Antiviral Activity of Resveratrol against Human and Animal Viruses

Antiviral Potential and In Silico Insights of Polyphenols as Sustainable Phytopharmaceuticals: A Comprehensive Review

Polyphenols, particularly flavonoids, are reported to have health-promoting, disease-preventing abilities and several polyphenols having a wide spectrum of antiviral activities can be explored for preventive and/or therapeutic purposes. We have compiled the updated literature of diverse polyphenols active against common viral diseases, including herpes, hepatitis, influenza, rota and SARS-corona-viruses. The antiviral activity of bioactive polyphenols depends on the hydroxyl and ester groups of polyphenol molecules, as compounds with five or more hydroxyl groups and three specific methoxy groups showed antiviral potential, like anti-rabies activity. This comprehensive review will explore selective polyphenols isolated from common ethnomedicinal or food plants. Comparing bioactivities of structurally related polyphenols and using bioinformatics studies, we have explored the three most promising phyto-antivirals, including chrysin, resveratrol and quercetin, available in many foods and medicinal plants. Quercetin showed a maximum interaction score with human genes. We also explore the intricate structure-activity relationship between these polyphenols and pathogenic viruses with their mechanisms of antiviral action in selected virus models. Here, we report the promising potential of some phyto-polyphenols in the management of viral diseases through an in-depth analysis of the structure and bioactivity of these compounds.

Fruit quality evaluation of different mulberry varieties

Introduction

The quality of fruits has long been a key focus for breeders, and the development of scientifically sound and reasonable methods for evaluating fruit quality is of great significance in selecting superior cultivars. The mulberry tree, as a plant resource that serves both medicinal and dietary purposes, contains rich nutritional components and various bioactive compounds. These include properties such as immune enhancement, lipid-lowering effects, and anti-tumor activities.

Methods

Therefore, to select mulberry varieties with superior quality and adapt to the diversification trends in mulberry development, this study uses 21 mulberry varieties to analyze and compare differences in fruit appearance quality, nutritional quality, functional components, and antioxidant capacity. Principal Component Analysis (PCA) was employed to identify core evaluation indices, and the Entropy Weight Method was used to assign weights based on these core quality indices. Subsequently, Grey Relational Analysis (GRA) was used for a comprehensive evaluation of the fruit quality of the 21 mulberry varieties.

Results

The results indicate that, in terms of appearance quality, varieties such as 'Ri Ben Guo Sang', 'Hong Guo 1', 'Lv Shen Zi', 'He Lan Sang', and 'Ju Shen' stand out overall. In terms of nutritional quality, 'Tang 10' has relatively higher levels of free amino acids and soluble proteins, but its solid-acid ratio is the lowest, which affects the taste of the fruit. Overall, varieties such as 'Jiang Mi Guo Sang', 'Bai Shen 2', 'Ji Gui Hua', 'Xiao Bai E', 'Da Bai E', and 'Da Yi Bai' stand out in terms of comprehensive quality. Regarding functional components, the four varieties-'Lv Shen Zi', 'Hei Zhen Zhu', 'He Lan Sang', and 'Da 10'-are prominent across all indicators. In terms of antioxidant capacity, 'Jiang Mi Guo Sang', 'Hong Guo 1', 'Xiao Bai E', 'Da Bai E', and 'Da Yi Bai' rank relatively high, which largely overlaps with the varieties selected for their nutritional quality. Regarding fruit enzyme activity, 'Ri Ben Guo Sang', 'Hong Guo 1', 'Lv Shen Zi 1', 'Lv Shen Zi 2', 'He Lan Sang', and 'Da 10' show high enzyme activities. Finally, based on Principal Component Analysis (PCA), the fruit's appearance quality, nutritional quality, functional components, and antioxidant capacity were categorized into seven principal components, covering 12 indicators, with a cumulative variance contribution rate of 88.424%. The Entropy Weight Method was used to assign weights to these 12 indicators, and the final correlation degree was calculated using Grey Relational Analysis (GRA), with a range from 0.406 to 0.817.

Conclusion

This study suggests that varieties such as 'Da 10', 'Feng Guo Sang', 'He Lan Sang', 'Lv Shen Zi', and 'Ri Ben Guo Sang' exhibit superior overall fruit quality and rich nutritional value, providing a theoretical basis for the selection, development, and utilization of future mulberry fruit varieties.

Suppression of virulence factors of uropathogenic Escherichia coli by Trans-resveratrol and design of nanoemulgel

BACKGROUND

Development of multidrug resistance in Uropathogenic Escherichia coli (UPEC) makes treatment of Urinary Tract Infections (UTIs) a major challenge. This study was conducted to investigate the effect of trans-resveratrol (t-RSV) at a subinhibitory concentration (sub-MIC-t-RSV) on phenotypic and genotypic expression of virulence factors of clinical isolates of UPEC and develop a nanoformulation of t-RSV. Fifty-five clinical UPEC strains were investigated for the presence of virulence factors by phenotypic methods and PCR detection of virulence genes. The effect of sub-MIC-t-RSV was studied on the phenotypic and genotypic expression of virulence factors. t-RSV-loaded nanoemulgel formulation was prepared and characterized.

RESULTS

Out of the 55 tested isolates, 50.9% were biofilm producers, 23.6% showed both mannose-sensitive and mannose-resistant hemagglutination, 21.8% were serum-resistant, 18.2% were hemolysin producers, while 36.4% showed cytotoxic effect on HEp-2 cells. A total of 25.5% of the isolates harbor one or more of hly-A, cnf-1 and papC genes, while 54.5% were positive for one or more of fimH, iss and BssS genes. A concentration of 100 µg/mL of t-RSV effectively downregulates the phenotypic and genotypic expression of the virulence factors in positive isolates. A stable t-RSV-nanaoemulgel with droplet size of 180.3 nm and Zetapotential of -46.9 mV was obtained.

CONCLUSION

The study proves the effective role of t-RSV as an antivirulence agent against clinical UPEC isolates in vitro and develops a stable t-RSV-nanoemulgel formulation to be assessed in vivo. The promising antibacterial and antivirulence properties of t-RSV place this natural compound to be a better alternative in the treatment of persistent UTIs.

Resveratrol inhibits rabies virus infection in N2a cells by activating the SIRT1/Nrf2/HO-1 pathway

Rabies is a highly lethal infectious disease with no existing treatment available, thus investigating effective antiviral compounds to control rabies virus (RABV) infection is of utmost importance. Resveratrol is a natural phenolic compound that, as a phytoalexin, exhibits several biological activities, including antiviral activity. In this study, we evaluated the inhibitory effect of resveratrol on RABV infection and investigated its molecular antiviral mechanism. We found that resveratrol significantly inhibited RABV infection, including the phases of adsorption, replication, and release, and also directly inactivated RABV and inhibited its infectivity. However, resveratrol had no significant effect on RABV internalization. Resveratrol also reduced RABV-induced oxidative stress, specifically reactive oxygen species and malondialdehyde levels. Western blotting analysis revealed that resveratrol enhanced antioxidant signaling via the SIRT1/Nrf2/HO-1 pathway and inhibited viral replication. Viral infection was enhanced after SIRT1 knockdown, which inhibited the SIRT1/Nrf2/HO-1 antioxidant signaling pathway, suggesting that this pathway plays an important role in RABV replication. Overall, resveratrol prevented the adsorption, replication, and release of RABV and directly inactivated RABV, but failed to inhibit RABV internalization. Furthermore, resveratrol activated the SIRT1/Nrf2/HO-1 pathway to inhibit RABV replication and suppressed RABV-induced oxidative stress. These findings highlight the therapeutic potential of resveratrol for fighting RABV infections.

Kaempferol as a novel inhibitor of SARS-CoV-2 RNA-dependent RNA polymerase

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has quickly become a global health pandemic. Among the viral proteins, RNA-dependent RNA polymerase (RdRp) is responsible for viral genome replication and has emerged as a promising target against SARS-CoV-2 infection. Dietary bioactive compounds represent an important source of evolutionarily optimized molecules with antiviral properties against SARS-CoV-2 RdRp. We investigated the inhibitory potential effects of different phytochemicals against SARS-CoV-2 RdRp, including andrographolide, kaempferol, resveratrol, and silibinin. Unlike the other investigated compounds, kaempferol exhibited a significant dose-dependent in vitro inhibition of SARS-CoV-2 RdRp activity. To assess the binding interactions and stability of the SARS-CoV-2 RdRp-kaempferol complex, we performed in silico techniques, including molecular docking, quantum chemical calculation, and molecular dynamics simulations. We found strong binding affinities and stability between kaempferol and SARS-CoV-2 RdRp variants (Wuhan and Omicron). These findings provide valuable insights into the antiviral properties of kaempferol as a stable inhibitor of SARS-CoV-2 RdRp.

Effects of Nasal Solution Incorporating Resveratrol and Carboxymethyl-Β-Glucan in Preschool Non-Atopic Children with Wheezing

Upper respiratory tract infections (URTI) account for more than 80% of wheezing episodes in children with a high incidence of hospitalization in preschool age. Most children with symptoms of wheezing during an URTI are usually non-atopic. As the majority of wheezing episodes resulting from URTI are attributed to viral triggers, several studies have suggested the potential anti-inflammatory and antiviral properties of resveratrol. This study aims to identify the effect of resveratrol for pediatric non-atopic patients with recurrent wheezing triggered by URTIs. We conducted a prospective single-blind study to assess the effectiveness of a short course of nasal solutions incorporating resveratrol and carboxymethyl-β-glucan, administered for 7 days at the onset of URTIs, compared to standard nasal lavage with 0.9% saline solution. A total of 19 patients entered the active group, 20 patients were assigned to the placebo group. The comparison of overall wheezing days (p < 0.001), mean wheezing days per month (p < 0.01), and wheezing episodes per patient (p < 0.001) in the two groups showed a significant reduction in the group receiving resveratrol compared with the placebo group, with less hospital access (p < 0.001) and oral corticosteroid administration (p < 0.01). Our findings seem to suggest that, in non-atopic children with recurrent wheezing secondary to URTIs, nasal resveratrol could be effective to prevent or reduce the occurrence of wheezing, when started from the onset of upper airway symptoms.

Enhancing the Bioavailability of Resveratrol: Combine It, Derivatize It, or Encapsulate It?

Overcoming the limited bioavailability and extensive metabolism of effective in vitro drugs remains a challenge that limits the translation of promising drugs into clinical trials. Resveratrol, despite its well-reported therapeutic benefits, is not metabolically stable and thus has not been utilized as an effective clinical drug. This is because it needs to be consumed in large amounts to overcome the burdens of bioavailability and conversion into less effective metabolites. Herein, we summarize the more relevant approaches to modify resveratrol, aiming to increase its biological and therapeutic efficacy. We discuss combination therapies, derivatization, and the use of resveratrol nanoparticles. Interestingly, the combination of resveratrol with established chemotherapeutic drugs has shown promising therapeutic effects on colon cancer (with oxaliplatin), liver cancer (with cisplatin, 5-FU), and gastric cancer (with doxorubicin). On the other hand, derivatizing resveratrol, including hydroxylation, amination, amidation, imidation, methoxylation, prenylation, halogenation, glycosylation, and oligomerization, differentially modifies its bioavailability and could be used for preferential therapeutic outcomes. Moreover, the encapsulation of resveratrol allows its trapping within different forms of shells for targeted therapy. Depending on the nanoparticle used, it can enhance its solubility and absorption, increasing its bioavailability and efficacy. These include polymers, metals, solid lipids, and other nanoparticles that have shown promising preclinical results, adding more "hype" to the research on resveratrol. This review provides a platform to compare the different approaches to allow directed research into better treatment options with resveratrol.

Recent Developments in Nanoparticle Formulations for Resveratrol Encapsulation as an Anticancer Agent

Resveratrol is a polyphenolic compound that has gained considerable attention in the past decade due to its multifaceted therapeutic potential, including anti-inflammatory and anticancer properties. However, its anticancer efficacy is impeded by low water solubility, dose-limiting toxicity, low bioavailability, and rapid hepatic metabolism. To overcome these hurdles, various nanoparticles such as organic and inorganic nanoparticles, liposomes, polymeric nanoparticles, dendrimers, solid lipid nanoparticles, gold nanoparticles, zinc oxide nanoparticles, zeolitic imidazolate frameworks, carbon nanotubes, bioactive glass nanoparticles, and mesoporous nanoparticles were employed to deliver resveratrol, enhancing its water solubility, bioavailability, and efficacy against various types of cancer. Resveratrol-loaded nanoparticle or resveratrol-conjugated nanoparticle administration exhibits excellent anticancer potency compared to free resveratrol. This review highlights the latest developments in nanoparticle-based delivery systems for resveratrol, focusing on the potential to overcome limitations associated with the compound's bioavailability and therapeutic effectiveness.

Insights into the Therapeutic and Pharmacological Properties of Resveratrol as a Nutraceutical Antioxidant Polyphenol in Health Promotion and Disease Prevention

Resveratrol (3, 5, 4'-trihydroxystilbene) is a polyphenolic derivative with herbal origin. It has attracted considerable attention in recent decades. Many studies have revealed the benefits of Resveratrol over several human disease models, including heart and neurological diseases, nephroprotective, immune regulation, antidiabetic, anti-obesity, age-related diseases, antiviral, and anticancer in experimental and clinical conditions. Recently, the antioxidant and anti-inflammatory activities of Resveratrol have been observed, and it has been shown that Resveratrol reduces inflammatory biomarkers, such as tissue degradation factor, cyclooxygenase 2, nitric oxide synthase, and interleukins. All of these activities appear to be dependent on its structural properties, such as the number and position of the hydroxyl group, which regulates oxidative stress, cell death, and inflammation. Resveratrol is well tolerated and safe even at higher pharmacological doses and desirably affects cardiovascular, neurological, and diabetic diseases. Consequently, it is plausible that Resveratrol can be regarded as a beneficial nutritional additive and a complementary drug, particularly for therapeutic applications. The present review provides an overview of currently available investigations on preventive and therapeutic characteristics and the main molecular mechanisms of Resveratrol and its potent derivatives in various diseases. Thus, this review would enhance knowledge and information about Resveratrol and encourage researchers worldwide to consider it as a pharmaceutical drug to struggle with future health crises against different human disorders.

The Pharmacological Properties of Red Grape Polyphenol Resveratrol: Clinical Trials and Obstacles in Drug Development

Resveratrol is a stilbenoid from red grapes that possesses a strong antioxidant activity. Resveratrol has been shown to have anticancer activity, making it a promising drug for the treatment and prevention of numerous cancers. Several in vitro and in vivo investigations have validated resveratrol's anticancer capabilities, demonstrating its ability to block all steps of carcinogenesis (such as initiation, promotion, and progression). Additionally, resveratrol has been found to have auxiliary pharmacological effects such as anti-inflammatory, cardioprotective, and neuroprotective activity. Despite its pharmacological properties, several obstacles, such as resveratrol's poor solubility and bioavailability, as well as its adverse effects, continue to be key obstacles to drug development. This review critically evaluates the clinical trials to date and aims to develop a framework to develop resveratrol into a clinically viable drug.

Exploiting the potential of natural polyphenols as antivirals against monkeypox envelope protein F13 using machine learning and all-atoms MD simulations

The re-emergence of monkeypox (MPX), in the era of COVID-19 pandemic is a new global menace. Regardless of its leniency, there are chances of MPX expediting severe health deterioration. The role of envelope protein, F13 as a critical component for production of extracellular viral particles makes it a crucial drug target. Polyphenols, exhibiting antiviral properties have been acclaimed as an effective alternative to the traditional treatment methods for management of viral diseases. To facilitate the development of potent MPX specific therapeutics, herein, we have employed state-of-the-art machine learning techniques to predict a highly accurate 3-dimensional structure of F13 as well as identify binding hotspots on the protein surface. Additionally, we have effectuated high-throughput virtual screening methodology on 57 potent natural polyphenols having antiviral activities followed by all-atoms molecular dynamics (MD) simulations, to substantiate the mode of interaction of F13 protein and polyphenol complexes. The structure-based virtual screening based on Glide SP, XP and MM/GBSA scores enables the selection of six potent polyphenols having higher binding affinity towards F13. Non-bonded contact analysis, of pre- and post- MD complexes propound the critical role of Glu143, Asp134, Asn345, Ser321 and Tyr320 residues in polyphenol recognition, which is well supported by per-residue decomposition analysis. Close-observation of the structural ensembles from MD suggests that the binding groove of F13 is mostly hydrophobic in nature. Taken together, this structure-based analysis from our study provides a lead on Myricetin, and Demethoxycurcumin, which may act as potent inhibitors of F13. In conclusion, our study provides new insights into the molecular recognition and dynamics of F13-polyphenol bound states, offering new promises for development of antivirals to combat monkeypox. However, further in vitro and in vivo experiments are necessary to validate these results.

Target specific inhibition of West Nile virus envelope glycoprotein and methyltransferase using phytocompounds: an in silico strategy leveraging molecular docking and dynamics simulation

Mosquitoes are the primary vector for West Nile virus, a flavivirus. The virus's ability to infiltrate and establish itself in increasing numbers of nations has made it a persistent threat to public health worldwide. Despite the widespread occurrence of this potentially fatal disease, no effective treatment options are currently on the market. As a result, there is an immediate need for the research and development of novel pharmaceuticals. To begin, molecular docking was performed on two possible West Nile virus target proteins using a panel of twelve natural chemicals, including Apigenin, Resveratrol, Hesperetin, Fungisterol, Lucidone, Ganoderic acid, Curcumin, Kaempferol, Cholic acid, Chlorogenic acid, Pinocembrin, and Sanguinarine. West Nile virus methyltransferase (PDB ID: 2OY0) binding affinities varied from -7.4 to -8.3 kcal/mol, whereas West Nile virus envelope glycoprotein affinities ranged from -6.2 to -8.1 kcal/mol (PDB ID: 2I69). Second, substances with larger molecular weights are less likely to be unhappy with the Lipinski rule. Hence, additional research was carried out without regard to molecular weight. In addition, compounds 01, 02, 03, 05, 06, 07, 08, 09, 10 and 11 are more soluble in water than compound 04 is. Besides, based on maximum binding affinity, best three compounds (Apigenin, Curcumin, and Ganoderic Acid) has been carried out molecular dynamic simulation (MDs) at 100 ns to determine their stability. The MDs data is also reported that these mentioned molecules are highly stable. Finally, advanced principal component analysis (PCA), dynamics cross-correlation matrices (DCCM) analysis, binding free energy and dynamic cross correlation matrix (DCCM) theoretical study is also included to established mentioned phytochemical as a potential drug candidate. Research has indicated that the aforementioned natural substances may be an effective tool in the battle against the dangerous West Nile virus. This study aims to locate a bioactive natural component that might be used as a pharmaceutical.

Resveratrol Attenuates the Mitochondrial RNA-Mediated Cellular Response to Immunogenic Stress

Human mitochondria contain a circular genome that encodes 13 subunits of the oxidative phosphorylation system. In addition to their role as powerhouses of the cells, mitochondria are also involved in innate immunity as the mitochondrial genome generates long double-stranded RNAs (dsRNAs) that can activate the dsRNA-sensing pattern recognition receptors. Recent evidence shows that these mitochondrial dsRNAs (mt-dsRNAs) are closely associated with the pathogenesis of human diseases that accompany inflammation and aberrant immune activation, such as Huntington's disease, osteoarthritis, and autoimmune Sjögren's syndrome. Yet, small chemicals that can protect cells from a mt-dsRNA-mediated immune response remain largely unexplored. Here, we investigate the potential of resveratrol (RES), a plant-derived polyphenol with antioxidant properties, on suppressing mt-dsRNA-mediated immune activation. We show that RES can revert the downstream response to immunogenic stressors that elevate mitochondrial RNA expressions, such as stimulation by exogenous dsRNAs or inhibition of ATP synthase. Through high-throughput sequencing, we find that RES can regulate mt-dsRNA expression, interferon response, and other cellular responses induced by these stressors. Notably, RES treatment fails to counter the effect of an endoplasmic reticulum stressor that does not affect the expression of mitochondrial RNAs. Overall, our study demonstrates the potential usage of RES to alleviate the mt-dsRNA-mediated immunogenic stress response.

Channel activity of SARS-CoV-2 viroporin ORF3a inhibited by adamantanes and phenolic plant metabolites

SARS-CoV-2 has been responsible for the major worldwide pandemic of COVID-19. Despite the enormous success of vaccination campaigns, virus infections are still prevalent and effective antiviral therapies are urgently needed. Viroporins are essential for virus replication and release, and are thus promising therapeutic targets. Here, we studied the expression and function of recombinant ORF3a viroporin of SARS-CoV-2 using a combination of cell viability assays and patch-clamp electrophysiology. ORF3a was expressed in HEK293 cells and transport to the plasma membrane verified by a dot blot assay. Incorporation of a membrane-directing signal peptide increased plasma membrane expression. Cell viability tests were carried out to measure cell damage associated with ORF3a activity, and voltage-clamp recordings verified its channel activity. The classical viroporin inhibitors amantadine and rimantadine inhibited ORF3a channels. A series of ten flavonoids and polyphenolics were studied. Kaempferol, quercetin, epigallocatechin gallate, nobiletin, resveratrol and curcumin were ORF3a inhibitors, with IC₅₀ values ranging between 1 and 6 µM, while 6-gingerol, apigenin, naringenin and genistein were inactive. For flavonoids, inhibitory activity could be related to the pattern of OH groups on the chromone ring system. Thus, the ORF3a viroporin of SARS-CoV-2 may indeed be a promising target for antiviral drugs.

Effectiveness of Apigenin, Resveratrol, and Curcumin as Adjuvant Nutraceuticals for Calvarial Bone Defect Healing: An In Vitro and Histological Study on Rats

Bone healing is a major clinical issue, especially in bone defects of critical dimensions. Some studies have reported in vivo positive effects on bone healing by some bioactive compounds, such as the phenolic derivatives found in vegetables and plants, such as resveratrol, curcumin, and apigenin. The aim of this work was (1) to analyze in vitro in human dental pulp stem cells the effects of these three natural compounds on the gene expression of related genes downstream to RUNX2 and SMAD5, key factor transcriptions associated with osteoblast differentiation, in order to better understand the positive effects that can occur in vivo in bone healing, and (2) to evaluate in vivo the effects on bone healing of critical-size defects in the calvaria in rats of these three nutraceuticals tested in parallel and for the first time administered by the gastric route. Upregulation of the RUNX2, SMAD5, COLL1, COLL4, and COLL5 genes in the presence of apigenin, curcumin, and resveratrol was detected. In vivo, apigenin induced more consistent significant bone healing in critical-size defects in rat calvaria compared to the other study groups. The study findings encourage a possible therapeutic supplementation with nutraceuticals during the bone regeneration process.

Sources of Antifungal Drugs

Due to their eukaryotic heritage, the differences between a fungal pathogen's molecular makeup and its human host are small. Therefore, the discovery and subsequent development of novel antifungal drugs are extremely challenging. Nevertheless, since the 1940s, researchers have successfully uncovered potent candidates from natural or synthetic sources. Analogs and novel formulations of these drugs enhanced the pharmacological parameters and improved overall drug efficiency. These compounds ultimately became the founding members of novel drug classes and were successfully applied in clinical settings, offering valuable and efficient treatment of mycosis for decades. Currently, only five different antifungal drug classes exist, all characterized by a unique mode of action; these are polyenes, pyrimidine analogs, azoles, allylamines, and echinocandins. The latter, being the latest addition to the antifungal armamentarium, was introduced over two decades ago. As a result of this limited arsenal, antifungal resistance development has exponentially increased and, with it, a growing healthcare crisis. In this review, we discuss the original sources of antifungal compounds, either natural or synthetic. Additionally, we summarize the existing drug classes, potential novel candidates in the clinical pipeline, and emerging non-traditional treatment options.

Suppression of porcine hemagglutinating encephalomyelitis virus replication by resveratrol

BACKGROUND

Porcine hemagglutinating encephalomyelitis virus (PHEV), a member of the genus Betacoronavirus, is the causative agent of neurological disease in pigs. No effective therapeutics are currently available for PHEV infection. Resveratrol has been shown to exert neuroprotective and antiviral effects. Here resveratrol was investigated for its ability to inhibit PHEV replication in nerve cells and central nervous system tissues.

METHODS

Anti-PHEV effect of resveratrol was evaluated using an in vitro cell-based PHEV infection model and employing a mouse PHEV infection model. The collected cells or tissues were used for quantitative PCR analysis, western blot analysis, or indirect immunofluorescence assay. The supernatants were collected to quantify viral loads by TCID₅₀ assay in vitro. EC50 and CC50 were determined by dose-response experiments, and the ratio (EC50/CC50) was used as a selectivity index (SI) to measure the antiviral versus cytotoxic activity.

RESULTS

Our results showed that resveratrol treatment reduced PHEV titer in a dose-dependent manner, with a 50% inhibition concentration of 6.24 μM. A reduction of > 70% of viral protein expression and mRNA copy number and a 19-fold reduction of virus titer were achieved when infected cells were treated with 10 µM resveratrol in a pre-treatment assay. Quantitative PCR analysis and TCID₅₀ assay results revealed that the addition of 10 μM resveratrol to cells after adsorption of PHEV significantly reduced 56% PHEV mRNA copy number and eightfold virus titer. 10 µM resveratrol treatment reduced 46% PHEV mRNA copy number and fourfold virus titer in virus inactivation assay. Moreover, the in vivo data obtained in this work also demonstrated that resveratrol inhibited PHEV replication, and anti-PHEV activities of resveratrol treatment via intranasal installation displayed better than oral gavage.

CONCLUSION

These results indicated that resveratrol exerted antiviral effects under various drug treatment and virus infection conditions in vitro and holds promise as a treatment for PHEV infection in vivo.

An Alternative Source of Biopesticides and Improvement in Their Formulation-Recent Advances

Plant protection in contemporary agriculture requires intensive pesticide application. Their use has enabled the increase in yields, simplifying cultivation systems and crop protection strategies, through successful control of harmful organisms. However, it has led to the accumulation of pesticides in agricultural products and the environment, contaminating the ecosystem and causing adverse health effects. Therefore, finding new possibilities for plant protection and effective control of pests without consequences for humans and the environment is imperative for agricultural production. The most important alternatives to the use of chemical plant protection products are biopesticides. However, in order to increase their application and availability, it is necessary to improve efficacy and stability through new active substances and improved formulations. This paper represents an overview of the recent knowledge in the field of biopesticides and discusses the possibilities of the use of some new active substances and the improvement of formulations.

Seabirds under environmental pressures: Food supplementation has a larger impact than selenium on chicks exposed to mercury and a viral disease

Although infectious disease outbreaks represent a serious threat for wildlife population viability, the environmental factors that underlie such outbreaks are poorly investigated. The French Guiana breeding population of Magnificent frigatebird Fregata magnificens is subjected to recurrent episodes of chicks’ mortality likely caused by a viral disease. We hypothesized that high mercury (Hg) concentrations may be responsible for the emergence of clinical signs. We therefore investigated whether healthy and sick chicks show different Hg concentrations in blood. Because the essential element selenium (Se) may be highly depleted during Hg poisoning, we further experimentally tested whether an increased intake of dietary Se has an effect on blood levels of Hg, increases circulating Se, and improves the oxidative status of chicks. Finally, we compared the results of this experiment with a previous food supplementation experiment. Our results show similar Hg concentrations between healthy and sick chicks with visible clinical signs of the disease. Se concentrations were significantly depleted in sick chicks. Se concentrations increased while Hg concentrations simultaneously decreased in chicks that naturally recovered from the disease. Both the Se and fish supplementation experiments significantly increased Se concentrations in blood, while Hg levels were only modestly affected. Providing food to chicks appeared to have greater benefits than only supplementing chicks with Se pills as, although food supplementation had an impact on blood Se similar to that of supplementation with Se pills, it also reduced the vulnerability of chicks to the viral disease, possibly by reducing nutritional stress and providing essential nutrients.

Phytochemicals in the Prevention and Treatment of SARS-CoV-2-Clinical Evidence

The first case of SARS-CoV-2 infection was reported in December 2019. Due to the rapid spread of the disease and the lack of adequate therapy, the use of plants that have a long history in the treatment of viral infections has often been considered. The aim of this paper is to provide a brief review of the literature on the use of phytochemicals during the new pandemic. An extensive search of published works was performed through platforms Google Scholar, PubMed, Science Direct, Web of Science and Clinicaltrials.gov. Numerous preclinical studies on the use of phytochemicals (quercetin, curcumin, baicalin, kaempferol, resveratrol, glycyrrhizin, lycorine, colchicine) against SARS-CoV-2 have shown that these components can be effective in the prevention and treatment of this infection. Clinical research has proven that the use of black cumin and green propolis as well as quercetin has positive effects. As for other phytochemicals, in addition to preclinical testing which has already been carried out, it would be necessary to conduct clinical tests in order to assert their effectiveness. For those phytochemicals whose clinical efficacy has been proven, it would be necessary to conduct research on a larger number of patients, so that the conclusions are more representative.

Insights into Antiviral Properties and Molecular Mechanisms of Non-Flavonoid Polyphenols against Human Herpesviruses

Herpesviruses are one of the most contagious DNA viruses that threaten human health, causing severe diseases, including, but not limited to, certain types of cancer and neurological complications. The overuse and misuse of anti-herpesvirus drugs are key factors leading to drug resistance. Therefore, targeting human herpesviruses with natural products is an attractive form of therapy, as it might improve treatment efficacy in therapy-resistant herpesviruses. Plant polyphenols are major players in the health arena as they possess diverse bioactivities. Hence, in this article, we comprehensively summarize the recent advances that have been attained in employing plant non-flavonoid polyphenols, such as phenolic acids, tannins and their derivatives, stilbenes and their derivatives, lignans, neolignans, xanthones, anthraquinones and their derivatives, curcuminoids, coumarins, furanocoumarins, and other polyphenols (phloroglucinol) as promising anti-herpesvirus drugs against various types of herpesvirus such as alpha-herpesviruses (herpes simplex virus type 1 and 2 and varicella-zoster virus), beta-herpesviruses (human cytomegalovirus), and gamma-herpesviruses (Epstein-Barr virus and Kaposi sarcoma-associated herpesvirus). The molecular mechanisms of non-flavonoid polyphenols against the reviewed herpesviruses are also documented.

Anti-hepatitis B virus activity of food nutrients and potential mechanisms of action

Hepatitis B virus (HBV) is endemic in many parts of the world and is a significant cause of chronic liver damage and hepatocellular carcinoma. HBV therapeutics vary according to the disease stage. The best therapeutic option for patients with end-stage liver disease is liver transplantation, while for chronic patients, HBV infection is commonly managed using antivirals (nucleos(t)ides analogs or interferons). However, due to the accessibility issues and the high cost of antivirals, most HBV patients do not have access to treatment. These complications have led researchers to reconsider treatment approaches, such as nutritional therapy. This review summarizes the nutrients reported to have antiviral activity against HBV and their possible mechanism of action. Recent studies suggest resveratrol, vitamin E, lactoferrin, selenium, curcumin, luteolin-7-O-glucoside, moringa extracts, chlorogenic acid, and epigallocatechin-3-gallate may be beneficial for patients with hepatitis B. The anti-HBV effect of most of these nutrients has been analyzed in vitro and in animal models. Different antiviral and hepatoprotective mechanisms have been proposed for these nutrients, such as the activation of antioxidant and anti-inflammatory pathways, regulation of metabolic homeostasis, epigenetic control, activation of the p53 gene, inhibition of oncogenes, inhibition of virus entry, and induction of autophagosomes. In conclusion, scientific evidence indicates that HBV replication, transcription, and expression of viral antigens can be affected directly by nutrients. In the future, these nutrients may be considered to develop appropriate nutritional management for patients with hepatitis B.

Synergistic delivery of resveratrol and ultrasmall copper-based nanoparticles by aptamer-functionalized ultrasound nanobubbles for the treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is related to the production of reactive oxygen species (ROS) and oxidative stress, so antioxidant treatment can prevent its further development. Ultrasmall copper-based nanoparticles (CuNPs) have shown multiple enzyme-like activities for scavenging oxygen species, providing a new strategy for the treatment of inflammatory diseases. Resveratrol (Res), a natural polyphenol compound, has attracted much attention due to its ability to inhibit oxidative stress. We therefore aimed to first combine these two agents for the treatment of NAFLD. However, due to the poor water solubility and stability of Res, which is easily metabolized in the intestine, the development of a stable and effective carrier became the key to achieving a synergistic effect. Liver-targeted nanocarriers loaded with bioactive compounds may provide a more effective approach for the treatment of NAFLD. Therefore, we developed a novel ultrasonic nanobubble carrying nucleic acid aptamers with liver targeting properties, which has the advantages of a small molecular weight, no immunogenicity, a low cost of synthesis, and high stability through chemical modification. Res and the ultrasmall CuNPs were specifically delivered to liver tissue to maximize therapeutic efficiency. This study found that the combination of these two components can effectively treat inflammation in NAFLD and suggested that liver-targeted NAFLD-specific aptamer-mediated targeted ultrasound nanobubbles that can simultaneously deliver Res and CuNPs may be a safe and effective new platform for NAFLD and other liver diseases.

Effects of resveratrol topical ointment on wound healing of full-thickness cutaneous burns in albino rats

OBJECTIVE

In this study, the effects of resveratrol topical ointment on wound contraction and histopathology of full-thickness cutaneous burn wounds were evaluated.

METHOD

Adult albino rats were grouped into four equal-sized groups of 15 rats each, as follows: Group A-no wound, no treatment (control); Group B-1% silver sulphadiazine; Group C-5% resveratrol, and Group D-wound without treatment (control). A burn wound measuring 23.5mm was created on the skin at the dorsum of all rats in groups B-D after shaving. The percentage of wound contraction was measured using a digital Vernier Caliper on days 1, 3, 5, 7, 10, 14, 16, 18 and 21, post-wounding. From each group, five rats were then euthanised and tissue samples of the skin, liver and kidney were collected in 10% buffered formalin for histopathology.

RESULTS

The percentage of wound contraction was significant (p<0.05) on 7, 14 and 18 days post treatment. Histopathologically, 5% resveratrol topical ointment application resulted in a thicker epidermis with neovascularisation and an increased collagen distribution. Resveratrol topical ointment ameliorated the extent of hepatocellular and nephrotubular injuries following burn-induced hepatocellular and acute kidney injuries.

CONCLUSION

In this study, topical application of 5% resveratrol ointment appeared to enhance burn wound healing by increasing the rate of wound contraction through collagen fibre synthesis, granulation tissue formation and epithelial regeneration.

Effects of Resveratrol, Curcumin and Quercetin Supplementation on Bone Metabolism—A Systematic Review

Phenolic compounds are natural phytochemicals that have recently reported numerous health benefits. Resveratrol, curcumin, and quercetin have recently received the most attention among these molecules due to their documented antioxidant effects. The review aims to investigate the effects of these molecules on bone metabolism and their role in several diseases such as osteopenia and osteoporosis, bone tumours, and periodontitis. The PubMed/Medline, Web of Science, Google Scholar, Scopus, Cochrane Library, and Embase electronic databases were searched for papers in line with the study topic. According to an English language restriction, the screening period was from January 2012 to 3 July 2022, with the following Boolean keywords: (“resveratrol” AND “bone”); (“curcumin” AND “bone”); (“quercetin” AND “bone”). A total of 36 papers were identified as relevant to the purpose of our investigation. The studies reported the positive effects of the investigated phenolic compounds on bone metabolism and their potential application as adjuvant treatments for osteoporosis, bone tumours, and periodontitis. Furthermore, their use on the titanium surfaces of orthopaedic prostheses could represent a possible application to improve the osteogenic processes and osseointegration. According to the study findings, resveratrol, curcumin, and quercetin are reported to have a wide variety of beneficial effects as supplement therapies. The investigated phenolic compounds seem to positively mediate bone metabolism and osteoclast-related pathologies.

Nitrostilbenes: Synthesis and Biological Evaluation as Potential Anti-Influenza Virus Agents

Resveratrol (RSV) is a natural stilbene polyphenolic compound found in several plant species. It is characterized by antioxidant properties, and its role in controlling viral replication has been demonstrated for different viral infections. Despite its promising antiviral properties, RSV biological activity is limited by its low bioavailability and high metabolic rate. In this study, we optimized its structure by synthesizing new RSV derivatives that maintained the phenolic scaffold and contained different substitution patterns and evaluated their potential anti-influenza virus activity. The results showed that viral protein synthesis decreased 24 h post infection; particularly, the nitro-containing compounds strongly reduced viral replication. The molecules did not exert their antioxidant properties during infection; in fact, they were not able to rescue the virus-induced drop in GSH content or improve the antioxidant response mediated by the Nrf2 transcription factor and G6PD enzyme. Similar to what has already been reported for RSV, they interfered with the nuclear-cytoplasmic traffic of viral nucleoprotein, probably inhibiting cellular kinases involved in the regulation of specific steps of the virus life cycle. Overall, the data indicate that more lipophilic RSV derivatives have improved antiviral efficacy compared with RSV and open the way for new cell-targeted antiviral strategies.

Cavernous Sinus Involvement and Near Miss Mediastinitis following Mandibular Tooth Infection Treated during the COVID-19 Pandemic: Clinical Diagnosis and Treatment

Odontogenic infections represent a frequent condition that in some cases, if not treated promptly, can spread quickly to the rest of the body and turn into life-threatening infections. In this work, the case is reported of a 59-year-old woman, diabetic and overweight, who presented to the Odontostomatology and Otolaryngology Section of the Policlinic of Bari with mandibular tooth infection that had developed into a deep neck space infection leading to the involvement of cavernous sinuses and near mediastinum. The diagnosis, the surgical drainage of the phlegmon and removal of infection foci, appropriate control of the airways, and a correct antibiotic therapy made it possible to avoid a potentially fatal condition. Prompt management and early diagnosis of deep space neck infections, such as phlegmon and/or necrotizing fasciitis, with the auxilium of CT scans and tools such as LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis), NLR (Neutrophil-to-Lymphocyte Ratio), and LRINECxNLR scores (Laboratory Risk Indicator for Necrotizing Fasciitis and Neutrophil to Lymphocyte Ratio), are advised to evade delays and complications that could potentially worsen the patient’s outcome.

From the forest to the plate - Hemicelluloses, galactoglucomannan, glucuronoxylan, and phenolic-rich extracts from unconventional sources as functional food ingredients

This study aimed to characterise pressurised hot water (PHW) extracts from nonconventional sources of functional carbohydrates and phenolic compounds in terms of antioxidant capacity, antiviral activity, toxicity, and human erythrocytes' protection antidiabetic potential. PHW extracts of Norway spruce bark (E1 + E2) and Birch sawdust (E3 + E4) contained mostly galactoglucomannan and glucuronoxylan. In contrast, samples E5 to E9 PHW extracted from Norway spruce, and Scots pine bark are rich sources of phenolic compounds. Overall, phenolic-rich extracts presented the highest inhibition of α-amylase and α-glucosidase and protection against stable non-enveloped enteroviruses. Additionally, all extracts protected human erythrocytes from hemolysis. Cell-based experiments using human cell lines (IMR90 and A549) showed extracts' non-toxicin vitroprofile. Considering the relative toxicological safety of extracts from these unconventional sources, functional carbohydrates and polyphenol-rich extracts can be obtained and further used in food models.

Randomized double-blind placebo-controlled proof-of-concept trial of resveratrol for outpatient treatment of mild coronavirus disease (COVID-19)

Resveratrol is a polyphenol that has been well studied and has demonstrated anti-viral and anti-inflammatory properties that might mitigate the effects of COVID-19. Outpatients (N = 105) were recruited from central Ohio in late 2020. Participants were randomly assigned to receive placebo or resveratrol. Both groups received a single dose of Vitamin D3 which was used as an adjunct. The primary outcome measure was hospitalization within 21 days of symptom onset; secondary measures were ER visits, incidence of pneumonia, and incidence of pulmonary embolism. Five patients chose not to participate after randomization. Twenty-one-day outcome was determined of all one hundred participants (mean [SD] age 55.6 [8.8] years; 61% female). There were no clinically significant adverse events attributed to resveratrol. Outpatients in this phase 2 study treated with resveratrol had a lower incidence compared to placebo of: hospitalization (2% vs. 6%, RR 0.33, 95% CI 0.04-3.10), COVID-19 related ER visits (8% vs. 14%, RR 0.57, 95% CI 0.18-1.83), and pneumonia (8% vs. 16%, RR 0.5, 95% CI 0.16-1.55). One patient (2%) in each group developed pulmonary embolism (RR 1.00, 95% CI: 0.06-15.55). This underpowered study was limited by small sample size and low incidence of primary adverse events consequently the results are statistically similar between treatment arms. A larger trial could determine efficacy.Trial Registrations: ClinicalTrials.gov NCT04400890 26/05/2020; FDA IND #150033 05/05/2020.

Nanoparticles Loaded with Docetaxel and Resveratrol as an Advanced Tool for Cancer Therapy

A growing interest in the use of a combination of chemosensitizers and cytostatics for overcoming cancer resistance to treatment and the development of their delivery systems has been observed. Resveratrol (Res) presents antioxidant, anti-inflammatory and chemopreventive properties but also limits multidrug resistance against docetaxel (Dtx), which is one of the main causes of failure in cancer therapy with this drug. However, the use of both drugs presents challenges, including poor bioavailability, the unfavourable pharmacokinetics and chemical instability of Res and the poor water solubility and dose-limiting toxicity of Dtx. In order to overcome these difficulties, attempts have been made to create different forms of delivery for both agents. This review is focused on the latest developments in nanoparticles for the delivery of Dtx, Res and for the combined delivery of those two drugs. The aim of this review was also to summarize the synergistic mechanism of action of Dtx and Res on cancer cells. According to recent reports, Dtx and Res loaded in a nano-delivery system exhibit better efficiency in cancer treatment compared to free drugs. Also, the co-delivery of Dtx and Res in one actively targeted delivery system providing the simultaneous release of both drugs in cancer cells has a chance to fulfil the requirements of effective anticancer therapy and reduce limitations in therapy caused by multidrug resistance (MDR).

The Importance of Nutraceuticals in COVID-19: What's the Role of Resveratrol?

Since COVID-19 has affected global public health, there has been an urgency to find a solution to limit both the number of infections, and the aggressiveness of the disease once infected. The main characteristic of this infection is represented by a strong alteration of the immune system which, day by day, increases the risk of mortality, and can lead to a multiorgan dysfunction. Because nutritional profile can influence patient’s immunity, we focus our interest on resveratrol, a polyphenolic compound known for its immunomodulating and anti-inflammatory properties. We reviewed all the information concerning the different roles of resveratrol in COVID-19 pathophysiology using PubMed and Scopus as the main databases. Interestingly, we find out that resveratrol may exert its role through different mechanisms. In fact, it has antiviral activity inhibiting virus entrance in cells and viral replication. Resveratrol also improves autophagy and decreases pro-inflammatory agents expression acting as an anti-inflammatory agent. It regulates immune cell response and pro-inflammatory cytokines and prevents the onset of thrombotic events that usually occur in COVID-19 patients. Since resveratrol acts through different mechanisms, the effect could be enhanced, making a totally natural agent particularly effective as an adjuvant in anti COVID-19 therapy.

Benefits and Implications of Resveratrol Supplementation on Microbiota Modulations: A Systematic Review of the Literature

Resveratrol is a polyphenol that has been shown to possess many applications in different fields of medicine. This systematic review has drawn attention to the axis between resveratrol and human microbiota, which plays a key role in maintaining an adequate immune response that can lead to different diseases when compromised. Resveratrol can also be an asset in new technologies, such as gene therapy. PubMed, Cochrane Library, Scopus, Web of Science, and Google Scholar were searched to find papers that matched our topic dating from 1 January 2017 up to 18 January 2022, with English-language restriction using the following Boolean keywords: ("resveratrol" AND "microbio*"). Eighteen studies were included as relevant papers matching the purpose of our investigation. Immune response, prevention of thrombotic complications, microbiota, gene therapy, and bone regeneration were retrieved as the main topics. The analyzed studies mostly involved resveratrol supplementation and its effects on human microbiota by trials in vitro, in vivo, and ex vivo. The beneficial activity of resveratrol is evident by analyzing the changes in the host's genetic expression and the gastrointestinal microbial community with its administration. The possibility of identifying individual microbial families may allow to tailor therapeutic plans with targeted polyphenolic diets when associated with microbial dysbiosis, such as inflammatory diseases of the gastrointestinal tract, degenerative diseases, tumors, obesity, diabetes, bone tissue regeneration, and metabolic syndrome.

Dietary Polyphenols and Their Role in Oxidative Stress-Induced Human Diseases: Insights Into Protective Effects, Antioxidant Potentials and Mechanism(s) of Action

Dietary polyphenols including phenolic acids, flavonoids, catechins, tannins, lignans, stilbenes, and anthocyanidins are widely found in grains, cereals, pulses, vegetables, spices, fruits, chocolates, and beverages like fruit juices, tea, coffee and wine. In recent years, dietary polyphenols have gained significant interest among researchers due to their potential chemopreventive/protective functions in the maintenance of human health and diseases. It is believed that dietary polyphenols/flavonoids exert powerful antioxidant action for protection against reactive oxygen species (ROS)/cellular oxidative stress (OS) towards the prevention of OS-related pathological conditions or diseases. Pre-clinical and clinical evidence strongly suggest that long term consumption of diets rich in polyphenols offer protection against the development of various chronic diseases such as neurodegenerative diseases, cardiovascular diseases (CVDs), cancer, diabetes, inflammatory disorders and infectious illness. Increased intake of foods containing polyphenols (for example, quercetin, epigallocatechin-3-gallate, resveratrol, cyanidin etc.) has been claimed to reduce the extent of a majority of chronic oxidative cellular damage, DNA damage, tissue inflammations, viral/bacterial infections, and neurodegenerative diseases. It has been suggested that the antioxidant activity of dietary polyphenols plays a pivotal role in the prevention of OS-induced human diseases. In this narrative review, the biological/pharmacological significance of dietary polyphenols in the prevention of and/or protection against OS-induced major human diseases such as cancers, neurodegenerative diseases, CVDs, diabetes mellitus, cancer, inflammatory disorders and infectious diseases have been delineated. This review specifically focuses a current understanding on the dietary sources of polyphenols and their protective effects including mechanisms of action against various major human diseases.

A Mechanistic Review on Plant-derived Natural Inhibitors of Human Coronaviruses with Emphasis on SARS-COV-1 and SARS-COV-2

Coronaviruses have been receiving continuous attention worldwide as they have caused a serious threat to global public health. This group of viruses is named so as they exhibit characteristic crown-like spikes on their protein coat. SARS-CoV-2, a type of coronavirus that emerged in 2019, causes severe infection in the lower respiratory tract of humans and is often fatal in immunocompromised individuals. No medications have been approved so far for the direct treatment of SARS-CoV-2 infection, and the currently available treatment options rely on relieving the symptoms. The medicinal plants occurring in nature serve as a rich source of active ingredients that could be utilized for developing pharmacopeial and non-pharmacopeial/synthetic drugs with antiviral properties. Compounds obtained from certain plants have been used for directly and selectively inhibiting different coronaviruses, including SARS-CoV, MERS-CoV, and SARS-CoV-2. The present review discusses the potential natural inhibitors against the highly pathogenic human coronaviruses, with a systematic elaboration on the possible mechanisms of action of these natural compounds while acting in the different stages of the life cycle of coronaviruses. Moreover, through a comprehensive exploration of the existing literature in this regard, the importance of such compounds in the research and development of effective and safe antiviral agents is discussed. We focused on the mechanism of action of several natural compounds along with their target of action. In addition, the immunomodulatory effects of these active components in the context of human health are elucidated. Finally, it is suggested that the use of traditional medicinal plants is a novel and feasible remedial strategy against human coronaviruses.

Polyphenols and their potential role to fight viral diseases: An overview

Fruits, vegetables, spices, and herbs are a potential source of phenolic acids and polyphenols. These compounds are known as natural by-products or secondary metabolites of plants, which are present in the daily diet and provide important benefits to the human body such as antioxidant, anti-inflammatory, anticancer, anti-allergic, antihypertensive and antiviral properties, among others. Plentiful evidence has been provided on the great potential of polyphenols against different viruses that cause widespread health problems. As a result, this review focuses on the potential antiviral properties of some polyphenols and their action mechanism against various types of viruses such as coronaviruses, influenza, herpes simplex, dengue fever, and rotavirus, among others. Also, it is important to highlight the relationship between antiviral and antioxidant activities that can contribute to the protection of cells and tissues of the human body. The wide variety of action mechanisms of antiviral agents, such as polyphenols, against viral infections could be applied as a treatment or prevention strategy; but at the same time, antiviral polyphenols could be used to produce natural antiviral drugs. A recent example of an antiviral polyphenol application deals with the use of hesperidin extracted from Citrus sinensis. The action mechanism of hesperidin relies on its binding to the key entry or spike protein of SARS-CoV-2. Finally, the extraction, purification and recovery of polyphenols with potential antiviral activity, which are essential for virus replication and infection without side-effects, have been critically reviewed.

An Update on Pharmacological Relevance and Chemical Synthesis of Natural Products and Derivatives with Anti SARS-CoV-2 Activity

Natural products recognized traditionally as a vital source of active constituents in pharmacotherapy. The COVID-19 infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is highly transmissible, pathogenic, and considered an ongoing global health emergency. The emergence of COVID-19 globally and the lack of adequate treatment brought attention towards herbal medicines, and scientists across the globe instigated the search for novel drugs from medicinal plants and natural products to tackle this deadly virus. The natural products rich in scaffold diversity and structural complexity are an excellent source for antiviral drug discovery. Recently the investigation of several natural products and their synthetic derivatives resulted in the identification of promising anti SARS-CoV-2 agents. This review article will highlight the pharmacological relevance and chemical synthesis of the recently discovered natural product and their synthetic analogs as SARS-CoV-2 inhibitors. The summarized information will pave the path for the natural product-based drug discovery of safe and potent antiviral agents, particularly against SARS-CoV-2.

Natural Products and Their Derivatives against Human Herpesvirus Infection

Herpesviruses establish long-term latent infection for the life of the host and are known to cause numerous diseases. The prevalence of viral infection is significantly increased and causes a worldwide challenge in terms of health issues due to drug resistance. Prolonged treatment with conventional antiviral drugs is more likely to develop drug-resistant strains due to mutations of thymidine nucleoside kinase or DNA polymerase. Hence, the development of alternative treatments is clearly required. Natural products and their derivatives have played a significant role in treating herpesvirus infection rather than nucleoside analogs in drug-resistant strains with minimal undesirable effects and different mechanisms of action. Numerous plants, animals, fungi, and bacteria-derived compounds have been proved to be efficient and safe for treating human herpesvirus infection. This review covers the natural antiherpetic agents with the chemical structural class of alkaloids, flavonoids, terpenoids, polyphenols, anthraquinones, anthracyclines, and miscellaneous compounds, and their antiviral mechanisms have been summarized. This review would be helpful to get a better grasp of anti-herpesvirus activity of natural products and their derivatives, and to evaluate the feasibility of natural compounds as an alternative therapy against herpesvirus infections in humans.

Resveratrol (RV): A pharmacological review and call for further research

Resveratrol (RV) is a well-known polyphenolic compound in various plants, including grape, peanut, and berry fruits, which is quite famous for its association with several health benefits such as anti-obesity, cardioprotective neuroprotective, antitumor, antidiabetic, antioxidants, anti-age effects, and glucose metabolism. Significantly, promising therapeutic properties have been reported in various cancer, neurodegeneration, and atherosclerosis and are regulated by several synergistic pathways that control oxidative stress, cell death, and inflammation. Similarly, RV possesses a strong anti-adipogenic effect by inhibiting fat accumulation processes and activating oxidative and lipolytic pathways, exhibiting their cardioprotective effects by inhibiting platelet aggregation. The RV also shows significant antibacterial effects against various food-borne pathogens (Listeria, Campylobacter, Staphylococcus aureus, and E. coli) by inhibiting an electron transport chain (ETC) and F0F1-ATPase, which decreases the production of cellular energy that leads to the spread of pathogens. After collecting and analyzing scientific literature, it may be concluded that RV is well tolerated and favorably affects cardiovascular, neurological, and diabetic disorders. As such, it is possible that RV can be considered the best nutritional additive and a complementary drug, especially a therapeutic candidate. Therefore, this review would increase knowledge about the blend of RV as well as inspire researchers around the world to consider RV as a pharmaceutical drug to combat future health crises against various inhumane diseases. In the future, this article will be aware of discoveries about the potential of this promising natural compound as the best nutraceuticals and therapeutic drugs in medicine.

Targeting autophagy with natural products to prevent SARS-CoV-2 infection

Autophagy is a catabolic process that maintains internal homeostasis and energy balance through the lysosomal degradation of redundant or damaged cellular components. During virus infection, autophagy is triggered both in parenchymal and in immune cells with different finalistic objectives: in parenchymal cells, the goal is to destroy the virion particle while in macrophages and dendritic cells the goal is to expose virion-derived fragments for priming the lymphocytes and initiate the immune response. However, some viruses have developed a strategy to subvert the autophagy machinery to escape the destructive destiny and instead exploit it for virion assembly and exocytosis. Coronaviruses (like SARS-CoV-2) possess such ability. The autophagy process requires a set of proteins that constitute the core machinery and is controlled by several signaling pathways. Here, we report on natural products capable of interfering with SARS-CoV-2 cellular infection and replication through their action on autophagy. The present study provides support to the use of such natural products as adjuvant therapeutics for the management of COVID-19 pandemic to prevent the virus infection and replication, and so mitigating the progression of the disease.

Therapeutic Potential of Nutraceuticals and Dietary Supplements in the Prevention of Viral Diseases: A Review

Nowadays, despite enormous scientific advances, viral diseases remain the leading cause of morbidity worldwide, and their potential to spread is escalating, eventually turning into pandemics. Nutrition can play a major role in supporting the immune system of the body and for the optimal functioning of the cells of the immune system. A healthy diet encompassing vitamins, multi-nutrient supplements, functional foods, nutraceuticals, and probiotics can play a pivotal role in combating several viral invasions in addition to strengthening the immune system. This review provides comprehensive information on diet-based scientific recommendations, evidence, and worldwide case studies in light of the current pandemic and also with a particular focus on virus-induced respiratory tract infections. After reviewing the immune potential of nutraceuticals based on the lab studies and on human studies, it was concluded that bioactive compounds such as nutraceuticals, vitamins, and functional foods (honey, berries, etc.) with proven antiviral efficacy, in addition to pharmaceutical medication or alone as dietary supplements, can prove instrumental in treating a range of virus-induced infections in addition to strengthening the immune system. Milk proteins and peptides can also act as adjuvants for the design of more potent novel antiviral drugs.

The Effect of Resveratrol on the Cardiovascular System from Molecular Mechanisms to Clinical Results

Cardiovascular diseases are the leading causes of death worldwide. The cardioprotective effects of natural polyphenols such as resveratrol (3,5,4-trihydroxystilbene) have been extensively investigated throughout recent decades. Many studies of RES have focused on its favorable effects on pathological conditions related to cardiovascular diseases and their risk factors. The aim of this review was to summarize the wide beneficial effects of resveratrol on the cardiovascular system, including signal transduction pathways of cell longevity, energy metabolism of cardiomyocytes or cardiac remodeling, and its anti-inflammatory and antioxidant properties. In addition, this paper discusses the significant preclinical and human clinical trials of recent years with resveratrol on cardiovascular system. Finally, we present a short overview of antiviral and anti-inflammatory properties and possible future perspectives on RES against COVID-19 in cardiovascular diseases.

Randomized Double-blind Placebo-controlled Proof-of-concept Trial of Resveratrol for Outpatient Treatment of Mild Coronavirus Disease (COVID-19)

Resveratrol is a polyphenol that has been well studied and has demonstrated anti-viral and anti-inflammatory properties that might mitigate the effects of COVID-19. Outpatients (N=105) were recruited from central Ohio in late 2020. Participants were randomly assigned to receive placebo or resveratrol. Both groups received a single dose of Vitamin D3 which was used as an adjunct. The primary outcome measure was hospitalization within 21 days of symptom onset; secondary measures were ER visits, incidence of pneumonia and pulmonary embolism. Five patients chose not to participate after randomization. Twenty-one day outcome was determined of all one hundred participants (mean [SD] age 55.6 [8.8] years; 61% female) (or their surrogates). There were no clinically significant adverse events attributed to resveratrol. Outpatients in this phase 2 study treated with resveratrol had a lower incidence compared to placebo of: hospitalization (2% vs. 6%, RR 0.33, 95% CI 0.04-3.10), COVID-related ER visits (8% vs. 14%, RR 0.57, 95% CI 0.18-1.83), and pneumonia (8% vs. 16%, RR 0.5, 95% CI 0.16-1.55). One patient (2%) in each group developed pulmonary embolism (RR 1.00, 95% CI: 0.06-15.55). This underpowered study was limited by small sample size and low incidence of primary adverse events. A larger trial could determine efficacy. TRIAL REGISTRATIONS: ClinicalTrials.gov NCT04400890 26/05/2020; FDA IND #150033 05/05/2020.

Resveratrol as an Adjunctive Therapy for Excessive Oxidative Stress in Aging COVID-19 Patients

The coronavirus disease 2019 (COVID-19) pandemic continues to burden healthcare systems worldwide. COVID-19 symptoms are highly heterogeneous, and the patient may be asymptomatic or may present with mild to severe or fatal symptoms. Factors, such as age, sex, and comorbidities, are key determinants of illness severity and progression. Aging is accompanied by multiple deficiencies in interferon production by dendritic cells or macrophages in response to viral infections, resulting in dysregulation of inflammatory immune responses and excess oxidative stress. Age-related dysregulation of immune function may cause a more obvious pathophysiological response to SARS-CoV-2 infection in elderly patients and may accelerate the risk of biological aging, even after recovery. For more favorable treatment outcomes, inhibiting viral replication and dampening inflammatory and oxidative responses before induction of an overt cytokine storm is crucial. Resveratrol is a potent antioxidant with antiviral activity. Herein, we describe the reasons for impaired interferon production, owing to aging, and the impact of aging on innate and adaptive immune responses to infection, which leads to inflammation distress and immunosuppression, thereby causing fulminant disease. Additionally, the molecular mechanism by which resveratrol could reverse a state of excessive basal inflammatory and oxidative stress and low antiviral immunity is discussed.

Molecular Docking and ADMET Prediction of Natural Compounds towards SARS Spike Glycoprotein-Human Angiotensin-Converting Enzyme 2 and SARS-CoV-2 Main Protease

More than a decade ago, a novel coronavirus that infects humans, bats, and certain other mammals termed severe acute respiratory syndrome coronavirus (SARS-CoV) caused an epidemic with ~ 10% case fatality, creating global panic and economic damage. Recently, another strain of the virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), caused an infectious disease (COVID-19) in humans which was detected for the first time in Wuhan, China. Presently, there is no specific therapy available for the treatment of COVID-19. However, social distancing, patient isolation, and supportive medical care make up the current management for this current infectious disease pandemic. The present in silico study evaluated the binding affinities of some natural products (resveratrol, xylopic acid, ellagic acid, kaempferol, and quercetin) to human angiotensin-converting enzyme 2 and coronavirus (SARS-CoV-2) main protease compared to chloroquine, an inhibitor known to prevent cellular entry and replication of the coronavirus. The respective binding energies of the selected natural compounds and chloroquine towards the proteins were computed using PyRx virtual screening tool. The pharmacodynamic and pharmacokinetic attributes of the selected compounds were predicted using admetSAR. Molecular docking analysis showed that the natural compounds had better scores towards the selected protein compared to chloroquine with polar amino acid residues present at the binding sites. The predicted ADMET properties revealed the lower acute oral toxicity of the natural products compared to chloroquine. The study provides evidence suggesting that the relatively less toxic compounds from the natural sources could be repositioned as anti-viral agents to prevent the entry and replication of SARS-CoV-2.

Interaction of SARS-CoV-2 spike protein with angiotensin converting enzyme inhibitors and selected compounds from the chemical entities of biological interest

BACKGROUND

Recent COVID-19 outbreak has prompted the search of novel therapeutic agents to treat the disease. The initial step of the infection involves the binding of the virus through the viral spike protein with the host angiotensin converting enzyme 2 (ACE2). In this study, the interaction of some ACE or ACE2 inhibitors and their analogues as well as selected compounds with the viral spike protein as a strategy to hinder viral-ACE2 interaction were investigated. SARS-CoV-2 spike protein as well as the ligands were retrieved from protein databank and ChEBI database respectively. The molecules were prepared before initiating the virtual screening using PyRx software. Discovery studio was used to further visualize the binding interactions between the compounds and the protein.

RESULTS

The ACE inhibitors and their analogues fosinopril (1-), fosinopril and moexipril have the best binding affinity to the protein with binding energies < - 7.0 kcal/mol while non-flavonoid stilben-4-ol binds with free binding energy of - 7.1 kcal/mol. Others compounds which belong to either the flavonoids, terpenes and alkaloid classes also have binding energies  < - 7.0 kcal/mol. Such high binding energies were enhanced via hydrogen bond (h-bond) interactions in addition to other interactions observed between the compounds and the amino acid residues of the protein.

CONCLUSIONS

The ACE inhibitors and their analogues as well as the selected compounds could serve as inhibitors of the spike protein as well as lead in drug discovery processes to target the SARS-CoV-2 virus.

Phytoconstituents as Lead Compounds for Anti-Dengue Drug Discovery

Dengue is an arthropod-borne viral disease common in subtropical and tropical regions. The widespread use of traditional medicines in these regions for dengue fever (DF) has encouraged researchers to explore the therapeutic effect of herbs and their phytochemicals in dengue infection. Phytochemicals such as quercetin, baicalein, luteolin, oxindole alkaloids, celastrol and geraniin have shown significant inhibition of dengue virus in vitro. Many phytoconstituents have better selectivity index supporting their safety profile for future development. However, in vivo studies supporting therapeutic potency for these active phytoconstituents are limited. There is a need for studies translating anti-dengue profile of active phytoconstituents to find successful anti-dengue compounds.