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DARK CHOCOLATE AND GREEN TEA COMPOUNDS BLOCK ACTION OF COVID ENZYME


The enzyme whose function is blocked is the main protease in SARS-COV2. The virus requires this enzyme to replicate. If this main protease is blocked, the virus cannot survive.


Flavan-3-ols and proanthocyanidins (PAs) are two groups of plant flavonoids. They commonly exist in fruits, food products, and beverages, such as grape, strawberry, persimmon, cranberry, blueberry, cacao nuts, chocolate, green tea, and wines (Monagas et al., 2003). Common flavan-3-ol aglycones in these plant products include (–)-epicatechin (EC), (+)-catechin (CA), (–)-epigallocatechin (EGC), (+)-gallocatechin (GC), (–)-epiafzelechin (EAF), and (+)-afzelechin (AF) (Figure 2; Xie and Dixon, 2005). Common flavan-3-ol gallates include (–)-epicatechin-3-O-gallate (ECG), (+)-catechin-3-O-gallate (CAG), (–)-gallatechin-3-O-gallate (GCG), (–)-epigallocatechin-3-O-galloate (EGCG), which are highly abundant in green tea.(Dai X. et al., 2020; Wang P. et al., 2020)


Multiple compounds from these two groups, such as CA, EPC, EGC, EGCG, procyanidin B2, and procyanidin A2, have been shown to have antiviral function (de Bruyne et al., 1999; Iwasawa et al., 2009), antibacterial activity (Molan et al., 2001; Howell et al., 2005), anticancer (Ohata et al., 2005; Suganuma et al., 2011), anti-cardiovascular diseases (Loke et al., 2008; Panneerselvam et al., 2010; MacRae et al., 2019), and anti-aging diseases (Levites et al., 2003; Li et al., 2004; Weinreb et al., 2004). In particular, the anti-viral activity suggests that flavan-3-ols and PAs are appropriate targets for screening potential anti-SARS-Cov-2 medicines.


Both docking simulation and in vitro assays showed that the stereo configurations, galloylation, and oligomeric types of flavan-3-ols affected the ligand-protein binding features and inhibitory activity.


In summary, although these natural extracts have not been tested for the inhibitory efficacy in animals and humans, based on their inhibitory activity in vitro, we propose that an increased consumption of these common products can enhance preventing against SARS-Cov-2 and improving the COVID-19.



Conclusion, both docking simulation and in vitro assay showed that (–)-catechin-3-O-gallate (7), (–)-epicatechin-3-O-gallate (8), (–)-gallocatechin-3-O-gallate (9), and (–)-epigallocatechin-3-O-gallate (10), procyanidin B1 (11) and B2 (12) inhibited the Mpro activity of SARS-Cov-2. Moreover, these compound-rich extracts of green tea, muscadine grape, cacao, and dark chocolate also inhibited the Mpro activity. Given that there is not an effective medicine for the treatment of COVID-19 and not a vaccine for preventing against the SARS-Cov-2 infection and transmission, these data recommend that these nutraceutical compounds and extracts of green tea, grape, and cacao can be utilized to interfere the devastation of SARS-Cov-2.


 

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