Tea cultivars possessing purple shoots have attracted global interest. In order to gain a better understanding of the major chemical constituents responsible for the purple colouration, we applied widely targeted metabolomics to investigate the pigmented flavonoids of freeze-dried purple-coloured tea leaves (PTLs) in comparison with green-coloured tea leaves (GTLs). Thirty-three anthocyanins were identified, and delphinidin 3-O-galactoside and cyanidin 3-O-galactoside were found to be the most abundant in PTLs. A total of 226 metabolites including 193 flavonoids and 33 tannins were identified, and the methylated, acylated, and glycosylated flavonoids differed significantly between PTLs and GTLs. Moreover, significant differences (p < 0.01) in the average anthocyanin, flavonoid, chlorophyll and catechin contents were also observed. Four PTLs were found to contain high levels of (-)-epigallocatechin-3-(3″-O-methyl) gallate (>10 mg/g). These results suggest that structurally modified anthocyanins and major potential co-pigmented flavonoids are the chemicals primarily responsible for the purple colouration of the tea leaves.
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http://dx.doi.org/10.1016/j.foodchem.2021.130278 | DOI Listing |
Nutrients
January 2025
Department of Medical Chemistry, Faculty of Chemistry, Adam Mickiewicz University, 61-614 Poznań, Poland.
Tea is a significant source of flavonoids in the diet. Due to different production processes, the amount of bioactive compounds in unfermented (green) and (semi-)fermented tea differs. Importantly, green tea has a similar composition of phenolic compounds to fresh, unprocessed tea leaves.
View Article and Find Full Text PDFInsects
January 2025
State Key Laboratory of Wheat Improvement, College of Plant Protection, Shandong Agricultural University, Tai'an 271000, China.
not only damages plant leaves directly but also causes a sooty blotch due to the honeydew secreted by the nymphs and adults. This pest is widespread and seems to be spreading from low latitude to higher latitude areas where winters are typically colder, indicating an increase in its cold tolerance. Changes in temperature help insects to anticipate the arrival of winter, allowing them to take defensive measures in advance.
View Article and Find Full Text PDFFoods
January 2025
Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing 100013, China.
L-theanine, a non-protein amino acid naturally occurring in tea leaves, is recognized for its antioxidant, anti-inflammatory, and neuroprotective properties. Despite its known benefits, the mechanisms by which L-theanine influences lifespan extension remain poorly understood. This study investigated the effects of L-theanine on the lifespan of and explored the underlying mechanisms.
View Article and Find Full Text PDFHereditas
January 2025
Health Management Research Center, School of Public Health, Southeast University, 87 Dingjiaqiao Road, Gulou District, Nanjing, 210009, P.R. China.
Objectives: Two-sample MR methods were employed to analyze the impact of smoking and bitter beverage consumption on the risk of osteoporosis and osteoporosis with pathological fractures, in order to assess the causal association.
Methods: Publicly available genome-wide association study summary data were analyzed using MR methods. The exposures investigated were smoking (smoking per day, smoking initiation, and lifetime smoking index) and bitter beverages (coffee, tea, bitter alcoholic beverages, bitter non-alcoholic beverages, and total bitter beverages).
Nutr Res
January 2025
Department of Molecular Medicine, University of Padova, Padova, Italy; IMDEA-Food, Madrid, Spain. Electronic address:
l-Theanine is a unique non-protein amino acid found abundantly in tea leaves. Interest in its potential use as a dietary supplement has surged recently, especially claims related to promoting relaxation and cognitive enhancement. This review surveys the chemistry, metabolism, and purported biological activities of l-theanine.
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