High-salt diet is well recognized as a risk factor for hypertension,and dietary intervention plays a critical role in the prevention of hypertension.The current study investigated the effects of selenium-enriched gree...High-salt diet is well recognized as a risk factor for hypertension,and dietary intervention plays a critical role in the prevention of hypertension.The current study investigated the effects of selenium-enriched green tea(Se-GT)and ordinary green tea(GT)on prevention of hypertension of rats induced by high-salt diet,as well as their potential regulatory and mechanism.Our results showed that GT and Se-GT supplementations significantly prevented the increase of blood pressure(BP),activated the phosphoinosmde-3-kinase/protein kinase B(PI3K/Akt)signaling pathway,and regulated the gene expression related to BP,as well as improved the tissue damage like heart,liver,and kidneys.Besides,the key parameters associated with oxidative stress,inflammation and endothelial dysfunction were also altered by GT and Se-GT treatments.Importantly,GT or Se-GT administration adjusted the diversity and composition of the intestinal flora.Moreover,GT and Se-GT supplementations increased the abundance of beneficial bacteria and reduced the abundance of harmful or conditional pathogenic bacteria.More specifically,GT intake specifically and significantly enriched the relative abundance of Paraprevotella and Bacteroides,whereas Se-GT was characterized by specific and significant enrichment for Allobaculum and Bifidobacterium.Our results proved that dietary supplement of GT and Se-GT remarkably improved the vascular functions and effectively prevented tissue damage by regulation of intestinal flora,and thus preventing hypertension induced by high-salt diet.展开更多
Once a mining village,Jingshan in Hangzhou has reinvented itself over the past 20 years as a thriving model of green transformation.STROLLING through a village named Jingshan located in Hangzhou City,east China’s Zhe...Once a mining village,Jingshan in Hangzhou has reinvented itself over the past 20 years as a thriving model of green transformation.STROLLING through a village named Jingshan located in Hangzhou City,east China’s Zhejiang Province,one will notice the image of a“little tea farmer”wearing a bamboo hat and carrying a tea basket in many places.展开更多
BACKGROUND Periodontal disease is a chronic inflammatory condition characterized by periodontal pocket formation,clinical attachment loss,and destruction of alveolar bone.Its conventional treatment primarily involves ...BACKGROUND Periodontal disease is a chronic inflammatory condition characterized by periodontal pocket formation,clinical attachment loss,and destruction of alveolar bone.Its conventional treatment primarily involves mechanical debridement and plaque control,but localized antimicrobial therapy offers site-specific advantages.While antibiotics such as metronidazole and doxycycline are commonly used,green tea extract,which is rich in epigallocatechin gallate,has been proposed as a promising alternative for local drug delivery due to its anti-inflammatory and antimicrobial properties.AIM To compare the clinical efficacy of green tea extract gel and ornidazole gel as adjuncts to scaling and root planing(SRP)in patients with periodontitis.METHODS Teeth with probing pocket depths(PPD)of 4-7 mm were selected.Participants’baseline oral hygiene index-simplified,plaque index,clinical attachment loss,and PPD were recorded.The participants were randomized into two groups:One received green tea extract gel after SRP,and the other received ornidazole gel.Subgingival drug delivery was performed,and participants refrained from brushing or interproximal cleaning for ten days.Their clinical parameters were re-evaluated after one month.RESULTS The PPD decreased significantly from baseline to one month in both groups.However,the green tea extract gel group exhibited superior outcomes to the ornidazole gel group,with a mean difference in PPD of 0.28±0.78 mm at one month(P<0.007).CONCLUSION As an adjunct to SRP,green tea extract gel showed greater efficacy in improving clinical periodontal parameters than ornidazole gel.展开更多
The catechin Epigallocatechin-3-O-Gallate (EGCG) which is found in of Green Tea extracts (GTE), displays a variety of microbicidal properties. It is largely believed that EGCG inhibits the growth of cariogenic and per...The catechin Epigallocatechin-3-O-Gallate (EGCG) which is found in of Green Tea extracts (GTE), displays a variety of microbicidal properties. It is largely believed that EGCG inhibits the growth of cariogenic and periodontopathic bacteria. Objective: In this paper we compared the inhibitory activity of EGCG and a commercial GTE on the growth of Veillonella parvula. Chlorhexidine was used as positive control. Methodology: V. parvula ATCC 10790 and a clinical isolate obtained from a periodontal disease patient were cultured in the presence of EGCG or a commercial GTE, and the measurements of bacterial growth inhibition were compared to the values obtained with 0.12 and 0.2% chlorhexidine. Results: Chlorhexidine inhibited bacterial growth, however in contrast to a previous report, neither EGCG nor the GTE showed any effect on bacterial growth. Conclusions: The data show and confirm that chlorhexidine is a growth inhibitor of V. parvula while EGCG and GTE do not display such effect.展开更多
Background:Green tea,mulberry leaf and corn silk are traditional herbs used in the prevention and treatment of diabetes in China for a long time,but their synergistic hypoglycemic effects and mechanisms remain unclear...Background:Green tea,mulberry leaf and corn silk are traditional herbs used in the prevention and treatment of diabetes in China for a long time,but their synergistic hypoglycemic effects and mechanisms remain unclear.Methods:The effective components of green tea,mulberry leaf and corn silk were extracted and enriched.Mixture design of experiments was used to study the influences of different combinations on the cell viability and glucose uptake level of L6 myoblasts,so as to determine the optimal synergistic hypoglycemic combination.The possible hypoglycemic mechanism of the optimal synergistic combination was explored by cytotoxicity assay,glucose uptake assay,and western blot.Results:Three polyphenol enrichment fractions of the herbs,30%ethanol elution fraction of green tea(GT),50%ethanol elution fraction of mulberry leaf(ML)and 60%ethanol elution fraction of corn silk(CS)were obtained.The antioxidant activities of GT-30%,ML-50%and CS-60%were superior to those of crude extracts,and showed strong potential inα-amylase andα-glucosidase inhibition activities.The optimal synergistic combination of crude extracts G7(crude extract of green tea:crude extract of mulberry leaf:crude extract of corn silk=1:5:3),polyphenol enrichment fractions R3(GT-30%:ML-50%:CS-60%=1:7:1)and monomers X2(epigallocatechin gallate:morusin:formononetin=3:1:2)were selected,respectively.G7,R3,and X2 showed promoting effects on the cell viability and glucose uptake of L6 myoblasts within the detected concentration range.In addition,G7,R3,and X2 could increase the expression levels of p-PI3K/PI3K and p-Akt/Akt in L6 myoblasts,and promote the translocation of Glut4,but G7 and R3 showed more significant effects.Conclusion:The synergistic hypoglycemic effects of green tea,mulberry leaf and corn silk had the characteristics of multiple-components and multiple-targets with p-PI3K/PI3K,p-Akt/Akt and the translocation of Glut4 signal pathways involved.The three traditional herbs might have the potential to be combined used for the prevention and treatment of diabetes based on the synergistic hypoglycemic effects.展开更多
As an important symbol of agricultural and sideline products in Ankang City,selenium-enriched tea affects the development of regional agricultural and sideline industries.In this paper,the development status and probl...As an important symbol of agricultural and sideline products in Ankang City,selenium-enriched tea affects the development of regional agricultural and sideline industries.In this paper,the development status and problems of the selenium-enriched tea products of Ankang were analyzed in terms of capital,technology,management and sales mode.This research is of positive significance to the development of selenium-enriched products and other agricultural and sideline products of health value,and plays a very important role in promoting the cultivation of village-level characteristic industries and the effective realization of targeted poverty alleviation.展开更多
[Objectives]To explore the hypoglycemic effect of Radix Et Rhizoma Salviae Miltiorrhizae,Guixi green tea and their compatibility on mice,so as to provide more options for the adjuvant treatment of diabetes and improve...[Objectives]To explore the hypoglycemic effect of Radix Et Rhizoma Salviae Miltiorrhizae,Guixi green tea and their compatibility on mice,so as to provide more options for the adjuvant treatment of diabetes and improve the comprehensive utilization value of Guixi green tea.[Methods]After being fed adaptively for 7 d,60 SPF-grade male mice were intraperitoneally injected with alloxouracil(180 mg/kg)to induce hyperglycemia model,from which 35 mice with a successful model were selected.They were randomly divided into 5 groups(Danshen group,green tea group,compatible group,positive control group and blank control group),with 7 animals in each group.The mice in all groups were administered according to the dose of 200 mg/kg once a day for 15 d.After the last administration,their body weight was measured on the 15 th day after fasting for 12 h,and their fasting blood glucose was measured by tail clipping.[Results]After modeling,the mice in each group showed typical hyperglycemia symptoms,namely obvious polydipsia,polyphagia,polyuria and weight loss.Compared with the blank control group,Danshen group and green tea group had obvious hypoglycemic effect(P<0.05),and compatible group had significant hypoglycemic effect(P<0.01).Compared with the blank control group,the weight loss of diabetic mice could also be inhibited in green tea group and compatible group(P<0.05).[Conclusions]Danshen,Guixi green tea and their compatibility had the effect of lowering blood sugar,among which the compatible group had the most obvious effect.展开更多
The global incidence of breast cancer remains high and is increasing annually in some regions.Despite the variety of current treatments for breast cancer,the preventive and therapeutic effects are still limited due to...The global incidence of breast cancer remains high and is increasing annually in some regions.Despite the variety of current treatments for breast cancer,the preventive and therapeutic effects are still limited due to the highly heterogeneous nature and complex biological mechanisms of breast cancer.In recent years,tea consumption has emerged as a research focus due to its possible anti-cancer properties.Numerous preclinical studies have demonstrated that regular tea intake could potentially curb the progression of breast cancer by influencing various biological mechanisms,including signaling pathways,cell cycle regulation,and immune system responses,among others.Nonetheless,the findings from epidemiological studies show considerable variability,and the connection between tea drinking and both the risk and outlook for breast cancer is shaped by numerous elements.These include the specific type of tea consumed,the quantity consumed,individual genetic variations,and environmental influences.This article summarizes the current research findings and delves into the connection between tea consumption and the risk as well as the prognosis of breast cancer among different regional populations.Meanwhile,it expounds on the potential molecular biological mechanisms behind it.The aim is to offer a theoretical foundation for the personalized prevention and treatment of breast cancer.展开更多
This study took Artemisia selengensis Turoz and green tea as primary materials and sugar, lemon acid potassium as supplementary materials to make compound health beverage.The main influence factors to the quality of t...This study took Artemisia selengensis Turoz and green tea as primary materials and sugar, lemon acid potassium as supplementary materials to make compound health beverage.The main influence factors to the quality of the compound beverage were investigated,such as addition amounts ofArtemisia selengensis juice, green tea juice,sugar and lemon acid.By orthogonal test ,the best formula of the compound health beverage is Artemisia selengensis juice 10 ml, green tea juice 200 ml, sugar 6 g and lemon acid 0.06 g. The optimum stabilizer of the beverage is CMC-Na with 0.03% amount.展开更多
[Objective] The aim of this study was to provide reference for the quality identification of green tea.[Method] Green Tea was used as materials,and its total DNA was extracted through improved CTAB method.And the obta...[Objective] The aim of this study was to provide reference for the quality identification of green tea.[Method] Green Tea was used as materials,and its total DNA was extracted through improved CTAB method.And the obtained DNA was used to carry out identification on 10 varieties of green tea through ISSR molecular markers.[Result] The high quality DNA from green tea could be obtained with new method,the DNA yield ranged from 101-498 μg/g tea sample for various green tea samples,and the average yield was 249 μg/g tea sample.The ISSR detection result showed that ISSR markers could effectively differentiate different varieties of green tea.[Conclusion] The result had provided reference for the further study on molecular identification of green tea.展开更多
Thirteen volatile compounds were identified from Flemingia macrophylla plants. Eight major components significantly attracted the tea green leafhoppers, Empoasca flavescens F. Based on their relative abundances, follo...Thirteen volatile compounds were identified from Flemingia macrophylla plants. Eight major components significantly attracted the tea green leafhoppers, Empoasca flavescens F. Based on their relative abundances, following synthetic blends were made for field experiments: 1) eight-component-attractant blend included Z-3-hexen-1-ol, Z-3-hexenyl acetate, Z-ocimene, Me SA, Z-3-hexenyl butyrate, dodecane, hexadecane and nonanal at 10, 10, 1, 11, 2, 6, 2 and 4 mg mL^-1 in n-hexane, respectively;2) four-component-attractant blend #1 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and nonanal at 2, 10, 10 and 4 mg mL^-1 in n-hexane, respectively;3) four-component-attractant blend #2 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and Me SA at 2, 10, 10 and 11 mg mL^-1 in n-hexane, respectively. Thymol and 1-methoxy-4-methyl-2-(1-methylethyl)-benzene, identified from Lavandula angustifolia aeration samples, significantly repelled the leafhopper as strong repellents when tested alone or in combination at 10 mg mL^-1. For field bioassays, each attractant lure was attached to a bud green sticky board hung from a bamboo stick at above tea plant level for catching the leafhoppers, whereas the repellent dispenser was tied to a tea branch inside tea clump for pushing the leafhoppers away from tea clumps. The results showed that the eight-component-attractant blend caught similar numbers of the leafhopper as did the four-component-attractant blend #1 at about 53–79 leafhoppers/trap/day, which were significantly higher than those on the hexane-control bud green sticky boards. Average leafhopper catches from un-baited sticky boards were about 51–73 leafhoppers/trap/day when pushed by the repellents placed inside tea plants, with the two-component-repellent blend being more effective than their single components. When the two-component-repellent blend was further tested with the three attractant blends in a push-pull fashion, average trap catches ranged from 62 to 92 leafhoppers/trap/day. Control efficacy on the leafhoppers within the push-pull zones increased progressively from day 1(43%) to day 5(73%). This push-pull approach might have a great potential as a green control strategy for combating the tea green leafhoppers.展开更多
Objective:To evaluate antibacterial activity of the Indonesian water soluble green tea extract,Camellia sinensis,against clinical isolates of methicillin-resistantStaphylococcus aureus (S.aureus)(MRSA)and multi-drug r...Objective:To evaluate antibacterial activity of the Indonesian water soluble green tea extract,Camellia sinensis,against clinical isolates of methicillin-resistantStaphylococcus aureus (S.aureus)(MRSA)and multi-drug resistant Pseudomonas aeruginosa(MDR-P.aeruginosa).Methods:Antimicrobial activity of green tea extract was determined by the disc diffusion method and the minimum inhibitory concentration(MIC)was determined by the twofold serial broth dilutions method.The tested bacteria using in this study were the standard strains and multi-drug resistant clinical isolates of S.aureus and P.aeruginosa,obtained from Laboratory of Clinical Microbiology,Faculty of Medicine,University of Indonesia.Results:The results showed that the inhibition zone diameter of green tea extracts forS.aureus ATCC 25923 and MRSA were(18.970依0.287)mm,and(19.130依0.250)mm respectively.While the inhibition zone diameter forP.aeruginosa ATCC 27853 and MDR-P.aeruginosawere(17.550依0.393)mm and(17.670依0.398)mm respectively.The MIC of green tea extracts againstS.aureus ATCC 25923 and MRSA were 400μg/mL and 400μg/mL,respectively,whereas the MIC for P.aeruginosa ATCC 27853 and MDR-P.aeruginosawere 800μg/mL,and 800μg/mL,respectively.Conclusions:Camellia sinensisleaves extract could be useful in combating emerging drug-resistance caused by MRSA andP.aeruginosa.展开更多
Gastric cancer (GC) is one of the leading causes of cancer death in the world. Numerous efforts are being made to find chemoprotective agents able to reduce its risk. Amongst these, green tea has been reported to have...Gastric cancer (GC) is one of the leading causes of cancer death in the world. Numerous efforts are being made to find chemoprotective agents able to reduce its risk. Amongst these, green tea has been reported to have a protective effect against stomach cancer. This article aims to critically evaluate all epidemiological studies reporting an association between green tea consumption and GC risk. MEDLINE, EBSCOHOST and Google Scholar were used to search for clinical trials of green tea and its correlation to stomach cancer. Studies include cohort and case-control studies. Outcome of interests are inverse association, no association, and positive association. Seventeen epidemiologic studies were reviewed. Eleven studies were conducted in Japan, five in China, and one with Japanese descendent in Hawaii. Ten case-control studies and seven cohortstudies were included. The relative risks or odds ratio of GC for the highest level of green tea consumption was compared. Seven studies suggested no association, eight an inverse association, and one a positive association. One study had shown a significantly lowered GC risk when tea was served warm to cold. Another study also showed a significantly risk with lukewarm tea. All studies that analyzed men and women separately have suggested a reduced risk in women than in men, albeit no significant difference. This review demonstrates that there is insufficient information to support green tea consumption reduces the risk of GC. More studies on the subject matter are warranted.展开更多
The relationship between the amount of tea cream and the chemical components contents in the original green tea infusion was investigated. The results showed that the amounts of tea cream in the green tea infusions ob...The relationship between the amount of tea cream and the chemical components contents in the original green tea infusion was investigated. The results showed that the amounts of tea cream in the green tea infusions obtained from different cultivars and different parts of new shoots were varied. There were many chemical components participating in the formation of green tea cream. However, there were only the contents of caffeine （Y=0.85, P〈0.01） and polyphenols （Y=0.65, P〈0.05） in the original green tea infusion highly correlated with the amount of green tea cream. Stepwise regression analysis of overall chemical components indicated that the contents of caffeine and gallated catechins in the original green tea infusion had a significant effect （P〈0.01） on green tea cream levels. Cream （g L-1）=-172.071＋ 0.129×Ccaffeine＋0.024×Ggallated catechins （R2=0.936）. The amount of green tea cream can be predicted by the contents of gallated catechins and caffeine in the original tea infusion. Principal component analysis also indicated that catechins, minerals, and polysaccharides were the important chemical components in the formation of green tea cream.展开更多
AIM To investigate protective effects and molecular mechanisms of green tea polyphenols(GTP) on nonalcoholic fatty liver disease(NAFLD) in Zucker fatty(ZF) rats.METHODS Male ZF rats were fed a high-fat diet(HFD) for 2...AIM To investigate protective effects and molecular mechanisms of green tea polyphenols(GTP) on nonalcoholic fatty liver disease(NAFLD) in Zucker fatty(ZF) rats.METHODS Male ZF rats were fed a high-fat diet(HFD) for 2 wk then treated with GTP(200 mg/kg) or saline(5 m L/kg) for 8 wk, with Zucker lean rat as their control. At the end of experiment, serum and liver tissue were collected for measurement of metabolic parameters, alanine aminotransferase(ALT) and aspartate aminotransferase(AST), inflammatory cytokines and hepatic triglyceride and liver histology. Immunoblotting was used to detect phosphorylation of AMP-activated protein kinase(AMPK) acetyl-Co A carboxylase(ACC), and sterol regulatory element-binding protein 1c(SREBP1c). RESULTS Genetically obese ZF rats on a HFD presented with metabolic features of hepatic pathological changes comparable to human with NAFLD. GTP intervention decreased weight gain(10.1%, P = 0.052) and significantly lowered visceral fat(31.0%, P < 0.01). Compared with ZF-controls, GTP treatment significantly reduced fasting serum insulin, glucose and lipids levels. Reduction in serum ALT and AST levels(both P < 0.01) were observed in GTP-treated ZF rats. GTP treatment also attenuated the elevated TNFα and IL-6 in the circulation. The increased hepatic TG accumulation and cytoplasmic lipid droplet were attenuated by GTP treatment, associated with significantly increased expression of AMPK-Thr172(P < 0.05) and phosphorylated ACC and SREBP1c(both P < 0.05), indicating diminished hepatic lipogenesis and triglycerides out flux from liver in GTP treated rats. CONCLUSION The protective effects of GTP against HFD-induced NAFLD in genetically obese ZF rats are positively correlated to reduction in hepatic lipogenesis through upregulating the AMPK pathway.展开更多
Breast cancer is the most common cancer among women. In recent years, many in vitro and in vivo studies indicate that green tea possesses anti-cancer effects. The epidemiological studies, however, have produced inconc...Breast cancer is the most common cancer among women. In recent years, many in vitro and in vivo studies indicate that green tea possesses anti-cancer effects. The epidemiological studies, however, have produced inconclusive results in humans. Likewise, results from animal models about the preventive or therapeutic effects of green tea components are inconclusive. The mechanisms by which green tea intake may influence the risk of breast cancer in humans remain elusive. Here, we review recent studies of green tea polyphenols and their applications in the prevention and treatment of breast cancer. Furthermore, we discuss the effect of green tea components on breast cancer by reviewing epidemiological studies, animal model studies and clinical trials. At last, we discuss the mechanisms by which green tea components suppress the develop-ment and recurrence of breast cancer. A better understanding of the mechanisms will improve the utilization of green tea in breast cancer prevention and therapy and pave the way to novel prevention and treatment strategies for breast cancer.展开更多
The use of herbal products has increased significantly in recent years.Because these products are not subject to regulation by the Food and Drug Administration and are often used without supervision by a healthcare pr...The use of herbal products has increased significantly in recent years.Because these products are not subject to regulation by the Food and Drug Administration and are often used without supervision by a healthcare provider,the indication for and consumption of these supplements is quite variable.Moreover,their use is generally regarded as safe and natural by the lay-public.Unfortunately,there has been an increase in the number of reported adverse events occurring with the use of herbal products.We present a case of acute impending liver failure in an adolescent male using a weightloss product containing green tea extract.Our case adds to the growing concern surrounding the ingestion of green tea extract and serves to heighten healthcare provider awareness of a potential green tea extract hepatotoxicity.Despite the generally touted benefits of green tea as a whole,clinical concern regarding its use is emerging and has been linked to its concentration in multiple herbal supplements.Interestingly,the suspected harmful compounds are those previously proposed to be advantageous for weight-loss,cancer remedy,and anti-inflammatory purposes.Yet,we emphasize the need to be aware of not just green tea extract,but the importance of monitoring patient use of all dietary supplements and herbal products.展开更多
[Objective] The aim was to understand the change of fermentation pro- cess of Chang-sheng-chuan green brick tea and analyze the changes in the con- tents of structure components of tea leaves before and after fermenta...[Objective] The aim was to understand the change of fermentation pro- cess of Chang-sheng-chuan green brick tea and analyze the changes in the con- tents of structure components of tea leaves before and after fermentation. [Method] Ten tea leaves before and after fermentation were chosen. The tea leaves sections were made using paraffin microtomy, PAS staining, and observed under light mi- croscopy. Through image analysis for the tea leaves, we compared the changes on the areas of the cellulose and colloid in cell before and after pile-fermentation. At the same time, the tea leaves were observed under transmission electron micro- scope. [Result] The results showed that the pile-fermentation process caused the tea leaves tissue to become loose, and expanded the cell space. Besides, the cell wall of tea leaves was obviously thinning, and even breaking which composed of cellulose. Image analysis showed that the leaf fiber composition reduced significant- ly, with a corresponding increase of yellow colloid in cell. Under observation of transmission electron microscope, there were large amounts of fungi located in the space between the colloid and the cell wall of the tea leaves after pile-fermentation. [Conclusion] The fermentation of Green brick tea is the process of microbial bio- transformation of tea, which is dominated by microbe and consumed the cellulose components of tea leaves.展开更多
Objective: To evaluate the antioxidant interactions between aqueous infusions of green tea and Ocimum gratissimum at different ratios. Methods: Antioxidant activities of aqueous infusion of green tea and Ocimum gratis...Objective: To evaluate the antioxidant interactions between aqueous infusions of green tea and Ocimum gratissimum at different ratios. Methods: Antioxidant activities of aqueous infusion of green tea and Ocimum gratissimum (leaves) alone or in combination at various proportions (3:1, 2:1, 1:1, 1:2, 1:3) were determined by DPPH, ABTS, NO and ex-vivo assays including lipid peroxidation and haemolysis. Total phenolic content and flavonoid content was calculated by Folin-Ciocalteu reagent and aluminum chloride colorimetry method, respectively. A correlation study was also conducted between the antioxidant activity and total phenolic/flavonoid content of various infusions. The interactions were analyzed by combination index applying CompuSyn software. Results: Green tea exhibited high radical scavenging ability as compared to Ocimum gratissimum infusion. Combination of green tea and Ocimum gratissimum exhibited moderate antagonism to strong synergistic interaction at various ratios. A strong correlation was found between total phenolic content/total flavonoid content and antioxidant activities of individual infusions (green tea and Ocimum gratissimum). For binary mixture at different ratios, a weak to strong correlation was observed between total phenolic content and antioxidant activity and almost no correlation between total flavonoid content and antioxidant potential. Conclusions: Overall, green tea and Ocimum gratissimum combination (1:1) displayed the highest antioxidant potential and maximum synergism.展开更多
This study investigated the acute effects of green tea extract （GTE） and its polyphenol constituents, （-）-epigallocatechin-3-gallate （EGCG） and （-）-epicatechin （EC）, on basal and stimulated testosterone prod...This study investigated the acute effects of green tea extract （GTE） and its polyphenol constituents, （-）-epigallocatechin-3-gallate （EGCG） and （-）-epicatechin （EC）, on basal and stimulated testosterone production by rat Leydig cells in vitro. Leydig cells purified in a Percoll gradient were incubated for 3 h with GTE, EGCG or EC and the testosterone precursor androstenedione, in the presence or absence of either protein kinase A （PKA） or protein kinase C （PKC） activators. The reversibility of the effect was studied by pretreating cells for 15 min with GTE or EGCG, allowing them to recover for 1 h and challenging them for 2 h with human chorionic gonadotropin （hCG）, luteinizing hormone releasing hormone （LHRH）, 22（R）-hydroxycholesterol or androstenedione. GTE and EGCG, but not EC, inhibited both basal and kinase-stimulated testosterone production. Under the pretreatment conditions, the inhibitory effect of the higher concentration of GTE/EGCG on hCG/LHRH-stimulated or 22（R）- hydroxycholesterol-induced testosterone production was maintained, whereas androstenedione-supported testosterone production returned to control levels. At the lower concentration of GTE/EGCG, the inhibitory effect of these polyphenols on 22（R）-hydroxycholesterol-supported testosterone production was reversed. The inhibitory effects of GTE may be explained by the action of its principal component, EGCG, and the presence of a gallate group in its structure seems important for its high efficacy in inhibiting testosterone production. The mechanisms underlying the effects of GTE and EGCG involve the inhibition of the PKA/PKC signalling pathways, as well as the inhibition of P450 side-chain cleavage enzyme and 17β-hydroxysteroid dehydrogenase function.展开更多
基金financial sponsored by the National Key R&D Program of China(No.2018YFC1604405)Fund of Shanghai Engineering Research Center of Plant Germplasm Resources(No.17DZ2252700)Research on the health function of tea and deep-processed products in preventing metabolic diseases(No.C-6105-20-074)。
文摘High-salt diet is well recognized as a risk factor for hypertension,and dietary intervention plays a critical role in the prevention of hypertension.The current study investigated the effects of selenium-enriched green tea(Se-GT)and ordinary green tea(GT)on prevention of hypertension of rats induced by high-salt diet,as well as their potential regulatory and mechanism.Our results showed that GT and Se-GT supplementations significantly prevented the increase of blood pressure(BP),activated the phosphoinosmde-3-kinase/protein kinase B(PI3K/Akt)signaling pathway,and regulated the gene expression related to BP,as well as improved the tissue damage like heart,liver,and kidneys.Besides,the key parameters associated with oxidative stress,inflammation and endothelial dysfunction were also altered by GT and Se-GT treatments.Importantly,GT or Se-GT administration adjusted the diversity and composition of the intestinal flora.Moreover,GT and Se-GT supplementations increased the abundance of beneficial bacteria and reduced the abundance of harmful or conditional pathogenic bacteria.More specifically,GT intake specifically and significantly enriched the relative abundance of Paraprevotella and Bacteroides,whereas Se-GT was characterized by specific and significant enrichment for Allobaculum and Bifidobacterium.Our results proved that dietary supplement of GT and Se-GT remarkably improved the vascular functions and effectively prevented tissue damage by regulation of intestinal flora,and thus preventing hypertension induced by high-salt diet.
文摘Once a mining village,Jingshan in Hangzhou has reinvented itself over the past 20 years as a thriving model of green transformation.STROLLING through a village named Jingshan located in Hangzhou City,east China’s Zhejiang Province,one will notice the image of a“little tea farmer”wearing a bamboo hat and carrying a tea basket in many places.
文摘BACKGROUND Periodontal disease is a chronic inflammatory condition characterized by periodontal pocket formation,clinical attachment loss,and destruction of alveolar bone.Its conventional treatment primarily involves mechanical debridement and plaque control,but localized antimicrobial therapy offers site-specific advantages.While antibiotics such as metronidazole and doxycycline are commonly used,green tea extract,which is rich in epigallocatechin gallate,has been proposed as a promising alternative for local drug delivery due to its anti-inflammatory and antimicrobial properties.AIM To compare the clinical efficacy of green tea extract gel and ornidazole gel as adjuncts to scaling and root planing(SRP)in patients with periodontitis.METHODS Teeth with probing pocket depths(PPD)of 4-7 mm were selected.Participants’baseline oral hygiene index-simplified,plaque index,clinical attachment loss,and PPD were recorded.The participants were randomized into two groups:One received green tea extract gel after SRP,and the other received ornidazole gel.Subgingival drug delivery was performed,and participants refrained from brushing or interproximal cleaning for ten days.Their clinical parameters were re-evaluated after one month.RESULTS The PPD decreased significantly from baseline to one month in both groups.However,the green tea extract gel group exhibited superior outcomes to the ornidazole gel group,with a mean difference in PPD of 0.28±0.78 mm at one month(P<0.007).CONCLUSION As an adjunct to SRP,green tea extract gel showed greater efficacy in improving clinical periodontal parameters than ornidazole gel.
文摘The catechin Epigallocatechin-3-O-Gallate (EGCG) which is found in of Green Tea extracts (GTE), displays a variety of microbicidal properties. It is largely believed that EGCG inhibits the growth of cariogenic and periodontopathic bacteria. Objective: In this paper we compared the inhibitory activity of EGCG and a commercial GTE on the growth of Veillonella parvula. Chlorhexidine was used as positive control. Methodology: V. parvula ATCC 10790 and a clinical isolate obtained from a periodontal disease patient were cultured in the presence of EGCG or a commercial GTE, and the measurements of bacterial growth inhibition were compared to the values obtained with 0.12 and 0.2% chlorhexidine. Results: Chlorhexidine inhibited bacterial growth, however in contrast to a previous report, neither EGCG nor the GTE showed any effect on bacterial growth. Conclusions: The data show and confirm that chlorhexidine is a growth inhibitor of V. parvula while EGCG and GTE do not display such effect.
基金the grant from National Key Research and Development Program of China(Grant No.2021YFE0110000)the grant from Tianjin Municipal Science and Technology Foundation(Grant No.22JCYBJC00160).
文摘Background:Green tea,mulberry leaf and corn silk are traditional herbs used in the prevention and treatment of diabetes in China for a long time,but their synergistic hypoglycemic effects and mechanisms remain unclear.Methods:The effective components of green tea,mulberry leaf and corn silk were extracted and enriched.Mixture design of experiments was used to study the influences of different combinations on the cell viability and glucose uptake level of L6 myoblasts,so as to determine the optimal synergistic hypoglycemic combination.The possible hypoglycemic mechanism of the optimal synergistic combination was explored by cytotoxicity assay,glucose uptake assay,and western blot.Results:Three polyphenol enrichment fractions of the herbs,30%ethanol elution fraction of green tea(GT),50%ethanol elution fraction of mulberry leaf(ML)and 60%ethanol elution fraction of corn silk(CS)were obtained.The antioxidant activities of GT-30%,ML-50%and CS-60%were superior to those of crude extracts,and showed strong potential inα-amylase andα-glucosidase inhibition activities.The optimal synergistic combination of crude extracts G7(crude extract of green tea:crude extract of mulberry leaf:crude extract of corn silk=1:5:3),polyphenol enrichment fractions R3(GT-30%:ML-50%:CS-60%=1:7:1)and monomers X2(epigallocatechin gallate:morusin:formononetin=3:1:2)were selected,respectively.G7,R3,and X2 showed promoting effects on the cell viability and glucose uptake of L6 myoblasts within the detected concentration range.In addition,G7,R3,and X2 could increase the expression levels of p-PI3K/PI3K and p-Akt/Akt in L6 myoblasts,and promote the translocation of Glut4,but G7 and R3 showed more significant effects.Conclusion:The synergistic hypoglycemic effects of green tea,mulberry leaf and corn silk had the characteristics of multiple-components and multiple-targets with p-PI3K/PI3K,p-Akt/Akt and the translocation of Glut4 signal pathways involved.The three traditional herbs might have the potential to be combined used for the prevention and treatment of diabetes based on the synergistic hypoglycemic effects.
基金National Key R&D Program of China(2018YFD1100202)Shaanxi Social Science Fund Program of China(2018S30)Shaanxi Undergraduate Innovation Planning Project of China(201829041).
文摘As an important symbol of agricultural and sideline products in Ankang City,selenium-enriched tea affects the development of regional agricultural and sideline industries.In this paper,the development status and problems of the selenium-enriched tea products of Ankang were analyzed in terms of capital,technology,management and sales mode.This research is of positive significance to the development of selenium-enriched products and other agricultural and sideline products of health value,and plays a very important role in promoting the cultivation of village-level characteristic industries and the effective realization of targeted poverty alleviation.
基金Supported by the National Innovation Planning Project for University Students (202210599001).
文摘[Objectives]To explore the hypoglycemic effect of Radix Et Rhizoma Salviae Miltiorrhizae,Guixi green tea and their compatibility on mice,so as to provide more options for the adjuvant treatment of diabetes and improve the comprehensive utilization value of Guixi green tea.[Methods]After being fed adaptively for 7 d,60 SPF-grade male mice were intraperitoneally injected with alloxouracil(180 mg/kg)to induce hyperglycemia model,from which 35 mice with a successful model were selected.They were randomly divided into 5 groups(Danshen group,green tea group,compatible group,positive control group and blank control group),with 7 animals in each group.The mice in all groups were administered according to the dose of 200 mg/kg once a day for 15 d.After the last administration,their body weight was measured on the 15 th day after fasting for 12 h,and their fasting blood glucose was measured by tail clipping.[Results]After modeling,the mice in each group showed typical hyperglycemia symptoms,namely obvious polydipsia,polyphagia,polyuria and weight loss.Compared with the blank control group,Danshen group and green tea group had obvious hypoglycemic effect(P<0.05),and compatible group had significant hypoglycemic effect(P<0.01).Compared with the blank control group,the weight loss of diabetic mice could also be inhibited in green tea group and compatible group(P<0.05).[Conclusions]Danshen,Guixi green tea and their compatibility had the effect of lowering blood sugar,among which the compatible group had the most obvious effect.
文摘The global incidence of breast cancer remains high and is increasing annually in some regions.Despite the variety of current treatments for breast cancer,the preventive and therapeutic effects are still limited due to the highly heterogeneous nature and complex biological mechanisms of breast cancer.In recent years,tea consumption has emerged as a research focus due to its possible anti-cancer properties.Numerous preclinical studies have demonstrated that regular tea intake could potentially curb the progression of breast cancer by influencing various biological mechanisms,including signaling pathways,cell cycle regulation,and immune system responses,among others.Nonetheless,the findings from epidemiological studies show considerable variability,and the connection between tea drinking and both the risk and outlook for breast cancer is shaped by numerous elements.These include the specific type of tea consumed,the quantity consumed,individual genetic variations,and environmental influences.This article summarizes the current research findings and delves into the connection between tea consumption and the risk as well as the prognosis of breast cancer among different regional populations.Meanwhile,it expounds on the potential molecular biological mechanisms behind it.The aim is to offer a theoretical foundation for the personalized prevention and treatment of breast cancer.
基金Supported by Huai’an Science&Technology Bureau(SN1082)the Practice Inovation Trainng Program Projects for Jiangsu Polytechnic of Finance&Economics Students~~
文摘This study took Artemisia selengensis Turoz and green tea as primary materials and sugar, lemon acid potassium as supplementary materials to make compound health beverage.The main influence factors to the quality of the compound beverage were investigated,such as addition amounts ofArtemisia selengensis juice, green tea juice,sugar and lemon acid.By orthogonal test ,the best formula of the compound health beverage is Artemisia selengensis juice 10 ml, green tea juice 200 ml, sugar 6 g and lemon acid 0.06 g. The optimum stabilizer of the beverage is CMC-Na with 0.03% amount.
基金Supported by National Science and Technology Infrastructure Plan(2005DKA21002)Natural Science Foundation of Yunnan Province(2006C0012Z)~~
文摘[Objective] The aim of this study was to provide reference for the quality identification of green tea.[Method] Green Tea was used as materials,and its total DNA was extracted through improved CTAB method.And the obtained DNA was used to carry out identification on 10 varieties of green tea through ISSR molecular markers.[Result] The high quality DNA from green tea could be obtained with new method,the DNA yield ranged from 101-498 μg/g tea sample for various green tea samples,and the average yield was 249 μg/g tea sample.The ISSR detection result showed that ISSR markers could effectively differentiate different varieties of green tea.[Conclusion] The result had provided reference for the further study on molecular identification of green tea.
基金financially supported by the National Key Research and Development Program of China (2018YFC1604402)the Natural Science Foundation of Zhejiang Province, China (LY17C140002)+1 种基金the Fundamental and Public Welfare of Zhejiang Province, China (LGN18C160006)the College Student Innovation and Entrepreneurship of Zhejiang Province, China (2017R409055)
文摘Thirteen volatile compounds were identified from Flemingia macrophylla plants. Eight major components significantly attracted the tea green leafhoppers, Empoasca flavescens F. Based on their relative abundances, following synthetic blends were made for field experiments: 1) eight-component-attractant blend included Z-3-hexen-1-ol, Z-3-hexenyl acetate, Z-ocimene, Me SA, Z-3-hexenyl butyrate, dodecane, hexadecane and nonanal at 10, 10, 1, 11, 2, 6, 2 and 4 mg mL^-1 in n-hexane, respectively;2) four-component-attractant blend #1 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and nonanal at 2, 10, 10 and 4 mg mL^-1 in n-hexane, respectively;3) four-component-attractant blend #2 contained hexadecane, Z-3-hexenyl acetate, Z-3-hexen-1-ol and Me SA at 2, 10, 10 and 11 mg mL^-1 in n-hexane, respectively. Thymol and 1-methoxy-4-methyl-2-(1-methylethyl)-benzene, identified from Lavandula angustifolia aeration samples, significantly repelled the leafhopper as strong repellents when tested alone or in combination at 10 mg mL^-1. For field bioassays, each attractant lure was attached to a bud green sticky board hung from a bamboo stick at above tea plant level for catching the leafhoppers, whereas the repellent dispenser was tied to a tea branch inside tea clump for pushing the leafhoppers away from tea clumps. The results showed that the eight-component-attractant blend caught similar numbers of the leafhopper as did the four-component-attractant blend #1 at about 53–79 leafhoppers/trap/day, which were significantly higher than those on the hexane-control bud green sticky boards. Average leafhopper catches from un-baited sticky boards were about 51–73 leafhoppers/trap/day when pushed by the repellents placed inside tea plants, with the two-component-repellent blend being more effective than their single components. When the two-component-repellent blend was further tested with the three attractant blends in a push-pull fashion, average trap catches ranged from 62 to 92 leafhoppers/trap/day. Control efficacy on the leafhoppers within the push-pull zones increased progressively from day 1(43%) to day 5(73%). This push-pull approach might have a great potential as a green control strategy for combating the tea green leafhoppers.
基金Supported by Collaborative Project Research,Faculty of Pharmacy and Department of Microbiology,Medical Faculty,University of Indonesia,Grant No.2012/0806327660
文摘Objective:To evaluate antibacterial activity of the Indonesian water soluble green tea extract,Camellia sinensis,against clinical isolates of methicillin-resistantStaphylococcus aureus (S.aureus)(MRSA)and multi-drug resistant Pseudomonas aeruginosa(MDR-P.aeruginosa).Methods:Antimicrobial activity of green tea extract was determined by the disc diffusion method and the minimum inhibitory concentration(MIC)was determined by the twofold serial broth dilutions method.The tested bacteria using in this study were the standard strains and multi-drug resistant clinical isolates of S.aureus and P.aeruginosa,obtained from Laboratory of Clinical Microbiology,Faculty of Medicine,University of Indonesia.Results:The results showed that the inhibition zone diameter of green tea extracts forS.aureus ATCC 25923 and MRSA were(18.970依0.287)mm,and(19.130依0.250)mm respectively.While the inhibition zone diameter forP.aeruginosa ATCC 27853 and MDR-P.aeruginosawere(17.550依0.393)mm and(17.670依0.398)mm respectively.The MIC of green tea extracts againstS.aureus ATCC 25923 and MRSA were 400μg/mL and 400μg/mL,respectively,whereas the MIC for P.aeruginosa ATCC 27853 and MDR-P.aeruginosawere 800μg/mL,and 800μg/mL,respectively.Conclusions:Camellia sinensisleaves extract could be useful in combating emerging drug-resistance caused by MRSA andP.aeruginosa.
文摘Gastric cancer (GC) is one of the leading causes of cancer death in the world. Numerous efforts are being made to find chemoprotective agents able to reduce its risk. Amongst these, green tea has been reported to have a protective effect against stomach cancer. This article aims to critically evaluate all epidemiological studies reporting an association between green tea consumption and GC risk. MEDLINE, EBSCOHOST and Google Scholar were used to search for clinical trials of green tea and its correlation to stomach cancer. Studies include cohort and case-control studies. Outcome of interests are inverse association, no association, and positive association. Seventeen epidemiologic studies were reviewed. Eleven studies were conducted in Japan, five in China, and one with Japanese descendent in Hawaii. Ten case-control studies and seven cohortstudies were included. The relative risks or odds ratio of GC for the highest level of green tea consumption was compared. Seven studies suggested no association, eight an inverse association, and one a positive association. One study had shown a significantly lowered GC risk when tea was served warm to cold. Another study also showed a significantly risk with lukewarm tea. All studies that analyzed men and women separately have suggested a reduced risk in women than in men, albeit no significant difference. This review demonstrates that there is insufficient information to support green tea consumption reduces the risk of GC. More studies on the subject matter are warranted.
基金supported by the Special Scientific Research Funds for Commonweal Section of the Ministry of Agriculture, China (nyhyzx07-3-35)the Natural Science Foundation of Zhejiang Province, China (R3090394)the Key Laboratory of Processing and Quality Control of Tea & Beverage Plants Products, Ministry of Agriculture, China (2010K1004)
文摘The relationship between the amount of tea cream and the chemical components contents in the original green tea infusion was investigated. The results showed that the amounts of tea cream in the green tea infusions obtained from different cultivars and different parts of new shoots were varied. There were many chemical components participating in the formation of green tea cream. However, there were only the contents of caffeine （Y=0.85, P〈0.01） and polyphenols （Y=0.65, P〈0.05） in the original green tea infusion highly correlated with the amount of green tea cream. Stepwise regression analysis of overall chemical components indicated that the contents of caffeine and gallated catechins in the original green tea infusion had a significant effect （P〈0.01） on green tea cream levels. Cream （g L-1）=-172.071＋ 0.129×Ccaffeine＋0.024×Ggallated catechins （R2=0.936）. The amount of green tea cream can be predicted by the contents of gallated catechins and caffeine in the original tea infusion. Principal component analysis also indicated that catechins, minerals, and polysaccharides were the important chemical components in the formation of green tea cream.
文摘AIM To investigate protective effects and molecular mechanisms of green tea polyphenols(GTP) on nonalcoholic fatty liver disease(NAFLD) in Zucker fatty(ZF) rats.METHODS Male ZF rats were fed a high-fat diet(HFD) for 2 wk then treated with GTP(200 mg/kg) or saline(5 m L/kg) for 8 wk, with Zucker lean rat as their control. At the end of experiment, serum and liver tissue were collected for measurement of metabolic parameters, alanine aminotransferase(ALT) and aspartate aminotransferase(AST), inflammatory cytokines and hepatic triglyceride and liver histology. Immunoblotting was used to detect phosphorylation of AMP-activated protein kinase(AMPK) acetyl-Co A carboxylase(ACC), and sterol regulatory element-binding protein 1c(SREBP1c). RESULTS Genetically obese ZF rats on a HFD presented with metabolic features of hepatic pathological changes comparable to human with NAFLD. GTP intervention decreased weight gain(10.1%, P = 0.052) and significantly lowered visceral fat(31.0%, P < 0.01). Compared with ZF-controls, GTP treatment significantly reduced fasting serum insulin, glucose and lipids levels. Reduction in serum ALT and AST levels(both P < 0.01) were observed in GTP-treated ZF rats. GTP treatment also attenuated the elevated TNFα and IL-6 in the circulation. The increased hepatic TG accumulation and cytoplasmic lipid droplet were attenuated by GTP treatment, associated with significantly increased expression of AMPK-Thr172(P < 0.05) and phosphorylated ACC and SREBP1c(both P < 0.05), indicating diminished hepatic lipogenesis and triglycerides out flux from liver in GTP treated rats. CONCLUSION The protective effects of GTP against HFD-induced NAFLD in genetically obese ZF rats are positively correlated to reduction in hepatic lipogenesis through upregulating the AMPK pathway.
基金Supported by National Natural Science Foundation of China,No.81001587
文摘Breast cancer is the most common cancer among women. In recent years, many in vitro and in vivo studies indicate that green tea possesses anti-cancer effects. The epidemiological studies, however, have produced inconclusive results in humans. Likewise, results from animal models about the preventive or therapeutic effects of green tea components are inconclusive. The mechanisms by which green tea intake may influence the risk of breast cancer in humans remain elusive. Here, we review recent studies of green tea polyphenols and their applications in the prevention and treatment of breast cancer. Furthermore, we discuss the effect of green tea components on breast cancer by reviewing epidemiological studies, animal model studies and clinical trials. At last, we discuss the mechanisms by which green tea components suppress the develop-ment and recurrence of breast cancer. A better understanding of the mechanisms will improve the utilization of green tea in breast cancer prevention and therapy and pave the way to novel prevention and treatment strategies for breast cancer.
文摘The use of herbal products has increased significantly in recent years.Because these products are not subject to regulation by the Food and Drug Administration and are often used without supervision by a healthcare provider,the indication for and consumption of these supplements is quite variable.Moreover,their use is generally regarded as safe and natural by the lay-public.Unfortunately,there has been an increase in the number of reported adverse events occurring with the use of herbal products.We present a case of acute impending liver failure in an adolescent male using a weightloss product containing green tea extract.Our case adds to the growing concern surrounding the ingestion of green tea extract and serves to heighten healthcare provider awareness of a potential green tea extract hepatotoxicity.Despite the generally touted benefits of green tea as a whole,clinical concern regarding its use is emerging and has been linked to its concentration in multiple herbal supplements.Interestingly,the suspected harmful compounds are those previously proposed to be advantageous for weight-loss,cancer remedy,and anti-inflammatory purposes.Yet,we emphasize the need to be aware of not just green tea extract,but the importance of monitoring patient use of all dietary supplements and herbal products.
基金Supported by Higher Education Institutions' Young Teacher In-Depth Business Project of Hubei Provincial Department of Education(XD2014056)~~
文摘[Objective] The aim was to understand the change of fermentation pro- cess of Chang-sheng-chuan green brick tea and analyze the changes in the con- tents of structure components of tea leaves before and after fermentation. [Method] Ten tea leaves before and after fermentation were chosen. The tea leaves sections were made using paraffin microtomy, PAS staining, and observed under light mi- croscopy. Through image analysis for the tea leaves, we compared the changes on the areas of the cellulose and colloid in cell before and after pile-fermentation. At the same time, the tea leaves were observed under transmission electron micro- scope. [Result] The results showed that the pile-fermentation process caused the tea leaves tissue to become loose, and expanded the cell space. Besides, the cell wall of tea leaves was obviously thinning, and even breaking which composed of cellulose. Image analysis showed that the leaf fiber composition reduced significant- ly, with a corresponding increase of yellow colloid in cell. Under observation of transmission electron microscope, there were large amounts of fungi located in the space between the colloid and the cell wall of the tea leaves after pile-fermentation. [Conclusion] The fermentation of Green brick tea is the process of microbial bio- transformation of tea, which is dominated by microbe and consumed the cellulose components of tea leaves.
文摘Objective: To evaluate the antioxidant interactions between aqueous infusions of green tea and Ocimum gratissimum at different ratios. Methods: Antioxidant activities of aqueous infusion of green tea and Ocimum gratissimum (leaves) alone or in combination at various proportions (3:1, 2:1, 1:1, 1:2, 1:3) were determined by DPPH, ABTS, NO and ex-vivo assays including lipid peroxidation and haemolysis. Total phenolic content and flavonoid content was calculated by Folin-Ciocalteu reagent and aluminum chloride colorimetry method, respectively. A correlation study was also conducted between the antioxidant activity and total phenolic/flavonoid content of various infusions. The interactions were analyzed by combination index applying CompuSyn software. Results: Green tea exhibited high radical scavenging ability as compared to Ocimum gratissimum infusion. Combination of green tea and Ocimum gratissimum exhibited moderate antagonism to strong synergistic interaction at various ratios. A strong correlation was found between total phenolic content/total flavonoid content and antioxidant activities of individual infusions (green tea and Ocimum gratissimum). For binary mixture at different ratios, a weak to strong correlation was observed between total phenolic content and antioxidant activity and almost no correlation between total flavonoid content and antioxidant potential. Conclusions: Overall, green tea and Ocimum gratissimum combination (1:1) displayed the highest antioxidant potential and maximum synergism.
文摘This study investigated the acute effects of green tea extract （GTE） and its polyphenol constituents, （-）-epigallocatechin-3-gallate （EGCG） and （-）-epicatechin （EC）, on basal and stimulated testosterone production by rat Leydig cells in vitro. Leydig cells purified in a Percoll gradient were incubated for 3 h with GTE, EGCG or EC and the testosterone precursor androstenedione, in the presence or absence of either protein kinase A （PKA） or protein kinase C （PKC） activators. The reversibility of the effect was studied by pretreating cells for 15 min with GTE or EGCG, allowing them to recover for 1 h and challenging them for 2 h with human chorionic gonadotropin （hCG）, luteinizing hormone releasing hormone （LHRH）, 22（R）-hydroxycholesterol or androstenedione. GTE and EGCG, but not EC, inhibited both basal and kinase-stimulated testosterone production. Under the pretreatment conditions, the inhibitory effect of the higher concentration of GTE/EGCG on hCG/LHRH-stimulated or 22（R）- hydroxycholesterol-induced testosterone production was maintained, whereas androstenedione-supported testosterone production returned to control levels. At the lower concentration of GTE/EGCG, the inhibitory effect of these polyphenols on 22（R）-hydroxycholesterol-supported testosterone production was reversed. The inhibitory effects of GTE may be explained by the action of its principal component, EGCG, and the presence of a gallate group in its structure seems important for its high efficacy in inhibiting testosterone production. The mechanisms underlying the effects of GTE and EGCG involve the inhibition of the PKA/PKC signalling pathways, as well as the inhibition of P450 side-chain cleavage enzyme and 17β-hydroxysteroid dehydrogenase function.
