A highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. The proposed method is based on liquid-liquid extraction followed ...A highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. The proposed method is based on liquid-liquid extraction followed by gas chromatographic determination, using nitrogen phosphorus detector (GC-NPD) for the identification and quantitation of hexaconazole. The most appropriate solvent mixture for extracting hexaconazole residues from black tea was n-hexane:acetone at 1:1 (v/v). The extract was cleaned up by adsorption column chromatography using activated florisil. Performance of the method was assessed by evaluating quality parameters such as recovery value, repeatability, reproducibility, linearity and limits of detection and quantitation. When the method was assessed for repeatability, the percentage of recovery ranged between 86% and 96% while the relative standard deviation was between 0.30% and 2.35%. In studies on reproducibility the recovery ranged from 81% to 85% and relative standard deviation from 1.68% to 5.13%, implying that the method was reliable. A field trial was conducted to verify the application of this method with real samples. Results prove that the validated method was suitable for extracting hexaconazole residues.展开更多
Pu-erh ripen tea becomes popular worldwide owing to its unique taste and aroma.In the present study,volatile compounds from Pu-erh ripen tea were extracted using a solvent assisted flavor evaporation(SAFE)and analyzed...Pu-erh ripen tea becomes popular worldwide owing to its unique taste and aroma.In the present study,volatile compounds from Pu-erh ripen tea were extracted using a solvent assisted flavor evaporation(SAFE)and analyzed with a gas chromatography-mass spectrometry(GC-MS)and a gas chromatography olfactometry(GC-O).Results demonstrated that 58 major volatile compounds and 24 aroma active substances of Pu-erh ripen tea were identified by GC-MS and GC-O analysis.Among volatile compounds identified,methoxyphenyl compounds were considered as the dominate compounds in the aroma of Pu-erh ripen tea.Further investigation showed that 6 methoxybenzenes were responsible for the aging aroma in Pu-erh ripen tea;α-ionone,3,4-dimethoxytoluene,1,3-dimethoxybenzene,etc.were responsible for the wood-like aroma.Linalool,α-terpineol,α-ionone,β-ionone,and benzeneacetaldehyde were responsible for the floral odor.Compared the odor detection threshold(ODT)among the 8 methoxyphenyl compounds in water,1,2,3-trimethoxybenzene showed the highest ODT,followed by 3,4-dimethoxyphenol.1,3-dimethoxybenzene(105μg/L)and 1,2,3-trimethoxy-5-methylbenzene(100μg/L)were present at relatively low odor threshold values.The result indicated that methoxyphenyl compounds play a vital role in the unique flavor of Pu-erh ripen tea.展开更多
Reducing oxidative stress and hepatoprotective effect of Pu-erh tea water extracts on rats fed with high-fat diet were researched for explaining health care of Pu-erh tea.Fifty SD rats were divided into five groups.Th...Reducing oxidative stress and hepatoprotective effect of Pu-erh tea water extracts on rats fed with high-fat diet were researched for explaining health care of Pu-erh tea.Fifty SD rats were divided into five groups.The body weight was measured once a day.The malondialdehyde(MDA)and glucose(Glu)levels and the activities of alanine aminotransferase(ALT),aspartate aminotransferase(AST),nitric oxide synthase(NOS),and pyruvate kinase(PK)in serum were determined.Furthermore,the hepatic glycogen level(HGL)and the activities of hepatic total superoxide dismutase(T-SOD),catalase(CAT),and glutathione peroxidase(GSH-Px)were also measured after continuous administration for 12 weeks.The result demonstrated that Pu-erh extract caused the decreases in body weight,fat index,MDA and NOS levels,and the increases in hepatic T-SOD,CAT and GSH-Px activities,indicating that the extract may be due to inhibiting the increases of body weight and fat index,reducing oxidant stress state and inhibiting lipid peroxidation,thus decreasing the activities of ALT and AST,and protecting the liver in rat.Meanwhile,the extracts could increase the production of hepatic glycogen and the activity of PK,and reduce glucose level,protecting the liver from the diseases associated with type II diabetes.展开更多
Pu-erh tea is one of post fermented tea manufactured through oxidative maturing by microorganisms. We investigated the preventive effects of pu-erh tea extract on oxazolone-induced type IV allergy in male (ICR) mice. ...Pu-erh tea is one of post fermented tea manufactured through oxidative maturing by microorganisms. We investigated the preventive effects of pu-erh tea extract on oxazolone-induced type IV allergy in male (ICR) mice. Oral administration of 50 mg/kg water extract of pu-erh tea leaves resulted in significant preventive effects against mouse type IV allergy. The hydrophilic Theabrownin-like fraction (TBW-ND), with a high molecular weight of approximately 12,000 or higher, was prepared from pu-erh tea leaves by a solvent-extraction method, followed by Diaion HP-20 column chro-matography and dialysis. Oral and percutaneous administrations of TBW-ND at doses of 18.7 mg/kg and 0.037 mg/ear also resulted in significant preventive effects, which included preventing increases in levels of the proinflam-matory cytokine interleukin-12. The anti-allergic ingredients in TBW-ND were predicted to be highly complex compounds containing of polyphenols, polysaccharides and/or proteins. The results suggest pu-erh tea leaves could be a beneficial food for protecting against delayed-type allergy.展开更多
Habitual tea consumption can reduce the risk of ASCVD morbidity and mortality and all-cause mortality in China,and long-term adherence to this habit can provide greater protection.Pu-erh tea is one of the representati...Habitual tea consumption can reduce the risk of ASCVD morbidity and mortality and all-cause mortality in China,and long-term adherence to this habit can provide greater protection.Pu-erh tea is one of the representatives of post-fermented teas,and the polymers in Pu-erh tea have anti-cancer and anti-hyperlipidemic activities,but their chemical composition is still unknown.In this study,the chemical composition of Pu-erh tea was investigated in detail and eight(1–8)known compounds were isolated.The polymers in Pu-erh tea were also degraded by thiol degradation,and the fragments of quercetin and(–)-epicatechin-3-O-gallate were found in the thiol degradation products of Pu-erh tea polymers by UPLC observation and separation and purification.This is the first time that this fragment was obtained in Pu-erh tea polymer.展开更多
Pu-erh tea, a traditional Chinese beverage, has been believed to have many benefits to human health and without side effects. In this study, we systematically analyzed the main active components of Pu-erh tea and inve...Pu-erh tea, a traditional Chinese beverage, has been believed to have many benefits to human health and without side effects. In this study, we systematically analyzed the main active components of Pu-erh tea and investigated its anti-obesity, anti-atherosclerotic and anti-oxidant effects using an obese rat model. Obesity was induced by feeding a high-fat diet and subsequently the experimental obese mice were fed with high-fat diet supplemented with low (2.5%), medium (5%) or high (7.5%) doses of Pu-erh tea powder for 6 weeks respectively. As result, the body weight gain of the rats was decreased by medium and high doses of Pu-erh tea treatments. Furthermore, the levels of serum total cholesterol (TC), triglyceride (TG) and atherosclerosis index (AI) were significantly lowered by Pu-erh tea compared to the control group. Conversely, high density lipoproteincholesterol (HDL-C) level of the rats was significantly elevated by Pu-erh tea treatments. In addition, Pu-erh tea treatments increased the activities of anti-oxidative enzymes such as superoxide dismutase (SOD) and glutathione peroxides (GSH-Px), whereas reduced the level of lipid peroxidation product malondialdehyde (MDA) in obese rats. Collectively, our find-ings revealed that Pu-erh tea exerts comprehensive benefits in anti-obesity, anti-atherosclerotic and anti-oxidant effects, therefore can be used as a promising functional food in obesity management.展开更多
Pu-erh tea has been used for thousands of years to treat metabolic diseases.Recognized in Shen Nong's Herbal Classic,a compendium kept by the first traditional Chinese practitioners,it is still highly valued for i...Pu-erh tea has been used for thousands of years to treat metabolic diseases.Recognized in Shen Nong's Herbal Classic,a compendium kept by the first traditional Chinese practitioners,it is still highly valued for its hypocholesterolemic and hypolipidemic effects.This review reports the processing and bioactive components of pu-erh tea.Recent human and animal studies of pu-erh tea and its potential therapeutic mechanisms have also been summarized.The interaction of liver and gut microbiome regulates the puerh tea biotransformation and endogenous metabolism,and thus contributes to the health benefits.展开更多
基金Project supported by the National Tea Research Foundation, Kolkata,India
文摘A highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. The proposed method is based on liquid-liquid extraction followed by gas chromatographic determination, using nitrogen phosphorus detector (GC-NPD) for the identification and quantitation of hexaconazole. The most appropriate solvent mixture for extracting hexaconazole residues from black tea was n-hexane:acetone at 1:1 (v/v). The extract was cleaned up by adsorption column chromatography using activated florisil. Performance of the method was assessed by evaluating quality parameters such as recovery value, repeatability, reproducibility, linearity and limits of detection and quantitation. When the method was assessed for repeatability, the percentage of recovery ranged between 86% and 96% while the relative standard deviation was between 0.30% and 2.35%. In studies on reproducibility the recovery ranged from 81% to 85% and relative standard deviation from 1.68% to 5.13%, implying that the method was reliable. A field trial was conducted to verify the application of this method with real samples. Results prove that the validated method was suitable for extracting hexaconazole residues.
基金supported by grants from the Chongqing Municipal Agriculture Committee(2020-7)。
文摘Pu-erh ripen tea becomes popular worldwide owing to its unique taste and aroma.In the present study,volatile compounds from Pu-erh ripen tea were extracted using a solvent assisted flavor evaporation(SAFE)and analyzed with a gas chromatography-mass spectrometry(GC-MS)and a gas chromatography olfactometry(GC-O).Results demonstrated that 58 major volatile compounds and 24 aroma active substances of Pu-erh ripen tea were identified by GC-MS and GC-O analysis.Among volatile compounds identified,methoxyphenyl compounds were considered as the dominate compounds in the aroma of Pu-erh ripen tea.Further investigation showed that 6 methoxybenzenes were responsible for the aging aroma in Pu-erh ripen tea;α-ionone,3,4-dimethoxytoluene,1,3-dimethoxybenzene,etc.were responsible for the wood-like aroma.Linalool,α-terpineol,α-ionone,β-ionone,and benzeneacetaldehyde were responsible for the floral odor.Compared the odor detection threshold(ODT)among the 8 methoxyphenyl compounds in water,1,2,3-trimethoxybenzene showed the highest ODT,followed by 3,4-dimethoxyphenol.1,3-dimethoxybenzene(105μg/L)and 1,2,3-trimethoxy-5-methylbenzene(100μg/L)were present at relatively low odor threshold values.The result indicated that methoxyphenyl compounds play a vital role in the unique flavor of Pu-erh ripen tea.
文摘Reducing oxidative stress and hepatoprotective effect of Pu-erh tea water extracts on rats fed with high-fat diet were researched for explaining health care of Pu-erh tea.Fifty SD rats were divided into five groups.The body weight was measured once a day.The malondialdehyde(MDA)and glucose(Glu)levels and the activities of alanine aminotransferase(ALT),aspartate aminotransferase(AST),nitric oxide synthase(NOS),and pyruvate kinase(PK)in serum were determined.Furthermore,the hepatic glycogen level(HGL)and the activities of hepatic total superoxide dismutase(T-SOD),catalase(CAT),and glutathione peroxidase(GSH-Px)were also measured after continuous administration for 12 weeks.The result demonstrated that Pu-erh extract caused the decreases in body weight,fat index,MDA and NOS levels,and the increases in hepatic T-SOD,CAT and GSH-Px activities,indicating that the extract may be due to inhibiting the increases of body weight and fat index,reducing oxidant stress state and inhibiting lipid peroxidation,thus decreasing the activities of ALT and AST,and protecting the liver in rat.Meanwhile,the extracts could increase the production of hepatic glycogen and the activity of PK,and reduce glucose level,protecting the liver from the diseases associated with type II diabetes.
文摘Pu-erh tea is one of post fermented tea manufactured through oxidative maturing by microorganisms. We investigated the preventive effects of pu-erh tea extract on oxazolone-induced type IV allergy in male (ICR) mice. Oral administration of 50 mg/kg water extract of pu-erh tea leaves resulted in significant preventive effects against mouse type IV allergy. The hydrophilic Theabrownin-like fraction (TBW-ND), with a high molecular weight of approximately 12,000 or higher, was prepared from pu-erh tea leaves by a solvent-extraction method, followed by Diaion HP-20 column chro-matography and dialysis. Oral and percutaneous administrations of TBW-ND at doses of 18.7 mg/kg and 0.037 mg/ear also resulted in significant preventive effects, which included preventing increases in levels of the proinflam-matory cytokine interleukin-12. The anti-allergic ingredients in TBW-ND were predicted to be highly complex compounds containing of polyphenols, polysaccharides and/or proteins. The results suggest pu-erh tea leaves could be a beneficial food for protecting against delayed-type allergy.
基金supported by the National Natural Science Foundation of China(31660099)。
文摘Habitual tea consumption can reduce the risk of ASCVD morbidity and mortality and all-cause mortality in China,and long-term adherence to this habit can provide greater protection.Pu-erh tea is one of the representatives of post-fermented teas,and the polymers in Pu-erh tea have anti-cancer and anti-hyperlipidemic activities,but their chemical composition is still unknown.In this study,the chemical composition of Pu-erh tea was investigated in detail and eight(1–8)known compounds were isolated.The polymers in Pu-erh tea were also degraded by thiol degradation,and the fragments of quercetin and(–)-epicatechin-3-O-gallate were found in the thiol degradation products of Pu-erh tea polymers by UPLC observation and separation and purification.This is the first time that this fragment was obtained in Pu-erh tea polymer.
文摘Pu-erh tea, a traditional Chinese beverage, has been believed to have many benefits to human health and without side effects. In this study, we systematically analyzed the main active components of Pu-erh tea and investigated its anti-obesity, anti-atherosclerotic and anti-oxidant effects using an obese rat model. Obesity was induced by feeding a high-fat diet and subsequently the experimental obese mice were fed with high-fat diet supplemented with low (2.5%), medium (5%) or high (7.5%) doses of Pu-erh tea powder for 6 weeks respectively. As result, the body weight gain of the rats was decreased by medium and high doses of Pu-erh tea treatments. Furthermore, the levels of serum total cholesterol (TC), triglyceride (TG) and atherosclerosis index (AI) were significantly lowered by Pu-erh tea compared to the control group. Conversely, high density lipoproteincholesterol (HDL-C) level of the rats was significantly elevated by Pu-erh tea treatments. In addition, Pu-erh tea treatments increased the activities of anti-oxidative enzymes such as superoxide dismutase (SOD) and glutathione peroxides (GSH-Px), whereas reduced the level of lipid peroxidation product malondialdehyde (MDA) in obese rats. Collectively, our find-ings revealed that Pu-erh tea exerts comprehensive benefits in anti-obesity, anti-atherosclerotic and anti-oxidant effects, therefore can be used as a promising functional food in obesity management.
基金supported by National Natural Science Foundation of China (82122012)
文摘Pu-erh tea has been used for thousands of years to treat metabolic diseases.Recognized in Shen Nong's Herbal Classic,a compendium kept by the first traditional Chinese practitioners,it is still highly valued for its hypocholesterolemic and hypolipidemic effects.This review reports the processing and bioactive components of pu-erh tea.Recent human and animal studies of pu-erh tea and its potential therapeutic mechanisms have also been summarized.The interaction of liver and gut microbiome regulates the puerh tea biotransformation and endogenous metabolism,and thus contributes to the health benefits.
