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1.
Pathogens ; 11(5)2022 May 02.
Article in English | MEDLINE | ID: covidwho-1875721

ABSTRACT

Using an effective natural virucidal substance may be a feasible approach for preventing food-borne viral contamination. Here, the virucidal efficacy of theaflavins (TFs)-enriched tea leaf extract (TY-1) against feline calicivirus (FCV) and murine norovirus (MNV), surrogates of human norovirus (HuNoV), was evaluated. The virus solutions were mixed with various dosages of TY-1 and incubated at 25 °C for different contact times. TY-1 reduced the viral titer of both surrogate viruses in a time- and dosage-dependent manner. A statistically significant reduction in the viral titer of FCV by 5.0 mg/mL TY-1 and MNV by 25.0 mg/mL TY-1 was observed in 10 s and 1 min, respectively. Furthermore, TY-1 reduced the viral titer of FCV and MNV on the dry surface in 10 min. The multiple compounds in TY-1, including TFs and catechins, contributed to its overall virucidal activity. Furthermore, the effect of TY-1 on viral proteins and genome was analyzed using Western blotting, RT-PCR, and transmission electron microscopy. TY-1 was found to promote the profound disruption of virion structures, including the capsid proteins and genome. Our finding demonstrates the potential of using TY-1 as a nature-derived disinfectant in food processing facilities and healthcare settings to reduce viral load and HuNoV transmission.

2.
Beverages ; 8(1):13, 2022.
Article in English | ProQuest Central | ID: covidwho-1760334

ABSTRACT

(1) Background: beverages based on extracts from Camellia sinensis are popular worldwide. Due to an increasing number of processed teas on the market, there is a need to develop unified classification standards based on chemical analysis. Meanwhile, phytochemical characterizations are mainly performed on tea samples from China (~80%). Hence, data on teas of other provenances is recommended. (2) Methods: in the present investigation, we characterized lyophilised extracts obtained by infusion, maceration and methanolic extraction derived from tea samples from China, Japan, Sri Lanka and Portugal by phytochemistry (catechins, oxyaromatic acids, flavonols, alkaloids and theanine). The real benefits of drinking the tea were analysed based on the bioavailability of the determined phytochemicals. (3) Results: the infusions revealed the highest total phenolic contents (TPC) amounts, while methanolic extracts yielded the lowest. The correlation matrix indicated that the levels of phenolic compounds were similar in the infusions and methanolic samples, while extractions made by maceration were significantly different. The differences could be partially explained by the different amounts of (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG) and gallic acids (GA). The catechin percentages were significantly lower in the macerations, especially the quantity of EGCG decreases by 4- to 5-fold after this process. (4) Conclusions: the results highlight the importance of the processing methodology to obtain “instant tea”;the composition of the extracts obtained with the same methodology is not significantly affected by the provenance of the tea. However, attention should be drawn to the specificities of the Japanese samples (the tea analysed in the present work was of Sencha quality). In contrast, the extraction methodology significantly affects the phytochemical composition, especially concerning the content of polyphenols. As such, our results indicate that instant tea classification based on chemical composition is sensible, but there is a need for a standard extraction methodology, namely concerning the temperature and time of contact of the tea leaves with the extraction solvent.

3.
Phyton-International Journal of Experimental Botany ; 91(5):1089-1104, 2022.
Article in English | Web of Science | ID: covidwho-1668061

ABSTRACT

Coronaviruses caused an outbreak pandemic disease characterized by a severe acute respiratory distress syndrome leading to the infection of more than 200 million patients and the death of more than 4 million individuals. The primary treatment is either supportive or symptomatic. Natural products have an important role in the development of various drugs. Thus, screening of natural compounds with reported antiviral activities can lead to the discovery of potential inhibitory entities against coronaviruses. In the current study, an in-silico molecular docking experiment was conducted on the effects of some of these natural antiviral phytoconstituents, (e.g., procyanidin B2, theaflavin, quercetin, ellagic acid, caffeoylquinic acid derivatives, berginin, eudesm-1 beta, 6 alpha, 11-triol and arbutin), on the crystal structure of SARS-CoV-2 main protease (PDB ID: 6w63) using AutoDock-Vina software. Many of the docked compounds revealed good binding affinity, with procyanidin B2 (-8.6 Kcal/mol) and theaflavin (-8.5 Kcal/mol) showing a better or similar binding score as the ligand (-8.5 Kcal/mol). Molecular dynamics simulations were carried out at 100 ns and revealed that procyanidin B2 forms a more stable complex with SARS-CoV-2 main protease than theaflavin. Procyanidin B2, theaflavin, and 4,5-dicaffeoylquinic acid were evaluated for toxicity by ProTox-II webserver and were non-toxic according to the predicted LD50 values and safe on different organs and pathways. Additionally, these phytoconstituents showed good ADME properties and acceptable lipophilicity, as evaluated using WLOGP. Amongst the tested compounds, procyanidin B2 showed the highest lipophilic value. It is worth mentioning that these natural inhibitiors of SARS-CoV-2 main protease are components of green and black tea that can be used as a supporting supplement for COVID patients or as potential nuclei for further drug design and development campaigns.

4.
Molecules ; 26(21)2021 Nov 08.
Article in English | MEDLINE | ID: covidwho-1512511

ABSTRACT

This work describes an untargeted analytical approach for the screening, identification, and characterization of the trans-epithelial transport of green tea (Camellia sinensis) catechin extracts with in vitro inhibitory effect against the SARS-CoV-2 papain-like protease (PLpro) activity. After specific catechin extraction, a chromatographic separation obtained six fractions were carried out. The fractions were assessed in vitro against the PLpro target. Fraction 5 showed the highest inhibitory activity against the SARS-CoV-2 PLpro (IC50 of 0.125 µg mL-1). The untargeted characterization revealed that (-)-epicatechin-3-gallate (ECG) was the most abundant compound in the fraction and the primary molecule absorbed by differentiated Caco-2 cells. Results indicated that fraction 5 was approximately 10 times more active than ECG (IC50 value equal to 11.62 ± 0.47 µg mL-1) to inhibit the PLpro target. Overall, our findings highlight the synergistic effects of the various components of the crude extract compared to isolated ECG.


Subject(s)
Catechin/pharmacology , Coronavirus Papain-Like Proteases/metabolism , Tea/metabolism , Antiviral Agents/chemistry , COVID-19/drug therapy , COVID-19/metabolism , Caco-2 Cells , Camellia sinensis/metabolism , Catechin/analogs & derivatives , Catechin/chemistry , Catechin/metabolism , Coronavirus Papain-Like Proteases/drug effects , Epithelium/drug effects , Epithelium/metabolism , Humans , Mass Spectrometry/methods , Plant Extracts/chemistry , Plant Extracts/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Tea/chemistry , Tea/physiology
5.
Phytomedicine ; 96: 153853, 2022 Feb.
Article in English | MEDLINE | ID: covidwho-1510181

ABSTRACT

BACKGROUND AND PURPOSE: Previous studies suggest that major Camellia sinensis (tea) catechins can inhibit 3-chymotrypsin-like cysteine protease (3CLpro), inspiring us to study 3CLpro inhibition of the recently discovered catechins from tea by our group. METHODS: Autodock was used to dock 3CLpro and 16 tea catechins. Further, a 3CLpro activity detection system was used to test their intra and extra cellular 3CLpro inhibitory activity. Surface plasmon resonance (SPR) was used to analyze the dissociation constant (KD) between the catechins and 3CLpro. RESULTS: Docking data suggested that 3CLpro interacted with the selected 16 catechins with low binding energy through the key amino acid residues Thr24, Thr26, Asn142, Gly143, His163, and Gln189. The selected catechins other than zijuanin D (3) and (-)-8-(5''R)-N-ethyl-2-pyrrolidinone-3-O-cinnamoylepicatechin (11) can inhibit 3CLpro intracellularly. The extracellular 3CLpro IC50 values of (-)-epicatechin 3-O-caffeoate (EC-C, 1), zijuanin C (2), etc-pyrrolidinone C and D (6), etc-pyrrolidinone A (9), (+)-gallocatechin gallate (GCG), and (-)-epicatechin gallate (ECG) are 1.58 ± 0.21, 41.2 ± 3.56, 0.90 ± 0.03, 46.71 ± 10.50, 3.38 ± 0.48, and 71.78 ± 8.36 µM, respectively. The KD values of 1, 6, and GCG are 4.29, 3.46, and 3.36 µM, respectively. CONCLUSION: Together, EC-C (1), etc-pyrrolidinone C and D (6), and GCG are strong 3CLpro inhibitors. Our results suggest that structural modification of catechins could be conducted by esterificating the 3-OH as well as changing the configuration of C-3, C-3''' or C-5''' to discover strong SARS-CoV-2 inhibitors.


Subject(s)
COVID-19 , Camellia sinensis , Catechin , Catechin/analysis , Catechin/pharmacology , Humans , Molecular Docking Simulation , Protease Inhibitors/pharmacology , SARS-CoV-2 , Tea
6.
J Biomol Struct Dyn ; 39(12): 4362-4374, 2021 08.
Article in English | MEDLINE | ID: covidwho-1317845

ABSTRACT

Coronavirus disease 2019 (COVID-19) is a viral respiratory disease which caused global health emergency and announced as pandemic disease by World Health Organization. Lack of specific drug molecules or treatment strategy against this disease makes it more devastating. Thus, there is an urgent need of effective drug molecules to fight against COVID-19. The main protease (Mpro) of SARS CoV-2, a key component of this viral replication, is considered as a prime target for anti-COVID-19 drug development. In order to find potent Mpro inhibitors, we have selected eight polyphenols from green tea, as these are already known to exert antiviral activity against many RNA viruses. We have elucidated the binding affinities and binding modes between these polyphenols including a well-known Mpro inhibitor N3 (having binding affinity -7.0 kcal/mol) and Mpro using molecular docking studies. All eight polyphenols exhibit good binding affinity toward Mpro (-7.1 to -9.0 kcal/mol). However, only three polyphenols (epigallocatechin gallate, epicatechingallate and gallocatechin-3-gallate) interact strongly with one or both catalytic residues (His41 and Cys145) of Mpro. Molecular dynamics simulations (100 ns) on these three Mpro-polyphenol systems further reveal that these complexes are highly stable, experience less conformational fluctuations and share similar degree of compactness. Estimation of total number of intermolecular H-bond and MM-GBSA analysis affirm the stability of these three Mpro-polyphenol complexes. Pharmacokinetic analysis additionally suggested that these polyphenols possess favorable drug-likeness characteristics. Altogether, our study shows that these three polyphenols can be used as potential inhibitors against SARS CoV-2 Mpro and are promising drug candidates for COVID-19 treatment.


Subject(s)
COVID-19 , Protease Inhibitors , COVID-19/drug therapy , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , Peptide Hydrolases , Polyphenols/pharmacology , Protease Inhibitors/pharmacology , SARS-CoV-2 , Tea
7.
Molecules ; 26(13)2021 Jun 30.
Article in English | MEDLINE | ID: covidwho-1304690

ABSTRACT

Influenza is one of the most serious respiratory viral infections worldwide. Although several studies have reported that green tea catechins (GTCs) might prevent influenza virus infection, this remains controversial. We performed a systematic review and meta-analysis of eight studies with 5,048 participants that examined the effect of GTC administration on influenza prevention. In a random-effects meta-analysis of five RCTs, 884 participants treated with GTCs showed statistically significant effects on the prevention of influenza infection compared to the control group (risk ratio (RR) 0.67, 95%CIs 0.51-0.89, P = 0.005) without evidence of heterogeneity (I2= 0%, P = 0.629). Similarly, in three cohort studies with 2,223 participants treated with GTCs, there were also statistically significant effects (RR 0.52, 95%CIs 0.35-0.77, P = 0.001) with very low evidence of heterogeneity (I2 = 3%, P = 0.358). Additionally, the overall effect in the subgroup analysis of gargling and orally ingested items (taking capsules and drinking) showed a pooled RR of 0.62 (95% CIs 0.49-0.77, P = 0.003) without heterogeneity (I2= 0%, P = 0.554). There were no obvious publication biases (Egger's test (P = 0.138) and Begg's test (P = 0.103)). Our analysis suggests that green tea consumption is effective in the prophylaxis of influenza infections. To confirm the findings before implementation, longitudinal clinical trials with specific doses of green tea consumption are warranted.


Subject(s)
Antiviral Agents/therapeutic use , Catechin/therapeutic use , Plant Extracts/chemistry , Tea/chemistry , Antiviral Agents/chemistry , Catechin/chemistry , Clinical Trials as Topic , Humans , Influenza, Human
8.
Mol Cell Biochem ; 476(11): 3911-3922, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1281314

ABSTRACT

Human SARS Coronavirus-2 (SARS-CoV-2) has infected more than 170 million people worldwide and resulted in more than 3.5 million deaths so far. The infection causes Coronavirus disease (COVID-19) in people of all age groups, notably diabetic and old age people, at a higher risk of infectivity and fatality. Around 35% of the patients who have died of the disease were diabetic. The infection is associated with weakening immune response, chronic inflammation, and potential direct pancreatic impairment. There seems to be a three-way association of the SARS-CoV-2 infection with diabetes and aging. The COVID-19 infection causes metabolism complications, which may induce diabetes and accelerate aging in healthy individuals. How does diabetes elevate the likelihood of the infection is not clearly understood. we summarize mechanisms of accelerated aging in COVID-19 and diabetes, and the possible correlation of these three diseases. Various drug candidates under different stages of pre-clinical or clinical developments give us hope for the development of COVID-19 therapeutics, but there is no approved drug so far to treat this disease. Here, we explored the potential of anti-diabetic and anti-aging natural compounds for the COVID-19 treatment. We have also reviewed different therapeutic strategies with plant-based natural products that may be used to cure patients infected with SARS-CoV-2 and post-infection syndrome.


Subject(s)
Aging/drug effects , COVID-19/drug therapy , Diabetes Mellitus/drug therapy , SARS-CoV-2/physiology , Age Factors , Animals , Antioxidants/therapeutic use , COVID-19/epidemiology , COVID-19/immunology , Humans , Hypoglycemic Agents/therapeutic use , Pandemics , Phytochemicals/therapeutic use
9.
Comput Biol Med ; 135: 104560, 2021 08.
Article in English | MEDLINE | ID: covidwho-1263240

ABSTRACT

BACKGROUND: The global pandemic caused by a RNA virus capable of infecting humans and animals, has resulted in millions of deaths worldwide. Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) infects the lungs, and the gastrointestinal tract to some extent. Rapid structural mutations have increased the virulence and infectivity of the virus drastically. One such mutated strain known as the UK variant has caused many deaths in the United Kingdom. HYPOTHESIS: Among several indigenous natural ingredients used for prevention and cure of many diseases, the catechins have been reported for their antiviral activity, even against SARS-CoV-2. Characteristic mutations present on the spike protein have presented the newer strain its enhanced infectivity. The spike protein helps the virus bind to ACE2 receptor of the host cell and hence is a drug target. Catechins have been reported for their entry-inhibitory activity against several viruses. METHOD: In this study, we performed molecular docking of different catechins with the wild and mutant variants of the spike protein of SARS-CoV-2. The stability of the best docked complexes was validated using molecular dynamics simulation. RESULTS: The in-silico studies show that the catechins form favourable interactions with the spike protein and can potentially impair its function. Epigallocatechin gallate (EGCG) showed the best binding among the catechins against both the strains. Both the protein-ligand complexes were stable throughout the simulation time frame. CONCLUSION: The outcomes should encourage further exploration of the antiviral activity of EGCG against SARS-CoV-2 and its variants.


Subject(s)
Catechin , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Catechin/pharmacology , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Binding
10.
Antioxidants (Basel) ; 10(6)2021 Jun 07.
Article in English | MEDLINE | ID: covidwho-1259421

ABSTRACT

Effective antiviral therapeutics are urgently required to fight severe acute respiratory syndrome (SARS) caused by a SARS coronavirus (SARS-CoV). Because polyphenol catechins could confer antioxidative, anti-inflammatory, antiviral, and antimicrobial activities, we assessed the therapeutic effects of catechins against SARS-CoV replication in Vero E6 cells, the preventive effect of catechins on CD25/CD69/CD94/CD8+ cytotoxic T lymphocytes-mediated adaptive immunity, and the protective effect on lipopolysaccharide-induced acute lung injury (ALI) in mice. We found that catechins containing 32.8% epigallocatechin gallate, 15.2% epicatechin gallate, 13.2 epicatechin, 10.8% epigallocatechin, 10.4% gallocatechin, and 4.4% catechin directly inhibited SARS-CoV replication at sub-micromolecular concentrations. Four-week catechins ingestion increased CD8+ T cell percentage, upregulated CD69+/CD25+/CD94-NKG2A/CD8+ T lymphocytes-mediated adaptive immunity, and increased type I cytokines release responding to ovalbumin/alum. Catechins significantly reduced lipopolysaccharide-induced cytokine storm and oxidative stress and ALI by inhibiting PI3K/AKT/mTOR signaling to upregulate Beclin-1/Atg5-Atg12/LC3-II-mediated autophagy mechanism. Pretreatment of autophagy inhibitor 3-Methyladenine reversed the inhibiting effects of catechins on the cytokines and oxidative stress levels and ALI. In conclusion, our data indicated that catechins directly inhibited SARS-CoV replication, potentiated the CD25/CD69/CD94/CD8+ T lymphocytes-mediated adaptive immunity and attenuated lipopolysaccharide-induced ALI and cytokine storm by PI3K/AKT/mTOR-signaling-mediated autophagy, which may be applied to prevent and/or treat SARS-CoV infection.

11.
Molecules ; 26(5)2021 Feb 24.
Article in English | MEDLINE | ID: covidwho-1100140

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has emerged to be the greatest threat to humanity in the modern world and has claimed nearly 2.2 million lives worldwide. The United States alone accounts for more than one fourth of 100 million COVID-19 cases across the globe. Although vaccination against SARS-CoV-2 has begun, its efficacy in preventing a new or repeat COVID-19 infection in immunized individuals is yet to be determined. Calls for repurposing of existing, approved, drugs that target the inflammatory condition in COVID-19 are growing. Our initial gene ontology analysis predicts a similarity between SARS-CoV-2 induced inflammatory and immune dysregulation and the pathophysiology of rheumatoid arthritis. Interestingly, many of the drugs related to rheumatoid arthritis have been found to be lifesaving and contribute to lower COVID-19 morbidity. We also performed in silico investigation of binding of epigallocatechin gallate (EGCG), a well-known catechin, and other catechins on viral proteins and identified papain-like protease protein (PLPro) as a binding partner. Catechins bind to the S1 ubiquitin-binding site of PLPro, which might inhibit its protease function and abrogate SARS-CoV-2 inhibitory function on ubiquitin proteasome system and interferon stimulated gene system. In the realms of addressing inflammation and how to effectively target SARS-CoV-2 mediated respiratory distress syndrome, we review in this article the available knowledge on the strategic placement of EGCG in curbing inflammatory signals and how it may serve as a broad spectrum therapeutic in asymptomatic and symptomatic COVID-19 patients.


Subject(s)
Antiviral Agents , COVID-19/drug therapy , Catechin/analogs & derivatives , Coronavirus 3C Proteases , Cysteine Proteinase Inhibitors , SARS-CoV-2/enzymology , Tea/chemistry , Antiviral Agents/chemistry , Antiviral Agents/therapeutic use , Binding Sites , COVID-19/enzymology , COVID-19/epidemiology , Catechin/chemistry , Catechin/therapeutic use , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/chemistry , Cysteine Proteinase Inhibitors/chemistry , Cysteine Proteinase Inhibitors/therapeutic use , Humans
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