Curcumin inhibits Zika and chikungunya virus infection by inhibiting cell binding

Oral nano-curcumin formulation efficacy in management of mild to moderate hospitalized coronavirus disease-19 patients: An open label nonrandomized clinical trial

Curcumin is proposed as a potential treatment option for coronavirus disease-19 (COVID-19) by inhibiting the virus entrance, encapsulation and replication, and modulating various cellular signaling pathways. In this open-label nonrandomized clinical trial, efficacy of nano-curcumin oral formulation has been evaluated in hospitalized patients with mild-moderate COVID-19. Forty-one patients who fulfilled the inclusion criteria were allocated to nano-curcumin (n = 21) group (Sinacurcumin soft gel, contains 40 mg curcuminoids as nanomicelles, two capsules twice a day) or control (n = 20) group, for 2 weeks. Patients' symptoms and laboratory data were assessed at baseline and during follow-up period. Most of symptoms including fever and chills, tachypnea, myalgia, and cough resolved significantly faster in curcumin group. Moreover, SaO2 was significantly higher in treatment group after 2, 4, 7, and 14 days of follow-up and lymphocyte count after 7 and 14 days. Duration of supplemental O2 use and hospitalization was also meaningfully shorter in treatment group. It is also noteworthy to mention that no patient in treatment group experienced deterioration of infection during follow-up period, but it occurred in 40% of control group. Oral curcumin nano-formulation can significantly improve recovery time in hospitalized COVID-19 patients. Further randomized placebo controlled trials with larger sample size are recommended.

Identification of phytochemicals as potential therapeutic agents that binds to Nsp15 protein target of coronavirus (SARS-CoV-2) that are capable of inhibiting virus replication

BACKGROUND

Coronavirus disease 2019 (COVID-19) playing havoc across the globe caused 585,727 deaths and 13,616,593 confirmed cases so far as per World Health Organization data released till 17th July 2020. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV- 2) is responsible for causing this pandemic across different continents. It is not only impacting the world economy but also quarantined millions of people in their homes or hospitals.

PURPOSE

At present, there is no Food and Drug Administration-approved drug or vaccine available to treat this disease. Still, people are trying various pre-existing medicines that are known to have anti-viral or anti-parasitic effects. In view of this, the present study aimed to study the binding potential of various phytochemicals present in multiple natural plant extract as a secondary metabolite to non-structural protein 15 (Nsp15) protein, a drug target known to play a crucial role in virulence of coronavirus.

METHOD

Nsp15 protein was selected because it shows 89% similarity to the other SARS-CoV, which caused the earlier outbreak. The assumption is that inhibition of Nsp15 slowdowns the viral replication. Phytochemicals are selected as these are present in various plant parts (seed, flower, roots, etc.), which are used in different food cuisines in different geographical regions across the globe. The molecular docking approach was performed using two different software, i.e., Autodock, and Swissdock, to study the interaction of various phytochemicals with Nsp15 protein. Hydroxychloroquine is used as a positive control as it is used by medical professionals showing some positive effects in dealing with coronavirus.

RESULTS

The present study demonstrated the binding potential of approximately 50 phytochemicals with Nsp15 and capable of inhibiting the viral replication, although in vitro and in vivo tests are required to confirm these findings.

CONCLUSIONS

In conclusion, the present study successfully demonstrated the binding of phytochemicals such as sarsasapogenin, ursonic acid, curcumin, ajmalicine, novobiocin, silymarin and aranotin, piperine, gingerol, rosmarinic acid, and alpha terpinyl acetate to Nsp15 viral protein and they might play a key role in inhibiting SARS-CoV-2 replication.

Spices and herbs: Potential antiviral preventives and immunity boosters during COVID-19

A severe acute respiratory syndrome is an unusual type of contagious pneumonia that is caused by SARS coronavirus. At present, the whole world is trying to combat this coronavirus disease and scientific communities are putting rigorous efforts to develop vaccines. However, there are only a few specific medical treatments for SARS-CoV-2. Apart from other public health measures taken to prevent this virus, we can boost our immunity with natural products. In this article, we have highlighted the potential of common spices and herbs as antiviral agents and immunity boosters. A questionnaire-based online survey has been conducted on home remedies during COVID-19 among a wide range of peoples (n-531) of different age groups (13-68 years) from various countries. According to the survey, 71.8% of people are taking kadha for combating infection and boosting immunity. Most people (86.1%) think that there is no side effect of kadha while 13.9% think vice versa. A total of 93.6% of people think that spices are helpful in curing coronavirus or other viral infection as well as boosting immunity. Most people are using tulsi drops, vitamin C, and chyawanprash for boosting their immunity. Therefore, we conclude from the survey and available literature that spices and herbs play a significant role against viral infections.

Curcumin nanoformulations for antimicrobial and wound healing purposes

The development and spread of resistance to antimicrobial drugs is hampering the management of microbial infectious and wound healing processes. Curcumin is the most active and effective constituent of Curcuma longa L., also known as turmeric, and has a very long and strong history of medicinal value for human health and skincare. Curcumin has been proposed as strong antimicrobial potentialities and many attempts have been made to determine its ability to conjointly control bacterial growth and promote wound healing. However, low aqueous solubility, poor tissue absorption and short plasma half-life due its rapid metabolism needs to be solved for made curcumin formulations as suitable treatment for wound healing. New curcumin nanoformulations have been designed to solve the low bioavailability problem of curcumin. Thus, in the present review, the therapeutic applications of curcumin nanoformulations for antimicrobial and wound healing purposes is described.

Anti-MRSA activity of curcumin in planktonic cells and biofilms and determination of possible action mechanisms

Staphylococcus aureus is a commensal bacterium and opportunistic human pathogen that can cause a wide variety of clinical infections. It is recognized for its ability to acquire antimicrobial resistance, so methicillin-resistant Staphylococcus aureus (MRSA) infections are a global healthcare challenge. Therefore, the development of new therapeutic options and alternative therapies for treatment is necessary. Curcumin, a polyphenolic substance found in the rhizome of turmeric longa L, has been shown to have several therapeutic properties, including antimicrobial activity. The objective of the study was to evaluate the in vitro antibacterial activity of curcumin alone and associated with oxacillin against MRSA strains, to analyze the mechanism of cell death involved in the isolated action of curcumin by means of flow cytometry and molecular docking, and to verify its superbiofilm action. Curcumin showed antibacterial activity in the range of 125-500 μg/mL against the tested strains, since it caused an increase in membrane permeability and DNA fragmentation, as revealed by flow cytometry analysis. Moreover, it was possible to observe interactions of curcumin with wild-type S. aureus DHFR, S. aureus gyrase and S. aureus gyrase complex with DNA, DNA (5'-D(*CP*GP*AP*TP*GP*CP*G)-3') and Acyl-PBP2a from MRSA by molecular docking. Curcumin also had a synergistic and additive effect when associated with oxacillin, and significantly reduced the cell viability of the analyzed biofilms. Thus, curcumin is a possible candidate for pharmaceutical formulation development for the treatment of MRSA infections.

Micronutrients and bioactive substances: Their potential roles in combating COVID-19

OBJECTIVES

The coronavirus disease 2019 (COVID-19) pandemic is seriously threatening public health and setting off huge economic crises across the world. In the absence of specific drugs for COVID-19, there is an urgent need to look for alternative approaches. Therefore, the aim of this paper was to review the roles of micronutrients and bioactive substances as potential alternative approaches in combating COVID-19.

METHODS

This review was based on the literature identified using electronic searches in different databases.

RESULTS

Vitamins (A, B, C, D, and E), minerals (selenium and zinc), and bioactive substances from curcumin, echinacea, propolis, garlic, soybean, green tea, and other polyphenols were identified as having potential roles in interfering with spike glycoproteins, angiotensin converting enzyme 2, and transmembrane protease serine 2 at the entry site, and inhibiting activities of papain-like protease, 3 chymotrypsin-like protease, and RNA-dependent RNA polymerase in the replication cycle of severe acute respiratory syndrome coronavirus 2. Having immunomodulating, antiinflammatory, antioxidant, and antiviral properties, such micronutrients and bioactive substances are consequently promising alterative nutritional approaches to combat COVID-19.

CONCLUSIONS

The roles of micronutrients and bioactive substances in the fight against COVID-19 are exciting areas of research. This review may suggest directions for further study.

A review targeting the infection by CHIKV using computational and experimental approaches

The rise of normal body temperature of 98.6 °F beyond 100.4 °F in humans indicates fever due to some illness or infection. Viral infections caused by different viruses are one of the major causes of fever. One of such viruses is, Chikungunya virus (CHIKV) is known to cause Chikungunya fever (CHIKF) which is transmitted to humans through the mosquitoes, which actually become the primary source of transmission of the virus. The genomic structure of the CHIKV consists of the two open reading frames (ORFs). The first one is a 5' end ORF and it encodes the nonstructural protein (nsP1-nsP4). The second is a 3' end ORF and it encodes the structural proteins, which is consisted of capsid, envelope (E), accessory peptides, E3 and 6 K. Till date, there is no effective vaccine or medicine available for early detection of the CHIKV infection and appropriate diagnosis to cure the patients from the infection. NSP3 of CHIKV is the prime target of the researchers as it is responsible for the catalytic activity. This review has updates of literature on CHIKV; pathogenesis of CHIKV; inhibition of CHIKV using theoretical and experimental approaches.Communicated by Ramaswamy H. Sarma.

Curcumin encapsulation in nanostructures for cancer therapy: A 10-year overview

Curcumin (CUR) is a phenolic compound present in some herbs, including Curcuma longa Linn. (turmeric rhizome), with a high bioactive capacity and characteristic yellow color. It is mainly used as a spice, although it has been found that CUR has interesting pharmaceutical properties, acting as a natural antioxidant, anti-inflammatory, antimicrobial, and antitumoral agent. Nonetheless, CUR is a hydrophobic compound with low water solubility, poor chemical stability, and fast metabolism, limiting its use as a pharmacological compound. Smart drug delivery systems (DDS) have been used to overcome its low bioavailability and improve its stability. The current work overviews the literature from the past 10 years on the encapsulation of CUR in nanostructured systems, such as micelles, liposomes, niosomes, nanoemulsions, hydrogels, and nanocomplexes, emphasizing its use and ability in cancer therapy. The studies highlighted in this review have shown that these nanoformulations achieved higher solubility, improved tumor cytotoxicity, prolonged CUR release, and reduced side effects, among other interesting advantages.

[6]-Gingerol Inhibits Chikungunya Virus Infection by Suppressing Viral Replication

Chikungunya (CHIK) is a reemerging arboviral disease caused by chikungunya virus (CHIKV) infection. The disease is clinically hallmarked by prolonged debilitating joint pain. Currently, there is no specific antiviral medication nor commercial vaccine available for treatment of the disease, which makes the discovery or development of specific anti-CHIKV compounds a priority. Ginger (Zingiber officinale Roscoe) is widely known for its various health benefits. The compound [6]-gingerol is the main active ingredient found in ginger. This study sought to determine the potential of [6]-gingerol antiviral activity against CHIKV infection using in vitro human hepatocyte HepG2 cells. The antiviral activity mechanism was investigated using direct virucidal and four indirect (pre-, post-, full-, and prevention) treatment assays. [6]-Gingerol showed weak virucidal activity but significant indirect antiviral activity against CHIKV through post- and full treatment with IC₅₀ of 0.038 mM and 0.031 mM, respectively, without showing cell cytotoxicity. The results indicated that [6]-gingerol inhibits CHIKV infection through suppression of viral replication. Together, this study confirms the potential use of [6]-gingerol for CHIK antiviral compound.

Molecules against Covid-19: An in silico approach for drug development

A large number of deaths have been caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide, turning it into a serious and momentous threat to public health. This study tends to contribute to the development of effective treatment strategies through a computational approach, investigating the mechanisms in relation to the binding and subsequent inhibition of SARS-CoV-2 ribonucleic acid (RNA)-dependent RNA polymerase (RdRp). Molecular docking was performed to screen six naturally occurring molecules with antineoplastic properties (Ellipticine, Ecteinascidin, Homoharringtonine, Dolastatin 10, Halichondrin, and Plicamycin). Absorption, distribution, metabolism, and excretion (ADME) investigation was also conducted to analyze the drug-like properties of these compounds. The docked results have clearly shown binding of ligands to the SARS-CoV-2 RdRp protein. Interestingly, all ligands were found to obey Lipinski’s rule of five. These results provide a basis for repurposing and using molecules, derived from plants and animals, as a potential treatment for the coronavirus disease 2019 (COVID-19) infection as they could be effective therapeutics for the same.

In vitro and in vivo studies reveal α-Mangostin, a xanthonoid from Garcinia mangostana, as a promising natural antiviral compound against chikungunya virus

Background

Chikungunya virus (CHIKV), a serious health problem in several tropical countries, is the causative agent of chikungunya fever. Approved antiviral therapies or vaccines for the treatment or prevention of CHIKV infections are not available. As diverse natural phenolic compounds have been shown to possess antiviral activities, we explored the antiviral activity of α-Mangostin, a xanthanoid, against CHIKV infection.

Methods

The in vitro prophylactic and therapeutic effects of α-Mangostin on CHIKV replication in Vero E6 cells were investigated by administering it under pre, post and cotreatment conditions. The antiviral activity was determined by foci forming unit assay, quantitative RT-PCR and cell-based immune-fluorescence assay. The molecular mechanism of inhibitory action was further proposed using in silico molecular docking studies.

Results

In vitro studies revealed that 8 µM α-Mangostin completely inhibited CHIKV infectivity under the cotreatment condition. CHIKV replication was also inhibited in virus-infected mice. This is the first in vivo study which clearly showed that α-Mangostin is effective in vivo by significantly reducing virus replication in serum and muscles. Molecular docking indicated that α-Mangostin can efficiently interact with the E2–E1 heterodimeric glycoprotein and the ADP-ribose binding cavity of the nsP3 macrodomain.

Conclusions

The findings suggest that α-Mangostin can inhibit CHIKV infection and replication through possible interaction with multiple CHIKV target proteins and might act as a prophylactic/therapeutic agent against CHIKV.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12985-021-01517-z.

Antiviral and immunomodulatory activity of curcumin: A case for prophylactic therapy for COVID-19

Coronavirus disease-19 (COVID-19), a devastating respiratory illness caused by SARS-associated coronavirus-2 (SARS-CoV-2), has already affected over 64 million people and caused 1.48 million deaths, just 12 months from the first diagnosis. COVID-19 patients develop serious complications, including severe pneumonia, acute respiratory distress syndrome (ARDS), and or multiorgan failure due to exaggerated host immune response following infection. Currently, drugs that were effective against SARS-CoV are being repurposed for SARS-CoV-2. During this public health emergency, food nutraceuticals could be promising prophylactic therapeutics for COVID-19. Curcumin, a bioactive compound in turmeric, exerts diverse pharmacological activities and is widely used in foods and traditional medicines. This review presents several lines of evidence, which suggest curcumin as a promising prophylactic, therapeutic candidate for COVID-19. First, curcumin exerts antiviral activity against many types of enveloped viruses, including SARS-CoV-2, by multiple mechanisms: direct interaction with viral membrane proteins; disruption of the viral envelope; inhibition of viral proteases; induce host antiviral responses. Second, curcumin protects from lethal pneumonia and ARDS via targeting NF-κB, inflammasome, IL-6 trans signal, and HMGB1 pathways. Third, curcumin is safe and well-tolerated in both healthy and diseased human subjects. In conclusion, accumulated evidence indicates that curcumin may be a potential prophylactic therapeutic for COVID-19 in the clinic and public health settings.

Can food and food supplements be deployed in the fight against the COVID 19 pandemic?

BACKGROUND

Due to lack of approved drugs and vaccines, the medical world has resorted to older drugs, produced for viral infections and other diseases, as a remedy to combat COVID-19. The accumulating evidence from in vitro and in vivo studies for SARS-CoV and MERS-CoV have demonstrated that several polyphenols found in plants and zinc- polyphenol clusters have been in use as herbal medicines have antiviral activities against viruses with various mechanisms.

SCOPE OF REVIEW

Curcumin, zinc and zinc-ionophores have been considered as nutraceuticals and nutrients showing great antiviral activities with their medicinal like activities.

MAJOR CONCLUSIONS

In this work, we discussed the potential prophylactic and/or therapeutic effects of curcumin, zinc and zinc-ionophores in treatment of viral infections including COVID-19.

GENERAL SIGNIFICANCE

Curcuminoids and Zinc classified as nutraceuticals under GRAS (Generally Recognized As Safe) by FDA can provide complementary treatment for COVID 19 patients with their immunity-boosting and antiviral properties.

Immunomodulatory and anti-cytokine therapeutic potential of curcumin and its derivatives for treating COVID-19 - a computational modeling

The unavailability of vaccine and medicines raised serious issues during COVID-19 pandemic and peoples from different parts of world relied on traditional medicine for their immediate recovery from COVID-19 and it found effective also. The current research aims to target COVID-19 immunological human host receptors i.e. angiotensin-converting enzyme (ACE)-2, interleukin (IL)-1β, IL-6, tumor necrosis factor-alpha (TNF-α) and protease-activated receptor (PAR)-1 using curcumin derivatives to prevent viral infection and control overproduction of early clinical responses of COVID-19. Targeting these host proteins will mitigate the infection and will filter out many complications caused by these proteins in COVID-19 patients. It is proven through computer-aided computational modeling approaches, total 30 compounds of curcumin and its derivatives were chosen. Drug-likeness parameters were calculated for curcumin and its derivatives and 20 curcumin analogs were selected for docking analysis. From docking analysis of 20 curcumin analogs against five chosen human host receptor targets reveals 11 curcumin analogs possess least binding affinity and best interaction at active sites subjected to absorption, distribution, metabolism, excretion (ADME) analysis. Density functional theory (DFT) analysis of five final shortlisted curcumin derivatives was done to show least binding affinity toward chosen host target protein. Molecular dynamics simulation (MDS) was performed to observe behavior and interaction of potential drug hydrazinocurcumin against target proteins ACE-2 and PAR-1. It was performed at 100 nanoseconds and showed satisfactory results. Finally, our investigation reveals that hydrazinocurcumin possesses immunomodulatory and anti-cytokine therapeutic potential against COVID-19 and it can act as COVID-19 warrior drug molecule and promising choice of drug for COVID-19 treatment, however, it needs further in vivo clinical evaluation to commercialize as COVID-19 drug.Communicated by Ramaswamy H. Sarma.

The Multifaced Actions of Curcumin in Pregnancy Outcome

Curcumin, also known as diferuloylmethane, is the main polyphenolic substance present in the rhizomes of Curcuma longa L. This plant showed many beneficial effects and has been used since ancient times for both food and pharmaceutical purposes. Due to its pleiotropic functions, curcumin consumption in the human diet has become very common thanks also to the fact that this natural compound is considered quite safe as it does not have serious side effects. Its functions as an anti-inflammatory, anti-oxidant, neuroprotective, immunomodulatory, anti-toxicant, anti-apoptotic, and anti-diabetic compound are already known and widely demonstrated. There are numerous studies concerning its effects on various human pathologies including cancer, diabetes and arthritis while the studies on curcumin during pregnancy have been performed only in animal models. Data concerning the role of curcumin as anti-inflammatory compound suggest a possible use of curcumin in managing pregnancy complications such as Preeclampsia (PE), Gestational Diabetes Mellitus (GDM), Fetal Growth Restriction (FGR), PreTerm Birth (PTB), and exposure to toxic agents and pathogens. The aim of this review is to present data to support the possible use of curcumin in clinical trials on human gestation complications.

D, P. R. R, K. M, E. M. A, Balachandran I. Chemical profiling of selected Ayurveda formulations recommended for COVID-19

BACKGROUND

The novel coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is the global health concern since December 2019. It has become a big challenge for the researchers to find a solution for this newly evolved pandemic. In Ayurveda point of view, COVID-19 is a Janapadodhwamsa vikara (epidemic disease), a situation where the environment-air, water, land, and seasons-is vitiated, causing a simultaneous manifestation of a disease among large populations. The aim of this study is to identify the active compounds of selected Ayurveda medicines recommended for COVID-19.

RESULTS

The selected preparations are traditionally recommended for the management of various kinds of fever including the infectious ones and to enhance the immunity. HPTLC analysis of the same showed presence of many active molecules like umbelliferone, scopoletin, caffeic acid, ferulic acid, gallic acid, piperine, curcumin, berberine, and palmatine.

CONCLUSION

The study provided valuable scientific data regarding the active ingredients of the selected medicines with proven therapeutic potentials like anti-viral, immunomodulatory, and anti-inflammatory activities.

Antiviral activity against Zika virus of a new formulation of curcumin in poly lactic-co-glycolic acid nanoparticles

OBJECTIVES

In the search of an effective antiviral formulation, the natural product curcumin (CUR) was encapsulated into poly(lactic-co-glycolic acid) nanoparticles, a non-toxic bioresorbable and biocompatible copolymer. The resulting CUR containing particles (PLGA-CUR NPs) were characterized and analysed for antiviral activity against Zika virus (ZIKV) infection.

METHODS

The PLGA-CUR NPs were characterized by Fourier transform infrared, differential scanning calorimetry, dynamic light scattering, scanning electron microscopy and thermogravimetric analysis and release profile. Cytotoxicity of PLGA-CUR and the antiviral activity against ZIKV were determined in Vero cells. The effect of PLGA-CUR NPs on viral RNA synthesis and protein expression was analysed by RT-qPCR and immunofluorescence staining, respectively.

KEY FINDINGS

The PLGA-CUR NPs showed an appropriate in vitro drug release profile. Our studies of the antiviral activity of PLGA-CUR NPs and CUR against ZIKV by virus yield reduction as well as viral RNA synthesis and protein expression have shown that PLGA-CUR formulation is more effective than free CUR to inhibit ZIKV infection of Vero cells.

CONCLUSIONS

Our results demonstrate for the first time the antiviral activity against ZIKV of PLGA nanoparticles charged with CUR, suggesting that PLGA-CUR NPs are promising candidates for a drug formulation against human pathogenic flaviviruses.

Perspective Adjunctive Therapies for COVID-19: Beyond Antiviral Therapy

The coronavirus disease 2019 (COVID-19) pandemic is the largest health crisis ever faced worldwide. It has resulted in great health and economic costs because no effective treatment is currently available. Since infected persons vary in presentation from healthy asymptomatic mild symptoms to those who need intensive care support and eventually succumb to the disease, this illness is considered to depend primarily on individual immunity. Demographic distribution and disease severity in several regions of the world vary; therefore, it is believed that natural inherent immunity provided through dietary sources and traditional medicines could play an important role in infection prevention and disease progression. People can boost their immunity to prevent them from infection after COVID-19 exposure and can reduce their inflammatory reactions to protect their organ deterioration in case suffering from the disease. Some drugs with in-situ immunomodulatory and anti-inflammatory activity are also identified as adjunctive therapy in the COVID-19 era. This review discusses the importance of COVID-19 interactions with immune cells and inflammatory cells; and further emphasizes the possible pathways related with traditional herbs, medications and nutritional products. We believe that such pathophysiological pathway approach treatment is rational and important for future development of new therapeutic agents for prevention or cure of COVID-19 infection.

Antiviral Role of Phenolic Compounds against Dengue Virus: A Review

Phenolic compounds have been related to multiple biological activities, and the antiviral effect of these compounds has been demonstrated in several viral models of public health concern. In this review, we show the antiviral role of phenolic compounds against dengue virus (DENV), the most widespread arbovirus globally that, after its re-emergence, has caused multiple epidemic outbreaks, especially in the last two years. Twenty phenolic compounds with anti-DENV activity are discussed, including the multiple mechanisms of action, such as those directed against viral particles or viral proteins, host proteins or pathways related to the productive replication viral cycle and the spread of the infection.

Anti-Viral Potential and Modulation of Nrf2 by Curcumin: Pharmacological Implications

Nuclear factor erythroid 2-related factor 2 (Nrf2) is an essential transcription factor that maintains the cell's redox balance state and reduces inflammation in different adverse stresses. Under the oxidative stress, Nrf2 is separated from Kelch-like ECH-associated protein 1 (Keap1), which is a key sensor of oxidative stress, translocated to the nucleus, interacts with the antioxidant response element (ARE) in the target gene, and then activates the transcriptional pathway to ameliorate the cellular redox condition. Curcumin is a yellow polyphenolic curcuminoid from Curcuma longa (turmeric) that has revealed a broad spectrum of bioactivities, including antioxidant, anti-inflammatory, anti-tumor, and anti-viral activities. Curcumin significantly increases the nuclear expression levels and promotes the biological effects of Nrf2 via the interaction with Cys151 in Keap1, which makes it a marvelous therapeutic candidate against a broad range of oxidative stress-related diseases, including type 2 diabetes (T2D), neurodegenerative diseases (NDs), cardiovascular diseases (CVDs), cancers, viral infections, and more recently SARS-CoV-2. Currently, the multifactorial property of the diseases and lack of adequate medical treatment, especially in viral diseases, result in developing new strategies to finding potential drugs. Curcumin potentially opens up new views as possible Nrf2 activator. However, its low bioavailability that is due to low solubility and low stability in the physiological conditions is a significant challenge in the field of its efficient and effective utilization in medicinal purposes. In this review, we summarized recent studies on the potential effect of curcumin to activate Nrf2 as the design of potential drugs for a viral infection like SARS-Cov2 and acute and chronic inflammation diseases in order to improve the cells' protection.

Do nutrients and other bioactive molecules from foods have anything to say in the treatment against COVID-19?

The repositioning of therapeutic agents already approved by the regulatory agencies for the use of drugs is very interesting due to the immediacy of their use; similarly, the possibility of using molecules derived from foods, whether nutrients or not, is of great importance, also because of their immediate therapeutic applicability. Candidates for these natural therapies against COVID-19 should show certain effects, such as restoring mitochondrial function and cellular redox balance. This would allow reducing the susceptibility of risk groups and the cascade of events after SARS-CoV-2 infection, responsible for the clinical picture, triggered by the imbalance towards oxidation, inflammation, and cytokine storm. Possible strategies to follow through the use of substances of food origin would include: a) the promotion of mitophagy to remove dysfunctional mitochondria originating from free radicals, proton imbalance and virus evasion of the immune system; b) the administration of transition metals whose redox activity would lead to their own oxidation and the consequent generation of a reduced environment, which would normalize the oxidative state and the intracellular pH; c) the administration of molecules with demonstrated antioxidant capacity; d) the administration of compounds with anti-inflammatory and vasodilatory activity; e) the administration of immunomodulatory compounds.

EGYVIR: An immunomodulatory herbal extract with potent antiviral activity against SARS-CoV-2

Due to the challenges for developing vaccines in devastating pandemic situations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), developing and screening of novel antiviral agents are peremptorily demanded. Herein, we developed EGYVIR as a potent immunomodulatory herbal extract with promising antiviral activity against SARS-CoV-2. It constitutes of a combination of black pepper extract with curcumin extract. The antiviral effect of EGYVIR extract is attributed to the two key phases of the disease in severe cases. First, the inhibition of the nuclear translocation of NF-kβ p50, attenuating the SARS-CoV-2 infection-associated cytokine storm. Additionally, the EGYVIR extract has an in vitro virucidal effect for SARS-CoV-2. The in vitro study of EGYVIR extract against SARS-CoV-2 on Huh-7 cell lines, revealed the potential role of NF-kβ/TNFα/IL-6 during the infection process. EGYVIR antagonizes the NF-kβ pathway in-silico and in-vitro studies. Consequently, it has the potential to hinder the release of IL-6 and TNFα, decreasing the production of essential cytokines storm elements.

Small-Molecule Inhibitors of Chikungunya Virus: Mechanisms of Action and Antiviral Drug Resistance

Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that has spread to more than 60 countries worldwide. CHIKV infection leads to a febrile illness known as chikungunya fever (CHIKF), which is characterized by long-lasting and debilitating joint and muscle pain. CHIKV can cause large-scale epidemics with high attack rates, which substantiates the need for development of effective therapeutics suitable for outbreak containment. In this review, we highlight the different strategies used for developing CHIKV small-molecule inhibitors, ranging from high-throughput cell-based screening to in silico screens and enzymatic assays with purified viral proteins.

Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that has spread to more than 60 countries worldwide. CHIKV infection leads to a febrile illness known as chikungunya fever (CHIKF), which is characterized by long-lasting and debilitating joint and muscle pain. CHIKV can cause large-scale epidemics with high attack rates, which substantiates the need for development of effective therapeutics suitable for outbreak containment. In this review, we highlight the different strategies used for developing CHIKV small-molecule inhibitors, ranging from high-throughput cell-based screening to in silico screens and enzymatic assays with purified viral proteins. We further discuss the current status of the most promising molecules, including in vitro and in vivo findings. In particular, we focus on describing host and/or viral targets, mode of action, and mechanisms of antiviral drug resistance and associated mutations. Knowledge of the key molecular determinants of drug resistance will aid selection of the most promising antiviral agent(s) for clinical use. For these reasons, we also summarize the available information about drug-resistant phenotypes in Aedes mosquito vectors. From this review, it is evident that more of the active molecules need to be evaluated in preclinical and clinical models to address the current lack of antiviral treatment for CHIKF.

Antiviral effect of silymarin against Zika virus in vitro

Zika virus (ZIKV) epidemic and its association with severe neurological syndromes have raised worldwide concern. Despite the great clinical relevance of this infection, no vaccine or specific treatment is available and the search for antiviral compounds against ZIKV is extremely necessary. Several natural compounds, such as silymarin, exhibit antioxidant, hepatoprotective, and antiviral properties; however, the antiviral potential of this compound remains partially investigated. Therefore, the objective of this study was to evaluate in vitro the antiviral activity of silymarin against ZIKV infection. Global antiviral activity, dose-dependent, plaque reduction, and time-of-drug-addition assays were used to determine the anti-ZIKV activity of silymarin. Additionally, to start characterizing the mechanisms of action we determined whether silymarin could have a virucidal effect and inhibit viral adsorption and penetration stages. Regarding its global antiviral activity, silymarin showed significant inhibition of ZIKV infection, protecting cells infected with EC₅₀ equal to 34.17μg/mL, with a selectivity index greater than 17 and 4x greater than that of the positive control (ribavirin). Its greatest efficiency was achieved at 125μg/mL, whose cell viability did not differ from the control without infection and treatment. Furthermore, treatment with silymarin reduced viral load by up to two logs (> 90%) concerning viral control, when evaluating virucidal activity and the precocious times of infection. Thus, our results set to show the promising anti-ZIKV activity of silymarin, which does not seem to have a single inhibition mechanism, acting at different times of infection, and still has the advantage of silymarin be a phytotherapy already available on the market.

Curcumin as an Antiviral Agent

Curcumin, the primary curcuminoid compound found in turmeric spice, has shown broad activity as an antimicrobial agent, limiting the replication of many different fungi, bacteria and viruses. In this review, we summarize recent studies supporting the development of curcumin and its derivatives as broad-spectrum antiviral agents.

A molecular understanding of alphavirus entry

Alphaviruses cause severe human illnesses including persistent arthritis and fatal encephalitis. As alphavirus entry into target cells is the first step in infection, intensive research efforts have focused on elucidating aspects of this pathway, including attachment, internalization, and fusion. Herein, we review recent developments in the molecular understanding of alphavirus entry both in vitro and in vivo and how these advances might enable the design of therapeutics targeting this critical step in the alphavirus life cycle.

Micronutrients and bioactive compounds in the immunological pathways related to SARS-CoV-2 (adults and elderly)

The new coronavirus pandemic is affecting the entire world with more than 25 million confirmed cases in August 2020 according to the World Health Organization. It is known that the virus can affect several tissues and can progress to a respiratory failure in severe cases. To prevent the progression to this stage of the disease and minimize all the damage caused by coronavirus (SARS-CoV-2) the immune system must be in its integrity. A healthy nutritional status are fundamental to efficient immunological protection and consequently a good response to SARS-CoV-2. Micronutrients and bioactive compounds perform functions in immune cells that are extremely essential to stop SARS-CoV-2. Their adequate consumption is part of a non-pharmacological intervention to keep the immune system functioning. This review has as main objective to inform how micronutrients and bioactive compounds could act in the essential immunological pathways could stop SARS-CoV-2, focusing on the functions that have already established in the literature and transposing to this scenario.

Potential therapeutic effect of turmeric contents against SARS-CoV-2 compared with experimental COVID-19 therapies: in silico study

Inspired by the 'There is no scientific evidence that turmeric prevents COVID-19' statement made by WHO, the protective or therapeutic potential of the compounds in turmeric contents was investigated against COVID-19 with in silico methodology. The drugs used for experimental COVID-19 therapies were included in this study using the same method for comparison with turmeric components. The 30 turmeric compounds and nine drugs were performed in the docking procedure for vital proteins of COVID-19. With evaluations based on docking scores, the Prime MMGBSA binding free energy and protein-ligand interactions were identified in detail. The 100 ns MD simulations were also performed to assess the stability of the ligands at the binding site of the target proteins. The Root Mean Square Deviation (RMSD) is used to obtain the average displacement for a particular frame concerning a reference frame. The results of this study are suggesting that turmeric spice have a potential to inhibit the SARS-CoV-2 vital proteins and can be use a therapeutic or protective agent against SARS-CoV-2 via inhibiting key protein of the SARS-CoV-2 virus. The compound 4, 23 and 6 are the most prominent inhibitor for the main protease, the spike glycoprotein and RNA polymerase of virus, respectively. The MD simulation validated the stability of ligand-protein interactions. The compactness of the complexes was shown using a radius of gyration. ADME properties of featured compounds are in range of 95% drug molecules. It is hoped that the outputs of this study will contribute to the struggle of humanity with COVID-19.Communicated by Ramaswamy H. Sarma.

Curcumin Allosterically Inhibits the Dengue NS2B-NS3 Protease by Disrupting Its Active Conformation

Flaviviruses including dengue virus and Zika virus encode a unique two-component NS2B-NS3 protease essential for maturation/infectivity, thus representing a key target for designing antiflavivirus drugs. Here, for the first time, by NMR and molecular docking, we reveal that curcumin allosterically inhibits the dengue protease by binding to a cavity with no overlap with the active site. Further molecular dynamics simulations decode that the binding of curcumin leads to unfolding/displacing the characteristic β-hairpin of the C-terminal NS2B and consequently disrupting the closed (active) conformation of the protease. Our study identified a cavity most likely conserved in all flaviviral NS2B-NS3 proteases, which could thus serve as a therapeutic target for the discovery/design of small-molecule allosteric inhibitors. Moreover, as curcumin has been used as a food additive for thousands of years in many counties, it can be directly utilized to fight the flaviviral infections and as a promising starting for further design of potent allosteric inhibitors.

Antiviral Effects of Curcumin on Adenovirus Replication

Human adenovirus (HAdV) is a common pathogen that can cause severe morbidity and mortality in certain populations, including pediatric, geriatric, and immunocompromised patients. Unfortunately, there are no approved therapeutics to combat HAdV infections. Curcumin, the primary curcuminoid compound found in turmeric spice, has shown broad activity as an antimicrobial agent, limiting the replication of many different bacteria and viruses. In this study, we evaluated curcumin as an anti-HAdV agent. Treatment of cells in culture with curcumin reduced HAdV replication, gene expression, and virus yield, at concentrations of curcumin that had little effect on cell viability. Thus, curcumin represents a promising class of compounds for further study as potential therapeutics to combat HAdV infection.

Antiviral effect of baicalin on Marek's disease virus in CEF cells

BACKGROUND

Baicalin, the main metabolic component of Scutellaria baicalensis Georgi, has various pharmacological properties including anti-inflammatory, anti-oxidant, anti-apoptotic, anti-bactericidal and anti-viral. The purpose of this study was to investigate the anti-Marek's disease virus (MDV) activities of baicalin in CEF cells.

RESULTS

Here, we showed that baicalin could inhibit viral mRNA, protein levels and overall plaque formation in a time-dependent manner. We also found that baicalin could consistently inhibit MDV replication and directly affect the virus infectivity. Moreover, baicalin treatment has no effect on expression level of antiviral cytokine and inflammatory cytokines in MDV infected CEFs.

CONCLUSIONS

These results demonstrate that baicalin could be a potential drug against MDV infection.

Comprehensive Review on Current Interventions, Diagnostics, and Nanotechnology Perspectives against SARS-CoV-2

The coronavirus disease 2019 (COVID-19) has dramatically challenged the healthcare system of almost all countries. The authorities are struggling to minimize the mortality along with ameliorating the economic downturn. Unfortunately, until now, there has been no promising medicine or vaccine available. Herein, we deliver perspectives of nanotechnology for increasing the specificity and sensitivity of current interventional platforms toward the urgent need of quickly deployable solutions. This review summarizes the recent involvement of nanotechnology from the development of a biosensor to fabrication of a multifunctional nanohybrid system for respiratory and deadly viruses, along with the recent interventions and current understanding about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Schinus terebenthifolius Raddi extracts: From sunscreen activity toward protection of the placenta to Zika virus infection, new uses for a well-known medicinal plant

Schinus terebinthifolius Raddi is a well-known medicinal plant native of South America. This species has demonstrated important biological activities such as antihypertensive and vasodilator, antimicrobial, anti-inflammatory and antioxidant. However, no studies have been, so far, reported with the fruits of S. terebinthifolius as a protector of the placenta against Zika virus infection and as sunscreen agents. The present study aimed to investigate new uses for the ethanolic fruit extracts of S. terebinthifolius, from fruits'peel (STPE) and from the whole fruits (STWFE). Zika virus (ZIKV) has been linked to several fetal malformations, such as microcephaly and other central nervous system abnormalities. Thus, the potential of these natural extracts against ZIKV infection was evaluated, using an in vitro method. The photoprotective potential, determined by spectrometry, along with phenolic content, antioxidant capacity, and chemical composition of both extracts were also evaluated. The chemical composition of the extracts was evaluated by HPLC-UV / vis. The cytotoxicity of peel and whole fruit extracts in vero E6 cell lines, in placental cell lines and placental explant cultures were evaluated by the MTT assay. The infectivity of placental cells and explants was evaluated by qRT-PCR and the effects of extracts on ZIKV infection were investigated using HTR-8/SVneo cells, pre-treated with 100 μg mL^-1 of STWFE for 1 h, and infected with MR766 (AD) or PE243 (EH) ZIKV strains. STFE and STWFE were well-tolerated by both placental-derived trophoblast cell line HTR-8/SVneo as well as by term placental chorionic villi explants, which indicate absence of cytotoxicity in all analysed concentrations. Two strains of ZIKV were tested to access if pre-treatment of trophoblast cells with the STWFE would protect them against infection. Flow cytometry analysis revealed that STWFE extract greatly reduced ZIKV infection. The extracts were also photoprotective with SPF values equivalent to the standard, benzophenone-3. The formulations prepared in different concentrations of the extracts (5-10 %) had shown maximum SPF values of 32.21. STWFE represents a potential natural mixture to be used in pregnancy in order to restrain placental infection by ZIKV and might potentially protect fetus against ZIKV-related malformations. The extracts exhibited photoprotective activity and some of the phenolic compounds, mainly resveratrol, catechin and epicatechin, are active ingredients in all assayed activities. The development of biotechnological/medical products, giving extra value to products from family farming, is expected, with strong prospects for success.

In Silico De Novo Curcuminoid Derivatives From the Compound Library of Natural Products Research Laboratories Inhibit COVID-19 3CLpro Activity

The coronavirus disease 2019 (COVID‐19) outbreak caused by the 2019 novel coronavirus (2019-nCOV) is becoming increasingly serious. In March 2019, the Food and Drug Administration (FDA) designated remdesivir for compassionate use to treat COVID-19. Thus, the development of novel antiviral agents, antibodies, and vaccines against COVID-19 is an urgent research subject. Many laboratories and research organizations are actively investing in the development of new compounds for COVID-19. Through in silico high-throughput virtual screening, we have recently identified compounds from the compound library of Natural Products Research Laboratories (NPRL) that can bind to COVID-19 3Lpro polyprotein and block COVID-19 3Lpro activity through in silico high-throughput virtual screening. Curcuminoid derivatives (including NPRL334, NPRL339, NPRL342, NPRL346, NPRL407, NPRL415, NPRL420, NPRL472, and NPRL473) display strong binding affinity to COVID-19 3Lpro polyprotein. The binding site of curcuminoid derivatives to COVID-19 3Lpro polyprotein is the same as that of the FDA-approved human immunodeficiency virus protease inhibitor (lopinavir) to COVID-19 3Lpro polyprotein. The binding affinity of curcuminoid derivatives to COVID-19 3Lpro is stronger than that of lopinavir and curcumin. Among curcuminoid derivatives, NPRL-334 revealed the strongest binding affinity to COVID-19 3Lpro polyprotein and is speculated to have an anti-COVID-19 effect. In vitro and in vivo ongoing experiments are currently underway to confirm the present findings. This study sheds light on the drug design for COVID-19 3Lpro polyprotein. Basing on lead compound development, we provide new insights on inhibiting COVID-19 attachment to cells, reducing COVID-19 infection rate and drug side effects, and increasing therapeutic success rate.

Review of Phytochemical Compounds as Antiviral Agents Against Arboviruses from the Genera Flavivirus and Alphavirus

Arboviruses are a diverse group of viruses that are among the major causes of emerging infectious diseases. Arboviruses from the genera flavivirus and alphavirus are the most important human arboviruses from a public health perspective. During recent decades, these viruses have been responsible for millions of infections and deaths around the world. Over the past few years, several investigations have been carried out to identify antiviral agents to treat these arbovirus infections. The use of synthetic antiviral compounds is often unsatisfactory since they may raise the risk of viral mutation; they are costly and possess either side effects or toxicity. One attractive strategy is the use of plants as promising sources of novel antiviral compounds that present significant inhibitory effects on these viruses. In this review, we describe advances in the exploitation of compounds and extracts from natural sources that target the vital proteins and enzymes involved in arbovirus replication.

In-silico screening of plant-derived antivirals against main protease, 3CLpro and endoribonuclease, NSP15 proteins of SARS-CoV-2

Novel Coronavirus or SARS-CoV-2 outbreak has developed a pandemic condition all over the world. The virus is highly infectious and spreads by human to human local transmission mode. Till date, there is no vaccination or drugs been approved for the treatment by the World Health Organisation. Henceforth, the discovery of the potential drugs is an urgent and utmost requirement for the medical fraternity. Since, the side effects of plant-derived compounds will be lower compared to synthetic/chemical drugs. The Main protease (3CL^pro or NSP5) and endoribonuclease (NSP15) proteins are necessity for viral replication and its survival in the host cell. In the present study, in-silico approach of drug development was used to search for potential antiviral plant-derived compounds as inhibitors against SARS-CoV-2 replication proteins. Eight plant-derived compounds of which the antiviral activity was known and available, and two reported drugs against SARS-CoV-2 selected for the molecular docking analysis. The docking results suggested that bisdemethoxycurcumin, demethoxycurcumin, scutellarin, quercetin and myricetin showed least binding energy, i.e., greater than −6.5 Kcal/mol against 3CL^pro and endoribonuclease of SARS-CoV-2. Further studies of ADME-Tox and bioavailability of drugs were also performed that exhibited efficient parameters of drug likeness. Molecular dynamics simulation calculations were performed for the most negative binding affinity of the compound to evaluate the dynamic behavior,and stability of protein-ligand complex. Our findings suggest that these compounds could be potential inhibitors of SARS‐CoV-2 main protease and endoribonuclease. However, further in-vitro and pre-clinical experiments would validate the potential inhibitors of SARS‐CoV‐2 proteins.

Papaya Fruit Pulp and Resulting Lactic Fermented Pulp Exert Antiviral Activity against Zika Virus

There are a several emerging and re-emerging RNA viruses that are prevalent around the world for which there are no licensed vaccines or antiviral drugs. Zika virus (ZIKV) is an example of an emerging virus that has become a significant concern worldwide because of its association with severe congenital malformations and neurological disorders in adults. Several polyphenol-rich extracts from plants were used as nutraceuticals which exhibit potent in vitro antiviral effects. Here, we demonstrated that the papaya pulp extracted from Carica papaya fruit inhibits the infection of ZIKV in human cells without loss of cell viability. At the non-cytotoxic concentrations, papaya pulp extract has the ability to reduce the virus progeny production in ZIKV-infected human cells by at least 4-log, regardless of viral strains tested. Time-of-drug-addition assays revealed that papaya pulp extract interfered with the attachment of viral particles to the host cells. With a view of preserving the properties of papaya pulp over time, lactic fermentation based on the use of bacterial strains Weissella cibaria 64, Lactobacillus plantarum 75 and Leuconostoc pseudomesenteroides 56 was performed and the resulting fermented papaya pulp samples were tested on ZIKV. We found that lactic fermentation of papaya pulp causes a moderate loss of antiviral activity against ZIKV in a bacterial strain-dependent manner. Whereas IC₅₀ of the papaya pulp extract was 0.3 mg/mL, we found that fermentation resulted in IC₅₀ up to 4 mg/mL. We can conclude that papaya pulp possesses antiviral activity against ZIKV and the fermentation process has a moderate effect on the antiviral effect.

Targeting SARS-CoV-2 spike protein of COVID-19 with naturally occurring phytochemicals: an in silico study for drug development

Spike glycoprotein, a class I fusion protein harboring the surface of SARS-CoV-2 (SARS-CoV-2S), plays a seminal role in the viral infection starting from recognition of the host cell surface receptor, attachment to the fusion of the viral envelope with the host cells. Spike glycoprotein engages host Angiotensin-converting enzyme 2 (ACE2) receptors for entry into host cells, where the receptor recognition and attachment of spike glycoprotein to the ACE2 receptors is a prerequisite step and key determinant of the host cell and tissue tropism. Binding of spike glycoprotein to the ACE2 receptor triggers a cascade of structural transitions, including transition from a metastable pre-fusion to a post-fusion form, thereby allowing membrane fusion and internalization of the virus. From ancient times people have relied on naturally occurring substances like phytochemicals to fight against diseases and infection. Among these phytochemicals, flavonoids and non-flavonoids have been the active sources of different anti-microbial agents. We performed molecular docking studies using 10 potential naturally occurring compounds (flavonoids/non-flavonoids) against the SARS-CoV-2 spike protein and compared their affinity with an FDA approved repurposed drug hydroxychloroquine (HCQ). Further, our molecular dynamics (MD) simulation and energy landscape studies with fisetin, quercetin, and kamferol revealed that these molecules bind with the hACE2-S complex with low binding free energy. The study provided an indication that these molecules might have the potential to perturb the binding of hACE2-S complex. In addition, ADME analysis also suggested that these molecules consist of drug-likeness property, which may be further explored as anti-SARS-CoV-2 agents.

Communicated by Ramaswamy H. Sarma

Antiviral and virucidal effects of curcumin on transmissible gastroenteritis virus in vitro

Emerging coronaviruses represent serious threats to human and animal health worldwide, and no approved therapeutics are currently available. Here, we used Transmissible gastroenteritis virus (TGEV) as the alpha-coronavirus model, and investigated the antiviral properties of curcumin against TGEV. Our results demonstrated that curcumin strongly inhibited TGEV proliferation and viral protein expression in a dose-dependent manner. We also observed that curcumin exhibited direct virucidal abilities in a dose-, temperature- and time-dependent manner. Furthermore, time-of-addition assays showed that curcumin mainly acted in the early phase of TGEV replication. Notably, in an adsorption assay, curcumin at 40 µM resulted in a reduction in viral titres of 3.55 log TCID₅₀ ml^-1, indicating that curcumin possesses excellent inhibitory effects on the adsorption of TGEV. Collectively, we demonstrate for the first time that curcumin has virucidal activity and virtual inhibition against TGEV, suggesting that curcumin might be a candidate drug for effective control of TGEV infection.

Potential effects of curcumin in the treatment of COVID-19 infection

Coronavirus disease 2019 (COVID-19) outbreak is an ongoing pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with considerable mortality worldwide. The main clinical manifestation of COVID-19 is the presence of respiratory symptoms, but some patients develop severe cardiovascular and renal complications. There is an urgency to understand the mechanism by which this virus causes complications so as to develop treatment options. Curcumin, a natural polyphenolic compound, could be a potential treatment option for patients with coronavirus disease. In this study, we review some of the potential effects of curcumin such as inhibiting the entry of virus to the cell, inhibiting encapsulation of the virus and viral protease, as well as modulating various cellular signaling pathways. This review provides a basis for further research and development of clinical applications of curcumin for the treatment of newly emerged SARS-CoV-2.

Antiviral Natural Products for Arbovirus Infections

Over the course of the last 50 years, the emergence of several arboviruses have resulted in countless outbreaks globally. With a high proportion of infections occurring in tropical and subtropical regions where arthropods tend to be abundant, Asia in particular is a region that is heavily affected by arboviral diseases caused by dengue, Japanese encephalitis, West Nile, Zika, and chikungunya viruses. Major gaps in protection against the most significant emerging arboviruses remains as there are currently no antivirals available, and vaccines are only available for some. A potential source of antiviral compounds could be discovered in natural products—such as vegetables, fruits, flowers, herbal plants, marine organisms and microorganisms—from which various compounds have been documented to exhibit antiviral activities and are expected to have good tolerability and minimal side effects. Polyphenols and plant extracts have been extensively studied for their antiviral properties against arboviruses and have demonstrated promising results. With an abundance of natural products to screen for new antiviral compounds, it is highly optimistic that natural products will continue to play an important role in contributing to antiviral drug development and in reducing the global infection burden of arboviruses.

Obesity as a risk factor for COVID-19: an overview

The current coronavirus disease-2019 (COVID-19) pandemic presents a huge challenge for health-care systems worldwide. Many different risk factors are associated with disease severity, such as older age, diabetes, hypertension, and most recently obesity. The incidence of obesity has been on the rise for the past 25 years, reaching over 2 billion people throughout the world, and obesity itself could be considered a pandemic. In this review, we summarize aspects involved with obesity, such as changes in the immune response, nutritional factors, physiological factors, and the gut-lung axis, that impact the viral response and the COVID-19 prognosis.

The Geraniin-Rich Extract from Reunion Island Endemic Medicinal Plant Phyllanthus phillyreifolius Inhibits Zika and Dengue Virus Infection at Non-Toxic Effect Doses in Zebrafish

The mosquito-borne viruses dengue (DENV) and Zika (ZIKV) viruses are two medically important pathogens in tropical and subtropical regions of the world. There is an urgent need of therapeutics against DENV and ZIKV, and medicinal plants are considered as a promising source of antiviral bioactive metabolites. In the present study, we evaluated the ability of Phyllanthus phillyreifolius, an endemic medicinal plant from Reunion Island, to prevent DENV and ZIKV infection in human cells. At non-cytotoxic concentration in vitro, incubation of infected A549 cells with a P. phillyreifolius extract or its major active phytochemical geraniin resulted in a dramatic reduction of virus progeny production for ZIKV as well as four serotypes of DENV. Virological assays showed that P. phillyreifolius extract-mediated virus inhibition relates to a blockade in internalization of virus particles into the host cell. Infectivity studies on ZIKV showed that both P. phillyreifolius and geraniin cause a loss of infectivity of the viral particles. Using a zebrafish model, we demonstrated that administration of P. phillyreifolius and geraniin has no effect on zebrafish locomotor activity while no morbidity nor mortality was observed up to 5 days post-inoculation. Thus, P. phillyreifolius could act as an important source of plant metabolite geraniin which is a promising antiviral compound in the fight against DENV and ZIKV.

Therapeutic opportunities to manage COVID-19/SARS-CoV-2 infection: Present and future

A severe form of respiratory disease - COVID-19, caused by SARS-CoV-2 infection, has evolved into a pandemic resulting in significant morbidity and mortality. The unabated spread of the disease is due to lack of vaccine and effective therapeutic agents against this novel virus. Hence, the situation demands an immediate need to explore all the plausible therapeutic and prophylactic strategies that can be made available to stem the spread of the disease. Towards this effort, the current review outlines the key aspects of the pathobiology associated with the morbidity and mortality in COVID-19 patients, which includes a viral response phase and an exaggerated host response phase. The review also summarizes therapeutic agents that are currently being explored along with those with potential for consideration. The broad groups of therapeutic agents discussed include those that: (i) block viral entry to host cells, (ii) block viral replication and survival in host cells, and (iii) dampen exaggerated host immune response. The various kinds of pharmaceutical prophylactic options that may be followed to prevent COVID-19 have also been discussed.

Serum albumin-mediated strategy for the effective targeting of SARS-CoV-2

Novel coronavirus (NCoV-19), also known as SARS CoV-2, is a pathogen causing an emerging infection that rapidly increases in incidence and geographic range, is associated with the ever-increasing morbidity and mortality rates, and shows sever economic impact worldwide. The WHO declares the NCoV-19 infection disease (COVID-19) a Public Health Emergency of International Concern on 30 January 2020 and subsequently, on March 11, 2020, declared it a Global Pandemic. Although some people infected with SARS CoV-2 have no symptoms, the spectrum of symptomatic infection ranges from mild to critical, with most COVID-19 infections being not severe. The common mild symptoms include body aches, dry cough, fatigue, low-grade fever, nasal congestion, and sore throat. More severe COVID-19 symptoms are typical of pneumonia, and upon progression, the patient's condition can worsen with severe respiratory and cardiac problems. Currently, there is no drug or vaccine for curing patients. It has been observed that people with challenged immunity are highly prone to SARS CoV-2 infection and least likely to recover. Also, older adults and people of any age with serious underlying medical conditions might be at higher risk for severe forms of COVID-19. We are suggesting here a strategy for the COVID-19 treatment that could be effective in curing the patients in the current scenario when no efficient medicine or Vaccine is currently available, and Clinicians solely depend upon the performing trials with drugs with known antiviral activities. Our proposed strategy is based on the compilation of published scientific research and concepts. The different published research indicates the success of a similar strategy in different physiological conditions, and such a strategy is widely studied at the cellular level and in animal models.