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[Display omitted] • Local EGCG injection suppressed the nociceptive TG neuronal activity. • Neuronal firing was dose-dependently inhibited by EGCG. • The inhibitory effect of EGCG lasted for 15 min and was reversible. • The potency of inhibition by EGCG almost equaled that of 1% lidocaine. • EGCG may be an effective treatment option for trigeminal pain. The phytochemical, polyphenolic compound, (-)-epigallocatechin-3-gallate (EGCG), is the main catechin found in green tea. Although a modulatory effect of EGCG on voltage-gated sodium and potassium channels has been reported in excitable tissues, the in vivo effect of EGCG on the excitability of nociceptive sensory neurons remains to be determined. Our aim was to investigate whether local administration of EGCG to rats attenuates the excitability of nociceptive spinal trigeminal nucleus caudalis (SpVc) neurons in response to mechanical stimulation in vivo. Extracellular single unit recordings were made from SpVc neurons in response to orofacial mechanical stimulation of anesthetized rats. The mean firing frequency of SpVc wide-dynamic range neurons following both non-noxious and noxious mechanical stimuli was significantly inhibited by EGCG in a dose-dependent and reversible manner. The mean magnitude of inhibition by EGCG on SpVc neuronal discharge frequency was similar to that of the local anesthetic, 1% lidocaine. Local injection of half-dose of lidocaine replaced the half-dose of EGCG. These results suggest that local injection of EGCG suppresses the excitability of nociceptive SpVc neurons, possibly via the inhibition of voltage-gated sodium channels and opening of voltage-gated potassium channels in the trigeminal ganglion. Therefore, administration of EGCG as a local anesthetic may provide relief from trigeminal nociceptive pain without side effects. [ABSTRACT FROM AUTHOR]

Chronic arsenic exposure in drinking water is associated with the abnormalities of cardiac tissue. Excessive generation of ROS induced by arsenic has a central role in arsenic-induced cardiotoxicity. (-)-Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea, possesses a potent antioxidant capacity and exhibits extensive pharmacological activities. This study was aim to evaluate the effect of EGCG on arsenic-induced cardiotoxicity in vivo and in vitro. Treatment with NaAsO 2 seriously affected the morphology and ultrastructure of myocardium, and induced cardiac injuries, oxidative stress, intracellular calcium accumulation and apoptosis in rats. In consistent with in vivo study, the injuries, oxidative stress and apoptosis were also observed in NaAsO 2 -treated H9c2 cells. All of these effects induced by NaAsO 2 were attenuated by EGCG. These results suggest EGCG could attenuate NaAsO 2 -induced cardiotoxicity, and the mechanism may involve its potent antioxidant capacity. [ABSTRACT FROM AUTHOR]

AIM (–)-Epigallocatechin-3-gallate (EGCG), a major compound of tea polyphenols, exhibited antitumor activity in previous studies. In these studies, EGCG usually inhibits EGFR, and impairs the ERK1/2 phosphorylation in tumor cells. The aim was to clarify the mechanism of ERK1/2 activation induced by EGCG. METHOD Jurkat and 293T cells were treated with EGCG in different culture conditions. Western Blotting (WB) was employed to analyze ERK1/2 and MEK phosphorylation. Cetuximab and FR180204 were used to inhibit cell signaling. The stability of EGCG was assessed by HPLC. The concentration of hydrogen peroxide generated by the auto-oxidation of EGCG was determined by photocolorimetric analysis. RESULTS Activation of ERK1/2 was observed to be both time-and dose-dependent. Stimulation of cell signaling was dependent on MEK activity, but independent of EGFR activity. Unexpectedly, EGCG was depleted within one hour of incubation under traditional culture conditions. Auto-oxidation of EGCG generated a high level of hydrogen peroxide in the medium. Addition of catalase and SOD to the acidic medium inhibited the oxidation of EGCG. However, this particular condition also prevented the phosphorylation of ERK1/2. The generation of ROS by hydrogen peroxide may also induce ERK1/2 activation in Jurkat cells. CONCLUSION ERK1/2 phosphorylation was caused by auto-oxidation of EGCG. Traditional culture conditions were determined to be inappropriate for EGCG research. [ABSTRACT FROM AUTHOR]

Abstract: Polyphenols are the most abundant antioxidants in the human diet and are widespread constituents of fruits and beverages, such as tea, coffee, and wine. Epidemiological, clinical, and animal studies support a role of polyphenols in the prevention of various chronic diseases. For a long time, their direct antioxidant effect has been reported as the mechanism responsible for the observed health properties. However, recent findings revealed that polyphenols could interact with cellular signaling cascades regulating the activity of transcription factors and consequently affecting the expression of genes. Together with this classical regulatory pathway, polyphenols have been shown to affect the expression of microRNAs (miRNA). miRNAs are small, noncoding RNAs implicated in the regulation of gene expression that control both physiological and pathological processes such as development and cancer. Furthermore, expression of miRNAs can be affected by different external stimuli including nutrients such as vitamins, lipids, and phytochemicals. In this paper, we review studies assessing modulation of miRNAs expression by dietary polyphenols that could constitute a new pathway by which these compounds may exert their health effects. Over 100 miRNAs, involved in the control of different cellular processes such as inflammation or apoptosis, were identified as modulated by polyphenols. Most of the studies were performed in vitro using different cell lines, particularly cancer cell lines, and few studies were performed in animals. From all these data, miRNAs appear as interesting mediators in regulating polyphenols' biological effects; however, further studies are needed to validate miRNA targets and particularly in physiologically relevant conditions taking into account the bioavailability of dietary polyphenols. [Copyright &y& Elsevier]

Abstract: (-)-Epigallocatechin-3-gallate (EGCG), which has been attributed with numerous health benefits, is an oxidation sensitive, water soluble polyphenol. We have recently shown that heat-denatured β-Lactoglobulin (β-Lg) forms nanoparticles (<50 nm) with EGCG, which confer considerable protection to EGCG against oxidative degradation, useful for clear beverage enrichment. The current study aimed at advancing our understanding by further characterizing the structure, properties and performance of this new nanodelivery system to facilitate its application. We found that although particle size increased with rising EGCG concentration, zeta potential (based on the Smoluchowski model) stayed around −40 mV up to 8:1 M EGCG:β-Lg ratio, suggesting particles are very stable in solution. Good loading efficiency (60–70%) of EGCG within β-Lg nanocomplexes was obtained. The loading efficiency was mostly dependent on β-Lg concentration. Freeze-dried nanoparticles showed an IR absorbance spectrum different from the spectra summation of the pure components, confirming the molecular level complexation. Following freeze drying, the reconstituted complexes were very similar in size to the pre-frozen ones. The nanoentrapment dramatically suppressed the bitterness and astringency of EGCG. Simulated gastric digestion of β-Lg–EGCG nanoparticles showed limited release of EGCG, suggesting they could potentially be used as vehicles for protection of EGCG in the stomach, and for its sustained release in the intestine. Our results suggest that denatured β-Lg may serve as an effective natural vehicle for nanoencapsulation, protection and sustained release of EGCG and possibly other polyphenols for clear beverage enrichment. [Copyright &y& Elsevier]

• Antioxidant high internal phase emulsion (HIPE) gels as nutraceutical containers were reported. • Co-assembled soy β -conglycinin-EGCG nanoparticles as HIPE stabilizers were fabricated. • The HIPE gels exhibited excellent thermal and storage stability. • The HIPE gels displayed an excellent oxidative protection of encapsulated lipophilic nutraceuticals. • The oxidative protection of the HIPEs was modulated by the EGCG loading amount in the nanoparticles. This work reports a kind of novel antioxidant Pickering high internal phase emulsions (HIPEs; with an oil fraction, ϕ > 0.74) stabilized by soy β -conglycinin (β -CG) and polyphenol complex nanoparticles, as outstanding protective containers for lipophilic nutraceuticals. The nanoparticles with a representative polyphenol ((-)-epigallocatechin-3-gallate; EGCG) encapsulated were fabricated through an ethanol-mediated dissociation and re-assembly process of β -CG, with greater particle size and higher surface hydrophilicity observed at higher initial EGCG concentrations. Using these co-assembled nanoparticles as sole stabilizers, a kind of HIPE gels with similar gel stiffness and microstructure, could be easily fabricated at ϕ = 0.8 and a protein concentration in the aqueous phase of 1.0 wt% using polyunsatuated fatty acid-rich flaxseed oil as the dispersed phase. These HIPE gels were extraordinarily stable against heating or long-term storage, but susceptible to freeze-thawing. The as-fabricated HIPEs showed an excellent protection to β -carotene (encapsulated in oil phase) against heating, as well as an inhibition of lipid oxidation. The oxidation protection was in an EGCG concentration dependent manner. The results would be of interest for providing a novel strategy to fabricate functionalized Pickering HIPEs as potential containers or delivery systems for lipophilic nutraceuticals. [ABSTRACT FROM AUTHOR]