Black Tea Extract Research Articles

Does the Type Matter? Verification of Different Tea Types' Potential in the Synthesis of SeNPs.

Selenium nanoparticles (SeNPs) are gaining popularity due to their potential biomedical applications. This work describes their green synthesis using various types of tea. Black, green, red and white tea infusions were tested for the content of polyphenolic compounds and antioxidant properties and then used in the synthesis of SeNPs. In each of the syntheses, nanoparticles with dimensions ranging from 3.9 to 12.5 nm, differing in shape and properties, were obtained. All of them were characterized by a very high ability to neutralize hydroxyl radicals, which was about three-times higher than for the tea infusions from which they were obtained. The main inconvenience in obtaining SeNPs was the difficulties with their purification, which should be a further stage in the described research.

Protective Effects of Black Tea (<i>Camellia sinensis</i>) Extract on Endosulfan Induced Oxidative Stress, Inflammation and Hepatic Damage in Rats

With the agricultural expansion the use of pesticides is increasing rapidly in developing countries. Endosulfan, an organochlorine insecticide, is a broadspectrum effective compound used in wide variety of agricultural crops but known to generate free radicals in the liver and caused hepatotoxicity. Thus, we considered it necessary to explore the protective effect of black tea extract against endusulfan mediated hepatotoxicity. 18 male albino Wistar rats were divided into 3 groups: Control, endosulfan treated (5mg/kg body weight/day) and endosulfan+black tea extract treated (1ml of 2.5gm%/100gm of body weight/day). After 30 days of treatment period, all the animals were sacrificed, and blood and liver tissue were collected. Serum and tissue cholesterol, serum liver function parameters, liver oxidative stress parameters and serum proinflammatory cytokines were measured. Liver sections were stained with haematoxylene and eosine and histological evaluation was done. Results revealed that endusulfan induces oxidative stress in liver by altering oxidant/antioxidant balance, and causes inflammation resulting into hepatic damage. Black tea extract supplementation shows considerable protection against endosulfan mediated changes in liver. Thus, black tea extract exerts ameliorative effect against endosulfan mediated liver toxicity.

Safety and Efficacy of Black Tea Extract in the Treatment of Acute Bacterial Conjunctivitis: A Rabbit Model.

To determine the safety and efficacy of black tea extract in the treatment of bacterial conjunctivitis in a rabbit model and compare it with that of gatifloxacin drops. Black tea extract was tested in vitro on bacterial cultures of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. Forty-two rabbit eyes were cultured with either MRSA (n=21) or P. aeruginosa (n=21) and further divided into a control group (n=5), a tea group (n=8) treated with black tea extract, and a gatifloxacin group (n=8) treated with 0.3% gatifloxacin eye drops. Conjunctival swabs were collected on the third and fifth days. The tea extract successfully inhibited the growth of both organisms at a concentration of 400 mg/mL. Rabbits in the treatment groups showed a reduction in the clinical index on day 2 (P<0.01), unlike the control group (P=0.1), for both organisms. Resolution of conjunctivitis was achieved on days 4 and 5 in the tea and gatifloxacin groups, respectively. On days 3 and 5, while the control group still showed considerable bacterial growth, the tea and gatifloxacin groups showed its inhibition. Tea extract has antimicrobial effects similar to those of gatifloxacin in a rabbit model of conjunctivitis.

Effects of different acetic acid bacteria strains on the bioactive compounds, volatile compounds and antioxidant activity of black tea vinegar

This study intends to produce a black tea vinegar (BTV) from low-quality bulk black tea in order to increase its consumption and added value, and to benefit from its functional characteristics. Three strains (Acetobacter sp. GDMCC1.152, Acetobacter pasteurianus GDMCC1.67, and Acetobacter aceti ATCC15973) of acetic acid bacteria (AAB) were inoculated into black tea infusion (BTI) with ethanol to produce BTV, and their effects on bioactive compounds, antioxidant activity, and volatile compounds in the vinegars were revealed. The results showed that the three strains were suitable for the production of BTV, and the vinegar quality was the best after acetic acid fermentation for 6 days. Compared with BTI, the contents of organic acids and volatile compounds and the antioxidant activity of the vinegars increased significantly. Among them, the vinegar produced by GDMCC1.152 strain had the highest content of organic acids, tea polyphenols (TPs), thearubigins (TRs), theabrownines (TBs), and volatile compounds. It also possessed the strongest antioxidant activity and a rich taste with an apple-like aroma. In summary, AAB fermentation can effectively improve the flavor and quality of BTI and produce a new healthy product with high activity, and Acetobacter sp. GDMCC1.152 is the most suitable strain for the production of BTV.

Impact of Xanthan Gum Incorporated with Black Tea Extract as Edible Coating for Shelf Life Extension and Quality Maintenance of Zander Fish Fillets (Sander lucioperca)

Impact of Xanthan Gum Incorporated with Black Tea Extract as Edible Coating for Shelf Life Extension and Quality Maintenance of Zander Fish Fillets (Sander lucioperca)

Preventive Effects of Different Black and Dark Teas on Obesity and Non-Alcoholic Fatty Liver Disease and Modulate Gut Microbiota in High-Fat Diet Fed Mice.

Non-alcoholic fatty liver disease (NAFLD) has emerged as a leading public health challenge and is closely associated with metabolic syndromes, such as obesity. Intestinal microbiota dysbiosis could play a vital role in the pathogenesis and progression of NAFLD. Tea is the second most popular health drink in the world behind water, and exhibits many health-promoting effects. In this study, the protective effects of different black and dark teas on NAFLD induced by long-term high-fat diet (HFD) exposure and their regulation of gut microbiota were evaluated and explored. The results indicated that supplementation with different black and dark tea extracts could significantly suppress the energy intake, alleviate abnormal accumulation of visceral fat, and prevent obesity, hepatic abnormal lipid deposition and liver steatosis in HFD-fed mice at varying degrees. In addition, Dianhong tea and Liupao tea interventions could significantly decrease the ratio of Firmicutes to Bacteroidetes, and selenium-enriched black tea and selenium-enriched dark rea supplementation could remarkably reduce the relative abundance of Actinobacteria compared to the model group. Moreover, these teas could partly shift the relative abundances of Allobaculum, Roseburia and Dubosiella. Taken together, black teas and dark teas could prevent HFD-induced features of obesity and NAFLD, which might partly be due to the modulation of gut microbiota.

Selenium-Enriched and Ordinary Black Teas Regulate the Metabolism of Glucose and Lipid and Intestinal Flora of Hyperglycemic Mice.

Black tea is one of the six major tea categories and has a variety of bioactivities. However, little is known about its comprehensive evaluation of hypoglycemic effects and potential mechanisms. In this study, we investigated the in vivo hypoglycemic activity and potential mechanism for aqueous extracts of ordinary black tea (BT) and selenium-enriched black tea (Se-BT) by using an established high-fat diet together with streptozotocin (STZ)-induced hyperglycemic mouse model. Additionally, we also explored their α-glucosidase inhibition activity. The results show that both BT and Se-BT had a favorable glycosidase inhibitory activity. Moreover, the intervention of BT and Se-BT could regulate the mRNA expression and the level of serum parameters related to glucose and lipid metabolisms. Accordingly, they could activate the phosphoinositide-3-kinase/protein kinase B (PI3K/Akt) signaling pathway and alleviate insulin resistance (IR) and hyperglycemia. Moreover, supplementation of BT and Se-BT increased the richness and diversity of intestinal flora and altered the abundance of beneficial and harmful bacteria. Both BT and Se-BT could regulate glucose metabolism, alleviate tissue damage, and restore intestinal flora dysbiosis, suggesting that they could be used as a natural functional food for preventing hyperglycemia.

Green synthesized Al-metal complex to reduce the crystalline phase and improve the optical properties of CS based polymer blends

In the present study, a green coordination chemistry technique is used for the preparation of Aluminum complexes (Al3+-polyphenol complex) by using black tea extract solution. Chitosan: Poly(2-ethyl-2-oxazoline) (CS: POZ) composite samples loaded with Al3+-complex was arranged by solution casting technique. Various techniques were used to characterize the films, such as UV–Visible spectroscopy, fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). The shifting of the peaks and their reduction in intensity in both XRD and FTIR confirmed the amorphous development with the loading of the Al3+-complex and the production of strong interaction between functional groups of the CS: POZ with the Al3+-complex, respectively. The insertion of the Al3+-complex into the host polymer matrix resulted in the creation of a polymer composite with controlled optical properties and improved optical parameters, including dielectric constant (εr), dielectric loss (εi) and refractive index (n). The complex dielectric constant's real and imaginary components as a function of photon wavelength were explored to derive various high-frequency characteristics. This includes extracting dielectric constant at short wavelength (ε∞), optical resistivity (ρopt), localized charge density values (N/m*), plasma angular frequency (ωp), optical mobility (μopt), and relaxation time (τ) of electrons, in which all these optical parameters are important for choosing suitable materials for optoelectronic applications. In accordance with (45 ml of Al3+-complex insertion), both ωpandN/m* magnitudes are enlarged up to 10-times, while the optical band gap is remarkably dropped (4.8–1.65 eV), which is calculated using Tauc's relation, and the electronic transition mode was identified by using optical dielectric loss (εi). Moreover, the Wemple–DiDomenico single oscillator model was applied to study the dispersion behavior of their refractive index and estimate the oscillator dispersion energy (Ed) and average oscillator energy (Eo) and parameters. The polymer composite with absorption performance in the visible region and other superior optical properties is fundamental for photo cells and commercialization in optoelectronic devices.

THE CHANGES IN SALIVARY PH BY CHEWING BLACK TEA (Camellia sinensis) CANDY CONTAINING THE SORBITOL

Background: Tea contains beneficial chemical compounds, one of which is polyphenols. The polyphenols in black tea can inhibit the growth of bacteria and prevent oral infections. Black tea extract has been proven to increase salivary pH, but children do not like it because of its bitter taste. Therefore, innovation is needed by incorporating black tea extract into candy containing sorbitol. Objective: To determine the effectiveness of chewing black tea candy containing sorbitol on salivary pH compared to non-black tea candy in children aged 7-8. Methods: This research is an experimental field study using a single-blind randomized controlled trial with a pretest-posttest control group design. The research subjects were of 42 children aged 7-8 years divided into two groups, the treatment group, and the placebo group, using a simple random sampling technique. A sampling of saliva was carried out before and after chewing hard candy. Monitoring was carried out for approximately 23 days, and pH was measured three times. Measurement of pH using a digital pH meter®. Results: After conducting the research, it can be seen that there is a significant difference between chewing hard candy made from black tea and sorbitol on the changes in salivary pH (p-value = 0.0001). Conclusion: Chewing hard candy made from black tea and sorbitol is likely to help increase salivary pH, and it could be a solution to prevent dental caries in the future. Keywords : Black tea; Dental caries; Hard candy; Salivary pH ; Sorbitol.

Tailoring the Optimized Fermentation Conditions of SCOBY-Based Membranes and Milk Kefir Grains to Promote Various Functional Properties.

Kombucha culture (named SCOBY-Symbiotic Culture of Bacteria and Yeasts) and milk kefir grains represent multiple consortia of wild microorganisms that include lactic acid bacteria, acetic acid bacteria and yeasts with valuable functional properties. Their fermentative potential provides a wide range of derivate metabiotics (prebiotics, probiotics, postbiotics and paraprobiotics) with valuable in vitro and in vivo benefits. This study targeted the evaluation of the functionality of a co-culture of SCOBY-based membranes and milk kefir grains, used as freeze-dried starter cultures, for the fermentation of a newly formulated medium based on black tea infusion, supplemented with bovine colostrum and sugar, in order to produce bioactive compounds with functional properties. The design and optimization of the biotechnological process were achieved by using the Plackett–Burman experimental design (six factorial points, three center points) and the response surface methodology and central composite design (three factorial points, six axial points and two center points in axial) tools. The statistical analysis and the mathematical modelling of the responses such as the pH, titratable acidity, antioxidant activity and antimicrobial activity (against Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Aspergillus niger) were investigated. Further, the composition of organic acids, polyphenols and flavonoids of the fermented product obtained under the optimized fermentation conditions was also analyzed. The fermentation of the medium containing 6.27% (w/v) bovine colostrum powder, 1.64% (w/v) black tea, 7.5% (w/w) sugar, pH 6.7, with an inoculum based of 0.36% (w/v) milk kefir grains powder and 0.5% (w/v) SCOBY-based membrane (both as freeze-dried culture), at 30 °C, for 5 days, in an aerobic stationary system, revealed an antifungal activity between 80 and 100% against Aspergillus niger, an antibacterial activity of 8–22 mm against Escherichia coli and Bacillus spp. And a titratable acidity of 445 °Th. The chemical composition of the obtained product had a positive impact on the functional properties of the fermented products in terms of the antimicrobial and antioxidant properties.

Establishment of a QuEChERS-UPLC-MS/MS Method for Simultaneously Detecting Tolfenpyrad and Its Metabolites in Tea

An analytical method simultaneously detecting pesticide and its metabolites, especially with higher toxicity, was urgently needed for supervision and safety evaluation of agricultural products. In the present study, a modified QuEChERS method coupled with a ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for simultaneous determination of tolfenpyrad (TFP) and its metabolites in tea matrices (fresh tea shoots, green tea, black tea, green tea infusion and black tea infusion) was established. The method validation showed good linearity (correlation coefficients ≥ 0.9945), accuracy (recoveries in 75.38–109.90%), sensitivity (limits of quantification ≤ 0.05 mg kg−1), and precision (relative standard deviations ≤ 19.09%). The established method was then applied to detect 40 market samples, resulting in 60.0% positive rate of TFP, besides, two metabolites including PT-CA, which is more toxic than the parent TFP, and PT-OH were also detected in the samples with high TFP residue (≥0.048 mg kg−1). The method established in the present work was thus of significant importance in comprehensive monitoring and of TFP in tea products.

Black tea extract prevents inorganic arsenic induced uncontrolled proliferation, epithelial to mesenchymal transition and induction of metastatic properties in HaCaT keratinocytes - an in vitro study

A major global problem is chronic exposure to inorganic arsenic (iAs) which causes various health hazards including cancer. Escalation of reactive oxygen species (ROS) generation by chronic iAs exposure promotes Epithelial to Mesenchymal transition (EMT) which is followed by metastatic progression. In the present study, skin keratinocyte cells (HaCaT) were divided into three groups: (i) untreated, (ii) chronically iAs exposed, (iii) black tea extract (BTE) along with iAs treated. ROS was estimated by flowcytometry, expression of EMT markers were assessed by flowcytometry, western-blotting and Immunofluorescence. For metastatic studies, wound-healing assay, gelatin zymography, western-blot, transwell migration/invasion assay had been performed. Long term exposure of HaCaT cells to iAs causes excess generation of ROS. Morphological transformation and EMT were apparent at 210 days of exposure. Development of metastatic characteristics were observed at 240 days. Alterations in the parameters induced by iAs were found to be ameliorated by BTE. BTE was found to quench excess generation of ROS by iAs, subsequently inhibiting the chain of events like EMT and metastasis. Therefore, BTE may be considered as a potential phytochemical to prevent the deleterious effect of iAs. Skin carcinogenesis induced by iAs may thus be prevented by BTE via inhibition of EMT.

Improvement of Antioxidant Activity and Sensory Quality of Pagilaran’s Tea Clones Treated by Tannase

PT. Pagilaran developed five new clones named PGL 9, PGL 10, PGL 11, PGL 12, and PGL 15 for black tea. These clones can be potentially made into ready-to-drink (RTD) instant tea beverages with low antioxidant activity. Tannase is an industrial enzyme with great potential for application in the food industry used to hydrolyze gallated ester catechin in green tea. There were no findings on the effects of this enzyme treatment on the chemical composition of PT Pagilaran’s tea clones. Therefore, this study is aimed to observe the effects of tannase treatment on five clones of black tea extracts to the antioxidant activity, profile of phenolic compounds, the tea brew color, consumer acceptance, and volatile compounds. The leaves of the plucking medium were traditionally processed into black tea. Furthermore, the tea brew was added at a 100 mg/100 mL concentration and then incubated for 1 hour at 37 °C. Additional tannase increased their antioxidant activities, the gallic acid, EC, and EGC concentrations due to hydrolysis of ECG, EGCG, or their derivatives. The color of the tea brew was brighter and yellower than the untreated, but the level of consumer acceptance was still good. The profile aroma and volatile compounds showed no significant changes after enzymatic treatment.

Assessment of Proximate Composition and Antioxidant Potential of Different Commercially Packaged Tea Samples in West Bengal

Background: Worldwide tea consumption as beverage ranks next to water. The high consumption of tea is attributed to richness in flavor, aroma, antioxidant properties and health benefits. Tea has complex chemical composition having catechins, flavonoids, alkaloids, carotenoids, chlorophyll, amino acids, polysaccharides, lipids, vitamins, minerals and more than 600 different volatile compounds. Methods: The present study focuses on determining the physicochemical parameters, phyto-chemical assay and microbiological qualities of commercially packaged green and black tea samples within West Bengal following standard methods. Result: The values of proximate parameters like moisture, ash, acid insoluble ash and water extractive have complied with standard specifications. High pressure liquid chromatography (HPLC) analysis quantified significantly higher polyphenol content of green tea in compare to black tea samples respectively with 65.12 ppm and 18.58 ppm with gallic acid equivalence and green tea epigallocatechin gallate (EGCG) content was found 449.28 ppm with respect to pure EGCG standard. In vitro antioxidant activity of green tea and black tea extracts as reported by IC50 value were found to be 192.97-301.08 μg/ ml and 342.54-481.91μg/ ml respectively.

Antioxidant Capacities and Polyphenol Contents of Kombucha Beverages Based on Vine Tea and Sweet Tea.

Kombucha beverage is commonly prepared by black tea infusion fermentation without tea residues, and possesses various health benefits. In this paper, kombucha beverages of two non-Camellia sinensis teas, including vine tea (Ampelopsis grossedentata) and sweet tea (Rubus suavissimus), were studied for the first time. The antioxidant activities and polyphenol contents of kombucha beverages were evaluated by ferric-reducing antioxidant power assay, Trolox equivalent antioxidant capacity assay, and Folin-Ciocalteu method, respectively. In addition, effects of tea residues on antioxidant capacities of kombucha beverages were evaluated. The results showed that kombucha beverages from vine tea and sweet tea possessed strong antioxidant activities (especially vine tea kombucha), and fermentation with tea residues could significantly increase antioxidant capacities (maximum increase of 38%) and total phenolic content (maximum increase of 55%) of two kombucha beverages compared with those without tea residues. Moreover, the sensory evaluations showed that the sensory evaluation scores of kombucha with tea residues could be improved compared with those without tea residues. Furthermore, the concentrations of several bioactive components in the kombucha beverages were detected by high-performance liquid chromatography. These kombucha beverages could be used for prevention of several diseases with related of oxidative stress.

Research of the technology of production of black and green tea extracts with antioxidant activity: determination of the effect of the extraction temperature

Many factors can influence the efficiency of the extraction of antioxidants from plants. The most important parameters that affect extraction efficiency in terms of yield and quality include temperature, extraction time, and particle size. The aim of our study was to select the optimal extraction temperature for two types of tea, to obtain extracts with high values of total phenols, flavonoids, antiradical activity according to the DPPH method, restoring strength according to the FRAP method and tannins. The objects of the study were extracts of two types of tea, obtained using one type of solvent - water, a grinding degree of 0.5 mm and three extraction temperatures of 20-25 °C, 40-50 °C and the boiling point of the solvent. A large amount of phenols is extracted from black tea extracts (493 mg (HA) / 100 g) with a temperature equal to the boiling point of the solvent, green tea (936 mg (HA) / 100 g) shows high values of phenol content at an extraction temperature of 40-50 (С. High values of the total content of flavonoids were observed at a temperature equal to the boiling point of the solvent in both black (456 mg (K) / 100 g) and green (502 mg (K) / 100 g) tea. The most tannins were found in extracts of black (98.3 mg catechin / 100 g) and green (224.9 mg catechin / 100 g) tea at a temperature of 40-50 °C. The lowest antiradical activity was found in extracts of black (Ec50 = 1.6 mg / cm3) and green (Ec50 = 4.0 mg / cm3) tea with an extraction temperature of 40-50 °C. The highest index of restorative power was in extracts of black (14.04 mmol Fe2+ / kg) tea with an extraction temperature equal to the boiling point of the solvent, and in green (12.15 mmol Fe2+ / kg) tea at a temperature of 40-50 (С.

Total phenolic content, total flavonoid content and in vitro antioxidant activities measured by the FRAP, ABTS, DPPH and ORAC assays of Sri Lankan black and green tea (Camellia sinensis) infusions

Tea is one of the most ancient and popular therapeutic beverages consumed by people all over the world. It is made from the leaves and buds of the plant “C. sinensis”. Tea is cultivated in more than thirty countries around the world as a plantation crop. In the present study, thirty tea samples of 20 black and 10 green tea manufactured in Sri Lanka were screened for antioxidant activities. Black tea samples were obtained from the three main geographical regions low (Dust (I), BOPF, BOPI, OPI, Pekoe), mid (Dust (I), Dust, BOPF Local, BOPI, BOP, OPI, Pekoe) and up (Dust, BOPF, BOP, FBOP, FBOPI, OPA, OPI, Pekoe) country of Sri Lanka. Green tea samples are manufactured by two different processing methods; panning (Ceylon GT Chunmee (I), Ceylon GT Chunmee (II), Ceylon GT Fanning’s, Ceylon GT Gun Powder (GP) (Extra Spl), Hyson, OPA green tea Ceylon GT Special Hyson) and steaming (Ceylon Sencha OPA, Ceylon Tencha, Cut Twist Curl (CTC) green tea) were used in the investigation. Total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities using ABTS, FRAP, DPPH and, ORAC assays were determined for each tea infusion. According to the results, phenolic content was higher in green tea than that of black tea and flavonoid content was lower in green tea than in black tea. Results of all antioxidants assays showed higher values for green tea than black tea. Neither the geographic area from which the samples of black tea came nor the method of preparation of green tea showed any significant differences in the activities. The results of the study have shown that Sri Lankan tea has compounds with antioxidant activities. Therefore, Sri Lankan tea can be used as a therapeutic beverage and a possibility to use the tea for producing antioxidant drugs through extraction and isolation processes.

Impact of Tea Processing on Tryptophan, Melatonin, Phenolic and Flavonoid Contents in Mulberry (Morus alba L.) Leaves: Quantitative Analysis by LC-MS/MS.

Mulberry (Morus alba L.) leaves from two cultivars, Yai-Burirum (YB) and Khunphai (KP), were prepared into green tea (GT) and black tea (BT). Compared to fresh leaf (FL) extract, GT and BT extracts were evaluated for their total phenolic and total flavonoid contents. Total phenolic content (TPCs) in all samples ranged between 129.93 and 390.89 mg GAE/g extract. The processing of tea decreased the levels of TPC when compared to FL extracts in both cultivars. The total flavonoid content (TFCs) in all samples was found in the range of 10.15–39.09 mg QE/g extract and TFCs in GT and BT extracts were higher than FL extracts. The change in tryptophan, melatonin, phenolic and flavonoid contents was investigated by liquid chromatography–mass spectroscopy (LC-MS). The results exhibited that tryptophan contents in all samples were detected in the range 29.54–673.72 µg/g extract. Both GT and BT extracts increased tryptophan content compared to FL extracts. BT extracts presented the highest amounts of tryptophan among others in both cultivars. Phenolic compounds were found in mulberry leaf extracts, including gallic acid, caffeic acid, gentisic acid, protocatechuic acid and chlorogenic acid. Chlorogenic acid presented the highest amount in all samples. Almost all phenolic acids were increased in the processed tea extracts except chlorogenic acid. Rutin was the only flavonoid that was detected in all extracts in the range 109.48–1009.75 mg/g extract. The change in phenolic and flavonoid compounds during tea processing resulted in the change in antioxidant capacities of the GT and BT extracts. All extracts presented acetylcholinesterase enzyme (AChE) inhibitory activity with IC50 in the range 146.53–165.24 µg/mL. The processing of tea slightly increased the AChE inhibitory effect of GT and BT extracts. In conclusion, processed tea from mulberry leaves could serve as a new alternative functional food for health-concerned consumers because it could be a promising source of tryptophan, phenolics and flavonoids. Moreover, the tea extracts also had antioxidative and anti-AChE activities.

Prevention of inorganic arsenic induced squamous cell carcinoma of the skin in Swiss albino mice by black tea through epigenetic modulation

Consumption of inorganic Arsenic (iAs) above the safe level may lead to many diseases including cancers of skin. It is known that carcinogenicity of iAs is mediated through generation of excessive reactive oxygen species and polyphenols present in black tea extract (BTE) ameliorate the deleterious effect. Epigenetics also plays vital roles in carcinogenesis. The aim of this paper is to study the influence of iAs on epigenetics and the modulatory effect of BTE.Male Swiss albino mice were divided into three groups, (i) control, (ii) iAs-administered and (iii) iAs + BTE administered. Group (ii) developed invasive squamous cell carcinoma (SCC) of the skin after 330 days, while only hyperplasic and dysplastic changes were observed in group (iii). Expression levels of histone methylation, acetylation marks and several histone methylases, demethylases and acetylases due to iAs were studied; most aberrant expression levels due to iAs were modulated by BTE. JARID1B, a histone demethylase implicated as one of the markers in SCC and a therapeutic target gets upregulated by iAs, but is not influenced by BTE. However, SCC is prevented by BTE. Upregulation of JARID1B by iAs represses H3K4me3; BTE upregulates H3K4me3 without influencing JARID1B expression level. It is known that theaflavin compounds in BTE are transported to the nucleus and interact with histone proteins. in-silico findings in this paper hint that theaflavin compounds present in BTE are very good inhibitors of JARID1B and BTE inhibits its demethylating activity. BTE reverses the epigenetic alterations caused by iAs, thus aids in prevention of SCC.

Simultaneous Quantitative Determination of Residues of Pyriproxyfen and Its Metabolites in Tea and Tea Infusion Using Ultra-Performance Liquid Chromatography–Tandem Mass Spectrometry

A reliable, simultaneous residue-analysis method for pyriproxyfen and its five metabolites in fresh tea leaves, green tea, black tea, green-tea infusion and black-tea infusion was developed and validated. The samples were extracted with acetonitrile, purified using a modified QuEChERs (quick, easy, cheap, effective, rugged and safe) method and determined using ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS). The method was successfully calibrated in the range of 0.005–2.50 mg/L with correlation coefficients (r) equal to or above 0.9957. The limits of detection (LODs) were less than 0.002 mg/L. The average spiked recoveries of pyriproxyfen and its metabolites at four levels were 71.2~102.9% with relative standard deviations (RSDs) of 0.3~14.4%. The limits of quantification (LOQs) in fresh tea leaves, tea and tea infusion were 0.002 mg/kg, 0.005 mg/kg and 0.0002 mg/L, respectively. This proposed method was feasible and was applied to analyze the residues of pyriproxyfen and its five metabolites on real fresh tea leaf samples. The results indicated that the half-life (t1/2) of pyriproxyfen on fresh tea leaves was 2.48 d, and the five metabolites were detected on fresh tea leaves during field growth after application.