Phytochemicals and Biological Properties of Azorean Black Tea Samples from Different Zones of Tea Plantation.

tea has received considerable attention due to its beneficial effects on health, particularly due to its antioxidant properties that are affected by several factors, which have a high influence on the final quality of black tea. The objective of this study was to investigate the biological properties of Azorean black tea from five different zones of tea plantation in order to select specific areas to cultivate tea rich in targeted compounds beneficial to human health. The free radical scavenging activity (FRSA), ferric reducing antioxidant power (FRAP), ferrous ion chelating (FIC) activities, total phenolic content (TPC), total flavonoid content (TFC), and tannins were determined by colorimetric methods, and catechin and theaflavin contents were analyzed by high-pressure liquid chromatography.

Investigation of the Azorean Processing Conditions to Maximize the Theaflavin 3,3'-di--Gallate Content as a Potential Antiviral Compound.

The molecular constituents of , in particular epigallocatechin-3--gallate (EGCG) and, more remarkably, the galloylated theaflavins, mainly theaflavin-3,3'-di--gallate (TF-3,3'-DG), have been reported to inhibit SARS-CoV-2 3-chymotrypsin-like protease (3CL), 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.

Variability of antioxidant properties, catechins, caffeine, L-theanine and other amino acids in different plant parts of Azorean .

During tea processing, manufacturers usually remove the internodes, which are classified as waste. This study presents the first determination of plant part contribution, particularly internodes, to green tea quality, in order to find the best blend to maximize impact on human health. Catechins, caffeine and free amino acid (FAA) profiles were determined by RP-HPLC/DAD, total phenolics (TPC) and total flavonoids (TFC) by Folin-Ciocalteu and colorimetric methodologies, respectively, and antioxidant activities by free radical-scavenging activity (FRSA), ferric-reducing antioxidant power (FRAP) and ferrous ion-chelating (FIC) methods.