Potential of green tea EGCG in neutralizing SARS-CoV-2 Omicron variant with greater tropism toward the upper respiratory tract

Comparison of Volatile Compounds in Jingshan Green Tea Scented with Different Flowers Using GC-IMS and GC-MS Analyses

Scented green tea (Camellia sinensis) is a type of reprocessed green tea produced by scenting with flowers. To investigate the differences in the volatiles of scented green tea processed with four different flowers (Jasminum sambac, Osmanthus fragrans, Michelia alba, and Rosa rugosa), gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS) were employed to detect and identify the volatile compounds in the four types of scented teas. GC-IMS and GC-MS identified 108 and 101 volatile compounds, respectively. The key characteristic volatile compounds, namely indole, linalool, β-myrcene, benzyl acetate, and ethyl benzoate (jasmine tea); cedrol, (E)-β-ionone, γ-decalactone, and dihydro-β-ionol (osmanthus tea); geraniol, phenylethyl alcohol, jasmone, methyl jasmonate, hexadecanoic acid, 4-ethyl-benzaldehyde, 2-methylbutyl hexanoate, and indole (michelia tea); and 3,5-dimethoxytoluene, (E)-β-ionone, and 2-methylbutyl hexanoate (rose tea), were identified through chemometric analysis combined with relative odor activity values (ROAVs) and sensory evaluation. This study provides new insights into the formation of aroma molecular fingerprints during green tea scenting with flowers, providing theoretical guidance for infusing distinct aroma characteristics into green tea during scented tea processing.

Analyzing the Effects of Rapid and Natural Cooling Techniques on the Quality of Hand-Shaken Green Tea Beverages

This study compared the quality of hand-shaken green tea prepared through rapid and natural cooling methods. Cooling is crucial in preserving green tea's flavor, aroma, and nutritional components. In the rapid cooling method, green tea is freshly brewed at an initial temperature of 95 °C for 25 min, and then rapidly cooled to 18 °C for 25 min. Conversely, the natural cooling method involves brewing tea at the same initial temperature and time, but allowing it to cool gradually to 30 °C over approximately 4-5 h at room temperature. This study's findings indicate that the rapid cooling method produced green tea with a more vibrant color and improved clarity versus the natural cooling method. Sensory analysis revealed that the taste and aroma of the hand-shaken green tea prepared using rapid cooling were perceived to be more refreshing and invigorating. However, the natural cooling method preserved a higher level of chemical components, including individual catechin caffeine, total polyphenol, soluble solids, reducing sugar, and total tannins. The essential amino acid content of the rapidly and naturally cooled green tea infusions was 6.85 and 13.55 μg/mL, respectively. The γ-Aminobutyric acid (GABA) content was 439.82 and 457.31 μg/mL, respectively. This study's findings suggest that rapid cooling during the preparation of hand-shaken green tea enhances its overall quality. The vibrant color, improved clarity, refreshing taste, and invigorating aroma make it a preferable choice for tea enthusiasts who seek an enhanced sensory experience and excellent quality.

Tannic acids and proanthocyanidins in tea inhibit SARS-CoV-2 variants infection

The COVID-19 pandemic has caused hundreds million cases and millions death as well as continues to infect human life in the world since late of 2019. The breakthrough infection caused from mutation of SARS-CoV-2 is rising even the vaccinated population has been increasing. Currently, the severe threat posed by SARS-CoV-2 has been alleviated worldwide, and the situation has transitioned to coexisting with the virus. The dietary food with antiviral activities may improve to prevent virus infection for living with COVID-19 pandemic. Teas containing enriched phenolic ingredients such as tannins have been reported to be antitumor agents as well as be good inhibitors for coronavirus. This study developed a highly sensitive and selective ultra-high performance liquid chromatography-high resolution mass spectrometric method for quantification of tannic acids, a hydrolysable tannin, and proanthocyanidins, a condense tannin, in teas with different levels of fermentation. The in vitro pseudoviral particles (Vpp) infection assay was used to evaluate the inhibition activities of various teas. The results of current research demonstrate that the tannins in teas are effective inhibitors against infection of SARS-CoV-2 and its variants.

Bile acids and coronavirus disease 2019

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been significantly alleviated. However, long-term health effects and prevention strategy remain unresolved. Thus, it is essential to explore the pathophysiological mechanisms and intervention for SARS-CoV-2 infection. Emerging research indicates a link between COVID-19 and bile acids, traditionally known for facilitating dietary fat absorption. The bile acid ursodeoxycholic acid potentially protects against SARS-CoV-2 infection by inhibiting the farnesoid X receptor, a bile acid nuclear receptor. The activation of G-protein-coupled bile acid receptor, another membrane receptor for bile acids, has also been found to regulate the expression of angiotensin-converting enzyme 2, the receptor through which the virus enters human cells. Here, we review the latest basic and clinical evidence linking bile acids to SARS-CoV-2, and reveal their complicated pathophysiological mechanisms.

Microfluidics-enabled fluorinated assembly of EGCG-ligands-siTOX nanoparticles for synergetic tumor cells and exhausted t cells regulation in cancer immunotherapy

Immune checkpoint inhibitor (ICI)-derived evolution offers a versatile means of developing novel immunotherapies that targets programmed death-ligand 1 (PD-L1)/programmed death-1 (PD-1) axis. However, one major challenge is T cell exhaustion, which contributes to low response rates in "cold" tumors. Herein, we introduce a fluorinated assembly system of LFNPs/siTOX complexes consisting of fluorinated EGCG (FEGCG), fluorinated aminolauric acid (LA), and fluorinated polyethylene glycol (PEG) to efficiently deliver small interfering RNA anti-TOX (thymus high mobility group box protein, TOX) for synergistic tumor cells and exhausted T cells regulation. Using a microfluidic approach, a library of LFNPs/siTOX complexes were prepared by altering the placement of the hydrophobe (LA), the surface PEGylation density, and the siTOX ratio. Among the different formulations tested, the lead formulation, LFNPs3-3/siTOX complexes, demonstrated enhanced siRNA complexation, sensitive drug release, improved stability and delivery efficacy, and acceptable biosafety. Upon administration by the intravenous injection, this formulation was able to evoke a robust immune response by inhibiting PD-L1 expression and mitigating T cell exhaustion. Overall, this study provides valuable insights into the fluorinated assembly and concomitant optimization of the EGCG-based delivery system. Furthermore, it offers a promising strategy for cancer immunotherapy, highlighting its potential in improving response rates in ''cold'' tumors.

Engineering Antimicrobial Metal-Phenolic Network Nanoparticles with High Biocompatibility for Wound Healing

Antibiotic-resistant bacteria pose a global health threat by causing persistent and recurrent microbial infections. To address this issue, antimicrobial nanoparticles (NPs) with low drug resistance but potent bactericidal effects have been developed. However, many of the developed NPs display poor biosafety and their synthesis often involves complex procedures and the antimicrobial modes of action are unclear. Herein, a simple strategy is reported for designing antimicrobial metal-phenolic network (am-MPN) NPs through the one-step assembly of a seeding agent (diethyldithiocarbamate), natural polyphenols, and metal ions (e.g., Cu2+ ) in aqueous solution. The Cu2+ -based am-MPN NPs display lower Cu2+ antimicrobial concentrations (by 10-1000 times) lower than most reported nanomaterials and negligible toxicity across various models, including, cells, blood, zebrafish, and mice. Multiple antimicrobial modes of the NPs have been identified, including bacterial wall disruption, reactive oxygen species production, and quinoprotein formation, with the latter being a distinct pathway identified for the antimicrobial activity of the polyphenol-based am-MPN NPs. The NPs exhibit excellent performance against multidrug-resistant bacteria (e.g., methicillin-resistant Staphylococcus aureus (MRSA)), efficiently inhibit and destroy bacterial biofilms, and promote the healing of MRSA-infected skin wounds. This study provides insights on the antimicrobial properties of metal-phenolic materials and the rational design of antimicrobial metal-organic materials.

Quercetin inhibits SARS-CoV-2 infection and prevents syncytium formation by cells co-expressing the viral spike protein and human ACE2

BACKGROUND

Several in silico studies have determined that quercetin, a plant flavonol, could bind with strong affinity and low free energy to SARS-CoV-2 proteins involved in viral entry and replication, suggesting it could block infection of human cells by the virus. In the present study, we examined the ex vivo ability of quercetin to inhibit of SARS-CoV-2 replication and explored the mechanisms of this inhibition.

METHODS

Green monkey kidney Vero E6 cells and in human colon carcinoma Caco-2 cells were infected with SARS-CoV-2 and incubated in presence of quercetin; the amount of replicated viral RNA was measured in spent media by RT-qPCR. Since the formation of syncytia is a mechanism of SARS-CoV-2 propagation, a syncytialization model was set up using human embryonic kidney HEK293 co-expressing SARS-CoV-2 Spike (S) protein and human angiotensin converting enzyme 2 (ACE2), [HEK293(S + ACE2) cells], to assess the effect of quercetin on this cytopathic event by microscopic imaging and protein immunoblotting.

RESULTS

Quercetin inhibited SARS-CoV-2 replication in Vero E6 cells and Caco-2 cells in a concentration-dependent manner with a half inhibitory concentration (IC50) of 166.6 and 145.2 µM, respectively. It also inhibited syncytialization of HEK293(S + ACE2) cells with an IC50 of 156.7 µM. Spike and ACE2 co-expression was associated with decreased expression, increased proteolytic processing of the S protein, and diminished production of the fusogenic S2' fragment of S. Furin, a proposed protease for this processing, was inhibited by quercetin in vitro with an IC50 of 116 µM.

CONCLUSION

These findings suggest that at low 3-digit micromolar concentrations of quercetin could impair SARS-CoV-2 infection of human cells partly by blocking the fusion process that promotes its propagation.

Plant-derived strategies to fight against severe acute respiratory syndrome coronavirus 2

The coronavirus disease 2019 (COVID-19) pandemic has caused an unprecedented crisis, which has been exacerbated because specific drugs and treatments have not yet been developed. In the post-pandemic era, humans and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will remain in equilibrium for a long time. Therefore, we still need to be vigilant against mutated SARS-CoV-2 variants and other emerging human viruses. Plant-derived products are increasingly important in the fight against the pandemic, but a comprehensive review is lacking. This review describes plant-based strategies centered on key biological processes, such as SARS-CoV-2 transmission, entry, replication, and immune interference. We highlight the mechanisms and effects of these plant-derived products and their feasibility and limitations for the treatment and prevention of COVID-19. The development of emerging technologies is driving plants to become production platforms for various antiviral products, improving their medicinal potential. We believe that plant-based strategies will be an important part of the solutions for future pandemics.

Chlorogenic acid as an indispensible partner of caffeic acid in coffee via selective regulation of prooxidative actions of caffeic acid

Chlorogenic acid (CGA) and caffeic acid (CA) are two major phenolic acids in coffee. Though the International Agency for Research on Cancer has classified CA as a Group2B carcinogen, coffee consumption seems generally safe within the usual levels of intake and is more likely to benefit health than to harm it. We thus speculated that CGA may effectively suppress the carcinogenic potential of CA. In a molar ratio achievable in vivo, this study shows that CGA can inhibit (i) copper reduction caused by CA, (ii) CA oxidation caused by copper, (iii) the formation of hydroxyl radicals by CA and copper, and (iv) DNA damage induced by CA, quercetin or (-)-epigallocatechin-3-gallate in the presence of copper. CA tends to undergo autoxidation to produce hydrogen peroxide and quinone, which further reacts with proteins to form quinoproteins. This autoxidation at a tolerable level normally induces beneficial adaptive responses. This study shows that CGA is less efficient than CA in producing hydrogen peroxide and quinoprotein; however, together they synergistically produce hydrogen peroxide and quinoprotein in vitro at a molar ratio achievable in vivo. In conclusion, CGA can selectively regulate the prooxidant activities of CA depending on whether copper is involved or not. CGA could be viewed as an indispensable partner of CA in coffee, given its dual role in suppressing the carcinogenic potential of CA and boosting CA autoxidation which is beneficial for disease prevention.

Dihydroisocoumarins of Hydrangea macrophylla var. thunbergia inhibit binding of the SARS-CoV-2 spike protein to ACE2

Binding of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to the cognate angiotensin-converting enzyme 2 (ACE2) receptor is the initial step in the viral infection process. In this study, we screened an in-house extract library to identify food materials with inhibitory activity against this binding using enzyme-linked immunosorbent assays and attempted to ascertain their active constituents. Hydrangea macrophylla var. thunbergia leaves were identified as candidate materials. Its active compounds were purified using conventional chromatographic methods and identified as naringenin, dihydroisocoumarins, hydrangenol, and phyllodulcin, which have affinities for the ACE2 receptor and inhibit ACE2 receptor-spike S1 binding. Given that boiled water extracts of H. macrophylla leaves are commonly consumed as sweet tea in Japan, we speculated that this tea could be used as a potential natural resource to reduce the risk of SARS-CoV-2 infection.

Comparative Analysis of Vaccine Inequity and COVID-19 Transmission Amid the Omicron Variant Among Countries - Six Countries, Asia-Pacific Region, 2022

What is already known about this topic?

The coronavirus disease 2019 (COVID-19) persists as a significant global public health crisis. The predominant strain, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), notably the Omicron variant, continues to undergo mutations. While vaccination is heralded as the paramount solution to cease the pandemic, challenges persist in providing equitable access to COVID-19 vaccines.

What is added by this report?

The distribution of vaccine coverage exhibited disparities between high-income and middle-income countries, with middle-income countries evidencing lower levels of vaccination. The data further suggested that countries with lesser vaccination levels tended to display a higher case fatality rate. Findings indicated that an increase in population-wide vaccination was effective in mitigating COVID-19 related mortalities.

What are the implications for public health practice?

The findings of this research underscore the pressing necessity for equitable access to vaccines to effectively mitigate the COVID-19 pandemic within the Asia-Pacific region.

The Therapeutic Potential of Natural Dietary Flavonoids against SARS-CoV-2 Infection

The exploration of non-toxic and cost-effective dietary components, such as epigallocatechin 3-gallate and myricetin, for health improvement and disease treatment has recently attracted substantial research attention. The recent COVID-19 pandemic has provided a unique opportunity for the investigation and identification of dietary components capable of treating viral infections, as well as gathering the evidence needed to address the major challenges presented by public health emergencies. Dietary components hold great potential as a starting point for further drug development for the treatment and prevention of SARS-CoV-2 infection owing to their good safety, broad-spectrum antiviral activities, and multi-organ protective capacity. Here, we review current knowledge of the characteristics-chemical composition, bioactive properties, and putative mechanisms of action-of natural bioactive dietary flavonoids with the potential for targeting SARS-CoV-2 and its variants. Notably, we present promising strategies (combination therapy, lead optimization, and drug delivery) to overcome the inherent deficiencies of natural dietary flavonoids, such as limited bioavailability and poor stability.

Green Tea Consumption and the COVID-19 Omicron Pandemic Era: Pharmacology and Epidemiology

In spite of the development of numerous vaccines for the prevention of COVID-19 and the approval of several drugs for its treatment, there is still a great need for effective and inexpensive therapies against this disease. Previously, we showed that green tea and tea catechins interfere with coronavirus replication as well as coronavirus 3CL protease activity, and also showed lower COVID-19 morbidity and mortality in countries with higher green tea consumption. However, it is not clear whether green tea is still effective against the newer SARS-CoV-2 variants including omicron. It is also not known whether higher green tea consumption continues to contribute to lower COVID-19 morbidity and mortality now that vaccination rates in many countries are high. Here, we attempted to update the information regarding green tea in relation to COVID-19. Using pharmacological and ecological approaches, we found that EGCG as well as green tea inhibit the activity of the omicron variant 3CL protease efficiently, and there continues to be pronounced differences in COVID-19 morbidity and mortality between groups of countries with high and low green tea consumption as of December 6, 2022. These results collectively suggest that green tea continues to be effective against COVID-19 despite the new omicron variants and increased vaccination.