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Cho WK, Choi HJ, Ma JY. Selaginella tamariscina Ethanol Extract Attenuates Influenza A Virus Infection by Inhibiting Hemagglutinin and Neuraminidase. Nutrients 2024; 16:2377. [PMID: 39064820 PMCID: PMC11280371 DOI: 10.3390/nu16142377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Revised: 07/08/2024] [Accepted: 07/11/2024] [Indexed: 07/28/2024] Open
Abstract
Selaginella tamariscina is a perennial plant that is used for diverse diseases. This study investigated whether Selaginella tamariscina has an antiviral effect against influenza A virus (IAV) infection. We used green fluorescent protein (GFP)-tagged influenza A virus (IAV) to examine the effect of Selaginella tamariscina ethanol extract (STE) on influenza viral infection. Fluorescence microscopy and flow cytometry showed that STE potently represses GFP expression by the virus, dose-dependently. STE significantly inhibited the expression of the IAV M2, NP, HA, NA, NS1, and PB2 proteins. Time-of-addition and hemagglutination inhibition assays showed that STE has an inhibitory effect on hemagglutinin and viral binding on the cells at an early infection time. In addition, STE exerted a suppressive effect on the neuraminidase activity of the H1N1 and H3N2 IAVs. Furthermore, dose-dependently, STE inhibited the cytopathic effect induced by H3N2, as well as by H1N1 IAV. Especially in the presence of 200 µg/mL STE, the cytopathic effect was completely blocked. Our findings suggest that STE has antiviral efficacy against IAV infection; thus, it could be developed as a natural IAV inhibitor.
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Affiliation(s)
- Won-Kyung Cho
- Korean Medicine (KM) Application Center, Korea Institute of Oriental Medicine, 70 Chemdanro, Dong-gu, Daegu 41062, Republic of Korea;
| | | | - Jin Yeul Ma
- Korean Medicine (KM) Application Center, Korea Institute of Oriental Medicine, 70 Chemdanro, Dong-gu, Daegu 41062, Republic of Korea;
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2
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Zhuang Y, Quan W, Wang X, Cheng Y, Jiao Y. Comprehensive Review of EGCG Modification: Esterification Methods and Their Impacts on Biological Activities. Foods 2024; 13:1232. [PMID: 38672904 PMCID: PMC11048832 DOI: 10.3390/foods13081232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/13/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Epigallocatechin gallate (EGCG), the key constituent of tea polyphenols, presents challenges in terms of its lipid solubility, stability, and bioavailability because of its polyhydroxy structure. Consequently, structural modifications are imperative to enhance its efficacy. This paper comprehensively reviews the esterification techniques applied to EGCG over the past two decades and their impacts on bioactivities. Both chemical and enzymatic esterification methods involve catalysts, solvents, and hydrophobic groups as critical factors. Although the chemical method is cost-efficient, it poses challenges in purification; on the other hand, the enzymatic approach offers improved selectivity and simplified purification processes. The biological functions of EGCG are inevitably influenced by the structural changes incurred through esterification. The antioxidant capacity of EGCG derivatives can be compromised under certain conditions by reducing hydroxyl groups, while enhancing lipid solubility and stability can strengthen their antiviral, antibacterial, and anticancer properties. Additionally, esterification broadens the utility of EGCG in food applications. This review provides critical insights into developing cost-effective and environmentally sustainable selective esterification methods, as well as emphasizes the elucidation of the bioactive mechanisms of EGCG derivatives to facilitate their widespread adoption in food processing, healthcare products, and pharmaceuticals.
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Affiliation(s)
- Yingjun Zhuang
- School of Food Science and Bioengineering, Changsha University of Science & Technology, Changsha 410114, China; (Y.Z.); (X.W.); (Y.C.)
| | - Wei Quan
- College of Food Science and Technology, Hunan Agricultural University, Changsha 410128, China;
| | - Xufeng Wang
- School of Food Science and Bioengineering, Changsha University of Science & Technology, Changsha 410114, China; (Y.Z.); (X.W.); (Y.C.)
| | - Yunhui Cheng
- School of Food Science and Bioengineering, Changsha University of Science & Technology, Changsha 410114, China; (Y.Z.); (X.W.); (Y.C.)
| | - Ye Jiao
- School of Food Science and Bioengineering, Changsha University of Science & Technology, Changsha 410114, China; (Y.Z.); (X.W.); (Y.C.)
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3
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Downard KM. 25 Years Responding to Respiratory and Other Viruses with Mass Spectrometry. Mass Spectrom (Tokyo) 2023; 12:A0136. [PMID: 38053835 PMCID: PMC10694638 DOI: 10.5702/massspectrometry.a0136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 10/24/2023] [Indexed: 12/07/2023] Open
Abstract
This review article presents the development and application of mass spectrometry (MS) approaches, developed in the author's laboratory over the past 25 years, to detect; characterise, type and subtype; and distinguish major variants and subvariants of respiratory viruses such as influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). All features make use of matrix-assisted laser desorption ionisation (MALDI) mass maps, recorded for individual viral proteins or whole virus digests. A MALDI-based immunoassay in which antibody-peptide complexes were preserved on conventional MALDI targets without their immobilisation led to an approach that enabled their indirect detection. The site of binding, and thus the molecular antigenicity of viruses, could be determined. The same approach was employed to study antivirals bound to their target viral protein, the nature of the binding residues, and relative binding affinities. The benefits of high-resolution MS were exploited to detect sequence-conserved signature peptides of unique mass within whole virus and single protein digests. These enabled viruses to be typed, subtyped, their lineage determined, and variants and subvariants to be distinguished. Their detection using selected ion monitoring improved analytical sensitivity limits to aid the identification of viruses in clinical specimens. The same high-resolution mass map data, for a wide range of viral strains, were input into a purpose-built algorithm (MassTree) in order to both chart and interrogate viral evolution. Without the need for gene or protein sequences, or any sequence alignment, this phylonumerics approach also determines and displays single-point mutations associated with viral protein evolution in a single-tree building step.
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Affiliation(s)
- Kevin M. Downard
- Infectious Disease Responses Laboratory, Prince of Wales Clinical Research Sciences, Sydney, NSW, Australia
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4
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Wang Y, Zhao X, Xiao M, Lin X, Chen Q, Qin S, Ti H, Yang Z. Network pharmacology associated anti-influenza mechanism research of Qingjie-Tuire Granule via STAT1/3 signaling pathway. Heliyon 2023; 9:e14649. [PMID: 37101493 PMCID: PMC10123184 DOI: 10.1016/j.heliyon.2023.e14649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/06/2023] [Accepted: 03/15/2023] [Indexed: 03/28/2023] Open
Abstract
Qingjie-Tuire (QT) granule was approved for clinical use and its combination was reported to treat influenza infection. To explore its active component and mechanism, the components of QT granule were retrieved from UPLC-UC-Q-TOF/MS analysis. The genes corresponding to the targets were retrieved using GeneCards and TTD database. The herb-compound-target network was constructed by Cytoscape. The target protein-protein interaction network was built using STRING database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of QT granule to IAV were performed for further study. The regulation to different signaling transduction events and cytokine/chemokine expression of QT granule was evaluated using Western blotting and real-time qPCR. Totally, 47 compounds were identified and effect of QT granule on cell STAT1/3 signaling pathways was confirmed by A549 cell model. The efficiency of QT granule on host cell contributes to its clinical application and mechanism research.
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5
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Cheng Y, Liu M, Yu Q, Huang S, Han S, Shi J, Wei H, Zou J, Li P. Effect of EGCG Extracted from Green Tea against Largemouth Bass Virus Infection. Viruses 2023; 15:151. [PMID: 36680191 PMCID: PMC9864265 DOI: 10.3390/v15010151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 12/29/2022] [Accepted: 12/31/2022] [Indexed: 01/05/2023] Open
Abstract
(1) Background: Largemouth bass virus (LMBV) is a major viral pathogen in largemouth bass (Micropterus salmoides) aquaculture that often causes high mortality and heavy economic losses, thus developing treatments to combat this pathogen is of great commercial importance. Green tea is a well-known medicinal plant that contains active ingredients with antiviral, antibacterial, and other biological activities. The goals of this study were to explore the effect and mechanism of green tea source compounds on LMBV and provide data to serve as the basis for the screening of targeted drugs in the future. In this study, we evaluated the effects of the main component of green tea, epigallocatechin-3-gallate (EGCG), against LMBV infection. (2) Methods: The safe working concentration of EGCG was identified by cell viability detection and light microscopy. The antiviral activity and mechanism of action of EGCG against LMBV infection were evaluated with light microscopy, an aptamer 6-carboxy-fluorescein-based fluorescent molecular probe, and reverse transcription quantitative PCR. (3) Results: The safe working concentration of EGCG was ≤10 μg/mL. EGCG showed significant anti-LMBV infection activity in a concentration-dependent manner, and it also destroyed the structure of virus particles. EGCG impacted the binding of virus particles to cell receptors and virus invasion into the host cells. Inhibitory effects of EGCG on LMBV particles, LMBV binding to the host-cell membrane, and LMBV invasion were 84.89%, 98.99%, and 95.23%, respectively. Meanwhile, the effects of EGCG subsequently were verified in vivo. The fatality rate of the LMBV + EGCG group was significantly lower than that of the LMBV group. (4) Conclusions: Our results suggest that EGCG has effective antiviral properties against LMBV and may be a candidate for the effective treatment and control of LMBV infections in largemouth bass aquaculture.
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Affiliation(s)
- Yuan Cheng
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning 530000, China
| | - Mingzhu Liu
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning 530000, China
| | - Qing Yu
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning 530000, China
- China-ASEAN Modern Fishery Industry Technology Transfer Demonstration Center, Nanning 530000, China
| | - Shuaishuai Huang
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning 530000, China
| | - Shuyu Han
- Guangxi Fisheries Technology Extension Station, Nanning 530000, China
| | - Jingu Shi
- Beihai Fisheries Technology Extension Station, Beihai 536001, China
| | - Hongling Wei
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning 530000, China
| | - Jianwei Zou
- Beihai Fisheries Technology Extension Station, Beihai 536001, China
| | - Pengfei Li
- Guangxi Key Laboratory of Aquatic Biotechnology and Modern Ecological Aquaculture, Guangxi Engineering Research Center for Fishery Major Diseases Control and Efficient Healthy Breeding Industrial Technology (GERCFT), Guangxi Academy of Sciences, Nanning 530000, China
- China-ASEAN Modern Fishery Industry Technology Transfer Demonstration Center, Nanning 530000, China
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6
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Bhasin S, Nadar M, Hasija Y. Epicatechin analogues may hinder human parainfluenza virus infection by inhibition of hemagglutinin neuraminidase protein and prevention of cellular entry. J Mol Model 2022; 28:319. [DOI: 10.1007/s00894-022-05310-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 08/30/2022] [Indexed: 10/14/2022]
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7
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Hanada A, Morimoto R, Horio Y, Shichiri M, Nakashima A, Ogawa T, Suzuki K, Sumitani H, Ogata T, Isegawa Y. Influenza virus entry and replication inhibited by 8-prenylnaringenin from Citrullus lanatus var. citroides (wild watermelon). Food Sci Nutr 2022; 10:926-935. [PMID: 35282012 PMCID: PMC8907720 DOI: 10.1002/fsn3.2725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 12/11/2021] [Accepted: 12/22/2021] [Indexed: 12/05/2022] Open
Abstract
We previously demonstrated the anti-influenza activity of Citrullus lanatus var. citroides (wild watermelon, WWM); however, the active ingredient was unknown. Here, we performed metabolomic analysis to evaluate the ingredients of WWM associated with antiviral activity. Many low-molecular weight compounds were identified, with flavonoids accounting for 35% of all the compounds in WWM juice. Prenylated flavonoids accounted for 30% of the flavonoids. Among the measurable components of phytoestrogens in WWM juice, 8-prenylnaringenin showed the highest antiviral activity. We synthesized 8-prenylnaringenin and used liquid chromatography-mass spectrometry to quantitate the active ingredient in WWM. The antiviral activities of 8-prenylnaringenin were observed against H1N1 and H3N2 influenza A subtypes and influenza B viruses. Moreover, 8-prenylnaringenin was found to inhibit virus adsorption and late-stage virus replication, suggesting that the mechanisms of action of 8-prenylnaringenin may differ from those of amantadine and oseltamivir. We confirmed that 8-prenylnaringenin strongly inhibited the viral entry of all the influenza virus strains that were examined, including those resistant to the anti-influenza drugs oseltamivir and amantadine. This result indicates that 8-prenylnaringenin may activate the host cell's defense mechanisms, rather than directly acting on the influenza virus. Since 8-prenylnaringenin did not inhibit late-stage virus replication of oseltamivir-resistant strains, 8-prenylnaringenin may interact directly with viral neuraminidase. These results are the first report on the anti-influenza virus activity of 8-prenylnaringenin. Our results highlight the potential of WWM and phytoestrogens to develop effective prophylactic and therapeutic approaches to the influenza virus.
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Affiliation(s)
- Akari Hanada
- Department of Food Sciences and NutritionMukogawa Women’s UniversityNishinomiyaJapan
| | - Ryosuke Morimoto
- Department of Food Sciences and NutritionMukogawa Women’s UniversityNishinomiyaJapan
- Present address:
Faculty of Human Life ScienceShikoku UniversityTokushimaJapan
| | - Yuka Horio
- Department of Food Sciences and NutritionMukogawa Women’s UniversityNishinomiyaJapan
| | - Mototada Shichiri
- Biomedical Research InstituteNational Institute of Advanced Industrial Science and Technology (AIST)IkedaJapan
| | | | | | | | | | - Tokutaro Ogata
- Faculty of Health and Medical SciencesHokuriku UniversityKanazawaJapan
| | - Yuji Isegawa
- Department of Food Sciences and NutritionMukogawa Women’s UniversityNishinomiyaJapan
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8
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Silva LR, da Silva-Júnior EF. Multi-Target Approaches of Epigallocatechin-3-O-gallate (EGCG) and its Derivatives Against Influenza Viruses. Curr Top Med Chem 2022; 22:1485-1500. [PMID: 35086449 DOI: 10.2174/1568026622666220127112056] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 12/13/2021] [Accepted: 12/30/2021] [Indexed: 11/22/2022]
Abstract
Influenza viruses (INFV), Orthomyxoviridae family, are mainly transmitted among humans, via aerosols or droplets from the respiratory secretions. However, fomites could be a potential transmission pathway. Annually, seasonal INFV infections account for 290-650 thousand deaths worldwide. Currently, there are two classes of approved drugs to treat INFV infections, being neuraminidase (NA) inhibitors and blockers of matrix-2 (M2) ion channel. However, cases of resistance have been observed for both chemical classes, reducing the efficacy of treatment. The emergence of influenza outbreaks and pandemics calls for new antiviral molecules more effective and that could overcome the current resistance to anti-influenza drugs. In this context, polyphenolic compounds are found in various plants and these have displayed different multi-target approaches against diverse pathogens. Among these, green tea (Camellia sinensis) catechins, in special epigallocatechin-3-O-gallate (EGCG), have demonstrated significant activities against the two most relevant human INFV, subtypes A and lineages B. In this sense, EGCG has been found a promising multi-target agent against INFV since can act inhibiting NA, hemagglutination (HA), RNA-dependent RNA polymerase (RdRp), and viral entry/adsorption. In general, the lack of knowledge about potential multi-target natural products prevents an adequate exploration of them, increasing the time for developing multi-target drugs. Then, this review aimed to compile to most relevant studies showing the anti-INFV effects of EGCG and its derivatives, which could become antiviral drug prototypes in the future.
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Affiliation(s)
- Leandro Rocha Silva
- Institute of Chemistry and Biotechnology, Federal University of Alagoas, Melo Mota Avenue, 57072-970, AC Simões campus, Maceió, Brazil
| | - Edeildo Ferreira da Silva-Júnior
- Institute of Chemistry and Biotechnology, Federal University of Alagoas, Melo Mota Avenue, 57072-970, AC Simões campus, Maceió, Brazil
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9
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10
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Zhao Z, Feng M, Wan J, Zheng X, Teng C, Xie X, Pan W, Hu B, Huang J, Liu Z, Wu J, Cai S. Research progress of epigallocatechin-3-gallate (EGCG) on anti-pathogenic microbes and immune regulation activities. Food Funct 2021; 12:9607-9619. [PMID: 34549212 DOI: 10.1039/d1fo01352a] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
At the end of 2019, the COVID-19 virus spread worldwide, infecting millions of people. Infectious diseases induced by pathogenic microorganisms such as the influenza virus, hepatitis virus, and Mycobacterium tuberculosis are also a major threat to public health. The high mortality caused by infectious pathogenic microorganisms is due to their strong virulence, which leads to the excessive counterattack by the host immune system and severe inflammatory damage of the immune system. This paper reviews the efficacy, mechanism and related immune regulation of epigallocatechin-3-gallate (EGCG) as an anti-pathogenic microorganism drug. EGCG mainly shows both direct and indirect anti-infection effects. EGCG directly inhibits early infection by interfering with the adsorption on host cells, inhibiting virus replication and reducing bacterial biofilm formation and toxin release; EGCG indirectly inhibits infection by regulating immune inflammation and antioxidation. At the same time, we reviewed the bioavailability and safety of EGCG in vivo. At present, the bioavailability of EGCG can be improved to some extent using nanostructured drug delivery systems and molecular modification technology in combination with other drugs. This study provides a theoretical basis for the development of EGCG as an adjuvant drug for anti-pathogenic microorganisms.
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Affiliation(s)
- Zijuan Zhao
- National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China. .,Key Laboratory of Ministry of Education for Tea Science, Hunan Agricultural University, Changsha 410128, China
| | - Meiyan Feng
- National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China. .,Key Laboratory of Ministry of Education for Tea Science, Hunan Agricultural University, Changsha 410128, China
| | - Juan Wan
- National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China. .,Key Laboratory of Ministry of Education for Tea Science, Hunan Agricultural University, Changsha 410128, China
| | - Xin Zheng
- National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China. .,Key Laboratory of Ministry of Education for Tea Science, Hunan Agricultural University, Changsha 410128, China
| | - Cuiqin Teng
- Wuzhou Institute of Agricultural, Wuzhou 543003, China
| | - Xinya Xie
- National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China. .,Key Laboratory of Ministry of Education for Tea Science, Hunan Agricultural University, Changsha 410128, China
| | - Wenjing Pan
- National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China. .,Key Laboratory of Ministry of Education for Tea Science, Hunan Agricultural University, Changsha 410128, China
| | - Baozhu Hu
- National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China. .,Key Laboratory of Ministry of Education for Tea Science, Hunan Agricultural University, Changsha 410128, China
| | - Jianan Huang
- National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China. .,Key Laboratory of Ministry of Education for Tea Science, Hunan Agricultural University, Changsha 410128, China.,Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China
| | - Zhonghua Liu
- National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China. .,Key Laboratory of Ministry of Education for Tea Science, Hunan Agricultural University, Changsha 410128, China.,Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China
| | - Jianhua Wu
- Wuzhou Institute of Agricultural, Wuzhou 543003, China
| | - Shuxian Cai
- National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China. .,Key Laboratory of Ministry of Education for Tea Science, Hunan Agricultural University, Changsha 410128, China.,Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha 410128, China
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11
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Mohamed IMA, Ogawa H, Takeda Y. In vitro virucidal activity of the theaflavin-concentrated tea extract TY-1 against influenza A virus. J Nat Med 2021; 76:152-160. [PMID: 34550554 PMCID: PMC8456404 DOI: 10.1007/s11418-021-01568-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 09/08/2021] [Indexed: 01/25/2023]
Abstract
The annual spread of influenza A virus (IAV) infection is a global concern. We examined the IAV-inactivating potential of theaflavin-concentrated tea extract TY-1, which contains abundant polyphenols, including concentrated theaflavins and catechins. TY-1 exhibited concentration- and time-dependent virucidal activity against IAV. Specifically, 5.0 mg/mL TY-1 induced a 1.33 and ≥ 5.17 log10 50% tissue culture infective dose/mL reduction of the viral titer compared with dextrin as the diluent control within 30 min and 6 h reaction time, respectively. The high virucidal activity of TY-1 was attributed to the combined additive activities of multiple virucidal components, including theaflavins, which led to an investigation of the virucidal mechanism of action of TY-1. Western blotting revealed that TY-1 treatment reduced the band intensity of hemagglutinin and induced the appearance of additional high molecular mass bands/ladders. In addition, TY-1 treatment also reduced the band intensity of neuraminidase (NA). A hemagglutination assay revealed that TY-1 reduced hemagglutination activity, and an NA assay revealed reduced NA activity. These results indicated that TY-1 caused structural abnormalities in IAV spike proteins, possibly leading to their destruction. Reverse transcription polymerase chain reaction (PCR) targeting the IAV genome and electron microscopic observation of viral particles revealed that upon application of TY-1, the PCR products dissipated, which indicates that TY-1 destroyed the IAV genome, and the number of viral particles reduced. Overall, TY-1 exhibited multiple modes of IAV-inactivating activity. Our findings support the possible future practical use of TY-1 as a virucidal supplemental agent that can contribute to IAV infection control.
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Affiliation(s)
- Israa M A Mohamed
- Graduate School of Animal and Veterinary Sciences and Agriculture, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido, 080-8555, Japan
- Department of Animal and Poultry Hygiene and Environmental Sanitation, Faculty of Veterinary Medicine, Assiut University, Assiut, 71526, Egypt
| | - Haruko Ogawa
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido, 080-8555, Japan
| | - Yohei Takeda
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido, 080-8555, Japan.
- Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido, 080-8555, Japan.
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12
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Rawangkan A, Kengkla K, Kanchanasurakit S, Duangjai A, Saokaew S. Anti-Influenza with Green Tea Catechins: A Systematic Review and Meta-Analysis. Molecules 2021; 26:molecules26134014. [PMID: 34209247 PMCID: PMC8272076 DOI: 10.3390/molecules26134014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 06/27/2021] [Accepted: 06/29/2021] [Indexed: 12/14/2022] Open
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 5048 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 2223 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.
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Affiliation(s)
- Anchalee Rawangkan
- School of Medical Sciences, University of Phayao, Phayao 56000, Thailand; (A.R.); (A.D.)
- Unit of Excellence on Clinical Outcomes Research and IntegratioN (UNICORN), School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
| | - Kirati Kengkla
- Division of Pharmacy Practice, Department of Pharmaceutical Care, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand; (K.K.); (S.K.)
- Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
- Unit of Excellence on Herbal Medicine, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
| | - Sukrit Kanchanasurakit
- Division of Pharmacy Practice, Department of Pharmaceutical Care, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand; (K.K.); (S.K.)
- Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
- Unit of Excellence on Herbal Medicine, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
- Division of Pharmaceutical Care, Department of Pharmacy, Phrae Hospital, Phrae 54000, Thailand
| | - Acharaporn Duangjai
- School of Medical Sciences, University of Phayao, Phayao 56000, Thailand; (A.R.); (A.D.)
- Unit of Excellence on Clinical Outcomes Research and IntegratioN (UNICORN), School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
- Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
| | - Surasak Saokaew
- Unit of Excellence on Clinical Outcomes Research and IntegratioN (UNICORN), School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
- Division of Pharmacy Practice, Department of Pharmaceutical Care, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand; (K.K.); (S.K.)
- Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
- Unit of Excellence on Herbal Medicine, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
- Division of Pharmaceutical Care, Department of Pharmacy, Phrae Hospital, Phrae 54000, Thailand
- Biofunctional Molecule Exploratory Research Group, Biomedicine Research Advancement Centre, School of Pharmacy, Monash University Malaysia, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia
- Novel Bacteria and Drug Discovery Research Group, Microbiome and Bioresource Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia
- Correspondence: ; Tel.: +66 (0)5446 6666; Fax: +66 (0)5446 6661
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13
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Khazeei Tabari MA, Iranpanah A, Bahramsoltani R, Rahimi R. Flavonoids as Promising Antiviral Agents against SARS-CoV-2 Infection: A Mechanistic Review. Molecules 2021; 26:3900. [PMID: 34202374 PMCID: PMC8271800 DOI: 10.3390/molecules26133900] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 01/03/2023] Open
Abstract
A newly diagnosed coronavirus in 2019 (COVID-19) has affected all human activities since its discovery. Flavonoids commonly found in the human diet have attracted a lot of attention due to their remarkable biological activities. This paper provides a comprehensive review of the benefits of flavonoids in COVID-19 disease. Previously-reported effects of flavonoids on five RNA viruses with similar clinical manifestations and/or pharmacological treatments, including influenza, human immunodeficiency virus (HIV), severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and Ebola, were considered. Flavonoids act via direct antiviral properties, where they inhibit different stages of the virus infective cycle and indirect effects when they modulate host responses to viral infection and subsequent complications. Flavonoids have shown antiviral activity via inhibition of viral protease, RNA polymerase, and mRNA, virus replication, and infectivity. The compounds were also effective for the regulation of interferons, pro-inflammatory cytokines, and sub-cellular inflammatory pathways such as nuclear factor-κB and Jun N-terminal kinases. Baicalin, quercetin and its derivatives, hesperidin, and catechins are the most studied flavonoids in this regard. In conclusion, dietary flavonoids are promising treatment options against COVID-19 infection; however, future investigations are recommended to assess the antiviral properties of these compounds on this disease.
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Affiliation(s)
- Mohammad Amin Khazeei Tabari
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran;
- USERN Office, Mazandaran University of Medical Sciences, Sari, Iran
| | - Amin Iranpanah
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran;
- Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
- Kermanshah USERN Office, Universal Scientific Education and Research Network (USERN), Kermanshah, Iran
| | - Roodabeh Bahramsoltani
- Department of Traditional Pharmacy, School of Persian Medicine, Tehran University of Medical Sciences, Tehran P.O. Box 1417653761, Iran;
- Research Center for Clinical Virology, Tehran University of Medical Sciences, Tehran, Iran
- PhytoPharmacology Interest Group (PPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Roja Rahimi
- Department of Traditional Pharmacy, School of Persian Medicine, Tehran University of Medical Sciences, Tehran P.O. Box 1417653761, Iran;
- PhytoPharmacology Interest Group (PPIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
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14
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Hurst BL, Dickinson D, Hsu S. Epigallocatechin-3-Gallate (EGCG) Inhibits SARS-CoV-2 Infection in Primate Epithelial Cells: (A Short Communication). MICROBIOLOGY & INFECTIOUS DISEASES (WILMINGTON, DEL.) 2021; 5. [PMID: 35291211 DOI: 10.33425/2639-9458.1116] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
SARS-CoV-2, the novel coronavirus responsible for the COVID-19 pandemic, caused >26 million cases in the United States and >437,000 deaths as of Jan 30, 2020. Worldwide by that date, there had been 102 million cases of infections, and deaths had climbed to 2.21 million. Mutated variants of SARS-CoV-2 that have emerged from the United Kingdom, Brazil, and South Africa are associated with higher transmission rates and associated deaths. Therefore, novel therapeutic and prophylactic methods against SARS-CoV-2 are in urgent need. While some antiviral drugs, such as Remdesivir, provide relief to certain patient populations, other existing antiviral drugs or combinations of FDA approved pharmaceuticals have yet to show clinical efficacy against COVID-19. Compounds that possess strong and broad antiviral properties with different mechanisms of action against respiratory viruses may provide novel approaches to combat SARS-CoV-2 and its variants, especially if the compounds are classified as generally recognized as safe (GRAS). A large body of evidence indicates a promising potential for the use of epigallocatechin-3-gallate (EGCG) and its derivatives as effective agents against infections from a wide range of pathogenic viruses. However, EGCG or its derivatives have not been tested directly against SARS-CoV-2. The current study was designed to evaluate the potential antiviral activity of EGCG against SARS-CoV-2 infection in primate epithelial cells. Methods applied in the study include cytopathic effect (CPE) assay and virus yield reduction (VYR) assays using Vero 76 (green monkey epithelial cells) and Caco-2 (human epithelial cells) cell lines, respectively. The results demonstrated that EGCG at 0.27 μg/ml (0.59 μM) inhibited SARS-CoV-2 infection in Vero 76 cells by 50% (i.e., EC50=0.27 μg/ml). EGCG also inhibited SARS-CoV-2 infection in Caco-2 cells with EC90=28 μg/ml (61 μM). These results, to the best of our knowledge, are the first observations on the antiviral activities of EGCG against SARS-CoV-2, and suggest that EGCG and its derivatives could be used to combat COVID-19 and other respiratory viral infection-induced illness, pending in vivo and clinical studies.
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Affiliation(s)
- Brett L Hurst
- Institute of Antiviral Research, Utah State University. Logan, UT. USA
| | | | - Stephen Hsu
- Camellix Research Laboratory, Augusta, GA. USA.,Department of Oral Biology & Diagnostic Sciences, Augusta University, Augusta, GA. USA
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15
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Sicari D, Chatziioannou A, Koutsandreas T, Sitia R, Chevet E. Role of the early secretory pathway in SARS-CoV-2 infection. J Cell Biol 2020; 219:151984. [PMID: 32725137 PMCID: PMC7480111 DOI: 10.1083/jcb.202006005] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 12/17/2022] Open
Abstract
Similar to other RNA viruses, SARS-CoV-2 must (1) enter a target/host cell, (2) reprogram it to ensure its replication, (3) exit the host cell, and (4) repeat this cycle for exponential growth. During the exit step, the virus hijacks the sophisticated machineries that host cells employ to correctly fold, assemble, and transport proteins along the exocytic pathway. Therefore, secretory pathway-mediated assemblage and excretion of infective particles represent appealing targets to reduce the efficacy of virus biogenesis, if not to block it completely. Here, we analyze and discuss the contribution of the molecular machines operating in the early secretory pathway in the biogenesis of SARS-CoV-2 and their relevance for potential antiviral targeting. The fact that these molecular machines are conserved throughout evolution, together with the redundancy and tissue specificity of their components, provides opportunities in the search for unique proteins essential for SARS-CoV-2 biology that could also be targeted with therapeutic objectives. Finally, we provide an overview of recent evidence implicating proteins of the early secretory pathway as potential antiviral targets with effective therapeutic applications.
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Affiliation(s)
- Daria Sicari
- Inserm U1242, Université de Rennes, Rennes, France.,Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France.,Università Vita-Salute San Raffaele, Milan, Italy
| | - Aristotelis Chatziioannou
- e-NIOS Applications PC, Kallithea-Athens, Greece.,Center of Systems Biology, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Theodoros Koutsandreas
- e-NIOS Applications PC, Kallithea-Athens, Greece.,Center of Systems Biology, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | | | - Eric Chevet
- Inserm U1242, Université de Rennes, Rennes, France.,Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France.,Università Vita-Salute San Raffaele, Milan, Italy
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16
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Takeda Y, Murata T, Jamsransuren D, Suganuma K, Kazami Y, Batkhuu J, Badral D, Ogawa H. Saxifraga spinulosa-Derived Components Rapidly Inactivate Multiple Viruses Including SARS-CoV-2. Viruses 2020; 12:v12070699. [PMID: 32605306 PMCID: PMC7411974 DOI: 10.3390/v12070699] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 06/21/2020] [Accepted: 06/26/2020] [Indexed: 12/23/2022] Open
Abstract
Novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (IAV), and norovirus (NV) are highly contagious pathogens that threaten human health. Here we focused on the antiviral potential of the medicinal herb, Saxifragaspinulosa (SS). Water-soluble extracts of SS were prepared, and their virus-inactivating activity was evaluated against the human virus pathogens SARS-CoV-2 and IAV; we also examined virucidal activity against feline calicivirus and murine norovirus, which are surrogates for human NV. Among our findings, we found that SS-derived gallocatechin gallate compounds were capable of inactivating all viruses tested. Interestingly, a pyrogallol-enriched fraction (Fr 1C) inactivated all viruses more rapidly and effectively than did any of the component compounds used alone. We found that 25 µg/mL of Fr 1C inactivated >99.6% of SARS-CoV-2 within 10 s (reduction of ≥2.33 log10 TCID50/mL). Fr 1C resulted in the disruption of viral genomes and proteins as determined by gel electrophoresis, electron microscopy, and reverse transcription–PCR. Taken together, our results reveal the potential of Fr 1C for development as a novel antiviral disinfectant.
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Affiliation(s)
- Yohei Takeda
- Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido 080-8555, Japan; (Y.T.); (K.S.)
| | - Toshihiro Murata
- Department of Pharmacognosy, Tohoku Medical and Pharmaceutical University, 4-1-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan;
| | - Dulamjav Jamsransuren
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido 080-8555, Japan; (D.J.); (Y.K.)
| | - Keisuke Suganuma
- Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido 080-8555, Japan; (Y.T.); (K.S.)
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
| | - Yuta Kazami
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido 080-8555, Japan; (D.J.); (Y.K.)
| | - Javzan Batkhuu
- School of Engineering and Applied Sciences, National University of Mongolia, P.O.B-617/46A, Ulaanbaatar 14201, Mongolia;
| | - Duger Badral
- Mongolian University of Pharmaceutical Sciences, Ulaanbaatar 18130, Mongolia;
| | - Haruko Ogawa
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido 080-8555, Japan; (D.J.); (Y.K.)
- Correspondence:
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17
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Muchtaridi M, Sugijanto M, Mohd Gazzali A, Wahab HA. Anti-Neuraminidase Bioactives from Manggis Hutan ( Garcinia celebica L.) Leaves: Partial Purification and Molecular Characterization. Molecules 2020; 25:molecules25040821. [PMID: 32070030 PMCID: PMC7070733 DOI: 10.3390/molecules25040821] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 01/25/2023] Open
Abstract
The neuraminidase enzyme (NA) from the influenza virus is responsible for the proliferation and infections of the virus progeny, prompting several efforts to discover and optimize effective neuraminidase inhibitors. The main aim of this study is to discover a new potential neuraminidase inhibitor that comes from Garcinia celebica leaves (GCL). The bioassay-guided isolation method was performed to obtain lead compounds. The binding interaction of the isolated compounds was predicted by using molecular docking studies. Friedeline (GC1, logP > 5.0), two lanastone derivatives (methyl-3α,23-dihydroxy-17,14-friedolanstan-8,14,24-trien-26-oat (GC2) and 24E-3a,9,23-trihydroxy-17,14-friedolanostan-14,24-dien-26-oate (GC3) with LogP > 5.0) and catechin (GC4, LogP = 1.4) were identified. The inhibitory potency of these four compounds on NA from C. perfringens and H1N1 was found to be as follows: GC4 > GC2 > GC3 > GC1. All compounds exhibited higher inhibitory activity towards C. perfringens NA compared to H1N1 NA. From the molecular docking results, GC4 favorably docked and interacted with Arg118, Arg371, Arg292, Glu276 and Trp178 residues, whilst GC2 interacted with Arg118, Arg371, Arg292, Ile222, Arg224 and Ser246. GC3 interacted with Tyr406 only. GC4 had potent NA inhibition with free energy of binding of −12 kcal/mol. In the enzyme inhibition study, GC4 showed the highest activity with an IC50 of 60.3 µM and 91.0 µM for C. perfringens NA and H1N1 NA—respectively.
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Affiliation(s)
- Muchtaridi Muchtaridi
- Department of Pharmaceutical Analysis and Medicinal Chemistry, Faculty of Pharmacy, Universitas Padjadjaran, Jl Raya 21.5 Bandung-Sumedang 45363, Indonesia;
- Correspondence: (M.M.); (H.A.W.); Tel.: +62-22-8784288888 (ext. 3210) (M.M.); +60-4-6532238 (H.A.W.)
| | - Milyadi Sugijanto
- Department of Pharmaceutical Analysis and Medicinal Chemistry, Faculty of Pharmacy, Universitas Padjadjaran, Jl Raya 21.5 Bandung-Sumedang 45363, Indonesia;
| | - Amirah Mohd Gazzali
- Department of Pharmaceutical Technology, School of Pharmaceutical Sciences, Universiti Sains Malaysia, P Pinang 11800, Malaysia;
| | - Habibah A. Wahab
- Department of Pharmaceutical Technology, School of Pharmaceutical Sciences, Universiti Sains Malaysia, P Pinang 11800, Malaysia;
- Pharmaceutical Design and Simulation Laboratory, School of Pharmaceutical Sciences, Universiti Sains Malaysia, P Pinang 11800, Malaysia
- Correspondence: (M.M.); (H.A.W.); Tel.: +62-22-8784288888 (ext. 3210) (M.M.); +60-4-6532238 (H.A.W.)
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18
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Furushima D, Nishimura T, Takuma N, Iketani R, Mizuno T, Matsui Y, Yamaguchi T, Nakashima Y, Yamamoto S, Hibi M, Yamada H. Prevention of Acute Upper Respiratory Infections by Consumption of Catechins in Healthcare Workers: A Randomized, Placebo-Controlled Trial. Nutrients 2019; 12:nu12010004. [PMID: 31861349 PMCID: PMC7019590 DOI: 10.3390/nu12010004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/12/2019] [Accepted: 12/16/2019] [Indexed: 01/14/2023] Open
Abstract
Catechins, phytochemicals contained mainly in green tea, exhibit antiviral activity against various acute infectious diseases experimentally. Clinical evidence supporting these effects, however, is not conclusive. We performed a placebo-controlled, single-blind, randomized control trial to evaluate the clinical effectiveness of consumption of catechins-containing beverage for preventing acute upper respiratory tract infections (URTIs). Two hundred and seventy healthcare workers were randomly allocated to high-catechin (three daily doses of 57 mg catechins and 100 mg xanthan gum), low-catechin (one daily dose of 57 mg catechins and 100 mg xanthan gum), or placebo (0 mg catechins and 100 mg xanthan gum) group. Subjects consumed a beverage with or without catechins for 12 weeks from December 2017 through February 2018. The primary endpoint was incidence of URTIs compared among groups using a time-to-event analysis. A total of 255 subjects were analyzed (placebo group n = 86, low-catechin group n = 85, high catechin group n = 84). The URTI incidence rate was 26.7% in the placebo group, 28.2% in the low-catechin group, and 13.1% in the high-catechin group (log rank test, p = 0.042). The hazard ratio (95% confidence interval (CI)) with reference to the placebo group was 1.09 (0.61-1.92) in the low-catechin group and 0.46 (0.23-0.95) in the high-catechin group. These findings suggest that catechins combined with xanthan gum protect against URTIs.
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Affiliation(s)
- Daisuke Furushima
- Department of Drug Evaluation and Informatics, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan; (T.N.); (R.I.); (H.Y.)
- Correspondence: ; Tel./Fax: +81-54-264-5591
| | - Takuma Nishimura
- Department of Drug Evaluation and Informatics, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan; (T.N.); (R.I.); (H.Y.)
| | | | - Ryo Iketani
- Department of Drug Evaluation and Informatics, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan; (T.N.); (R.I.); (H.Y.)
| | - Tomohito Mizuno
- Biological Science Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan; (T.M.); (Y.M.); (M.H.)
| | - Yuji Matsui
- Biological Science Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan; (T.M.); (Y.M.); (M.H.)
| | - Tohru Yamaguchi
- Health Care Food Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan;
| | - Yu Nakashima
- Personal Healthcare Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan; (Y.N.); (S.Y.)
| | - Shinji Yamamoto
- Personal Healthcare Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan; (Y.N.); (S.Y.)
| | - Masanobu Hibi
- Biological Science Research Laboratories, Kao Corporation, Tokyo 131-8501, Japan; (T.M.); (Y.M.); (M.H.)
| | - Hiroshi Yamada
- Department of Drug Evaluation and Informatics, Graduate School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan; (T.N.); (R.I.); (H.Y.)
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19
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Nagai E, Iwai M, Koketsu R, Okuno Y, Suzuki Y, Morimoto R, Sumitani H, Ohshima A, Enomoto T, Isegawa Y. Anti-Influenza Virus Activity of Adlay Tea Components. PLANT FOODS FOR HUMAN NUTRITION (DORDRECHT, NETHERLANDS) 2019; 74:538-543. [PMID: 31728799 DOI: 10.1007/s11130-019-00773-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Our previous study showed anti-influenza virus activity in adlay tea prepared from adlay seeds, naked barley seeds, soybean, and cassia seeds. In this study, we evaluated the anti-influenza virus activity of each component of this tea and analyzed their active ingredients. Each component was roasted and extracted in hot water; the extracts were tested for antiviral activity and their mechanisms of action were studied. All the tea components showed antiviral activity against the H1N1 and H3N2 influenza subtypes and against influenza B. The viral stages inhibited by the components were virus adsorption and replication in proliferative process, suggesting that the action mechanisms of the components might differ from those of oseltamivir acid. Of the tea components, soybean showed the strongest activity. Therefore, we analyzed its active ingredients by liquid chromatography quadruple time-of-flight mass spectrometry (LC/qTOF-MS) and daidzein and glycitein were detected as active ingredients. Here, anti-influenza virus action of glycitein was the first report.
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Affiliation(s)
- Emiko Nagai
- Department of Food Science, Ishikawa Prefectural University, Nonoichi, Ishikawa, 921-8836, Japan
| | - Miwa Iwai
- Department of Food Sciences and Nutrition, Mukogawa Women's University, Ikebiraki, Nishinomiya, Hyogo, 663-8558, Japan
| | - Ritsuko Koketsu
- Research Foundation for Microbial Diseases of Osaka University, Osaka University, Suita, Osaka, 565-0871, Japan
| | | | - Yuri Suzuki
- Department of Food Sciences and Nutrition, Mukogawa Women's University, Ikebiraki, Nishinomiya, Hyogo, 663-8558, Japan
| | - Ryosuke Morimoto
- Department of Food Sciences and Nutrition, Mukogawa Women's University, Ikebiraki, Nishinomiya, Hyogo, 663-8558, Japan
| | - Hidenobu Sumitani
- Toyo Institute of Food Technology, Kawanishi, Hyogo, 666-0026, Japan
| | - Atsushi Ohshima
- Genomics Program, Nagahamabio Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan
| | - Toshiki Enomoto
- Department of Food Science, Ishikawa Prefectural University, Nonoichi, Ishikawa, 921-8836, Japan
| | - Yuji Isegawa
- Department of Food Sciences and Nutrition, Mukogawa Women's University, Ikebiraki, Nishinomiya, Hyogo, 663-8558, Japan.
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20
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Akand EH, Downard KM. Mechanisms of antiviral resistance in influenza neuraminidase revealed by a mass spectrometry based phylonumerics approach. Mol Phylogenet Evol 2019; 135:286-296. [DOI: 10.1016/j.ympev.2019.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 02/11/2019] [Accepted: 03/17/2019] [Indexed: 12/01/2022]
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21
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Sialic acid as a target for the development of novel antiangiogenic strategies. Future Med Chem 2018; 10:2835-2854. [PMID: 30539670 DOI: 10.4155/fmc-2018-0298] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Sialic acid is associated with glycoproteins and gangliosides of eukaryotic cells. It regulates various molecular interactions, being implicated in inflammation and cancer, where its expression is regulated by sialyltransferases and sialidases. Angiogenesis, the formation of new capillaries, takes place during inflammation and cancer, and represents the outcome of several interactions occurring at the endothelial surface among angiogenic growth factors, inhibitors, receptors, gangliosides and cell-adhesion molecules. Here, we elaborate on the evidences that many structures involved in angiogenesis are sialylated and that their interactions depend on sialic acid with implications in angiogenesis itself, inflammation and cancer. We also discuss the possibility to exploit sialic acid as a target for the development of novel antiangiogenic drugs.
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22
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Kaihatsu K, Yamabe M, Ebara Y. Antiviral Mechanism of Action of Epigallocatechin-3- O-gallate and Its Fatty Acid Esters. Molecules 2018; 23:E2475. [PMID: 30262731 PMCID: PMC6222519 DOI: 10.3390/molecules23102475] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/20/2018] [Accepted: 09/22/2018] [Indexed: 01/28/2023] Open
Abstract
Epigallocatechin-3-O-gallate (EGCG) is the major catechin component of green tea (Cameria sinensis), and is known to possess antiviral activities against a wide range of DNA viruses and RNA viruses. However, few studies have examined chemical modifications of EGCG in terms of enhanced antiviral efficacy. This paper discusses which steps of virus infection EGCG interferes with, citing previous reports. EGCG appears most likely to inhibits the early stage of infections, such as attachment, entry, and membrane fusion, by interfering with viral membrane proteins. According to the relationships between structure and antiviral activity of catechin derivatives, the 3-galloyl and 5'-OH group of catechin derivatives appear critical to antiviral activities. Enhancing the binding affinity of EGCG to virus particles would thus be important to increase virucidal activity. We propose a newly developed EGCG-fatty acid derivative in which the fatty acid on the phenolic hydroxyl group would be expected to increase viral and cellular membrane permeability. EGCG-fatty acid monoesters showed improved antiviral activities against different types of viruses, probably due to their increased affinity for virus and cellular membranes. Our study promotes the application of EGCG-fatty acid derivatives for the prevention and treatment of viral infections.
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Affiliation(s)
- Kunihiro Kaihatsu
- Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Kobe, Hyogo 657-8501, Japan.
| | - Miyuki Yamabe
- Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Kobe, Hyogo 657-8501, Japan.
| | - Yasuhito Ebara
- Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Kobe, Hyogo 657-8501, Japan.
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23
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Furushima D, Ide K, Yamada H. Effect of Tea Catechins on Influenza Infection and the Common Cold with a Focus on Epidemiological/Clinical Studies. Molecules 2018; 23:molecules23071795. [PMID: 30037024 PMCID: PMC6100025 DOI: 10.3390/molecules23071795] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 07/18/2018] [Accepted: 07/20/2018] [Indexed: 01/14/2023] Open
Abstract
Influenza and the common cold are acute infectious diseases of the respiratory tract. Influenza is a severe disease that is highly infectious and can progress to life-threating diseases such as pneumonia or encephalitis when aggravated. Due to the fact that influenza infections and common colds spread easily via droplets and contact, public prevention measures, such as hand washing and facial masks, are recommended for influenza prophylaxis. Experimental studies have reported that tea catechins inhibited influenza viral adsorption and suppressed replication and neuraminidase activity. They were also effective against some cold viruses. In addition, tea catechins enhance immunity against viral infection. Although the antiviral activity of tea catechins has been demonstrated, the clinical evidence to support their utility remains inconclusive. Since the late 1990s, several epidemiological studies have suggested that the regular consumption of green tea decreases influenza infection rates and some cold symptoms, and that gargling with tea catechin may protect against the development of influenza infection. This review briefly summarizes the effect of tea catechins on influenza infection and the common cold with a focus on epidemiological/clinical studies, and clarifies the need for further studies to confirm their clinical efficacy.
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Affiliation(s)
- Daisuke Furushima
- Department of Drug Evaluation & Informatics, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8002, Japan.
| | - Kazuki Ide
- Department of Drug Evaluation & Informatics, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8002, Japan.
- Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health, Kyoto University, Kyoto 606-8501, Japan.
- Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto 606-8501, Japan.
| | - Hiroshi Yamada
- Department of Drug Evaluation & Informatics, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8002, Japan.
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You HL, Huang CC, Chen CJ, Chang CC, Liao PL, Huang ST. Anti-pandemic influenza A (H1N1) virus potential of catechin and gallic acid. J Chin Med Assoc 2018; 81:458-468. [PMID: 29287704 PMCID: PMC7105043 DOI: 10.1016/j.jcma.2017.11.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 08/27/2017] [Accepted: 09/01/2017] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The pandemic influenza A (H1N1) virus has spread worldwide and infected a large proportion of the human population. Discovery of new and effective drugs for the treatment of influenza is a crucial issue for the global medical community. According to our previous study, TSL-1, a fraction of the aqueous extract from the tender leaf of Toonasinensis, has demonstrated antiviral activities against pandemic influenza A (H1N1) through the down-regulation of adhesion molecules and chemokine to prevent viral attachment. METHODS The aim of the present study was to identify the active compounds in TSL-1 which exert anti-influenza A (H1N1) virus effects. XTT assay was used to detect the cell viability. Meanwhile, the inhibitory effect on the pandemic influenza A (H1N1) virus was analyzed by observing plaque formation, qRT-PCR, neuraminidase activity, and immunofluorescence staining of influenza A-specific glycoprotein. RESULTS Both catechin and gallic acid were found to be potent inhibitors in terms of influenza virus mRNA replication and MDCK plaque formation. Additionally, both compounds inhibited neuraminidase activities and viral glycoprotein. The 50% effective inhibition concentration (EC50) of catechin and gallic acid for the influenza A (H1N1) virus were 18.4 μg/mL and 2.6 μg/mL, respectively; whereas the 50% cytotoxic concentrations (CC50) of catechin and gallic acid were >100 μg/mL and 22.1 μg/mL, respectively. Thus, the selectivity indexes (SI) of catechin and gallic acid were >5.6 and 22.1, respectively. CONCLUSION The present study demonstrates that catechin might be a safe reagent for long-term use to prevent influenza A (H1N1) virus infection; whereas gallic acid might be a sensitive reagent to inhibit influenza virus infection. We conclude that these two phyto-chemicals in TSL-1 are responsible for exerting anti-pandemic influenza A (H1N1) virus effects.
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Affiliation(s)
- Huey-Ling You
- Department of Laboratory Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, ROC; Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan, ROC
| | - Chao-Chun Huang
- Division of General Surgery, Ministry of Health and Welfare Pingtung Hospital, Pingtung, Taiwan, ROC
| | - Chung-Jen Chen
- Division of General Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, ROC
| | - Cheng-Chin Chang
- Department of Chinese Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, ROC
| | - Pei-Lin Liao
- Division of Pediatric Surgery and Mitochondrial Research Unit, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, ROC
| | - Sheng-Teng Huang
- Department of Chinese Medicine, China Medical University Hospital, Taichung, Taiwan, ROC; School of Chinese Medicine, China Medical University, Taichung, Taiwan, ROC.
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Cody RB, Tamura J, Downard KM. Quantitation of anthocyanins in elderberry fruit extracts and nutraceutical formulations with paper spray ionization mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2018; 53:58-64. [PMID: 28960779 DOI: 10.1002/jms.4033] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/17/2017] [Accepted: 09/19/2017] [Indexed: 06/07/2023]
Abstract
The ability to rapidly identify and quantitate, over a wide range of concentrations, anthocyanins in food and therapeutic products is important to ensuring their presence at medicinally significant levels. Sensitive, yet mild, analysis conditions are required given their susceptibility to degradation and transformation. Paper spray ionization has been used to detect and quantify the levels of anthocyanin levels in extracts of fresh and dried elderberries, and elderberry stems, as well as 3 commercially available nutraceutical formulations. The component cyanidin glucosides, including cyanidin-3-sambubioside, cyanidin-3-glucoside, cyanidin-3,5-diglucoside, cyanidin-3-sambubioside-5-glucoside, and the aglycone cyanidin, were readily detected in a range of sources. Quantitation was achieved by establishing a calibration plot from dilutions of a stock solution of cyanidin-3,5-diglucoside containing malvidin-3,5-diglucoside as an internal standard at a fixed concentration. The same standard was used to quantify the anthocyanin content in the fruit and nutraceutical formulations. Wide 5-fold variations in anthocyanin concentration were detected in the nutraceutical formulations from different suppliers ranging from 1050 to 5430 mg/100 g. These concentrations compared with 500 to 2370 mg/100 g measured in the dried stems and fruit, respectively.
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Inhibition activity of a traditional Chinese herbal formula Huang-Lian-Jie-Du-Tang and its major components found in its plasma profile on neuraminidase-1. Sci Rep 2017; 7:15549. [PMID: 29138445 PMCID: PMC5686190 DOI: 10.1038/s41598-017-15733-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 10/31/2017] [Indexed: 12/25/2022] Open
Abstract
Huang-Lian-Jie-Du-Tang (HLJDT), a traditional formula with four TCM herbs, has been used for hundred years for different diseases. The current study aimed to assess the inhibitory activity of HLJDT against H1N1 neuraminidase (NA-1), and identify potent NA-1 inhibitors from its plasma profile. The in vitro NA-1 study has shown that the water extract of HLJDT potently inhibited NA-1 (IC50 = 112.6 μg/ml; Ki = 55.6 μg/ml) in a competitive mode. The IC50 values of the water extracts of its four herbs were as follows: Coptidis Rhizoma, 96.1 μg/ml; Phellodendri Chinensis Cortex, 108.6 μg/ml; Scutellariae Radix, 303.5 μg/ml; Gardeniae Fructus, 285.0 μg/ml. Thirteen compounds found in the plasma profile of HLJDT were also identified as potent NA-1 inhibitors, which included jatrorrhizine, palmatine, epiberberine, geniposide, oroxylin A, berberine, coptisine, baicalein, wogonoside, phellodendrine, wogonin, oroxylin A-7-O-glucuronide and baicalin (sorted in ascending order by their IC50 values). Their inhibitory activities were consistent with molecular docking analysis when considering crystallographic water molecules in the ligand-binding pocket of NA-1. Our current findings suggested that HLJDT can be used as a complementary medicine for H1N1 infection and its potent active compounds can be developed as NA-1 inhibitors.
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van de Wakker SI, Fischer MJ, Oosting RS. New drug-strategies to tackle viral-host interactions for the treatment of influenza virus infections. Eur J Pharmacol 2017; 809:178-190. [DOI: 10.1016/j.ejphar.2017.05.038] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 04/24/2017] [Accepted: 05/19/2017] [Indexed: 12/13/2022]
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Downard KM. Indirect study of non-covalent protein complexes by MALDI mass spectrometry: Origins, advantages, and applications of the "intensity-fading" approach. MASS SPECTROMETRY REVIEWS 2016; 35:559-573. [PMID: 26250984 DOI: 10.1002/mas.21480] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 07/07/2015] [Accepted: 07/07/2015] [Indexed: 06/04/2023]
Abstract
This review article describes the origins, advantages, and application of an indirect approach with which to study protein and other macromolecular complexes and identify the nature and site of interaction interfaces by means of conventional matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS). First reported in 1999, it involves the detection of ion depletion or the absence of ions associated with a binding partner or domain in the MALDI mass spectrum of a mixture of interacting components compared to that for an untreated control. Later referred to as intensity-fading in some applications, the method offers numerous advantages over the direct detection of protein and other macromolecule complexes by MALDI-MS and even electrospray ionization (ESI) MS. The origins of this indirect method, its development for use with gel-separated components, validation using companion biochemical assays, and application to a range of protein-antibody and protein-drug complexes are reviewed together with software specifically developed to aid with data interpretation. The sensitivity of the approach for revealing how subtle differences in the structure of the binding partners can be detected by MALDI-MS is also demonstrated. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 35:559-573, 2016.
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Han X, Wu MQ, Yang ZR, Zhang DK, Mao Y, Han J, Huang YQ, Zhou YF, Zhao YL, Wang JB, Xiao XH. Comprehensive Evaluation of Powdered Chinese Herbal Medicines-An Exemplification of Isatidis Radix. CHINESE HERBAL MEDICINES 2016. [DOI: 10.1016/s1674-6384(16)60052-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Lu R, Müller P, Downard KM. Molecular basis of influenza hemagglutinin inhibition with an entry-blocker peptide by computational docking and mass spectrometry. Antivir Chem Chemother 2016; 24:109-17. [PMID: 26759268 DOI: 10.1177/2040206615622920] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 11/24/2015] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The increased resistance of circulating strains to current antiviral inhibitors of the influenza virus necessitates that new antivirals and their mode of action are identified. Influenza hemagglutinin is an ideal target given inhibitors of its function can block the entry of the virus into host cells during the early stages of replication. This article describes the molecular basis for the inhibition of H1 and H5 hemagglutinin by an entry-blocker peptide using companion molecular docking and mass spectrometry-based experiments. METHODS A combination of hemagglutination inhibition assays, computational molecular docking and a novel mass spectrometry-based approach are employed to explore the mode of action of the entry-blocker peptide at a molecular level. RESULTS The entry-blocker peptide is shown to be able to maximally inhibit blood cell hemagglutination at a concentration of between 6.4 and 9.2 µM. The molecular basis for this inhibition is derived from the binding of the peptide to hemagglutinin in the vicinity of the reported sialic acid binding site surrounded by an α-helix (190-helix) and two loop (130-loop and 220-loop) regions in the case of a H1 hemagglutinin and the second loop region in the case of a H5 hemagglutinin. CONCLUSIONS The results support the recognized potential of the entry-blocker peptide as an effective antiviral agent that can inhibit the early stages of viral replication and further illustrate the power of a combination of docking and a mass spectrometry approach to screen the molecular basis of new antiviral inhibitors to the influenza virus.
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Affiliation(s)
- Robert Lu
- University of New South Wales, Sydney, Australia
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