Relationship of the structures of tannins to the binding activities with hemoglobin and methylene blue.

Okuda, Takuo; Mori, Kazuko; Hatano, Tsutomu

doi:10.1248/cpb.33.1424

Cited by 106 publications

(71 citation statements)

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“…Inhibition of lipid peroxidation is not well correlated with antitumor promoting activity in mouse skin, but some antitumor promoters, such as flavonoids and tannins, are known to act as radical scavengers (Fujita et al, 1987). One cup of green tea infusion often contains 100-200 mg of polyphenolic constituents which are thought to be tannins judging from their relative astringency, and relative affinity to methylene blue (Okuda et al, 1985) and their behavior on HPLC. EGCG is one of the main constituents of green tea, and also of partly fermented tea, oolong tea, in which some of the EGCG is converted to condensates.…”

Section: Resultsmentioning

confidence: 99%

Antitumor promoting activity of (−)‐epigallocatechin gallate, the main constituent of “Tannin” in green tea

Yoshizawa¹,

Horiuchi²,

Fujiki³

et al. 1987

Phytotherapy Research

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273

115

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INTRODUCTIONVarious kinds of compounds have been found to inhibit tumor promotion in mouse skin. These include protease inhibitors, vitamin A derivatives, anti-inflammatory steroids, phosphodiesterase inhibitors, lipoxygenase inhibitors, phospholipase A, inhibitors, inhibitors of polyamine synthesis and of histidine decarboxylase, and calmodulin antagonists (Troll et al., 1970;Hozumi et a/., 1972; Verma et a/., 1979;Schwarz et al., 1977;Fischer et al., 1982;Nakadate et al., 1982; Takigawa et al., 1982; Umezawa et al., 1983; Belman and Troll, 1974;Nishino et al., 1984a;Slaga et al., 1982). Tumor promotion can be inhibited by use of various known inhibitors of specific biochemical reactions induced by tumor promoters, but we considered that the inhibitory effects of natural compounds present in daily foods should also be investigated.Recently, quercetin was found to inhibit the tumor promoting activity of 12-U-tetradecanoylphorbol-13-acetate (TPA), or teleocidin in two-stage carcinogenesis experiments in mouse skin initiated with 7,12-dimethylbenz(a)anthracene (DMBA) (Kato et al., 1983;Nishino et al., 1984a;Fujiki et al., 1986). In addition, we demonstrated that other flavonoids inhibit the in uitro and in vivo effects induced by tumor promoters (Horiuchi et al., 1986). Since quercetin and other flavonoids are present in foods, such as vegetables and fruits, we realized that antitumor promoters are present in daily foods.Every day Japanese people drink green tea, which contains (-)-epigallocatechin gallate, EGCG (Fig. I), as its main polyphenolic constituent. Therefore, in this work, we studied the influence of EGCG on tumor promotion such as its effects on the specific binding of [3H]TPA to a mouse particulate fraction in uitro, its effect on phorbol ester receptors in uiuo and its effect on activation of protein kinase C by teleocidin in uitro. EGCG inhibited tumor promotion by teleocidin in a two-stage chemical carcinogenesis experiment on mouse skin. MATERIALS AND METHODSMaterials. The preparation of EGCG used contained EGCG (85%), ( -)-epicatechin (10%) and ( -)-epicatechin gallate ( 5 % ) , as determined by high performance liquid chromatography (HPLC) on a YMC-A312 (ODS) column (6 x 150 mm), with water-acetonitrile cetic acid (85 : 10 : 5) as a solvent, monitoring the UV absorption at 254nm. This EGCG was isolated from Japanese green tea leaves as follows: the tea leaves were extracted with a boiling mixture of methanol-water ( I : l), the solvent was evaporated, and the residue was dissolved in water and applied to a column of DIAION HP-20 [ Mitsubishi, Kasei, Japan]. Material was eluted with stepwise increasing concentrations of methanol, and fractions containing EGCG were detected by HPLC. These fractions were pooled, concentrated, and extracted with ethyl acetate. The ethyl acetate extract was chromatographed on a column of Toyo-pearl HW-40 (coarse) [Toyo Soda, Japan], by elution with a water- Inhibition of specific I'HJTPA binding. A particulate fraction containing phorbol ester receptors was prepared...

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Section: Resultsmentioning

confidence: 99%

Antitumor promoting activity of (−)‐epigallocatechin gallate, the main constituent of “Tannin” in green tea

Yoshizawa¹,

Horiuchi²,

Fujiki³

et al. 1987

Phytotherapy Research

Self Cite

273

115

View full text Add to dashboard Cite

show abstract

“…5 Although the tanning properties increase with the degree of polymerization, the highly polymerized compounds are either too insoluble or too large to ®t between protein molecules. 3,6,7 It has also been demonstrated that during grape ripening, tannins bind to the proteins of the internal face of the tonoplast, and also to the cell wall polysaccharides, through osidic bonds. 8 This period is characterized by the color change of the grape, as a result of the accumulation of anthocyans, in the skins of the red varieties.…”

Section: ±3mentioning

confidence: 99%

Concentration and compositional changes of procyanidins in grape seeds and skin of whiteVitis vin�fera varieties

Freitas

Glories

1999

J. Sci. Food Agric.

104

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“…TF2 and TA showed stronger binding affinity to PPA than the other phenolic compounds in this study due to their higher K FQ values (Table 4.1), presumably due to the large number of potential hydrogen bonds and hydrophobic interactions (Miao, Jiang, Jiang, Zhang, & Li, 2015;Okuda, Mori, & Hatano, 1985), consistent with the prevalence of the static mechanism in comparison to the dynamic one for PPA fluorescence quenching by TF2 and TA. Trp may also affect the fluorescence of a fluorophore (Soares, Mateus, & Freitas, 2007).…”

Section: Discussionsupporting

confidence: 66%

Studying the interactions between tea polyphenols and α-amylase

Sun¹

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Dixon, Cornish-Bowden and Lineweaver-Burk plot analyses were applied to study the detailed kinetics of inhibition of porcine pancreatic α-amylase (PPA) by tea polyphenols.Fluorescence quenching (FQ), differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC) were combined with the kinetics of inhibition to elucidate the mechanism of binding interactions of tea polyphenols and PPA. Then, the reciprocal of competitive inhibition constant (1/K ic ), fluorescence quenching constant (K FQ ) and binding constant (K itc ) obtained from these measurements were compared and correlated to analyse the relations between PPA inhibition and binding behaviour. The role of the galloyl moiety in binding of catechins and theaflavins with PPA was highlighted as well. In addition, the effects of three soluble polysaccharides (citrus pectin (CP), wheat arabinoxylan (WAX) and oat β-glucan (OBG)) on the inhibition of PPA by tea polyphenols were studied through PPA inhibition, IC 50 value, inhibition kinetics and fluorescence quenching methods. Furthermore, the effects of tea polyphenols on binding of PPA with normal maize starch granules were studied in terms of binding ratio, dissociation constant (K d ) and binding rate. Then, the association constant (1/K d ), 1/K ic and K FQ of tea polyphenols were correlated to analyse the effects of PPA inhibition on the binding of the enzyme with starch.The results show that green, oolong and black tea extracts, epigallocatechin gallate, theaflavin-3, 3'-digallate and tannic acid were competitive inhibitors of PPA, whereas epicatechin gallate, theaflavin-3'-gallate and theaflavin were mixed-type inhibitors with both competitive and uncompetitive inhibitory characteristics. Only catechins with a galloyl substituent at the 3-position showed measurable inhibition. K ic values were lower for theaflavins than catechins, with the lowest value for theaflavin-3, 3'-digallate. The lower K ic than the uncompetitive inhibition constant for the mixed-type inhibitors suggests that they bind more tightly with free PPA than with the PPA-starch complex. A 3 and/or 3'-galloyl moiety in catechin and theaflavin structures was consistently found to increase inhibition of PPA through enhanced association with the enzyme active site. A higher quenching effect of polyphenols corresponded to a stronger inhibitory activity against PPA. The red-shift of maximum emission wavelength of PPA bound with some polyphenols indicated a potential IV

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Relationship of the structures of tannins to the binding activities with hemoglobin and methylene blue.

Cited by 106 publications

References 0 publications

Antitumor promoting activity of (−)‐epigallocatechin gallate, the main constituent of “Tannin” in green tea

Antitumor promoting activity of (−)‐epigallocatechin gallate, the main constituent of “Tannin” in green tea

Concentration and compositional changes of procyanidins in grape seeds and skin of whiteVitis vin�fera varieties

Studying the interactions between tea polyphenols and α-amylase

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