Antiviral effect of theaflavins against caliciviruses

Ohba, Mai; Oka, Takahiro; Ando, Takayuki; Arahata, Saori; Ikegaya, Asaka; Takagi, Hirotaka; Ogo, Naohisa; Zhu, Chelsea; Owada, Kazuhiro; Kawamori, Fumihiko; Wang, Qiuhong; Saif, Linda J.; Asai, Akira

doi:10.1038/ja.2016.128

Cited by 29 publications

(27 citation statements)

References 27 publications

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“…Figure 7 shows the binding poses of the top natural products in terms of both

and d dyad , which are theacitrin A, corilagin, theaflavin, amentoflavone, epigallocatechin gallate (EGCG), and neodiosmin. It is pertinent to note that all six natural products, together with rhoifolin, daidzein, ginkgetin, proanthocyanidins and epitaraxerol, or their closely related derivatives and plant preparations have been reported to possess antiviral, and in some cases anti-coronavirus activities [ 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ].…”

Section: Resultsmentioning

confidence: 99%

High Throughput Virtual Screening to Discover Inhibitors of the Main Protease of the Coronavirus SARS-CoV-2

et al. 2020

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We use state-of-the-art computer-aided drug design (CADD) techniques to identify prospective inhibitors of the main protease enzyme, 3CLpro of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing COVID-19. From our screening of over one million compounds including approved drugs, investigational drugs, natural products, and organic compounds, and a rescreening protocol incorporating enzyme dynamics via ensemble docking, we have been able to identify a range of prospective 3CLpro inhibitors. Importantly, some of the identified compounds had previously been reported to exhibit inhibitory activities against the 3CLpro enzyme of the closely related SARS-CoV virus. The top-ranking compounds are characterized by the presence of multiple bi- and monocyclic rings, many of them being heterocycles and aromatic, which are flexibly linked allowing the ligands to adapt to the geometry of the 3CLpro substrate site and involve a high amount of functional groups enabling hydrogen bond formation with surrounding amino acid residues, including the catalytic dyad residues H41 and C145. Among the top binding compounds we identified several tyrosine kinase inhibitors, which include a bioflavonoid, the group of natural products that binds best to 3CLpro. Another class of compounds that decently binds to the SARS-CoV-2 main protease are steroid hormones, which thus may be endogenous inhibitors and might provide an explanation for the age-dependent severity of COVID-19. Many of the compounds identified by our work show a considerably stronger binding than found for reference compounds with in vitro demonstrated 3CLpro inhibition and anticoronavirus activity. The compounds determined in this work thus represent a good starting point for the design of inhibitors of SARS-CoV-2 replication.

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“…Figure 7 shows the binding poses of the top natural products in terms of both

Section: Resultsmentioning

confidence: 99%

High Throughput Virtual Screening to Discover Inhibitors of the Main Protease of the Coronavirus SARS-CoV-2

et al. 2020

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“…Among all tea polyphenols, epigallocatechin gallate (EGCG) has been found to be responsible for much of the health-promoting ability of green tea. (7) In recent years, theaflavins of black tea have also attracted considerable interest, as they are shown to have various physiological actions, including antioxidant, (8) anticancer, (9) anti-atherosclerotic, (10) anti-inflammatory, (11) antiviral, (12) and anti-periodontitis (13) effects, as well as the prevention of osteoporosis (14) . Furthermore, these compounds have been shown to have human health benefits including glucose-lowering (15) and anti-obesity actions, (16) as a prevention of lifestyle-related diseases.…”

Section: B a C K G R O U N Dmentioning

confidence: 99%

Antibacterial Activity of Black Tea Extract against S. mutans, S. aureus, L. acidophilus, Klebsiella and E. coli

Goswami¹,

Kalita²,

Bhuyan³

2020

jemds

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BACKGROUND Drinking tea has antioxidant, anti-inflammatory and anti-carcinogenic properties. In addition, tea is also considered beneficial for cardiovascular health and oral health. Health benefits of green tea are attributed to its polyphenol content. Catechins are the major polyphenols in green tea and in black tea the catechins are oxidized to theaflavins. Polyphenols present in tea have exhibited antimicrobial effects against a wide range of pathogenic bacteria. Studies have shown that green tea catechins are bioavailable in both plasma and urine. The aim of the present study is to evaluate the antibacterial activity of black tea extract against standard strains of S. mutans, S. aureus, L. acidophilus, Klebsiella and E. coli. METHODS Black tea extract was prepared by boiling black tea leaves in distilled water. It was then filtered, and the filtrate was treated with chloroform and ethyl acetate. The ethyl acetate was evaporated in a rotary evaporator and a brown coloured residue was obtained. Its antibacterial activity was studied against standard strains of five common bacteria i.e.; S. mutans, L. acidophilus, S. aureus, Klebsiella spp, and E. coli and the MIC of the black tea extract was determined using serial dilution method. RESULTS Black tea extract showed sufficient antibacterial activity against the tested bacteria. The MIC of black tea extract was lowest against Staphylococcus aureus. CONCLUSIONS Tea extracts have significant antimicrobial activity at varying concentrations against different bacterial pathogens.

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“…For this reason, the establishment of new disinfection methods that can also be used for fingers is required. Ohba et al conducted cytopathic effect-based screening of 2080 selected compounds to find antiviral compounds against three culturable caliciviruses: feline calicivirus, murine norovirus, and porcine sapovirus [ 16 ]. As a result, TF2a, TF2b, and TF3 showed broad antiviral activities against all three caliciviruses.…”

Section: Health Benefits Of Tfsmentioning

confidence: 99%

“…The major component of black tea extracts are TFs, including TF1, TF2a, TF2b, and TF3, which are the main red pigments in black tea ( Figure 1 ). In recent years, TFs have attracted considerable interest, as they have been shown to have various physiological actions, including antioxidant [ 12 ], anticancer [ 13 ], anti-atherosclerotic [ 14 ], anti-inflammatory [ 15 ], antiviral [ 16 , 17 , 18 ], and anti-periodontitis [ 19 , 20 ] effects, as well as the prevention of osteoporosis [ 21 , 22 ]. Furthermore, these compounds have been shown to have human health benefits including glucose-lowering [ 23 , 24 , 25 , 26 ] and anti-obesity actions [ 10 , 27 , 28 ], as a prevention of lifestyle-related diseases.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Theaflavins and Their Functions

Takemoto

2018

Molecules

104

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Numerous epidemiological and interventional clinical studies have consistently reported that black tea is good for human health. The polyphenolic compound, theaflavin, and its galloyl esters (theaflavins) are the primary red pigments in black tea that possess several health benefits, including fat-reducing and glucose-lowering capabilities and lifestyle-related disease prevention related to anti-obesity, anticancer, anti-atherosclerotic, anti-inflammatory, antiviral, antibacterial, anti-osteoporotic, and anti-dental caries properties. These compounds are produced by key enzymes, such as polyphenol oxidase and peroxidase, from parent green tea catechins present in fresh green tea leaves during the production of black tea leaves or the fermentation of green tea. However, theaflavins are only present in low concentrations in black tea; thus, their extraction from black tea leaves at sufficient levels for use in medical studies has been difficult. To circumvent this issue, different procedures for the synthesis of theaflavins using chemical oxidizing reagents or enzymes have been studied; however, low yields have limited their utility. Recently, however, several biosynthetic methods have been developed for the mass production of theaflavins. Using these methods, the physiological functions of theaflavins in lifestyle-related diseases in mice and humans have also been studied. In this review, we present the synthesis of theaflavins and their health benefits.

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Antiviral effect of theaflavins against caliciviruses

Cited by 29 publications

References 27 publications

High Throughput Virtual Screening to Discover Inhibitors of the Main Protease of the Coronavirus SARS-CoV-2

High Throughput Virtual Screening to Discover Inhibitors of the Main Protease of the Coronavirus SARS-CoV-2

Antibacterial Activity of Black Tea Extract against S. mutans, S. aureus, L. acidophilus, Klebsiella and E. coli

Synthesis of Theaflavins and Their Functions

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