to a better clinical score on day 6 with normal activity resumption in 63.6% vs. 10.9% among moderate cases (OR: 0.07; 95% CI: 0.03-0.13, p < 0.0001) and hospital discharge in 50% versus 2.8% in severe cases (OR: 0.03; 95% CI: 0.01-0.09, p < 0.0001). In severe cases, the mortality rate was less than 1/4th in the HNS group than in placebo (4% vs. 18.87%, OR: 0.18; 95% CI: 0.02-0.92, p = 0.029). No HNS-related adverse effects were observed. HNS, compared with placebo, significantly improved symptoms, expedited viral load clearance, and reduced mortality in COVID-19 patients. This trial was registered on April 15, 2020 with ClinicalTrials.gov Identifier: NCT04347382.

Non-pharmacological remedies for the common cold

Acute rhinopharyngitis, usually called common cold, is a widespread disease, mainly in childhood and adolescence. The use of common cold relievers is, therefore, prevalent as documented by the market data. A well-established tradition considers natural remedies an effective and safe way to relieve the common cold. Hundreds of products for treating the common cold contain non-pharmacological components. Nevertheless, a few studies investigated the role of non-pharmacologic remedies for the common cold. The current study reported the most common non-pharmacological remedies for the common cold, including herbal medicines and other substances. As ancient people used traditional herbs to treat and prevent the common cold, various herbs are widely used to clear viral infections. The herbal agents include polyphenols, flavonoids, saponins, glucosides, and alkaloids. Moreover, other non-pharmacological agents are widely used in real-life. Many multi- or monocomponent dietary supplements or medical devices contain these substances and are available in the market as tablets, syrups, drops, nasal or oral sprays, and nebulization solutions. Many products are available in the market. However, there is some evidence only for some substances. Consequently, further rigorous studies should confirm natural products' efficacy and safety to relieve the common cold.

Investigation of supplement products preferred by healthcare professionals during COVID-19 pandemic process

Objective: Various products are used to strengthen immunity in prevention and treatment during the COVID-19 pandemic affecting the whole world, which has no cure yet, and the vaccine has just been used. This study was planned to learn about the supplements used by healthcare professionals. Methods: A questionnaire was applied to the physicians, nurses, technicians, secretaries, and staff working in the operating room, intensive care, ward, and outpatient clinic by e-mail, WhatsApp, or face-to-face interview method. Results: There was no difference between the groups in terms of being COVID-19-positive. The most used products were primarily Mg and vitamin D, and vitamin C, ginger, Zn, turmeric, green tea, vitamin complex, thyme, black elderberry (sambucus nigra), propolis, prebiotic/probiotic, acetylsalicylic acid (ASA), black cumin (niger sativa), N-acetyl cysteine (NAC), selenium (Se), Coenzyme-Q10, cinnamon, glutathione (GSH) and quercetin respectively. No one had used alpha lipoic acid (ALA). The products that showed significant differences between the groups with and without COVID-19 were vitamin C, prebiotic/probiotic, propolis and ASA. Conclusıon: Since it is not asked when the product is used, although it is not possible to evaluate its effectiveness for preventive or therapeutic purposes, known to be natural, inexpensive, and easily accessible antiviral products may be preferred.

Neuroprotective Potentials of Flavonoids: Experimental Studies and Mechanisms of Action

Neurological and neurodegenerative diseases, particularly those related to aging, are on the rise, but drug therapies are rarely curative. Functional disorders and the organic degeneration of nervous tissue often have complex causes, in which phenomena of oxidative stress, inflammation and cytotoxicity are intertwined. For these reasons, the search for natural substances that can slow down or counteract these pathologies has increased rapidly over the last two decades. In this paper, studies on the neuroprotective effects of flavonoids (especially the two most widely used, hesperidin and quercetin) on animal models of depression, neurotoxicity, Alzheimer's disease (AD) and Parkinson's disease are reviewed. The literature on these topics amounts to a few hundred publications on in vitro and in vivo models (notably in rodents) and provides us with a very detailed picture of the action mechanisms and targets of these substances. These include the decrease in enzymes that produce reactive oxygen and ferroptosis, the inhibition of mono-amine oxidases, the stimulation of the Nrf2/ARE system, the induction of brain-derived neurotrophic factor production and, in the case of AD, the prevention of amyloid-beta aggregation. The inhibition of neuroinflammatory processes has been documented as a decrease in cytokine formation (mainly TNF-alpha and IL-1beta) by microglia and astrocytes, by modulating a number of regulatory proteins such as Nf-kB and NLRP3/inflammasome. Although clinical trials on humans are still scarce, preclinical studies allow us to consider hesperidin, quercetin, and other flavonoids as very interesting and safe dietary molecules to be further investigated as complementary treatments in order to prevent neurodegenerative diseases or to moderate their deleterious effects.

The possible therapeutic role of curcumin and quercetin in the early-stage of COVID-19-Results from a pragmatic randomized clinical trial

Background

Curcumin (CUR) and quercetin (QUE), two natural polyphenols, possess diverse biological activities including broad-spectrum antiviral, antioxidant, and immunomodulatory effects. Both CUR and QUE have shown inhibition of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in in vitro assays.

Objective

In the present study we aimed to assess the possible treatment benefits of a combined curcumin and quercetin (CUR-QUE) oral supplement, alongside standard of care (SOC), in the early-stage COVID-19 infection.

Methods

This was an exploratory, pragmatic, open-label, randomized controlled clinical trial, conducted at the Department of Pathology, Liaquat University of Medical and Health Sciences, Jamshoro, PK. The study compared the treatment effect of an oral CUR-QUE supplement plus SOC vs. SOC alone, in the early-stage/mild to moderately symptomatic COVID-19 outpatients. Patients were randomized in a 1:1 ratio to CUR-QUE (n = 25) and control (n = 25) treatment groups. The CUR-QUE supplementation consisted of a daily intake of 168 mg curcumin and 260 mg quercetin, as two soft capsules, to be taken twice a day at home for 14 days.

Results

After one-week of treatment, most of the patients in the CUR-QUE group showed an expedited clearance of the viral infection i.e., 18 (72.0%) vs. 6 (24.0%) patients in the control group tested negative for SARS-CoV-2 in the nasal-oropharyngeal swab reverse transcription-polymerase chain reaction (RT-PCR) analysis (p = 0.0002). In addition, COVID-19-associated acute symptoms were also speedily resolved in the CUR-QUE treated patients, i.e., 10 (40.0%) vs. 4 (16.0%) patients in the control group (p = 0.061). The CUR-QUE supplementation therapy was well-tolerated by all 25 patients and no treatment-emergent effects or serious adverse events were reported.

Conclusion

The results revealed in this exploratory study suggest a possible therapeutic role of curcumin and quercetin in the early-stage of COVID-19. It is proposed that the two agents possibly acting in synergy, interfere the SARS-CoV-2 replication, and thus help a speedy recovery in the early-stage of COVID-19. Further research is highly encouraged.

Clinical trial registration

Clinicaltrials.gov, Identifier NCT04603690.