Coordination of aluminium with purpurogallin and theaflavin digallate

Ó’Coinceanainn, Máirtı́n; Astill, Conrad; Baderschneider, Beate

doi:10.1016/s0162-0134(03)00248-4

Cited by 13 publications

(9 citation statements)

References 22 publications

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“…As an antioxidant, purpurogallin influences the bioavailability of metals in the body [245]. Purpurogallin is a stronger antioxidant than Trolox and a more potent inhibitor of xanthine oxidase than allopurinol as well as oxypurinol [246].…”

Section: Benzotropolone Purpurogallinmentioning

confidence: 99%

Plant Troponoids: Chemistry, Biological Activity, and Biosynthesis

Zhao

2007

CMC

113

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Tropone or tropolone and its derivatives (here together called troponoids) belong to a family of natural products with a seven-membered aromatic ring and various side groups. They are mainly synthesized by plants and fungi, and most troponoids play roles of antibacterial defenses in these organisms. With an increasingly severe situation of antibiotic resistant bacteria, as well as a requirement for antifungal medicines, troponoids have attracted extensive studies since they have powerful antibacterial and antifungal activity, particularly against antibiotic-resistant bacteria. In addition, many other biological activities such as antiviral, antitumor, antioxidant, anti-inflammatory, insecticidal, or enzyme inhibitor activities are associated with troponoids. After extensive studies in the 1960s-70s, interests in natural troponoids dedclined. However, chemical and biomedical studies on troponoids bloom again from the 1990s. To date great progress has been made with troponoid study in terms of identification of new natural troponoids, chemical synthesis and properties, biological activity, biosynthesis and metabolism. Particularly, bioassay-guided screening strategy and structure-activity relation-directed structure modification and drug design has resulted in the synthesis and discovery of many new derivatives. Many of them have great promise to be developed into new medicines for their potent and specific activities. This review presents the recent advances in troponoid studies and highlights multiple faceted biological activities of troponoids, as well as their relationships with chemical structures. Chemistry, biosynthesis, and production via biotechnology of troponoids are also briefly reviewed. Applications of troponoids in daily life, agriculture, medicine, and industry, and the related patents have been considered to further extend our understanding of the increasing impact of troponoids on humans.

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Section: Benzotropolone Purpurogallinmentioning

confidence: 99%

Plant Troponoids: Chemistry, Biological Activity, and Biosynthesis

Zhao

2007

CMC

113

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“…2 (22,32). That includes the interaction of TFs with Me(II) and Me(III) forming complexes (22,33,34). The number of possible isomers ranges from two in case 1:1 cation:TF molecule (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…iii) The coordination of aluminium, Ca, Fe, Mg, Mn, Na with TFs has been reported by a number of studies (33,(41)(42)(43)(44)(45)(46)(47)(48)(49). However, O'Coinceanainn et al (22) and Tanaka et al (35) suggested that the reaction between TFs involves the formation of a metal complex, followed by subsequent decomposition or formation of the non-metallic intermediates that generate high molecular weight oxidized TF products.…”

Section: Discussionmentioning

confidence: 98%

Analysis of the inhibition of PAI-1 by metal theaflavin complexes and their degradation products

Jankun

Kondray

Skrzypczak‐Jankun

2013

International Journal of Molecular Medicine

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The inhibition of elements of the plasminogen activator system [urokinase (uPA), tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1)] plays an important role in human diseases. PAI-1 is overexpressed in obesity and diabetes, and the inhibition of this protein has been postulated to alleviate the symptoms of both disorders. We found that two theaflavins (TFs) from black tea inhibit PAI-1 and we suggest that the beneficial effects of drinking tea may be associated with the suppression of PAI-1 activity by theaflavins. Epidemiological studies are controversial; some studies show the beneficial effects of drinking black tea on obesity and diabetes, while others do not. TFs, a family of compounds that can comprise up to 40% the dry weight of black tea, are responsible for the characteristic color, and they are known to chelate metals. We hypothesized that the content/variety of metals present in drinking water may be one of the reasons for such controversies in the population studies. TFs are excellent chelating compounds by trapping metals into complexes; thus, the quality of water used for tea preparation may influence changes in the formation of new products according to TF affinity for different metals, as well as their high molecular weight oxidation products. Our modeling and docking studies suggest that TF/metal complexes have similar affinity to PAI-1 as native TFs. However, analyses using liquid chromatography-mass spectroscopy (LC-MS) revealed the presence of TF degradation products in tea brewed using water containing metal salts. These can further form high molecular weight oxidation products. Thus, metals present in tea could diminish the beneficial effects of black tea by reducing TF concentration via metal-induced degradation and precipitation.

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“…Theaflavins have been found effective in preventing Cu 2+ -mediated LDL oxidation (27). O'Coinceanainn et al (28) proposed theaflavin-3,3'-digallate has three potential chelating positions: two in galloyl moiety, and one in the benzotropolone moiety. Yoshida et al (29) reported pretreatment with theaflavin-3,3'-digallate reduced cell-mediated LDL oxidation and inhibited superoxide anion production from macrophage, and that such inhibitory activity was higher for this compound than for the tea catechins EGC and EGCG.…”

Section: Antioxidant Activiy Of Tea Polyphenolsmentioning

confidence: 99%

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

Jhoo

2007

Antioxidant Measurement and Applications

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Coordination of aluminium with purpurogallin and theaflavin digallate

Cited by 13 publications

References 22 publications

Plant Troponoids: Chemistry, Biological Activity, and Biosynthesis

Plant Troponoids: Chemistry, Biological Activity, and Biosynthesis

Analysis of the inhibition of PAI-1 by metal theaflavin complexes and their degradation products

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

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