Characterization of the Trans-Epithelial Transport of Green Tea (C. sinensis) Catechin Extracts with In Vitro Inhibitory Effect against the SARS-CoV-2 Papain-like Protease Activity

Abstract

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

Targeting proteases involved in the viral replication of SARS-CoV-2 by sesquiterpene lactones from chicory (Cichorium intybus L.)

“…A recent in vitro study using a green tea (C. sinensis) extract reported a high variability in the inhibition of the SARS-CoV-2 PLpro activity between the crude extract and its 6 different fractions. 43 In our case, F2 was the fraction with the most potent inhibitory capacity, even higher than the specific PLpro inhibitor (Fig. 4B), similarly to that observed for the inhibition of Mpro (Fig.…”

“…A recent in vitro study using a green tea ( C. sinensis ) extract reported a high variability in the inhibition of the SARS-CoV-2 PLpro activity between the crude extract and its 6 different fractions. 43…”

“…67 In our study, lactucin was the SL with the highest inhibitory activity against SARS-CoV-2 PLpro at the concentration of 174 µM, which is clearly a higher concentration than that reported for other active compounds. 43,67 Nonetheless, this is the first screening study using these STLs (11β,13-dihydrolactucopicrin, lactucopicrin, 11β,13-dihydrolactucin and lactucin), so even though these compounds seem to be suitable natural inhibitors to PLpro, further studies are required to confirm their potential.…”

“…66 Regarding the studies that are specifically focused on the inhibitory activity of natural compounds against the SARS-CoV-2 PLpro, Montone et al reported a IC 50 value equal to 11.62 ± 0.47 μg mL −1 (about 25 µM) of (−)-epicatechin-3gallate inhibiting this protease. 43 Other compounds with inhibitory activity towards this protease were ginkgolic acid and anacardic acid with IC 50 values of 16.30 ± 0.64 µM and 17.08 ± 1.30, respectively. 67 In our study, lactucin was the SL with the highest inhibitory activity against SARS-CoV-2 PLpro at the concentration of 174 µM, which is clearly a higher concentration than that reported for other active compounds.…”

COVID-19 and per capitagreen tea consumption: update

“…There is mounting evidence suggesting the therapeutic potential of green tea catechins in prevention/treatment of COVID19. In particular, in addition to numerous docking studies (for instance, [1][2][3][4][5][6][7]) there is growing number of studies showing direct antiviral activity of at least one catechin epigallocatechin-3-gallate (EGCG) against SARS-CoV-2 in in vitro experiments ( [8][9][10][11][12][13][14][15][16][17] see also [18][19][20] for review). Moreover, a recent work [21] reports that EGCG from green tea effectively blocks infection of SARS-CoV-2 and new variants.…”