Natural products can be used in therapeutic management of COVID-19: Probable mechanistic insights

Harnessing the Power of Natural Products for Targeted Protein Degradation

Natural products have garnered significant attention due to their complex chemical structures and remarkable pharmacological activities. With inherent recognition capabilities for protein surfaces, natural products serve as ideal candidates for designing proteolysis-targeting chimeras (PROTACs). The utilization of natural products in PROTAC development offers distinct advantages, including their rich chemical diversity, multitarget activities, and sustainable sourcing. This comprehensive review explores the vast potential of harnessing natural products in PROTAC research. Moreover, the review discusses the application of natural degradant technology, which involves utilizing natural product-based compounds to selectively degrade disease-causing proteins, as well as the implementation of computer-aided drug design (CADD) technology in identifying suitable targets for degradation within the realm of natural products. By harnessing the power of natural products and leveraging computational tools, PROTACs derived from natural products have the potential to revolutionize drug discovery and provide innovative therapeutic interventions for various diseases.

Understanding of Alzheimer's disease pathophysiology for therapeutic implications of natural products as neuroprotective agents

Alzheimer's disease (AD) is a leading cause of dementia, affecting more than 24.3 million people worldwide in 2024. Sporadic AD (SAD) is more common and occurs in the geriatric population, while familial AD (FAD) is rare and appears before the age of 65 years. Due to progressive cholinergic neuronal loss and modulation in the PKC/MAPK pathway, β-secretase gets upregulated, leading to Aβ aggregation, which further activates tau kinases that form neurofibrillary tangles (NFT). Simultaneously, antioxidant enzymes are also upregulated, increasing oxidative stress (OS) and reactive species by impairing mitochondrial function, leading to DNA damage and cell death. This review discusses the classifications and components of several natural products (NPs) that target these signaling pathways for AD treatment. NPs, including alkaloids, polyphenols, flavonoids, polysaccharides, steroids, fatty acids, tannins, and polypeptides derived from plants, microbes, marine animals, venoms, insects, and mushrooms, are explored in detail. A synergistic combination of plant metabolites, together with prebiotics and probiotics has been shown to decrease Aβ aggregates by increasing the production of bioactive compounds. Toxins derived from venomous organisms have demonstrated effectiveness in modulating signaling pathways and reducing OS. Marine metabolites have also shown neuroprotective and anti-inflammatory properties. The cholera toxin B subunit and an Aβ15 fragment have been combined to create a possible oral AD vaccine, that showed enhancement of cognitive function in mice. Insect tea is also a reliable source of antioxidants. A functional edible mushroom snack bar showed an increment in cognitive markers. Future directions and therapeutic approaches for the treatment of AD can be improved by focusing more on NPs derived from these sources.

Evaluation of the Potency of Repurposed Antiretrovirals in HBV Therapy: A Narrative Investigation of the Traditional Medicine Alternatives

Hepatitis B is one of the killer communicable diseases, with a global estimation of 1.1 million deaths resulting from liver diseases annually. The search for HBV therapeutics has resulted in repurposing the existing antiretrovirals (ARVs) for HBV treatment, considering their shared common replication mechanisms. This review is aimed at evaluating the potencies of some of the repurposed ARVs used for HBV treatment, analyzing the common mechanisms of viral replications in HBV and HIV, and investigating the potentials of traditional medicines as an alternative treatment for HBV patients. The topical keywords drug repurposing, drug repositioning, antiretrovirals, hepatitis B treatment, HBV, natural products, traditional medicines, title, and abstract were searched in PubMed, Web of Science, and Google Scholar. The advanced search included the five years, 2019-2024. The search result was filtered from 377 to 110 relevant articles. The evaluation reveals that CD4+ T cells are targeted by HIV, while HBV targets the liver with its associated diseases (cirrhosis and hepatocellular carcinoma (HCC)). Furthermore, treatments with the available repurposed ARVs only prevent or slow down the progression to cirrhosis, reduce the HCC incidence, and can improve the quality of life and increase life expectancy; however, they are not curative for HBV. Traditional medicines/natural product extracts or their phytochemicals exert anti-HBV effects through different mechanisms. Traditional medicines exert improved therapeutic effects when combined properly. The investigation further reveals that consideration of an in silico approach in HBV therapeutics might not only streamline drug development but also contribute to a deeper understanding of viral pathogenesis. Therefore, we recommend the integration of computational drug design methods with traditional medicine and natural product screening for discovering new bioactive HBV drug candidates.

Investigating the chemo-preventive role of noscapine in lung carcinoma via therapeutic targeting of human aurora kinase B

Lung carcinoma is the major contributor to global cancer incidence and one of the leading causes of cancer-related mortality worldwide. Irregularities in signal transduction events, genetic alterations, and mutated regulatory genes trigger cancer development and progression. Selective targeting of molecular modulators has substantially revolutionized cancer treatment strategies with improvised efficacy. The aurora kinase B (AURKB) is a critical component of the chromosomal passenger complex and is primarily involved in lung cancer pathogenesis. Since AURKB is an important therapeutic target, the design and development of its potential inhibitors are attractive strategies. In this study, noscapine was selected and validated as a possible inhibitor of AURKB using integrated computational, spectroscopic, and cell-based assays. Molecular docking analysis showed noscapine occupies the substrate-binding pocket of AURKB with strong binding affinity. Subsequently, MD simulation studies confirmed the formation of a stable AURKB-noscapine complex with non-significant alteration in various trajectories, including RMSD, RMSF, Rg, and SASA. These findings were further experimentally validated through fluorescence binding studies. In addition, dose-dependent noscapine treatment significantly attenuated recombinant AURKB activity with an IC50 value of 26.6 µM. Cell viability studies conducted on A549 cells and HEK293 cells revealed significant cytotoxic features of noscapine on A549 cells. Furthermore, Annexin-PI staining validated that noscapine triggered apoptosis in lung cancer cells, possibly via an intrinsic pathway. Our findings indicate that noscapine-based AURKB inhibition can be implicated as a potential therapeutic strategy in lung cancer treatment and can also provide a novel scaffold for developing next-generation AURKB-specific inhibitors.

Ahmed L. Chamomile in combating SARS-Cov-2

Traditional herbal medicine is of known history for the complementary treatment of viral infections and was recently suggested for COVID-19. Therefore, it is of interest to investigate chamomile decoction for its neutralizing activity against SARS-CoV-2 In vitro. Our experiments highlight the potential antiviral effect of chamomile. In vitro results show a significant inhibition of SARS-CoV-2. Our results recommend the use of chamomile as a potential natural remedy for COVID-19.

Development of an Antiviral Medicinal Plant and Natural Product Database (avMpNp Database) from Biodiversity

The construction of compound databases (DB) is a strategy for the rational search of bioactive compounds and drugs for new and old diseases. In order to bring greater impact to drug discovery, we propose the development of a DB of bioactive antiviral compounds. Several research groups have presented evidence of the antiviral activity of medicinal plants and compounds isolated from these plants. We believe that compiling these discoveries in a DB would benefit the scientific research community and increase the speed to discover new potential drugs and medicines. Thus, we present the Antiviral Medicinal Plant and Natural Product DB (avMpNp DB) as an important source for acquiring, organizing, and distributing knowledge related to natural products and antiviral drug discovery. The avMpNp DB contains a series of chemically diverse compounds with drug-like profiles. To test the potential of this DB, SARS-CoV-2 Mpro and PLpro enzymatic inhibition assays were performed for available compounds resulting in IC50 values ranging from 6.308±0.296 to 15.795±0.155 μM. As a perspective, artificial intelligence tools will be added to implement computational predictions, as well as other chemical functionalities that allow data validation.

Computational screening of phytocompounds from C. amboinicus identifies potential inhibitors of influenza A (H3N2) virus by targeting hemagglutinin

The H3N2 subtype of the influenza A virus continues to be a notable public health issue due to its association with seasonal epidemics and severe human morbidity. The constrained effectiveness of current antiviral medications, combined with the inevitable emergence of drug-resistant variants, mandates the exploration of innovative therapeutic approaches. This study focuses on the identification of phytocompounds from Coleus amboinicus with the potential to target hemagglutinin, viral protein involved in viral entry by binding to sialyl glycoconjugates receptors on the surface of host cells. Molecular docking studies were carried out to assess the efficacy of C. amboinicus phytocompounds with hemagglutinin receptor-binding site. The study revealed that among the 84 signature phytocompounds, isosalvianolic acid and salvianolic acid C showed the highest docking scores and favourable intermolecular interactions. Pharmacokinetic analysis and Pan-assay interference compounds (PAINS) filtering confirmed that isosalvianolic acid meets the criteria outlined in Lipinski's rule of five, exhibits favourable ADMET profiles and passes PAINS filters. Furthermore, the molecular dynamics simulations followed by radius of gyration (Rg), solvent accessible surface area (SASA), and MM-PBSA calculations for binding free energy, verified the stability of the docked complexes. Together, the study identifies isosalvianolic acid as a promising inhibitor of the H3N2 virus by binding to hemagglutinin, indicating its potential as a strategy for therapeutic intervention.

Potential of traditional medicines in alleviating COVID-19 symptoms

This review discusses the prevention and treatment of coronavirus disease 2019 (COVID-19) caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Mutations in its spike glycoprotein have driven the emergence of variants with high transmissibility and immune escape capabilities. Some antiviral drugs are ineffective against the BA.2 subvariant at the authorized dose. Recently, 150 natural metabolites have been identified as potential candidates for development of new anti-COVID-19 drugs with higher efficacy and lower toxicity than those of existing therapeutic agents. Botanical drug-derived bioactive molecules have shown promise in dampening the COVID-19 cytokine storm and thus preventing pulmonary fibrosis, as they exert a strong binding affinity for viral proteins and inhibit their activity. The Health Ministry of Thailand has approved Andrographis paniculata (Jap. Senshinren) extracts to treat COVID-19. In China, over 85% of patients infected with SARS-CoV-2 receive treatments based on traditional Chinese medicine. A comprehensive map of the stages and pathogenetic mechanisms related to the disease and effective natural products to treat and prevent COVID-19 are presented. Approximately 10% of patients with COVID-19 are affected by long COVID, and COVID-19 infection impairs mitochondrial DNA. As the number of agents to treat COVID-19 is limited, adjuvant botanical drug treatments including vitamin C and E supplementation may reduce COVID-19 symptoms and inhibit progression to long COVID.

Eucalyptus Essential Oil Inhibits Cell Infection by SARS-CoV-2 Spike Pseudotyped Lentivirus

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a public health concern due to infections with new SARS-CoV-2 variants. Therefore, finding effective preventive and therapeutic treatments against all SARS-CoV-2 variants is of great interest. In this study, we examined the capacity of eucalyptus essential oil (EEO) and eucalyptol (EOL) to prevent SARS-CoV-2 infection, using as a model SARS-CoV-2 Spike pseudotyped lentivirus (SARS-CoV-2 pseudovirus) and 293T cells transfected with human angiotensin-converting enzyme 2 (hACE2-293T cells). First, we determined the cytotoxicity of EEO and EOL using the MTT colorimetric assay, selecting non-cytotoxic concentrations ≤ 0.1% (v/v) for further analysis. Subsequently, we evaluated the capacity of EEO and EOL in cell cultures to preclude infection of hACE2-293T cells by SARS-CoV-2 pseudovirus, using a luciferase-based assay. We found that EEO and EOL significantly reduced SARS-CoV-2 pseudovirus infection, obtaining IC50 values of 0.00895% and 0.0042% (v/v), respectively. Likewise, EEO and EOL also reduced infection by vesicular stomatitis virus (VSV) pseudovirus, although higher concentrations were required. Hence, EEO and EOL may be able to inhibit SARS-CoV-2 infection, at least partially, through a Spike-independent pathway, supporting the implementation of aromatherapy with these agents as a cost-effective antiviral measure.

Computational Exploration of Berberis lycium Royle: A Hidden Treasure Trove for Antiviral Development

Viral infections and associated illnesses account for approximately 3.5 million global fatalities and public health problems. Medicinal plants, with their wide therapeutic range and minimal side effects, have gained limelight particularly in response to growing concerns about drug resistance and sluggish development of antiviral drugs. This study computationally assessed 11 chemical compounds from Berberis lycium along with two antiviral drugs to inhibit SARS CoV 2 (coronavirus disease 2019 [COVID-19]) RNA-dependent RNA polymerase (RdRP), influenza virus RdRP, and two crucial dengue virus (DENV) enzymes (NS2B/NS3 protease and NS5 polymerase). Berberine and oxyberberine passed all pharmacokinetics analysis filters including Lipinski rule, blood-brain barrier permeant, and cytochrome suppression and demonstrated drug-likeness, bioavailability, and a non-toxic profile. Docking of phytochemicals from B lycium returned promising results with selected viral proteins, ie, DENV NS2BNS3 (punjabine -10.9 kcal/mol), DENV NS5 (punjabine -10.4 kcal/mol), COVID-19 RdRP (oxyacanthine -9.5 kcal/mol), and influenza RdRP (punjabine -10.4 kcal/mol). The optimal pharmacokinetics of berberine exhibited good binding energies with NS2BNS3 (-8.0 kcal/mol), NS5 (-8.3 kcal/mol), COVID RdRP (-7.7 kcal/mol), and influenza RdRP (-8.3 kcal/mol), while molecular dynamics simulation of a 50-ns time scale by GROMACS software package provided insights into the flexibility and stability of the complexes. A hidden treasure trove for antiviral research, berberine, berbamine, berbamunine, oxyberberine, oxyacanthine, baluchistanamine, and sindamine has showed encouraging findings as possible lead compounds. Pharmacological analyses provide credence for the proposed study; nevertheless, as the antiviral mechanisms of action of these phytochemicals are not well understood, additional research and clinical trials are required to demonstrate both their efficacy and toxicity through in vitro and in vivo studies.

Honokiol and magnolol: A review of structure-activity relationships of their derivatives

Honokiol (HK) and magnolol (MAG) are typical representatives of neolignans possessing a wide range of biological activities and are employed as traditional medicines in Asia. In the past few decades, HK and MAG have been proven to be promising chemical scaffolds for the development of novel neolignan drugs. This review focuses on recent advances in the medicinal chemistry of HK and MAG derivatives, especially their structure-activity relationships. In addition, it also presents a comprehensive summary of the pharmacology, biosynthetic pathways, and metabolic characteristics of HK and MAG. This review can provide pharmaceutical chemists deeper insights into medicinal research on HK and MAG, and a reference for the rational design of HK and MAG derivatives.

Effect and mechanism of quercetin or quercetin-containing formulas against COVID-19: From bench to bedside

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the global coronavirus disease 2019 (COVID-19) pandemic since 2019. Immunopathogenesis and thromboembolic events are central to its pathogenesis. Quercetin exhibits several beneficial activities against COVID-19, including antiviral, anti-inflammatory, immunomodulatory, antioxidative, and antithrombotic effects. Although several reviews have been published, these reviews are incomplete from the viewpoint of translational medicine. The authors comprehensively evaluated the evidence of quercetin against COVID-19, both basically and clinically, to apply quercetin and/or its derivatives in the future. The authors searched the PubMed, Embase, and the Cochrane Library databases without any restrictions. The search terms included COVID-19, SARS-CoV-2, quercetin, antiviral, anti-inflammatory, immunomodulatory, thrombosis, embolism, oxidative, and microbiota. The references of relevant articles were also reviewed. All authors independently screened and reviewed the quality of each included manuscript. The Cochrane Risk of Bias Tool, version 2 (RoB 2) was used to assess the quality of the included randomized controlled trials (RCTs). All selected studies were discussed monthly. The effectiveness of quercetin against COVID-19 is not solid due to methodological flaws in the clinical trials. High-quality studies are also required for quercetin-containing traditional Chinese medicines. The low bioavailability and highly variable pharmacokinetics of quercetin hinder its clinical applications. Its positive impact on immunomodulation through reverting dysbiosis of gut microbiota still lacks robust evidence. Quercetin against COVID-19 does not have tough clinical evidence. Strategies to improve its bioavailability and/or to develop its effective derivatives are needed. Well-designed RCTs are also crucial to confirm their effectiveness in the future.

The Efficacy of Multivitamin, Vitamin A, Vitamin B, Vitamin C, and Vitamin D Supplements in the Prevention and Management of COVID-19 and Long-COVID: An Updated Systematic Review and Meta-Analysis of Randomized Clinical Trials

This review aims to evaluate the efficacy of any vitamin administration(s) in preventing and managing COVID-19 and/or long-COVID. Databases were searched up to May 2023 to identify randomized clinical trials comparing data on the effects of vitamin supplementation(s) versus placebo or standard of care on the two conditions of interest. Inverse-variance random-effects meta-analyses were conducted to estimate pooled risk ratios (RRs) and 95% confidence intervals (CIs) for all-cause mortality between supplemented and non-supplemented individuals. Overall, 37 articles were included: two regarded COVID-19 and long-COVID prevention and 35 records the COVID-19 management. The effects of vitamin D in preventing COVID-19 and long-COVID were contrasting. Similarly, no conclusion could be drawn on the efficacy of multivitamins, vitamin A, and vitamin B in COVID-19 management. A few positive findings were reported in some vitamin C trials but results were inconsistent in most outcomes, excluding all-cause mortality (RR = 0.84; 95% CI: 0.72-0.97). Vitamin D results were mixed in most aspects, including mortality, in which benefits were observed in regular administrations only (RR = 0.67; 95% CI: 0.49-0.91). Despite some benefits, results were mostly contradictory. Variety in recruitment and treatment protocols might explain this heterogeneity. Better-designed studies are needed to clarify these vitamins' potential effects against SARS-CoV-2.

Insights into the preventive actions of natural compounds against Klebsiella pneumoniae infections and drug resistance

Klebsiella pneumoniae is a type of Gram-negative bacteria that causes a variety of infections, including pneumonia, bloodstream infections, wound infections, and meningitis. The treatment of K. pneumoniae infection depends on the type of infection and the severity of the symptoms. Antibiotics are generally used to treat K. pneumoniae infections. However, some strains of K. pneumoniae have become resistant to antibiotics. This comprehensive review examines the potential of natural compounds as effective strategies against K. pneumonia infections. The alarming rise in antibiotic resistance underscores the urgent need for alternative therapies. This article represents current research on the effects of diverse natural compounds, highlighting their anti-microbial and antibiofilm properties against K. pneumonia. Notably, compounds such as andrographolide, artemisinin, baicalin, berberine, curcumin, epigallocatechin gallate, eugenol, mangiferin, piperine, quercetin, resveratrol, and thymol have been extensively investigated. These compounds exhibit multifaceted mechanisms, including disruption of bacterial biofilms, interference with virulence factors, and augmentation of antibiotic effectiveness. Mechanistic insights into their actions include membrane perturbation, oxidative stress induction, and altered gene expression. While promising, challenges such as limited bioavailability and varied efficacy across bacterial strains are addressed. This review further discusses the potential of natural compounds as better alternatives in combating K. pneumonia infection and emphasizes the need for continued research to harness their full therapeutic potential. As antibiotic resistance persists, these natural compounds offer a promising avenue in the fight against K. pneumonia and other multidrug-resistant pathogens.

Identification of new pharmacophore against SARS-CoV-2 spike protein by multi-fold computational and biochemical techniques

COVID-19 appeared as a highly contagious disease after its outbreak in December 2019 by the virus, named SARS-CoV-2. The threat, which originated in Wuhan, China, swiftly became an international emergency. Among different genomic products, spike protein of virus plays a crucial role in the initiation of the infection by binding to the human lung cells, therefore, SARS-CoV-2's spike protein is a promising therapeutic target. Using a combination of a structure-based virtual screening and biochemical assay, this study seeks possible therapeutic candidates that specifically target the viral spike protein. A database of ~ 850 naturally derived compounds was screened against SARS-CoV-2 spike protein to find natural inhibitors. Using virtual screening and inhibitory experiments, we identified acetyl 11-keto-boswellic acid (AKBA) as a promising molecule for spike protein, which encouraged us to scan the rest of AKBA derivatives in our in-house database via 2D-similarity searching. Later 19 compounds with > 85% similarity with AKBA were selected and docked with receptor binding domain (RBD) of spike protein. Those hits declared significant interactions at the RBD interface, best possess and excellent drug-likeness and pharmacokinetics properties with high gastrointestinal absorption (GIA) without toxicity and allergenicity. Our in-silico observations were eventually validated by in vitro bioassay, interestingly, 10 compounds (A3, A4, C3, C6A, C6B, C6C, C6E, C6H, C6I, and C6J) displayed significant inhibitory ability with good percent inhibition (range: > 72-90). The compounds C3 (90.00%), C6E (91.00%), C6C (87.20%), and C6D (86.23%) demonstrated excellent anti-SARS CoV-2 spike protein activities. The docking interaction of high percent inhibition of inhibitor compounds C3 and C6E was confirmed by MD Simulation. In the molecular dynamics simulation, we observed the stable dynamics of spike protein inhibitor complexes and the influence of inhibitor binding on the protein's conformational arrangements. The binding free energy ΔGTOTAL of C3 (-38.0 ± 0.08 kcal/mol) and C6E (-41.98 ± 0.08 kcal/mol) respectively indicate a strong binding affinity to Spike protein active pocket. These findings demonstrate that these molecules particularly inhibit the function of spike protein and, therefore have the potential to be evaluated as drug candidates against SARS-CoV-2.

Probing Baicalin as potential inhibitor of Aurora kinase B: A step towards lung cancer therapy

Cell cycle regulators play pivotal roles as their dysregulation, leads to atypical proliferation and intrinsic genomic instability in cancer cells. Abnormal expression and functioning of Aurora kinase B (AURKB) are associated with cancer pathogenesis and thus exploited as a potential therapeutic target for the development of anti-cancer therapeutics. To identify effective AURKB inhibitors, a series of polyphenols was investigated to check their potential to inhibit recombinant AURKB. Their binding affinities were experimentally validated through fluorescence binding studies. Enzyme inhibition assay revealed that Mangiferin and Baicalin significantly inhibited AURKB activity with an IC50 values of 20.0 μM and 31.1 μM, respectively. To get atomistic insights into the binding mechanism, molecular docking and MD simulations of 100 ns were performed. Both compounds formed many non-covalent interactions with the residues of the active site pocket of AURKB. In addition, minimal conformational changes in the structure and formation of stable AURKB-ligand complex were observed during MD simulation analysis. Finally, cell-based studies suggested that Baicalin exhibited in-vitro cytotoxicity and anti-proliferative effects on lung cancer cell lines. Conclusively, Baicalin may be considered a promising therapeutic molecule against AURKB, adding an additional novel lead to the anti-cancer repertoire.

The neuroprotective potential of phytochemicals in traumatic brain injury: mechanistic insights and pharmacological implications

Traumatic brain injury (TBI) leads to brain damage, comprising both immediate primary damage and a subsequent cascade of secondary injury mechanisms. The primary injury results in localized brain damage, while the secondary damage initiates inflammatory responses, followed by the disruption of the blood-brain barrier, infiltration of peripheral blood cells, brain edema, and the release of various immune mediators, including chemotactic factors and interleukins. TBI disrupts molecular signaling, cell structures, and functions. In addition to physical tissue damage, such as axonal injuries, contusions, and haemorrhages, TBI interferes with brain functioning, impacting cognition, decision-making, memory, attention, and speech capabilities. Despite a deep understanding of the pathophysiology of TBI, an intensive effort to evaluate the underlying mechanisms with effective therapeutic interventions is imperative to manage the repercussions of TBI. Studies have commenced to explore the potential of employing natural compounds as therapeutic interventions for TBI. These compounds are characterized by their low toxicity and limited interactions with conventional drugs. Moreover, many natural compounds demonstrate the capacity to target various aspects of the secondary injury process. While our understanding of the pathophysiology of TBI, there is an urgent need for effective therapeutic interventions to mitigate its consequences. Here, we aimed to summarize the mechanism of action and the role of phytochemicals against TBI progression. This review discusses the therapeutic implications of various phytonutrients and addresses primary and secondary consequences of TBI. In addition, we highlighted the roles of emerging phytochemicals as promising candidates for therapeutic intervention of TBI. The review highlights the neuroprotective roles of phytochemicals against TBI and the mechanistic approach. Furthermore, our efforts focused on the underlying mechanisms, providing a better understanding of the therapeutic potential of phytochemicals in TBI therapeutics.

Repurposing of Plant-based Antiviral Molecules for the Treatment of COVID-19

COVID-19, stemming from SARS-CoV-2, poses a formidable threat to global healthcare, with a staggering 77 million confirmed cases and 690,067 deaths recorded till December 24, 2023. Given the absence of specific drugs for this viral infection, the exploration of novel antiviral compounds becomes imperative. High-throughput technologies are actively engaged in drug discovery, and there is a parallel effort to repurpose plant-based molecules with established antiviral properties. In this context, the review meticulously delves into the potential of plant-based folk remedies and existing molecules. These substances have showcased substantial viral inhibition in diverse in vivo, in silico, and in vitro studies, particularly against critical viral protein targets, including SARS-CoV-2. The findings position these plant-based molecules as promising antiviral drug candidates for the swift advancement of treatments for COVID-19. It is noteworthy that the inherent attributes of these plant-based molecules, such as their natural origin, potency, safety, and cost-effectiveness, contribute to their appeal as lead candidates. The review advocates for further exploration through comprehensive in vivo studies conducted on animal models, emphasizing the potential of plant-based compounds to help in the ongoing quest to develop effective antivirals against COVID-19.

Discovery of Anti-Coronavirus Cinnamoyl Triterpenoids Isolated from Hippophae rhamnoides during a Screening of Halophytes from the North Sea and Channel Coasts in Northern France

The limited availability of antiviral therapy for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spurred the search for novel antiviral drugs. Here, we investigated the potential antiviral properties of plants adapted to high-salt environments collected in the north of France. Twenty-five crude methanolic extracts obtained from twenty-two plant species were evaluated for their cytotoxicity and antiviral effectiveness against coronaviruses HCoV-229E and SARS-CoV-2. Then, a bioguided fractionation approach was employed. The most active crude methanolic extracts were partitioned into three different sub-extracts. Notably, the dichloromethane sub-extract of the whole plant Hippophae rhamnoides L. demonstrated the highest antiviral activity against both viruses. Its chemical composition was evaluated by ultra-high performance liquid chromatography (UHPLC) coupled with mass spectrometry (MS) and then it was fractionated by centrifugal partition chromatography (CPC). Six cinnamoyl triterpenoid compounds were isolated from the three most active fractions by preparative high-performance liquid chromatography (HPLC) and identified by high resolution MS (HR-MS) and mono- and bi-dimensional nuclear magnetic resonance (NMR). Specifically, these compounds were identified as 2-O-trans-p-coumaroyl-maslinic acid, 3β-hydroxy-2α-trans-p-coumaryloxy-urs-12-en-28-oic acid, 3β-hydroxy-2α-cis-p-coumaryloxy-urs-12-en-28-oic acid, 3-O-trans-caffeoyl oleanolic acid, a mixture of 3-O-trans-caffeoyl oleanolic acid/3-O-cis-caffeoyl oleanolic acid (70/30), and 3-O-trans-p-coumaroyl oleanolic acid. Infection tests demonstrated a dose-dependent inhibition of these triterpenes against HCoV-229E and SARS-CoV-2. Notably, cinnamoyl oleanolic acids displayed activity against both SARS-CoV-2 and HCoV-229E. Our findings suggest that Hippophae rhamnoides could represent a source of potential antiviral agents against coronaviruses.

Usage of Natural Health Products (NHPs) for respiratory diseases: user characteristics and NHP-Consumption behavior during the Covid-19 pandemic in Germany

BACKGROUND

Respiratory diseases (RD) can challenge healthcare systems around the globe. Natural health products (NHPs) are popular complementary and alternative medicine options for health issues concerning non-fatal RD. Little is known about the characteristics of the users of RD-NHPs and about their NHP consumption behavior during the Covid-19 pandemic in Germany.

METHODS

A representative online survey was conducted in Germany in 2022. 1707 participants were classified based on having used NHPs for RD within the previous 12 months, having used NHPs but not for RD within the previous 12 months and not having used NHPs. Data were analyzed using descriptive and inferential statistical methods as well as a multinomial logistic regression model.

RESULTS

Users of RD-NHPs within the previous 12 months were more likely to be employed and to consult pharmacists more often for non-fatal health issues than individuals who did not take RD-NHPs. RD-NHP users were more likely to suffer from a Covid-19 infection and to have children living in the same household than other NHP users. Compared to non-NHP users, RD-NHP users were more likely to be female, highly educated and have stronger openness-to-change value orientations. Vaccination-related behavior was no indicator of RD-NHP usage. Most RD-NHP users took NHPs in self-medication. Few reported informing their practitioner about their self-medication. Drugstores were the most visited supply source for NHPs during the pandemic, followed by pharmacies. Common information sources regarding NHPs were the products themselves and pharmacists.

CONCLUSION

This study emphasized the important role of NHPs as a popular prevention and treatment option for RD. RD-NHPs were more likely used by individuals who were employed, who suffered from a RD and who consult pharmacists for non-fatal health issues. The importance of product information and pharmacies as information sources should be considered to make communication strategies about safe self-medication options with RD-NHPs more effective, which could help to reduce the burden of health facilities regarding non-fatal RD. To improve and develop future pandemic-control strategies, health professionals and policy makers should consider NHP usage behavior and provide critical information about chances and risks of self-medicated NHP consumption.

Reducing lipid peroxidation attenuates stress-induced susceptibility to herpes simplex virus type 1

Psychological stress increases the susceptibility to herpes simplex virus type 1 (HSV-1) infection. There is no effective intervention due to the unknown pathogenesis mechanisms. In this study we explored the molecular mechanisms underlying stress-induced HSV-1 susceptibility and the antiviral effect of a natural compound rosmarinic acid (RA) in vivo and in vitro. Mice were administered RA (11.7, 23.4 mg·kg-1·d-1, i.g.) or acyclovir (ACV, 206 mg·kg-1·d-1, i.g.) for 23 days. The mice were subjected to restraint stress for 7 days followed by intranasal infection with HSV-1 on D7. At the end of RA or ACV treatment, mouse plasma samples and brain tissues were collected for analysis. We showed that both RA and ACV treatment significantly decreased stress-augmented mortality and alleviated eye swelling and neurological symptoms in HSV-1-infected mice. In SH-SY5Y cells and PC12 cells exposed to the stress hormone corticosterone (CORT) plus HSV-1, RA (100 μM) significantly increased the cell viability, and inhibited CORT-induced elevation in the expression of viral proteins and genes. We demonstrated that CORT (50 μM) triggered lipoxygenase 15 (ALOX15)-mediated redox imbalance in the neuronal cells, increasing the level of 4-HNE-conjugated STING, which impaired STING translocation from the endoplasmic reticulum to Golgi; the abnormality of STING-mediated innate immunity led to HSV-1 susceptibility. We revealed that RA was an inhibitor of lipid peroxidation by directly targeting ALOX15, thus RA could rescue stress-weakened neuronal innate immune response, thereby reducing HSV-1 susceptibility in vivo and in vitro. This study illustrates the critical role of lipid peroxidation in stress-induced HSV-1 susceptibility and reveals the potential for developing RA as an effective intervention in anti-HSV-1 therapy.

Development and efficacy assessment of hand sanitizers and polylactic acid films incorporating caffeic acid and vanillin for enhanced antiviral properties against HCoV-229E

BACKGROUND

Although three years after the outbreak of SARS-CoV-2, the virus is still having a significant impact on human health and the global economy. Infection through respiratory droplets is the main transmission route, but the transmission of the virus by surface contact cannot be ignored. Hand sanitizers and antiviral films can be applied to control SARS-CoV-2, but sanitizers and films show drawbacks such as resistance of the virus against ethanol and environmental problems including the overuse of plastics. Therefore, this study suggested applying natural substrates to hand sanitizers and antiviral films made of biodegradable plastic (PLA). This approach is expected to provide advantages for the easy control of SARS-CoV-2 through the application of natural substances.

METHODS

Antiviral disinfectants and films were manufactured by adding caffeic acid and vanillin to ethanol, isopropyl alcohol, benzalkonium chloride, and PLA. Antiviral efficacies were evaluated with slightly modified international standard testing methods EN 14,476 and ISO 21,702.

RESULTS

In suspension, all the hand sanitizers evaluated in this study showed a reduction of more than 4 log within 2 min against HCoV-229E. After natural substances were added to the hand sanitizers, the time needed to reach the detection limit of the viral titer was shortened both in suspension and porcine skin. However, no difference in the time needed to reach the detection limit of the viral titer was observed in benzalkonium chloride. In the case of antiviral films, those made using both PLA and natural substances showed a 1 log reduction of HCoV-229E compared to the neat PLA film for all treatment groups. Furthermore, the influence of the organic load was evaluated according to the number of contacts of the antiviral products with porcine skin. Ten rubs on the skin resulted in slightly higher antiviral activity than 50 rubs.

CONCLUSION

This study revealed that caffeic acid and vanillin can be effectively used to control HCoV-229E for hand sanitizers and antiviral films. In addition, it is recommended to remove organic matter from the skin for maintaining the antiviral activity of hand sanitizer and antiviral film as the antiviral activity decreased as the organic load increased in this study.

Advances in detecting fruit aroma compounds by combining chromatography and spectrometry

Fruit aroma is produced by volatile compounds, which can significantly enhance fruit flavor. These compounds are highly complex and have remarkable pharmacological effects. The synthesis, concentration, type, and quantity of fruit aroma substances are affected by various factors, both abiotic and biotic. To fully understand the aroma substances of various fruits and their influencing factors, detection technology can be used. Many methods exist for detecting aroma compounds, and approaches combining multiple instruments are widely used. This review describes and compares each detection technology and discusses the potential use of combined technologies to provide a comprehensive understanding of fruit aroma compounds and the factors influencing their synthesis. These results can inform the development and utilization of fruit aroma substances. © 2023 Society of Chemical Industry.

Therapeutic Targeting of Regulated Signaling Pathways of Non-Small Cell Lung Carcinoma

Non-small cell lung carcinoma (NSCLC) is the most common cancer globally. Phytochemicals and small molecule inhibitors significantly prevent varying types of cancers, including NSCLC. These therapeutic molecules serve as important sources for new drugs that interfere with cellular proliferation, apoptosis, metastasis, and angiogenesis by regulating signaling pathways. These molecules affect several cellular signaling cascades, including p53, NF-κB, STAT3, RAS, MAPK/ERK, Wnt, and AKT/PI3K, and are thus implicated in the therapeutic management of cancers. This review aims to describe the bioactive compounds and small-molecule inhibitors, their anticancer action, and targeting cellular signaling cascades in NSCLC. We highlighted the therapeutic potential of Epigallocatechin gallate (EGCG), Perifosine, ABT-737, Thymoquinine, Quercetin, Venetoclax, Gefitinib, and Genistein. These compounds are implicated in the therapeutic management of NSCLC. This review further offers deeper mechanistic insights into different signaling pathways that could be targeted for NSCLC therapy by phytochemicals and small-molecule inhibitors.

Biochemical features and therapeutic potential of α-Mangostin: Mechanism of action, medicinal values, and health benefits

α-Mangostin (α-MG) is a natural xanthone obtained from the pericarps of mangosteen. It exhibits excellent potential, including anti-cancer, neuroprotective, antimicrobial, antioxidant, and anti-inflammatory properties, and induces apoptosis. α-MG controls cell proliferation by modulating signaling molecules, thus implicated in cancer therapy. It possesses incredible pharmacological features and modulates crucial cellular and molecular factors. Due to its lesser water solubility and pitiable target selectivity, α-MG has limited clinical application. As a known antioxidant, α-MG has gained significant attention from the scientific community, increasing interest in extensive technical and biomedical applications. Nanoparticle-based drug delivery systems were designed to improve the pharmacological features and efficiency of α-MG. This review is focused on recent developments on the therapeutic potential of α-MG in managing cancer and neurological diseases, with a special focus on its mechanism of action. In addition, we highlighted biochemical and pharmacological features, metabolism, functions, anti-inflammatory, antioxidant effects and pre-clinical applications of α-MG.

Anti-COVID-19 Potential of Ellagic Acid and Polyphenols of Punica granatum L

Pomegranate (Punica granatum L.) is a rich source of polyphenols, including ellagitannins and ellagic acid. The plant is used in traditional medicine, and its purified components can provide anti-inflammatory and antioxidant activity and support of host defenses during viral infection and recovery from disease. Current data show that pomegranate polyphenol extract and its ellagitannin components and metabolites exert their beneficial effects by controlling immune cell infiltration, regulating the cytokine secretion and reactive oxygen and nitrogen species production, and by modulating the activity of the NFκB pathway. In vitro, pomegranate extracts and ellagitannins interact with and inhibit the infectivity of a range of viruses, including SARS-CoV-2. In silico docking studies show that ellagitannins bind to several SARS-CoV-2 and human proteins, including a number of proteases. This warrants further exploration of polyphenol-viral and polyphenol-host interactions in in vitro and in vivo studies. Pomegranate extracts, ellagitannins and ellagic acid are promising agents to target the SARS-CoV-2 virus and to restrict the host inflammatory response to viral infections, as well as to supplement the depleted host antioxidant levels during the stage of recovery from COVID-19.

Radical Scavenging Is Not Involved in Thymoquinone-Induced Cell Protection in Neural Oxidative Stress Models

Thymoquinone (TQ), an active compound from Nigella sativa seeds, is often described as a pharmacologically relevant compound with antioxidative properties, while the synthesis of TQ in the plant via oxidations makes it inapplicable for scavenging radicals. Therefore, the present study was designed to reassess the radical scavenging properties of TQ and explore a potential mode of action. The effects of TQ were studied in models with mitochondrial impairment and oxidative stress induced by rotenone in N18TG2 neuroblastoma cells and rotenone/MPP+ in primary mesencephalic cells. Tyrosine hydroxylase staining revealed that TQ significantly protected dopaminergic neurons and preserved their morphology under oxidative stress conditions. Quantification of the formation of superoxide radicals via electron paramagnetic resonance showed an initial increase in the level of superoxide radicals in the cell by TQ. Measurements in both cell culture systems revealed that the mitochondrial membrane potential was tendentially lowered, while ATP production was mostly unaffected. Additionally, the total ROS levels were unaltered. In mesencephalic cell culture under oxidative stress conditions, caspase-3 activity was decreased when TQ was administered. On the contrary, TQ itself tremendously increased the caspase-3 activity in the neuroblastoma cell line. Evaluation of the glutathione level revealed an increased level of total glutathione in both cell culture systems. Therefore, the enhanced resistance against oxidative stress in primary cell culture might be a consequence of a lowered caspase-3 activity combined with an increased pool of reduced glutathione. The described anti-cancer ability of TQ might be a result of the pro-apoptotic condition in neuroblastoma cells. Our study provides evidence that TQ has no direct scavenging effect on superoxide radicals.

Investigating regulated signaling pathways in therapeutic targeting of non-small cell lung carcinoma

Non-small cell lung carcinoma (NSCLC) is the most common malignancy worldwide. The signaling cascades are stimulated via genetic modifications in upstream signaling molecules, which affect apoptotic, proliferative, and differentiation pathways. Dysregulation of these signaling cascades causes cancer-initiating cell proliferation, cancer development, and drug resistance. Numerous efforts in the treatment of NSCLC have been undertaken in the past few decades, enhancing our understanding of the mechanisms of cancer development and moving forward to develop effective therapeutic approaches. Modifications of transcription factors and connected pathways are utilized to develop new treatment options for NSCLC. Developing designed inhibitors targeting specific cellular signaling pathways in tumor progression has been recommended for the therapeutic management of NSCLC. This comprehensive review provided deeper mechanistic insights into the molecular mechanism of action of various signaling molecules and their targeting in the clinical management of NSCLC.

Spatial and Temporal Distribution of Phenolic and Flavonoid Compounds in Sour Jujube (Ziziphus. Acidojujuba Cheng et Liu) and Their Antioxidant Activities

In order to comprehensively analyze the antioxidant substances in sour jujube, total phenolic content (TPC) and total flavonoids contents (TFC) in different organs, including stem, leaf, flower, fruit pulp, and seed were analyzed for their contents and antioxidant activities. The results showed that leaves possessed significantly higher TPC and TFC (20.4 and 20.5 mg/g, respectively) than the other organs and have the highest antioxidant activity, which were also higher than the wild blueberry (A well-known for its high TPC). Subsequently, the variations in the antioxidant content and antioxidant activity of leaves were analyzed during leaf development. TPC in leaves sampled in may and august were significantly higher than that in other months, while the highest one was found in may. The n-hexane, ethyl acetate, n-butanol, and water fractions obtained from the main methanol extract of sour jujube leaves were evaluated for TPC and TFC and their antioxidant activity and it was found that ethyl acetate fraction displayed the highest TPC and TFC (184.5 and 193.3 mg/g, respectively), as well as the best antioxidant activity. In addition, using LC-MS and HPLC, ethyl acetate fraction was analyzed from qualitative and quantitative aspects; 31-one phenolic compounds, including catechin (33.0 mg/g), epigallocatechin (15.3 mg/g), quercetin 3-O-glucoside (11.4 mg/g), naringenin (6.7 mg/g), esculetin (4.8 mg/g), and chlorogenic acid (4.6 mg/g) were identified. Catechin, esculetin, epigallocatechin, chlorogenic acid, quercetin 3-O-glucoside, and naringenin exhibited high antioxidant activity. These results provide a theoretical basis for further study and utilization of flavonoid and polyphenols in sour jujube.

COVID-19 and Thymoquinone: Clinical Benefits, Cure, and Challenges

In today’s world, the outbreak of the coronavirus disease 2019 (COVID-19) has spread throughout the world, causing severe acute respiratory syndrome (SARS) and several associated complications in various organs (heart, liver, kidney, and gastrointestinal tract), as well as significant multiple organ dysfunction, shock, and even death. In order to overcome the serious complications associated with this pandemic virus and to prevent SARS-CoV-2 entry into the host cell, it is necessary to repurpose currently available drugs with a broad medicinal application as soon as they become available. There are several therapeutics under investigation for improving the overall prognosis of COVID-19 patients, but none of them has demonstrated clinical efficacy to date, which is disappointing. It is in this pattern that Nigella sativa seeds manifest their extensive therapeutic effects, which have been reported to be particularly effective in the treatment of skin diseases, jaundice, and gastrointestinal problems. One important component of these seeds is thymoquinone (TQ), which has a wide range of beneficial properties, including antioxidant and anti-inflammatory properties, as well as antibacterial and parasitic properties, in addition to anticarcinogenic, antiallergic, and antiviral properties. This comprehensive review discussed the possibility of an emerging natural drug with a wide range of medical applications; the use of TQ to overcome the complications of COVID-19 infection; and the challenges that are impeding the commercialization of this promising phytochemical compound. TQ is recommended as a highly effective weapon in the fight against the novel coronavirus because of its dual antiviral action, in addition to its capacity to lessen the possibility of SARS-CoV-2 penetration into cells. However, future clinical trials are required to confirm the role of TQ in overcoming the complications of COVID-19 infection.

Anti-Entry Activity of Natural Flavonoids against SARS-CoV-2 by Targeting Spike RBD

COVID-19 is still a global public health concern, and the SARS-CoV-2 mutations require more effective antiviral agents. In this study, the antiviral entry activity of thirty-one flavonoids was systematically evaluated by a SARS-CoV-2 pseudovirus model. Twenty-four flavonoids exhibited antiviral entry activity with IC50 values ranging from 10.27 to 172.63 µM and SI values ranging from 2.33 to 48.69. The structure-activity relationship of these flavonoids as SARS-CoV-2 entry inhibitors was comprehensively summarized. A subsequent biolayer interferometry assay indicated that flavonoids bind to viral spike RBD to block viral interaction with ACE2 receptor, and a molecular docking study also revealed that flavonols could bind to Pocket 3, the non-mutant regions of SARS-CoV-2 variants, suggesting that flavonols might be also active against virus variants. These natural flavonoids showed very low cytotoxic effects on human normal cell lines. Our findings suggested that natural flavonoids might be potential antiviral entry agents against SARS-CoV-2 via inactivating the viral spike. It is hoped that our study will provide some encouraging evidence for the use of natural flavonoids as disinfectants to prevent viral infections.

Utilisation of Mangifera indica plant extracts and parts in antimicrobial formulations and as a pharmaceutical excipient: a review

Background

Antimicrobial resistance and the environmental threat posed by some synthetic antimicrobial agents necessitate more research into development of novel pharmaceutical products that are environmentally friendly. Also, the use of plant derived excipients is growing and opening up new avenue to solve current drug delivery issues in the pharmaceutical industry.

Main body

This review summarizes studies related to the antimicrobial property of Mangifera indica extracts, possible mechanisms of antimicrobial action and antimicrobial formulations from the plant and overview of researches relating to the use of M. indica as a pharmaceutical excipient. Electronic searches were conducted on databases such as Pub Med, Wiley Online Library (WOL) and Google Scholar with focus on published articles relating to M. indica. Inclusion and exclusion criteria include publications relating to antimicrobial properties of M. indica extracts, its antimicrobial formulations and its use as a pharmaceutical excipient. The electronic searches yielded about 190 articles. From the studies reviewed, the mechanisms of action of phytochemicals described corroborate the antimicrobial activity exhibited by M. indica extracts and its selected formulations. In addition, mango pectin was observed to possess potential as a pharmaceutical excipient. Very few previous review articles based their focus on incorporating mechanism of action of phytochemicals with antimicrobial activity.This review examined antimicrobial properties of M. indica extracts and formulations, major phytochemicals in the plant parts and their possible modes of action. In addition, the study assessed the use of natural polymer derived from mango plant as excipients in pharmaceutical and pharmacological preparations.

Conclusion

The study concluded that effective antimicrobial activity of mango plant extracts and formulations requires synergy of actions among various phytochemical constituents of the extract or formulation. It is recommended that more researches focused on discovery of new phytochemicals in M. indica, their mechanisms of action and effective utilization of the plant in the pharmaceutical industry should be further explored.

Identification of Novel Artemisinin Hybrids Induce Apoptosis and Ferroptosis in MCF-7 Cells

A series of novel 1,3,4-oxadiazole-artemisinin hybrids have been designed and synthesized. An MTT assay revealed that most of tested hybrids showed more enhanced anti-proliferative activities than artemisinin, among which A8 had the superior potency with IC50 values ranging from 4.07 μM to 9.71 μM against five tested cancer cell lines. Cell colony formation assays showed that A8 could inhibit significantly more cell proliferation than artemisinin and 5-fluorouracil. Further mechanism studies reveal that A8 induces apoptosis and ferroptosis in MCF-7 cells in a dose-dependent manner, and CYPs inhibition assays reveal that A8 has a moderate inhibitory effect on CYP1A2 and CYP3A4 in the human body at 10 μM. The present work indicates that hybrid A8 may merit further investigation as a potential therapeutic agent.

Tackling the Future Pandemics: Broad-Spectrum Antiviral Agents (BSAAs) Based on A-Type Proanthocyanidins

A-type proanthocyanidins (PAC-As) are plant-derived natural polyphenols that occur as oligomers or polymers of flavan-3-ol monomers, such as (+)-catechin and (-)-epicatechin, connected through an unusual double A linkage. PAC-As are present in leaves, seeds, flowers, bark, and fruits of many plants, and are thought to exert protective natural roles against microbial pathogens, insects, and herbivores. Consequently, when tested in isolation, PAC-As have shown several biological effects, through antioxidant, antibacterial, immunomodulatory, and antiviral activities. PAC-As have been observed in fact to inhibit replication of many different human viruses, and both enveloped and non-enveloped DNA and RNA viruses proved sensible to their inhibitory effect. Mechanistic studies revealed that PAC-As cause reduction of infectivity of viral particles they come in contact with, as a result of their propensity to interact with virion surface capsid proteins or envelope glycoproteins essential for viral attachment and entry. As viral infections and new virus outbreaks are a major public health concern, development of effective Broad-Spectrum Antiviral Agents (BSAAs) that can be rapidly deployable even against future emerging viruses is an urgent priority. This review summarizes the antiviral activities and mechanism of action of PAC-As, and their potential to be deployed as BSAAs against present and future viral infections.

Plant Spices as a Source of Antimicrobial Synergic Molecules to Treat Bacterial and Viral Co-Infections

The COVID-19 pandemic exposed the lack of antiviral agents available for human use, while the complexity of the physiological changes caused by coronavirus (SARS-CoV-2) imposed the prescription of multidrug pharmacotherapy to treat infected patients. In a significant number of cases, it was necessary to add antibiotics to the prescription to decrease the risk of co-infections, preventing the worsening of the patient's condition. However, the precautionary use of antibiotics corroborated to increase bacterial resistance. Since the development of vaccines for COVID-19, the pandemic scenario has changed, but the development of new antiviral drugs is still a major challenge. Research for new drugs with synergistic activity against virus and resistant bacteria can produce drug leads to be used in the treatment of mild cases of COVID-19 and to fight other viruses and new viral diseases. Following the repurposing approach, plant spices have been searched for antiviral lead compounds, since the toxic effects of plants that are traditionally consumed are already known, speeding up the drug discovery process. The need for effective drugs in the context of viral diseases is discussed in this review, with special focus on plant-based spices with antiviral and antibiotic activity. The activity of plants against resistant bacteria, the diversity of the components present in plant extracts and the synergistic interaction of these metabolites and industrialized antibiotics are discussed, with the aim of contributing to the development of antiviral and antibiotic drugs. A literature search was performed in electronic databases such as Science Direct; SciELO (Scientific Electronic Library Online); LILACS (Latin American and Caribbean Literature on Health Sciences); Elsevier, SpringerLink; and Google Scholar, using the descriptors: antiviral plants, antibacterial plants, coronavirus treatment, morbidities and COVID-19, bacterial resistance, resistant antibiotics, hospital-acquired infections, spices of plant origin, coronaviruses and foods, spices with antiviral effect, drug prescriptions and COVID-19, and plant synergism. Articles published in English in the period from 2020 to 2022 and relevant to the topic were used as the main inclusion criteria.

Natural Product-Inspired Targeted Protein Degraders: Advances and Perspectives

Targeted protein degradation (TPD), a promising therapeutic strategy in drug discovery, has great potential to regulate the endogenous degradation of undruggable targets with small molecules. As vital resources that provide diverse structural templates for drug discovery, natural products (NPs) are a rising and robust arsenal for the development of therapeutic TPD. The first proof-of-concept study of proteolysis-targeting chimeras (PROTACs) was a natural polyketide ovalicin-derived degrader; since then, NPs have shown great potential to promote TPD technology. The use of NP-inspired targeted protein degraders has been confirmed to be a promising strategy to treat many human conditions, including cancer, inflammation, and nonalcoholic fatty liver disease. Nevertheless, the development of NP-inspired degraders is challenging, and the field is currently in its infancy. In this review, we summarize the bioactivities and mechanisms of NP-inspired degraders and discuss the associated challenges and future opportunities in this field.

Recent advances in the therapeutic potential of emodin for human health

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a bioactive compound, a natural anthraquinone aglycone, present mainly in herbaceous species of the families Fabaceae, Polygonaceae and Rhamnaceae, with a physiological role in protection against abiotic stress in vegetative tissues. Emodin is mainly used in traditional Chinese medicine to treat sore throats, carbuncles, sores, blood stasis, and damp-heat jaundice. Pharmacological research in the last decade has revealed other potential therapeutic applications such as anticancer, neuroprotective, antidiabetic, antioxidant and anti-inflammatory. The present study aimed to summarize recent studies on bioavailability, preclinical pharmacological effects with evidence of molecular mechanisms, clinical trials and clinical pitfalls, respectively the therapeutic limitations of emodin. For this purpose, extensive searches were performed using the PubMed/Medline, Scopus, Google scholar, TRIP database, Springer link, Wiley and SciFinder databases as a search engines. The in vitro and in vivo studies included in this updated review highlighted the signaling pathways and molecular mechanisms of emodin. Because its bioavailability is low, there are limitations in clinical therapeutic use. In conclusion, for an increase in pharmacotherapeutic efficacy, future studies with carrier molecules to the target, thus opening up new therapeutic perspectives.

Phytotherapy and Dietotherapy of COVID-19—An Online Survey Results from Central Part of Balkan Peninsula

Since the appearance of the novel coronavirus disease of 2019—COVID-19, various therapeutic approaches were attempted, with complementary and alternative medicine (CAM) taking an important place. The aim of this study was to investigate the use of CAM with the purpose of prevention or treatment of COVID-19 during the pandemics. A prospective, cross-sectional study, in the form of an on-line survey was conducted. A total of 1704 responses were collected. Among the respondents, 2.76% declared currently and 22.12% previously having COVID-19. Approximately one quarter of interviewees (23.24%) declared themselves as phytotherapy users. The most frequently used medicinal plants were garlic, ginger and chamomile. The majority of respondents stated that they expected positive effects on immune and respiratory system. Medicinal plants were frequently used, on a daily basis. The main sources of information for applied self-medication were populistic thematic literature, followed by the Internet. Approximately one-third of phytotherapy users (35.25%) consulted with a medical professional before the application of phytotherapy. Regarding dietotherapy, 41.14% of respondents reported using non-herbal dietary supplements, while only 7.16% reported specific diet. The presented results suggest that CAM is recognized and readily used as a potential alternative and complementary regimen in the fight against COVID-19.

Phenolic compounds versus SARS-CoV-2: An update on the main findings against COVID-19

The COVID-19 pandemic caused by SARS-CoV-2 remains an international concern. Although there are drugs to fight it, new natural alternatives such as polyphenols are essential due to their antioxidant activity and high antiviral potential. In this context, this review reports the main findings on the effect of phenolic compounds (PCs) against SARS-CoV-2 virus. First, the proven activity of PCs against different human viruses is briefly detailed, which serves as a starting point to study their anti-COVID-19 potential. SARS-CoV-2 targets (its proteins) are defined. Findings from in silico, in vitro and in vivo studies of a wide variety of phenolic compounds are shown, emphasizing their mechanism of action, which is fundamental for drug design. Furthermore, clinical trials have demonstrated the effectiveness of PCs in the prevention and as a possible therapeutic management against COVID-19. The results were complemented with information on the influence of polyphenols in strengthening/modulating the immune system. It is recommended to investigate compounds such as vitamins, minerals, alkaloids, triterpenes and fatty acids, and their synergistic use with PCs, many of which have been successful against SARS-CoV-2. Based on findings on other viruses, synergistic evaluation of PCs with accepted drugs against COVID-19 is also suggested. Other recommendations and limitations are also shown, which is useful for professionals involved in the development of efficient, safe and low-cost therapeutic strategies based on plant matrices rich in PCs. To the authors' knowledge, this manuscript is the first to evaluate the relationship between the antiviral and immunomodulatory (including anti-inflammatory and antioxidant effects) activity of PCs and their underlying mechanisms in relation to the fight against COVID-19. It is also of interest for the general population to be informed about the importance of consuming foods rich in bioactive compounds for their health benefits.

Therapeutic implications and clinical manifestations of thymoquinone

Thymoquinone (TQ), a natural phytochemical predominantly found in Nigella sativa, has been investigated for its numerous health benefits. TQ showed anti-cancer, anti-oxidant, and anti-inflammatory properties, validated in various disease models. The anti-cancer potential of TQ is goverened by anti-proliferation, cell cycle arrest, apoptosis induction, ROS production, anti-metastasis and anti-angiogenesis, inhibition of cell migration and invasion action. Additionally, TQ exhibited antitumor activity via the modulation of multiple pathways and molecular targets, including Akt, ERK1/2, STAT3, and NF-κB. The present review highlighted the anticancer potential of TQ . We summarize the anti-cancer, anti-oxidant, and anti-inflammatory properties of TQ, focusing on its molecular targets and its promising action in cancer therapy. We further described the molecular mechanisms by which TQ prevents signaling pathways that mediate cancer progression, invasion, and metastasis.

Bio-Guided Isolation of SARS-CoV-2 Main Protease Inhibitors from Medicinal Plants: In Vitro Assay and Molecular Dynamics

Since the emergence of the pandemic of the coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the discovery of antiviral phytoconstituents from medicinal plants against SARS-CoV-2 has been comprehensively researched. In this study, thirty-three plants belonging to seventeen different families used traditionally in Saudi Arabia were tested in vitro for their ability to inhibit the SARS-CoV-2 main protease (M^PRO). Major constituents of the bio-active extracts were isolated and tested for their inhibition potential against this enzyme; in addition, their antiviral activity against the SARS-CoV-2 Egyptian strain was assessed. Further, the thermodynamic stability of the best active compounds was studied through focused comparative insights for the active metabolites regarding ligand–target binding characteristics at the molecular level. Additionally, the obtained computational findings provided useful directions for future drug optimization and development. The results revealed that Psiadia punctulata, Aframomum melegueta, and Nigella sativa extracts showed a high percentage of inhibition of 66.4, 58.7, and 31.5%, against SARS-CoV-2 M^PRO, respectively. The major isolated constituents of these plants were identified as gardenins A and B (from P. punctulata), 6-gingerol and 6-paradol (from A. melegueta), and thymoquinone (from N. sativa). These compounds are the first to be tested invitro against SARS-CoV-2 M^PRO. Among the isolated compounds, only thymoquinone (THY), gardenin A (GDA), 6-gingerol (GNG), and 6-paradol (PAD) inhibited the SARS-CoV-2 M^PRO enzyme with inhibition percentages of 63.21, 73.80, 65.2, and 71.8%, respectively. In vitro assessment of SARS-CoV-2 (hCoV-19/Egypt/NRC-03/2020 (accession number on GSAID: EPI_ISL_430820) revealed a strong-to-low antiviral activity of the isolated compounds. THY showed relatively high cytotoxicity and was anti-SARS-CoV-2, while PAD demonstrated a cytotoxic effect on the tested VERO cells with a selectivity index of CC₅₀/IC₅₀ = 1.33 and CC₅₀/IC₅₀ = 0.6, respectively. Moreover, GNG had moderate activity at non-cytotoxic concentrations in vitro with a selectivity index of CC₅₀/IC₅₀ = 101.3/43.45 = 2.3. Meanwhile, GDA showed weak activity with a selectivity index of CC₅₀/IC₅₀ = 246.5/83.77 = 2.9. The thermodynamic stability of top-active compounds revealed preferential stability and SARS-CoV-2 M^PRO binding affinity for PAD through molecular-docking-coupled molecular dynamics simulation. The obtained results suggest the treating potential of these plants and/or their active metabolites for COVID-19. However, further in-vivo and clinical investigations are required to establish the potential preventive and treatment effectiveness of these plants and/or their bio-active compounds in COVID-19.

Structure-guided design and development of cyclin-dependent kinase 4/6 inhibitors: A review on therapeutic implications

Cyclin-dependent kinase 6 (EC 2.7.11.22) play significant roles in numerous biological processes and triggers cell cycle events. CDK6 controlled the transcriptional regulation. A dysregulated function of CDK6 is linked with the development of progression of multiple tumor types. Thus, it is considered as an effective drug target for cancer therapy. Based on the direct roles of CDK4/6 in tumor development, numerous inhibitors developed as promising anti-cancer agents. CDK4/6 inhibitors regulate the G1 to S transition by preventing Rb phosphorylation and E2F liberation, showing potent anti-cancer activity in several tumors, including HR+/HER2- breast cancer. CDK4/6 inhibitors such as abemaciclib, palbociclib, and ribociclib, control cell cycle, provoke cell senescence, and induces tumor cell disturbance in pre-clinical studies. Here, we discuss the roles of CDK6 in cancer along with the present status of CDK4/6 inhibitors in cancer therapy. We further discussed, how structural features of CDK4/6 could be implicated in the design and development of potential anti-cancer agents. In addition, the therapeutic potential and limitations of available CDK4/6 inhibitors are described in detail. Recent pre-clinical and clinical information for CDK4/6 inhibitors are highlighted. In addition, combination of CDK4/6 inhibitors with other drugs for the therapeutic management of cancer are discussed.

p53/NF-kB Balance in SARS-CoV-2 Infection: From OMICs, Genomics and Pharmacogenomics Insights to Tailored Therapeutic Perspectives (COVIDomics)

SARS-CoV-2 infection affects different organs and tissues, including the upper and lower airways, the lung, the gut, the olfactory system and the eye, which may represent one of the gates to the central nervous system. Key transcriptional factors, such as p53 and NF-kB and their reciprocal balance, are altered upon SARS-CoV-2 infection, as well as other key molecules such as the virus host cell entry mediator ACE2, member of the RAS-pathway. These changes are thought to play a central role in the impaired immune response, as well as in the massive cytokine release, the so-called cytokine storm that represents a hallmark of the most severe form of SARS-CoV-2 infection. Host genetics susceptibility is an additional key side to consider in a complex disease as COVID-19 characterized by such a wide range of clinical phenotypes. In this review, we underline some molecular mechanisms by which SARS-CoV-2 modulates p53 and NF-kB expression and activity in order to maximize viral replication into the host cells. We also face the RAS-pathway unbalance triggered by virus-ACE2 interaction to discuss potential pharmacological and pharmacogenomics approaches aimed at restoring p53/NF-kB and ACE1/ACE2 balance to counteract the most severe forms of SARS-CoV-2 infection.

Therapeutic targeting of TANK-binding kinase signaling towards anticancer drug development: Challenges and opportunities

TANK-binding kinase 1 (TBK1) plays a fundamental role in regulating the cellular responses and controlling several signaling cascades. It regulates inflammatory, interferon, NF-κB, autophagy, and Akt pathways. Post-translational modifications (PTM) of TBK1 control its action and subsequent cellular signaling. The dysregulation of the TBK1 pathway is correlated to many pathophysiological conditions, including cancer, that implicates the promising therapeutic advantage for targeting TBK1. The present study summarizes current updates on the molecular mechanisms and cancer-inducing roles of TBK1. Designed inhibitors of TBK1 are considered a potential therapeutic agent for several diseases, including cancer. Data from pre-clinical tumor models recommend that the targeting of TBK1 could be an attractive strategy for anti-tumor therapy. This review further highlighted the therapeutic potential of potent and selective TBK1 inhibitors, including Amlexanox, Compound II, BX795, MRT67307, SR8185 AZ13102909, CYT387, GSK8612, BAY985, and Domainex. These inhibitors may be implicated to facilitate therapeutic management of cancer and TBK1-associated diseases in the future.

Potential of Natural Alkaloids From Jadwar (Delphinium denudatum) as Inhibitors Against Main Protease of COVID-19: A Molecular Modeling Approach

The ongoing pandemic coronavirus disease (COVID-19) caused by a novel corona virus, namely, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has had a major impact on global public health. COVID-19 cases continue to increase across the globe with high mortality rates in immunocompromised patients. There is still a pressing demand for drug discovery and vaccine development against this highly contagious disease. To design and develop antiviral drugs against COVID-19, the main protease (M^pro) has emerged as one of the important drug targets. In this context, the present work explored Jadwar (Delphinium denudatum)-derived natural alkaloids as potential inhibitors against M^pro of SARS-CoV-2 by employing a combination of molecular docking and molecular dynamic simulation-based methods. Molecular docking and interaction profile analysis revealed strong binding on the M^pro functional domain with four natural alkaloids viz. panicutine (-7.4 kcal/mol), vilmorrianone (-7.0 kcal/mol), denudatine (-6.0 kcal/mol), and condelphine (-5.9 kcal/mol). The molecular docking results evaluated by using the MD simulations on 200 nanoseconds confirmed highly stable interactions of these compounds with the M^pro. Additionally, mechanics/generalized Born/Poisson-Boltzmann surface area (MM/G/P/BSA) free energy calculations also affirmed the docking results. Natural alkaloids explored in the present study possess the essential drug-likeness properties, namely, absorption, distribution, metabolism, and excretion (ADME), and are in accordance with Lipinski's rule of five. The results of this study suggest that these four bioactive molecules, namely, condelphine, denudatine, panicutine, and vilmorrianone, might be effective candidates against COVID-19 and can be further investigated using a number of experimental methods.

Efficacy of a multiple-indication antiviral herbal drug (Saliravira®) for COVID-19 outpatients: A pre-clinical and randomized clinical trial study

Background

The scientific researches on COVID-19 pandemic topics are headed to an explosion of scientific literature. Despite these global efforts, the efficient treatment of patients is an in-progress challenge. Based on a meta-study of published shreds of evidence about compounds and their botanic sources in the last six decades, a novel multiple-indication herbal compound (Saliravira®) has been developed. Based on the antiviral, anti-inflammatory, and immune-enhancing properties of its ingredients, we hypothesized that Saliravira® has the potential to act as an antiviral agent, accelerate treatment, and reduce undesirable effects of COVID-19.

Methods

In this randomized, controlled, open-label clinical trial, COVID-19 outpatients were included by RT-PCR test or diagnosis of physicians according to the symptoms. Participants were randomly divided into intervention and control groups to receive Saliravira® package plus routine treatments of COVID-19 or routine treatments of COVID-19 alone, respectively. Saliravira® package includes tablets, nasal-sinuses spray, oral-pharynx spray, and inhaler drops. The treatment was for 10 days and followed up till 23 days after admission.

Results

On the 8th day, the “mean reduction rates” of viral load of the patients in the intervention group was 50% lower compared to the control group with a p-value < 0.05. The improvement of 10 out of 14 COVID-19 symptoms in the intervention group was significantly accelerated. The mean treatment duration of patients in the intervention group was 4.9 days less than the control group. In addition, no patients in the intervention group were hospitalized compared to 28% of the control group needed to be hospitalized.

Food-Derived Bioactive Molecules from Mediterranean Diet: Nanotechnological Approaches and Waste Valorization as Strategies to Improve Human Wellness

The beneficial effects of the Mediterranean diet (MedDiet), the most widely followed healthy diet in the world, are principally due to the presence in the foods of secondary metabolites, mainly polyphenols, whose healthy characteristics are widely recognized. However, one of the biggest problems associated with the consumption of polyphenols as nutraceutical adjuvant concerns their bioavailability. During the last decades, different nanotechnological approaches have been developed to enhance polyphenol bioavailability, avoiding the metabolic modifications that lead to low absorption, and improving their retention time inside the organisms. This review focuses on the most recent findings regarding the encapsulation and delivery of the bioactive molecules present in the foods daily consumed in the MedDiet such as olive oil, wine, nuts, spice, and herbs. In addition, the possibility of recovering the polyphenols from food waste was also explored, taking into account the increased market demand of functional foods and the necessity to obtain valuable biomolecules at low cost and in high quantity. This circular economy strategy, therefore, represents an excellent approach to respond to both the growing demand of consumers for the maintenance of human wellness and the economic and ecological exigencies of our society.

Biomedical features and therapeutic potential of rosmarinic acid

For decades, the use of secondary metabolites of various herbs has been an attractive strategy in combating human diseases. Rosmarinic acid (RA) is a bioactive phenolic compound commonly found in plants of Lamiaceae and Boraginaceae families. RA is biosynthesized using amino acids tyrosine and phenylalanine via enzyme-catalyzed reactions. However, the chemical synthesis of RA involves an esterification reaction between caffeic acid and 3,4-dihydroxy phenyl lactic acid contributing two phenolic rings to the structure of RA. Several studies have ascertained multiple therapeutic benefits of RA in various diseases, including cancer, diabetes, inflammatory disorders, neurodegenerative disorders, and liver diseases. Many previous scientific papers indicate that RA can be used as an anti-plasmodic, anti-viral and anti-bacterial drug. In addition, due to its high anti-oxidant capacity, this natural polyphenol has recently gained attention for its possible application as a nutraceutical compound in the food industry. Here we provide state-of-the-art, flexible therapeutic potential and biomedical features of RA, its implications and multiple uses. Along with various valuable applications in safeguarding human health, this review further summarizes the therapeutic advantages of RA in various human diseases, including cancer, diabetes, neurodegenerative diseases. Furthermore, the challenges associated with the clinical applicability of RA have also been discussed.