OBJECTIVETo observe the effect of green tea extractive epigallocatechin-3-gallate (EGCG) on degradation of collagen in dental erosion.

METHODSSixty-four volunteers with dental erosion were randomly divided into two groups. The custom fitted trays were made from the heat curable braces and were injected with carboxymethyl cellulose sodium (CMC) hydrogel in one group (control group) or CMC hydrogel with EGCG added in another (experimental group). These trays were used during sleep and removed from oral cavity in the next morning. The content of carboxy-terminal telopeptide of type I collagen (ICTP) were determined by radioimmunoassay kit at 1 d before the experiment, and 1, 2, 3, 4 weeks after the experiment.

RESULTSBoth the types and time showed significant effects on ICTP. The incubation in EGCG resulted in relatively rapid and significant (P < 0.05) decrease in the expression level of ICTP compared with the control group.

CONCLUSIONEGCG can inhibit collagen degradation and improve the antierosive effect of dentine.

Catechin ; analogs & derivatives ; Collagen ; Humans ; Pilot Projects ; Tea

Previously, we reported that epigallocatechin 3-O-gallate (EGCg) has growth-inhibitory effect on clinical isolates of Candida species. In this study, we investigated the antifungal activity of EGCg and antifungal agents against thirty-five of dermatophytes clinically isolated by the international guidelines (M38-A2). All isolates exhibited good susceptibility to EGCg (MIC50, 2-4 microg/mL, MIC90, 4-8 microg/mL, and geometric mean (GM) MICs, 3.36-4 microg/mL) than those of fluconazole (MIC50, 2-16 microg/mL, MIC90, 4-32 microg/mL, and GM MICs, 3.45-25.8 microg/mL) and flucytosin (MIC50, MIC90, and GM MICs, >64 microg/mL), although they were less susceptible to other antifungal agents, such as amphotericin B, itraconazole, and miconazole. These activities of EGCg were approximately 4-fold higher than those of fluconazole, and were 4 to 16-fold higher than flucytosin. This result indicates that EGCg can inhibit pathogenic dermatophyte species. Therefore, we suggest that EGCg may be effectively used solely as a possible agent or combined with other antifungal agents for antifungal therapy in dermatophytosis.
Antifungal Agents/*pharmacology ; Arthrodermataceae/*drug effects/isolation & purification ; Catechin/*analogs & derivatives/pharmacology ; Microbial Sensitivity Tests

OBJECTIVETo explore the driving force of the oral astringency produced by the interaction of theaflavin (TF) and epigallocatechin-3-gallate (EGCG) to human salivary a-amylase(HSA).

METHODSThe constants of the rate, equilibrium of reaction (k(a), k(d), K(A), and K(D)) and Langmuir, Freundlich adsorption isotherm (K(L), K(f), and Mm) were determined by surface plasmon resonance (SPR) technique and adsorption kinetics.

RESULTSBoth of Langmuir and Freundlich models could be used for describing the binding processes of TF and EGCG onto HSA surfaces, and there were no significant differences of the correlation coefficient of determination between these two models (P > 0.05). The constants of adsorption isotherm, the rate and equilibrium constants of the association for TF were higher than those of EGCG (P < 0.05). The rate and equilibrium constants of the dissociation for TF were lower than those of EGCG (P < 0.05). The affinity of TF to HSA was higher than that of EGCG.

CONCLUSIONThe sorely oral astringency is much easily produced by TF from the black tea rather than EGCG from the green tea. The driving force of the oral astringency is attributed to the hydrogen bonds of hydroxyl groups and hydrophobic interaction of galloyl groups in polyphenolic structures.

Adsorption ; Animals ; Antioxidants ; Biflavonoids ; Catechin ; analogs & derivatives ; Cercopithecus aethiops ; Humans ; Salivary alpha-Amylases ; Tea ; alpha-Amylases

To study the chemical constituents of Camellia sinensis var. assamica. The compounds were isolated by NKA Macroporous resin silica gel, Sephadex LH-20, RP-C18 column chromatographies and semi-preparative HPLC,and their structures were elucidated by physicochemical properties and spectral analysis. Thirteen compounds were isolated and identified as caffeine (1), theobromine (2), gallic acid (3), (+)-catechin (4), ampelopsin (5), (-)-epicatechin (6), (-)-epiafzelechin (7), (-)-epicatechin-3-O-gallate (8), (-)-epiafzelechin-3-O-gallate (9) , (+)-catechin-3-O-gallate (10) , (+)-afzelechin-3-O-gallate (11), quemefin-3-O-alpha-L-arabinopyranosid (12), and (-)-epicatechin-3-O-p-hydroxybenzoate (13). Compounds 2, 5, 10-13 were isolated from this plant for the first time, and compound 11 is a new natural product.
Camellia sinensis ; chemistry ; Catechin ; analogs & derivatives ; analysis ; Chromatography, High Pressure Liquid ; Flavonoids ; analysis

OBJECTIVE: To study the effect of epigallocatechin-3-gallate (EGCG) on liver lipid metabolism in rats with intrauterine growth restriction (IUGR) and related mechanism. METHODS: A rat model of IUGR was established by food restriction during entire pregnancy, and then the rats were randomly divided into an IUGR group and an EGCG group (n=8 each). The rats in the EGCG group were fed with water containing EGCG from after weaning to 10 weeks. Eight pup rats born from the pregnant maternal rats without food restriction were used as the control group. At the age of 13 weeks, body weight was measured. Blood and liver tissue samples were collected to measure fasting total cholesterol (TC), triglyceride (TG), free fatty acid (FFA), fasting plasma glucose (FPG), fasting insulin (FINS), and liver lipids. Homeostasis model assessment of insulin resistance (HOMA-IR) and adipose insulin resistance (adipo-IR) were calculated. Pathological sections of the liver were observed and quantitative real-time PCR was used to measure the mRNA expression of related genes in the liver. RESULTS: At the age of 13 weeks, there was no significant difference in body weight between groups (P=0.067). There were significant differences between groups in FPG, FFA, FINS, HOMA-IR, and adipo-IR (P<0.05). There were no significant differences in the serum levels of TC and TG between groups (P>0.05), while the IUGR group had significantly higher levels of TC and TG in the liver than the EGCG group (P<0.05). Oil red staining showed that the IUGR group had a significant increase in hepatic lipid accumulation, while the EGCG group had certain improvement after EGCG treatment. PCR results suggested that compared with the control group, the IUGR group had significant reductions in the mRNA expression of Ampk and Adipor1 and a significant increase in the mRNA expression of Srebf1 (P<0.05), while EGCG increased the mRNA expression of Ampk and reduced the mRNA expression of Srebf1, with no significant differences in the two indices between the EGCG and control groups (P>0.05). CONCLUSIONS Early EGCG intervention can down-regulate the de novo synthesis of fatty acids through the Ampk/Srebf1 signaling pathway and reduce hepatic lipid accumulation in IUGR rats by improving insulin resistance of hepatocytes.
Animals ; Catechin ; analogs & derivatives ; Female ; Fetal Growth Retardation ; Insulin Resistance ; Lipid Metabolism ; Lipids ; Liver ; Pregnancy ; Rats

OBJECTIVETo study the effect of epigallocatechin gallate (EGCG) against lactacystin induced PC12 cell injury.

METHODSThe inoculated rat PC12 cells were cultured for 24 h, followed by intervention. The cells were divided into 5 groups, i.e., the normal control group, 10 micromol/L lactacystin injury group, and the EGCG pretreated groups (at the final concentration of 5, 10, and 50 micromol/L, respectively). The cytoactive was detected by MTT colorimetry. Morphological changes of the cell nucleus were observed by Hoechst 33,258 staining, and the apoptosis ratio was detected by flow cytometry (FCM).

RESULTSEGCG at different doses showed protective effect on lactacystin-induced PC12 cell injury. Compared with the lactacystin injury group [(61.22 +/- 1.02)%], the cytoactive in EGCG pretreated groups at the final concentration of 5, 10, and 50 micromol/L, respectively increased obviously to (66.99 +/- 1.30)%, (66.67 +/- 0.65)%, and (73.4 +/- 0.67)%, respectively. Hoechst 33 258 staining found that more nuclear pyknosis and aggregation occurred in the lactacystin injury group, but less occurred in EGCG pretreated groups. FCM indicated that the apoptosis ratio was reduced by EGCG pretreatment. It was 3.0%, 60.4%, 59.8%, 57.5%, and 38.6%, respectively in the normal control group, the lactacystin injury group, and EGCG pretreated groups (at the final concentration of 5, 10, and 50 micromol/L, respectively).

CONCLUSIONEGCG could attenuate lactacystin induced PC 12 cell injury.

Acetylcysteine ; adverse effects ; analogs & derivatives ; Animals ; Apoptosis ; drug effects ; Catechin ; analogs & derivatives ; pharmacology ; Flow Cytometry ; PC12 Cells ; Rats

Catechin ; analogs & derivatives ; pharmacology ; Melanoma ; prevention & control ; Nitric Oxide ; physiology ; Skin Neoplasms ; prevention & control ; Sunburn ; prevention & control ; Tea ; Ultraviolet Rays

This study was aimed to explore the change of aggregation and activation of platelets loaded with epigallocatechin gallate (EGCG). The platelets were treated by loading buffer with different concentrations of EGCG (0, 2.5, 5, 7.5, 10, 12.5, 15, 20 and 30 mmol/L) and were divided into 2.5, 5, 10 mmol/L groups and control group. The physiological and biochemical functions of platelets were observed, including recovery rate, aggregation and activation of platelets. The platelet counts were determined by Counter Cell-DYN 1200. The aggregation activities were tested through turbidimetry, the platelet apoptosis was detected by flow cytometry. The results showed that the concentrations of EGCG loading in platelets of 2.5, 5 and 10 mmol/L groups were 0.4006 ± 0.12, 1.0527 ± 0.1503, 1.6902 ± 0.1112 mmol/L respectively. Along with the increasing of EGCG concentrations in loading-buffer, the EGCG absorbed by platelets increased too. When the concentration of EGCG in loading-buffer exceeded 15 mmol/L, the EGCG absorbed by platelets did not increase. The recovery rate in 2.5 mmol/L loading buffer group was 82.45 ± 0.360% which was lower than that in control group (90.33 ± 1.115%) (p < 0.05). As compared with control group, the recovery rate in 5 mmol/L loading buffer group (57.51 ± 2.468)% and 10 mmol/L loading buffer group (47.45 ± 2.030)% were even significantly lower (p < 0.01). When ADP was used as the inducer, the maximal aggregation rate (MAR) in control group was (63.6 ± 4.037)%, which was higher than that in other EGCG-loading groups (p < 0.01). And the aggregation activity of platelets negatively correlated with the concentration of EGCG in loading-buffer. When THR was used as the inducer, the MAR in control group was (89.3 ± 6.533)% and higher than that those in other groups (p < 0.05), especially in groups with loading-buffer higher than 10 mmol/L EGCG (70.1 ± 5.400%) (p < 0.01). In the experiment of cellular apoptosis, the early apoptosis easy appeared in platelets loaded with EGCG. It is concluded that the EGCG loading in platelets markedly influences the physiological and biochemical functions of platelets, the apoptosis easy occurs in platelets loaded with EGCG. The EGCG accelerates the course of platelet apoptosis.
Apoptosis ; drug effects ; Blood Platelets ; drug effects ; Catechin ; analogs & derivatives ; pharmacology ; Flow Cytometry ; Humans ; Platelet Aggregation ; drug effects ; Platelet Count

OBJECTIVETo investigate the protective effect of epigallocatechin gallate (EGCG) on mouse sperm in vivo.

METHODSA total of 64 six-week-old male Kuming mice were randomly divided into eight groups of equal number to be treated with normal saline (negative control), Cyclophosphamide (CP) at 30 mg/kg (positive control), and CP followed by EGCG (experimental) at 20, 40, and 80 mg/kg, respectively, given every other day for 10 days. At 4 and 5 weeks after treatment, the bilateral testes of the mice were harvested for examination of sperm abnormality.

RESULTSEGCG did not increase the rate of CP-induced sperm abnormality in the mice, but reduced it instead with the prolonged time of treatment.

CONCLUSIONEGCG protects mouse sperm in vivo.

Animals ; Catechin ; analogs & derivatives ; pharmacology ; Cyclophosphamide ; toxicity ; Male ; Mice ; Mutagens ; toxicity ; Random Allocation ; Spermatozoa ; drug effects ; Time Factors

Catechin and its analogues are varied and distributed widely. They have significant bioactivity on clearing free radical, anti-cancer, anti-flammatory, anti-allergic, anti-mutation, anti-aging, improving liver function, and so on. Recently, catechins (GTC) in green tea have given rise to comprehensive attention all over the world, and will have a wonderful prospect. The progress in studies of the structures, spectrum characters, resources and bioactivities of catechin and its analogues has been reviewed.
Animals ; Antineoplastic Agents, Phytogenic ; pharmacology ; Catechin ; analogs & derivatives ; chemistry ; pharmacology ; Free Radical Scavengers ; pharmacology ; Humans ; Platelet Aggregation Inhibitors ; pharmacology