Browsing by Author "Motta, Madalena"
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- Os efeitos benéficos do chá de Camellia sinensis (L.) na saúde humanaPublication . Paiva, Lisete S.; Lima, Elisabete; Motta, Madalena; Baptista, JoséOriginária da China, a planta do chá (Camellia sinensis) expandiu-se gradualmente por vários países subtropicais e, desde a última década do século XIX, o chá é também produzido e comercializado num único lugar na Europa, a Ilha de São Miguel, Açores. O chá de C. sinensis tem recebido muita atenção, particularmente da comunidade científica, devido aos seus diversos efeitos benéficos na saúde humana, nomeadamente: redução do risco do cancro, pois inibem o desenvolvimento de células cancerígenas, e incentivam a sua autodestruição; diminuição do risco de doenças cardiovasculares, arteriosclerose, hipercolesterolemia e doenças neurodegenerativas, nomeadamente doença de Alzheimer e doença de Parkinson; prevenção da diabetes e propriedades antibacterianas e antivirais, entre outros efeitos terapêuticos. Os polifenóis do chá, devido às suas potentes propriedades antioxidantes, são os principais responsáveis pela ampla variedade de benefícios do chá na saúde humana. […].
- Influence of Seasonal and Yearly Variation on Phenolic Profiles, Caffeine, and Antioxidant Activities of Green Tea (Camellia sinensis (L.) Kuntze) from AzoresPublication . Paiva, Lisete S.; Lima, Elisabete; Motta, Madalena; Marcone, Massimo; Baptista, JoséThis study compares the antioxidant properties (RSA(DPPH)-DPPH radical scavenging activity, FRAP-ferric reducing activity power, and FIC-ferrous ion-chelating activity), the total phenolics (TP), total flavonoids (TF), and catechin profiles, as well as the caffeine content of Azorean Camellia sinensis green tea collected in seasons of two different years. The RSA(DPPH) showed some variation between 2019 and 2020, and presented, in general, better results in 2020 as well as during the summer seasons. The FRAP was also noted to be at its highest in July and August of the two investigated years (6.64 and 6.40 mu g/mL in 2019 and 5.85 and 5.46 mu g/mL in 2020). According to FIC activity, the August 2019 sample exhibited the highest value (76.18%). The TP varied between 291.14 and 326.93 mg gallic acid equivalents (GAE)/g of dried extract (DE) in 2019 and between 300.25 and 320.58 mg GAE/g DE in 2020. Concerning the TF, the values varied between 51.85 and 67.93 mg rutin equivalents (RE)/g DE in 2019 and between 50.27 and 69.57 mg RE/g DE in 2020. Epicatechins derivatives, determined by HPLC, presented higher values in all samples from 2020 compared to 2019, and the same was observed for esterified catechins. The epigallocatechin-3-gallate content was also higher in all samples from 2020 (214.52-240.16 mg/g DE) compared to 2019 (140.91-210.83 mg/g DE). Regarding caffeine content (12.86-20.45 mg/g DE in 2019 and 13.19-29.35 mg/g DE in 2020), the samples from April and June exhibited similar values in both years. In general, green tea samples exhibited better results in 2020 than in 2019, with the exception of FIC activity, while the varied TP and TF contents in certain months reflect the impact of climatic variation on tea quality.
- 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.
- The surplus value of Azorean Camellia sinensis flowers as an important contributor affecting the nutraceutical benefits of green tea qualityPublication . Baptista, José; Paiva, Lisete S.; Lima, Elisabete; Motta, MadalenaLeaves from Camellia sinensis have been used to make teas for a long time, however, less attention has been paid to the flowers, which is a waste of an abundant resource that should be valorized. This study evaluates the representative tea metabolites content (dry weight basis) and antioxidant properties of Azorean C. sinensis flowers as compared to commercial Gorreana green tea (GorGT), the only one produced in Europe. We determined the variability of catechins, caffeine and L-theanine (THEA) by RP-HPLC/DAD and the confirmation of THEA by GC/MS. The antioxidants activities were determined by FRSA, FRAP and FIC methods. The total phenolics and total flavonoids were determined by the Folin-Ciocalteu and colorimetric methodologies. The results showed that flowers presented higher L-theanine (5.88 mg/g) but lower caffeine (4.10 mg/g) contents than GorGT (2.59 and 12.42 mg/g, respectively) and, therefore, a lower caffeine/theanine ratio (0.70 versus 4.80). The esterified catechins content (in percentage of total catechins) showed similar values for flowers (85.34%) and GorGT (86.45%), and the individual catechins decreased as follows: epigallocatechin-3-gallate > epicatechin-3-gallate ≫ gallocatecin-3-gallate. In antioxidant assays, GorGT presented better FRSA and FRAP but similar FIC as compared to flowers. Also, the total phenolics and flavonoids contents of dried extract presented higher values in GorGT: 321.56 mg gallic acid equivalents (GAE)/g and 47.17 mg rutin equivalents (RE)/g as compared to 141.94 mg GAE/g and 24.14 mg RE/g, respectively, for flowers. This study represents the first contribute to Azorean C. sinensis flowers valorization as a new-added material with nutraceutical benefits.
- Variability of antioxidant properties, catechins, caffeine, L-theanine and other amino acids in different plant parts of Azorean Camellia sinensisPublication . Paiva, Lisete S.; Lima, Elisabete; Motta, Madalena; Marcone, Massimo; Baptista, JoséDuring Camellia sinensis 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 FolinCiocalteu and colorimetric methodologies, respectively, and antioxidant activities by free radical-scavenging activity (FRSA), ferric-reducing antioxidant power (FRAP) and ferrous ion-chelating (FIC) methods. Individual esterified catechins content decreased as follows: epicatechin-3-gallate > epigallocatechin-3-gallate ≫ gallocatecin-3-gallate, and epicatechin derivatives content ranged from 63.91 to 91.22% of total catechins. Caffeine content was higher in internodes. L-theanine, histidine, asparagine, phenylalanine, glutamic acid and methionine were the major FAAs, and internodes contained the highest amounts of L-theanine and histidine (17 and 13.73 mg/g of sample, respectively). TPC ranged from 201.51 to 265.48 mg gallic acid equivalents/g dry extract (DE) and TFC ranged from 23.84 to 72.02 mg rutin equivalents/g DE. Internodes presented the lowest FRSA (EC50 ¼ 6.10–13.50 μg/mL), FRAP (EC50 ¼ 5.70–11.40 μg/mL) and FIC activity (36.96–79.21%). Bud presented the highest FRSA and FRAP, and budþ1stþ2ndleaves þ internodes the highest FIC activity. The results revealed the potential contribution of the internodes to green tea quality and, consequently, to human health.