Disease relevance of AIDS-051702

• Our objective was to study the impact of a theaflavin-enriched green tea extract on the lipids and lipoproteins of subjects with mild to moderate hypercholesterolemia [1].
• Here, we demonstrated the effects of theanaphthoquinone (TNQ), a member of the thearubigins generated by the oxidation of theaflavin (TF-1), on the expression of FAS in human breast cancer cells [2].
• Study by electron microscope revealed that EGCg and TF3 (1 mM) agglutinated influenza viruses as well as did antibody, and that they prevented the viruses from adsorbing to MDCK cells [3].
• The exposure of human stomach cancer KATO III cells to black tea theaflavin extract, free theaflavin, and theaflavin digallate that are main components of the extract, led to both growth inhibition and the induction of programmed cell death (apoptosis) [4].
• These results indicate that tea, especially black tea, may be used as a source of anti-HIV agents and theaflavin derivatives may be applied as lead compounds for developing HIV-1 entry inhibitors targeting gp41 [5].

High impact information on AIDS-051702

• Differential effects of theaflavin monogallates on cell growth, apoptosis, and Cox-2 gene expression in cancerous versus normal cells [6].
• TFG exhibited a lower inhibitory activity (IC(50) 37 microM) and TF was even less effective (IC(50) 47 microM) in this cell line [7].
• The biological activities of theaflavin (TF), theaflavin gallate (TFG) and theaflavin digallate (TFdiG) from black tea and (-)-epigallocatechin 3-gallate (EGCG) and (-)-epigallocatechin (EGC) from green tea were investigated using SV40-immortalized (33BES) and Ha-ras gene transformed (21BES) human bronchial epithelial cell lines [7].
• The relative prostate bioavailability of theaflavin was 70% higher than that of epigallocatechin gallate (EGCG) [8].
• This effect appears to primarily involve inhibition of interleukin-8 transcription because theaflavin inhibited tumor necrosis factor-alpha-mediated activation of the interleukin-8 promoter in cells transiently transfected with an interleukin-8 promoter-luciferase reporter plasmid [9].

Biological context of AIDS-051702

• INTERVENTIONS: A549 cells were exposed to varying concentrations of theaflavin and analyzed for tumor necrosis factor-alpha-mediated interleukin-8 gene expression [9].
• Hydrolysis of theaflavin gallates, apparently by salivary esterases, was observed in vitro and in vivo [10].
• CONCLUSIONS: Theaflavin and its galloyl esters in black tea extract, and isoprenyl gallates were potent inhibitors of PAF synthesis and platelet aggregation and these activities may be relevant to the claimed therapeutic effects of tea extracts [11].
• Two types of oxidative dimerization of the black tea polyphenol theaflavin [12].
• In both types of cells, cell growth inhibition was observed 24 hrs after treatment with BT, TF and TR [13].

Anatomical context of AIDS-051702

• Although theaflavin inhibited ovine COX-2, its activity in the formation of PGE(2) was stimulated by theaflavin when ovine COX-2 was mixed with microsomes, suggesting that theaflavin affects the interaction of COX-2 with other microsomal factors (e.g. PGE synthase) [14].
• The theaflavin fraction is responsible for the facilitatory effect of black tea at the skeletal myoneural junction [15].
• The theaflavin fraction (Tfs) produced a concentration- dependent facilitation of indirect twitch responses of the rat phrenic nerve diaphragm preparation and the facilitation was dependent on the amount of calcium present in the bathing fluid [15].
• The stability of theaflavin was studied in varying pH solutions: simulated gastric juice and buffer solutions of pH 5.5, pH 7.4, and pH 8 [16].
• The growth inhibitory effects of a theaflavin mixture from black tea were more pronounced to malignant (CAL27; HSC-2; HSG1) and immortalized (S-G; GT1) cells than to normal (HGF-2) cells from the human oral cavity [17].

Associations of AIDS-051702 with other chemical compounds

• Ester-type catechins (ECg and EGCg) and theaflavin strongly suppressed the gelatin degradation mediated by matrix metalloproteinase (MMP) 2 and MMP-9, which were secreted into the conditioned medium of HT1080 cells [18].
• (-)-Epigallocatechin gallate, theasinensin D, compound OH-5, theaflavin, and theaflavin digallate induced apoptosis as evidenced by DNA ladder formation, its inhibition by a caspase inhibitor, and chromatin condensation [19].
• Hydrogen peroxide (H(2)O(2)) was detected in cell culture medium amended with the theaflavin mixture [17].
• The expression of FAS was also suppressed by the tea polyphenol (-)-epigallocatechin 3-gallate (EGCG), theaflavin (TF-1), TF-2 and theaflavin 3,3'-digallate(TF-3) at both protein and mRNA levels that may lead to the inhibition of cell lipogenesis and proliferation [20].
• The cytotoxicity of the theaflavin mixture was due, in part, to the generation in the cell culture medium of H(2)O(2), which lessened the intracellular levels of glutathione in the CAL27 cells and, to a lesser extent, in the GT1 cells [17].

Gene context of AIDS-051702

• Catechins and all other low-molecular-weight polyphenols except theaflavin derived from balck tea did not show significant GTase-inhibitory activities [21].
• Theaflavin also significantly reduced tumor necrosis factor-alpha-mediated DNA binding of activator protein-1 [9].
• RT-PCR analysis also showed theaflavin to be the most important constituent in down-regulating synthesis of iNOS [22].
• From the estimation of five major catechins, PPO activities in young shoots, and theaflavin and thearubigin contents of crushed, torn, and curled (CTC) black teas, the superior variety and flavorful flush characteristics were refined [23].
• This result indicated that the benzotropolone moiety in theaflavin may play an important role in its antioxidant properties [16].

Analytical, diagnostic and therapeutic context of AIDS-051702

• MEASUREMENTS AND MAIN RESULTS: Theaflavin inhibited tumor necrosis factor-alpha-mediated interleukin-8 gene expression, as measured by luciferase assay and Northern blot analysis, at concentrations of 10 and 30 microg/mL [9].
• Crude theaflavin was extracted from black tea and then fractionated by HPLC into five components (initial peaks (IP), TF1, TF2A, TF2B, and TF3) [24].
• The interaction of iron(III) with theaflavin at pH < 3.0 is investigated by means of liquid chromatography mass spectroscopy (LC-MS), stopped flow spectroscopy and multivariate data analysis [25].

References