Chemical studies on antioxidant mechanism of tea catechins: analysis of radical reaction products of catechin and epicatechin with 2,2-Diphenyl-1-picrylhydrazyl

Sang, Shengmin; Cheng, Xiaofang; Rosén, Robert; Yang, Chung S.; Ho, Chi‐Tang

doi:10.1016/s0968-0896(02)00089-5

Cited by 86 publications

(56 citation statements)

References 25 publications

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“…25,26 The radical scavenging properties of catechins towards diphenylpicrylhydrazyl have been reported and oxidation products identified. 27 Furthermore the reaction of EGCG with diphenylpicrylhydrazyl has been investigated using EPR spectroscopy. 28 Our results are summarized in Tables 1-2.…”

Section: Resultsmentioning

confidence: 99%

Antioxidant activity of O-protected derivatives of (-)-epigallocatechin-3-gallate: inhibition of soybean and rabbit 15-lipoxygenases

Utenova¹,

Malterud²,

Rise³

2006

Arkivoc

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Abstract(-)-Epigallocatechin-3-gallate (EGCG) was protected at all eight phenolic groups as the methyl ether or acetate, propionate or butyrate esters. The synthetic derivatives were examined for antioxidant activities. The compounds were tested as potential diphenylpicrylhydrazyl (DPPH) radical scavengers and as inhibitors of 15-lipoxygenase (15-LO) enzymes from soybeans and rabbit reticulocytes. The O-protected EGCG derivatives were essentially inactive as DPPH scavengers but showed profound inhibiting effects on both types of 15-LO, and the inhibitory effects towards the two enzymes were significantly correlated. The O-protected EGCG derivatives inhibited 15-LO more strongly that EGCG itself. EGCG and its O-protected derivatives were also screened for antibacterial activity against M. tuberculosis.

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Section: Resultsmentioning

confidence: 99%

Antioxidant activity of O-protected derivatives of (-)-epigallocatechin-3-gallate: inhibition of soybean and rabbit 15-lipoxygenases

Utenova¹,

Malterud²,

Rise³

2006

Arkivoc

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“…The activity of scavenging free radicals usually depends on the number of hydroxyl groups in the chemical structure of the compound; however, the reaction and the type of radical scavengers are also important factors (1) . The studies by Sang et al (2002) showed that in the case of scavenging DPPH radicals both rings A and B of fl avonoid structures play an equally important role in this reaction. According to Salah et al (1995), the antioxidant capacity of tea catechins is due to the structure of the molecule, and especially the presence of at least fi ve hydroxyl groups.…”

Section: Discussionmentioning

confidence: 99%

PCL assay application in superoxide anion-radical scavenging capacity of tea Camellia sinensis extracts

Gramza‐Michałowska

Sidor

Reguła

et al. 2015

Acta Sci Pol Technol Aliment

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“…Karori, Washira, Wanyoko, and Ngure (2007) found that high levels of EGCG, EC, EGC, C, and ECG in green tea extracts strongly correlated to high DPPH radical inhibition. The presence of a trihydroxyphenyl B-ring in EGCG and EGC would explain the potent free radical scavenging properties of such gallocatechins (Shang et al, 2002).…”

Section: Total Phenolic Contentsmentioning

confidence: 99%

Phenolic compounds, antioxidant capacity, andin vitro α-amylase inhibitory potential of tea infusions (Camellia sinensis) commercialized in Chile

Quesille-Villalobos

Torrico

Ranilla

2013

CyTA - Journal of Food

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(2013) Phenolic compounds, antioxidant capacity, and invitro α-amylase inhibitory potential of tea infusions (Camelliasinensis) commercialized in Chile, CyTA -Journal of Food, 11:1, 60-67, DOI: 10.1080/19476337.2012 To link to this article: https://doi.org/10. 1080/19476337.2012 Chile is considered the largest tea consumer in America, so a broad variety of tea types and brands are available in Chilean markets. Thirty-four commercial teas (white, green, red, oolong, and black) commonly found in Chile were evaluated according to their phenolic profiles, antioxidant capacity, and in vitro inhibition against a-amylase relevant for hyperglycemia control. Multivariate tools were used to evidence patterns among samples respect their biochemical parameters. Green and white tea groups showed higher total phenolic contents than red and black teas. All tea samples inhibited the 2,2-diphenyl-1-picrylhydrazyl free radical and black teas significantly inhibited the a-amylase enzyme. Major phenolics detected by liquid chromatography in green and white teas were epigallocatechingallate and epicatechingallate, whereas gallic acid was common in black, red, and oolong teas. Caffeine was found across all samples. The multivariate analysis evidenced a high variability among analyzed tea and even from brand to brand.Keywords: Camellia sinensis; phenolics; free radical inhibition; a-amylase inhibition Chile es considerado el mayor consumidor de te´en Ame´rica y una amplia variedad en tipos y marcas de te´existen en el mercado chileno. Un total de treinta y cuatro muestras de te´(blanco, verde, rojo, oolong y negro) fueron evaluadas de acuerdo a sus perfiles de compuestos feno´licos, capacidad antioxidante e inhibicio´n in vitro de la a-amilasa, relevante en el control de la hiperglicemia. Se utilizaron herramientas multivariantes para evidenciar patrones entre las muestras respecto a sus para´metros bioquı´micos. Los grupos de te´verdes y blancos presentaron los valores ma´s altos en feno´licos totales. Todas las muestras inhibieron el radical libre 2,2-difenil-1-picrilhidracilo, en cambio so´lo los te´s negros inhibieron significativamente la enzima a-amilasa. Los principales compuestos feno´licos detectados por cromatografı´a lı´quida en te´verde y blanco fueron la epigalocatequina-galato y epicatequinagalato, mientras que a´cido ga´lico fue detectado en las muestras de te´negro, rojo y oolong. Se detecto´cafeı´na en todas las muestras evaluadas. El ana´lisis multivariante demostro´una alta variabilidad entre las muestras de te´y aú n entre las diferentes marcas procedentes de un mismo tipo de te´.

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Chemical studies on antioxidant mechanism of tea catechins: analysis of radical reaction products of catechin and epicatechin with 2,2-Diphenyl-1-picrylhydrazyl

Cited by 86 publications

References 25 publications

Antioxidant activity of O-protected derivatives of (-)-epigallocatechin-3-gallate: inhibition of soybean and rabbit 15-lipoxygenases

Antioxidant activity of O-protected derivatives of (-)-epigallocatechin-3-gallate: inhibition of soybean and rabbit 15-lipoxygenases

PCL assay application in superoxide anion-radical scavenging capacity of tea Camellia sinensis extracts

Phenolic compounds, antioxidant capacity, andin vitro α-amylase inhibitory potential of tea infusions (Camellia sinensis) commercialized in Chile

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