Antioxidant and Anti-Cancer Activities of Green and Black Tea Polyphenols

Jhoo, Jin‐Woo

doi:10.1021/bk-2007-0956.ch015

Cited by 5 publications

(10 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Its popularity is as a result of its potential health benefits and a characteristic flavour . The health benefits in teas of different types is associated with preventing heart disease and cancer and enhancing endothelial function and reduced cardiovascular risk . Teas in China are usually categorised as green tea (non‐fermented), Oolong tea (semi‐fermented), black tea (fully fermented), white tea (slightly fermented) and dark tea (post‐fermented) based on the different processing methods or the degree of the fermentation .…”

Section: Introductionmentioning

confidence: 99%

Characterization of aroma compositions in different Chinese congou black teas using GC–MS and GC–O combined with partial least squares regression

Xiao

Wang

Niu

et al. 2017

Flavour & Fragrance J

View full text Add to dashboard Cite

To characterise the volatile aroma compositions of Chinese congou black teas, four types were analysed by quantitative descriptive sensory analysis, gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O). The aroma of Chinese congou black tea was described using six sensory terms: ‘Roasted’, ‘Sweet’, ‘Malty’, ‘Green grassy’, ‘Floral’ and ‘Woody’. A total of 64 compounds including alcohols (20), aldehydes (12), ketones (12), esters and lactones (9), pyrazines (7) and other compounds (4) were identified and quantified in four Chinese black tea samples. The highest amount of volatile aroma compounds was found in Tanyang congou black tea (TY) (29.8 mg/kg), followed by Dianhong congou black tea (DH) (29.4 mg/kg), Keemun congou black tea (KM) (24.1 mg/kg) and Yixing congou black tea (YH) (23.6 mg/kg). Through aroma extract dilution analysis (AEDA) on the black tea extract, the flavour dilution factor (FD factor) ranged from 41 to 46. Trans‐linalool oxide in DH, geraniol in TY, DH and KM were identified with the highest flavour dilution (FD = 4096) factors. The relationship between tea samples, sensory attributes and aroma‐active compounds was modelled by partial least squares regression (PLSR), and the PLSR analysis revealed that pentanal showed a significant and positive correlation with the ‘Malty’ attribute, (Z)‐3‐hexen‐1‐ol showed a significant and negative correlation with the ‘Green grassy’ attribute, 2‐methylpyrazine showed a significant and negative correlation with the ‘Floral’ attribute, cis‐linalool oxide, trans‐linalool oxide and nerolidol showed a significant and positive correlation with the ‘Woody’ attribute, cis‐6‐nonen‐1‐ol and 2‐methylpyrazine showed a significant and negative correlation with the ’Woody‘ attribute.

show abstract

Section: Introductionmentioning

confidence: 99%

Characterization of aroma compositions in different Chinese congou black teas using GC–MS and GC–O combined with partial least squares regression

Xiao

Wang

Niu

et al. 2017

Flavour & Fragrance J

View full text Add to dashboard Cite

show abstract

“…52 For example, a previous study showed that green tea reduces iron and erythrocyte ROS in the rat plasma. 39 Still another study showed that green tea reduced oxidative stress induced by tert-butylhydroperoxide treatment of cultured mouse C2C12 myotubes.…”

Section: Discussionmentioning

confidence: 99%

Determining the Effects of Antioxidants on Oxidative Stress Induced Carbonylation of Proteins

et al. 2011

View full text Add to dashboard Cite

There is potential that the pathological effects of oxidative stress (OS) associated diseases such as diabetes could be ameliorated with antioxidants, but this will require a clearer understanding of the pathway(s) by which proteins are damaged by OS. This study reports the development and use of methods that assess the efficacy of dietary antioxidant supplementation at a mechanistic level. Data reported here evaluate the impact of green tea supplementation on oxidative stress induced post-translational modifications (OSi-PTMs) in plasma proteins of Zucker diabetic fatty (ZDF) rats. The mechanism of antioxidant protection was examined through both the type and amount of OSi~PTMs using mass spectrometry based identification and quantification. Carbonylated proteins in freshly drawn blood samples were derivatized with biotin hydrazide. Proteins thus biotinylated were selected from plasma samples of green tea fed diabetic rats and control animals by avidin affinity chromatography, further fractionated by reversed phase chromatography (RPC), fractions from the RPC column were tryptic digested, and the tryptic digest fractionated by RPC before identified by tandem mass spectrometry (MS/MS). Relative quantification of peptides bearing carbonylation sites was achieved for the first time by RPC-MS/MS using selective reaction monitoring (SRM). Seventeen carbonylated peptides were detected and quantified in both control and treated plasma. The relative concentration of eight was dramatically different between control and green tea treated animals. Seven of the OSi-PTM bearing peptides had dropped dramatically in concentration with treatment while one increased, indicating differential regulation of carbonylation by antioxidants. Green tea antioxidants were found to reduce carbonylation of proteins by lipid peroxidation end products most, followed by advanced glycation end products to a slightly lower extent. Direct oxidation of proteins by reactive oxygen species (ROS) was protected the least by green tea.

show abstract

“…Epicatechin (EC) + Epigallocatechin(EGC) -→ Simple theaflavin (TF). EC + Epigallocatechin gallate (EGCG) ----→ Theaflavin-3-gallate (TF-3-g) Epicatechin gallate (ECG) + EGC -------→ Theaflavin-3 -gallate (TF-3 -g) ECG + EGCG -------------------→ Theaflavin-3, 3 -digallate (TF dg) thearubigins are products of polyphenols oxidation during black tea processing (Davis et al, 1997;Jhoo, 2007). The polyphenols, (flavanols, flavonol glycosides, polyphenolic acids and depsides) make up to between 30% and 40% of the dry weight in tea shoots (Harbowy and Balentine, 1997).…”

Section: Introductionmentioning

confidence: 99%

“…In Central and Southern African black teas, high levels of EC and EGC (Hilton et al, 1973) and EC and ECG levels (Wright et al, 2000) were associated with high quality black teas. But in Kenya, high EGCG and low EC levels were indicators of high black tea quality potential of clonal tea bushes (Owuor and Obanda, 1997;2007;Owuor et al, 2006). The green leaf EGCG levels correlated significantly with black tea total theaflavin, liquor brightness and sensory evaluation, while EC correlated positively with thearubigins and negatively with theaflavin digallate equivalent and sensory evaluation (Owuor and Obanda, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…The sum of gallated flavan-3-ols (flavan-3-gallates), trihydroxyflavan-3-ols (gallocatechins) and ratios of trihydroxyflavan-3-ols:dihydroxyflavan-3-ols in green tea leaf predicted plain black tea quality potential (Owuor and Obanda, 2007). Indeed, flavan-3-ols composition was a better quality indicator than total polyphenols or total flavan-3-ols (Owuor and Obanda, 1997;2007). These results demonstrated the importance of the flavan-3-ols composition and levels as indicators of black tea quality potential of green tea leaf.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Variations in the Precursors of Plain Black Tea Quality Parameters Due to Location of Production and Nitrogen Fertilizer Rates in Eastern African Clonal Tea Leaves

Kwach

Owuor

Kamau³

et al. 2015

Ex. Agric.

View full text Add to dashboard Cite

Theaflavins contribute to astringency and brightness while thearubigins contribute to colour and mouth feel of black tea. Green leaf flavan-3-ols influence levels and distribution of theaflavins and thearubigins in black tea and are black tea quality precursor compounds. Caffeine also contributes to tea quality. Although location of production and nitrogenous fertilizer rates influence black tea quality, it is not known if the variations arise from the levels and distribution of the precursor compounds in green leaf or other factors. The variations and distribution of the flavan-3-ols and caffeine in young green leaves of clone TRFK 6/8 due to nitrogen fertiliser rates in seven locations within Eastern Africa were evaluated. Green leaf comprising two leaves and a bud were harvested from each plot, and subjected to HPLC analysis for caffeine, total polyphenol, dihydroxyflavan-3-ols, trihydroxyflavan-3-ols, ratios of trihydroxyflavan-3-ols to dihydroxyflavan-3-ols and total catechins levels. Results were subjected to statistical analysis using split plot design, with locations as main treatments and nitrogen rates as the sub-treatment. Caffeine and flavan-3-ols levels changed (p ࣘ 0.05) with location of production, demonstrating that even with use of same cultivar and similar agronomic management quality of tea from one location cannot be replicated in another location. Caffeine levels increased (p ࣘ 0.05) with rise in nitrogen fertilizer rate in all locations, but the extent depended on location. Total polyphenols and individual flavan-3-ols showed an inverse quadratic response, except EGCG that linearly decreased (p ࣘ 0.05) in some locations, due to increasing rates of nitrogen fertilizer. Similar responses in the black tea quality parameters had been observed in previous studies. The black tea quality results were therefore directly influenced by the green leaf precursor compound patterns. Region specific nitrogenous fertilizer rates need development to ensure high tea quality. I N T RO D U C T I O NIn tea trade, African black teas are classified as plain to medium flavoury. Such teas are valued for taste and colour characteristics; factors attributed to the non-volatile components of black tea. The black tea theaflavins contribute to the astringency (briskness) and brightness while thearubigins contribute to the colour and thickness (mouth-feel) of plain black tea (Biswas et al., 1971;. The theaflavins and ‡Corresponding author.

show abstract

Antioxidant and Anti-Cancer Activities of Green and Black Tea Polyphenols

Cited by 5 publications

References 35 publications

Characterization of aroma compositions in different Chinese congou black teas using GC–MS and GC–O combined with partial least squares regression

Characterization of aroma compositions in different Chinese congou black teas using GC–MS and GC–O combined with partial least squares regression

Determining the Effects of Antioxidants on Oxidative Stress Induced Carbonylation of Proteins

Variations in the Precursors of Plain Black Tea Quality Parameters Due to Location of Production and Nitrogen Fertilizer Rates in Eastern African Clonal Tea Leaves

Contact Info

Product

Resources

About