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- Investigation of the Azorean Camellia sinensis Processing Conditions to Maximize the Theaflavin 3,3'-di-O-Gallate Content as a Potential Antiviral CompoundPublication . Paiva, Lisete; Lima, Elisabete; Motta, Madalena; Marcone, Massimo; Baptista, JoséABSTRACT: The molecular constituents of Camellia sinensis, in particular epigallocatechin‐3‐O‐gallate (EGCG) and, more remarkably, the galloylated theaflavins, mainly theaflavin‐3,3′‐di‐O‐gallate (TF‐3,3′‐DG), have been reported to inhibit SARS‐CoV‐2 3‐chymotrypsin‐like protease (3CLpro), an enzyme required for the cleavage of its polyproteins, to produce vital individual functional proteins for viral cell replication. Our results for total catechin content revealed the values of 174.72, 200.90, and 211.75 mg/g dry weight (DW) in spring, and the values of 183.59, 191.36, and 215.09 mg/g DW in summer, for tea plantation zones 1, 2, and 3, respectively. For the TF‐3,3′‐DG content, the values of 2.68, 1.13, and 3.72 mg/g DW were observed in spring, and the values of 3.78, 2.06, and 8.91 mg/g DW in summer for zones 1, 2, and 3, respectively. In the same zone, different contents of TF‐3,3′‐DG were observed across plucking months of April, June, and August, with values of 1.13, 2.77, and 4.18 mg/g DW, respectively, showing higher values in summer. Different values of TF‐3,3′‐DG contents were also observed in the same tea plantation zone but from different plant parts, revealing higher values in the bud and the first and second leaves (3.62 mg/g DW) and lower values in the third and fourth leaves (1.14 mg/g DW). The TF‐3,3′‐DG content increased from 3.31 to 4.98 mg/g DW with increased fermentation time from 1 to 3 h, respectively, and increased for lower temperature and longer fermentation time. The aim of this study was to investigate the processing conditions that lead to maximum TF‐3,3′‐DG content and, given its potential impact as an inhibitor of the 3CLpro enzyme, to create a novel antiviral Azorean black tea.
- Angiotensin I-converting enzyme (ACE) inhibition and biological activities of green and black tea samples from Azorean Camellia sinensisPublication . Paiva, Lisete; Lima, Elisabete; Marcone, Massimo; Baptista, JoséABSTRACT: The inhibition of ACE can be targeted in order to control hypertension and much attention has recently been paid towards the search for natural products as alternatives to synthetic drugs due to their adverse side effects associated with them. Camellia sinensis tea has received considerable attention due to the beneficial effects on health, particularly as a result of its antioxidant properties. The objective of this study was to investigate the ACE inhibition of different types of Azorean C. sinensis tea samples and consequently its ability to reduce hypertension, relating it to antioxidant activity, catechin profiles, total phenolic content (TPC) and total flavonoid content (TFC) in different seasons. The results clearly highlighted differences in ACE-inhibition, FRSA, FRAP, FIC activity, TPC and epicatechin content among samples and the best results were observed in green tea collected in the summer. For TFC, higher values were observed in black tea harvested during the summer. In conclusion, the differences are related to the effect of collecting seasons, with the higher values being found in the summer with respect to the spring season.