Novel Electrochemical Sensing of Catechins in Raw Green Tea Extract via a Trimetallic Zeolitic Imidazolate Fibrous Framework
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ABSTRACT:
SUBMITTER: Thenrajan T
PROVIDER: S-EPMC9202283 | biostudies-literature | 2022 Jun
REPOSITORIES: biostudies-literature
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Project description:Green tea (Camellia sinesis) is widely known for its anticancer and anti-inflammatory properties. Among the biologically active compounds contained in Camellia sinesis, the main antioxidant agents are catechins. Recent scientific research indicates that the number of hydroxyl groups and the presence of characteristic structural groups have a major impact on the antioxidant activity of catechins. The best source of these compounds is unfermented green tea. Depending on the type and origin of green tea leaves, their antioxidant properties may be uneven. Catechins exhibit the strong property of neutralizing reactive oxygen and nitrogen species. The group of green tea catechin derivatives includes: epicatechin, epigallocatechin, epicatechin gallate and epigallocatechin gallate. The last of these presents the most potent anti-inflammatory and anticancer potential. Notably, green tea catechins are widely described to be efficient in the prevention of lung cancer, breast cancer, esophageal cancer, stomach cancer, liver cancer and prostate cancer. The current review aims to summarize the potential anticancer effects and molecular signaling pathways of major green tea catechins. It needs to be clearly emphasized that green tea as well as green tea catechols cannot replace the standard chemotherapy. Nonetheless, their beneficial effects may support the standard anticancer approach.
| S-EPMC7084675 | biostudies-literature
Project description:Green tea catechins have various potential health benefits in humans including anti-inflammatory, anti-oxidative and hepato-protective effects. If present in the circulation, they might have similar effects in ruminants, which are exposed to oxidative stress and fatty liver disease such as dairy cows during the periparturient phase. However, the bioavailability of a substance is a prerequisite for any post absorptive effect in vivo. This study aimed to investigate the appearance of catechins from a green tea extract (GTE) in cattle plasma after intraruminal and intraduodenal administration because absorption is of major importance regarding the bioavailability of catechins. The studies were performed in 5 rumen-fistulated non-lactating heifers and 6 duodenally fistulated lactating dairy cows, respectively, equipped with indwelling catheters placed in a jugular vein. The GTE was applied intraruminally (10 and 50 mg/kg BW, heifers) or duodenally (10, 20 and 30 mg/kg BW, dairy cows) in a cross-over design with a 2 d washout period between different dosages. Blood samples were drawn following the GTE administration at various pre-defined time intervals. The concentration of the major GTE catechins (gallocatechin, epigallocatechin, catechin, epicatechin, epigallocatechin-gallate, epicatechin-gallate) in plasma samples were analysed by HPLC with electrochemical detection. Irrespective of the dose, almost none of the catechins originally contained in the GTE were detected in plasma samples after intraruminal application. In contrast, intraduodenal administration of GTE resulted in increased plasma concentrations of epicatechin, epigallocatechin, epigallocatechin gallate in a dose-dependent manner. Thus, we can conclude that intraruminally or orally administered catechins are intensively metabolized by ruminal microorganisms.
| S-EPMC4948893 | biostudies-literature
Project description:Glaucoma is the leading cause of irreversible blindness and visual impairment, affecting more than 80 million individuals worldwide. Oxidative stress and inflammation-induced neurodegenerative insults to retinal ganglion cells are the main pathogenesis of glaucoma. Retinal ganglion cells, the retinal neurons transmitting the visual signals to the visual cortex in the brain, have very limited regeneration or recovery capacity after damages. Apart from intraocular pressure-lowering treatments, there is still no clinically effective treatment to rescue the degeneration of retinal ganglion cells in glaucoma. Dietary antioxidants are easily accessible and can be applied as supplements assisting in the clinical treatments. Catechins, a chemical family of flavonoids, are the phenolic compounds found in many plants, especially in green tea. The anti-oxidative and anti-inflammatory properties of green tea catechins in vitro and in vivo have been well proven. They could be a potential treatment ameliorating retinal ganglion cell degeneration in glaucoma. In this review, the chemistry, pharmacokinetics, and therapeutic properties of green tea catechins were summarized. Research updates on the biological effects of green tea catechins in cellular and animal experimental glaucoma models were reviewed. In addition, clinical potentials of green tea catechins for glaucoma treatment were also highlighted.
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Project description:B-hive? A family of crystalline materials analogous to porous AlPO(4) but based on boron imidazolate frameworks (BIFs) can be formed by the crosslinking of various presynthesized boron imidazolates with monovalent cations (Li(+) and Cu(+), see picture). This synthetic method is capable of generating a large variety of open frameworks, ranging from the four-connected zeolitic sodalite type to the three-connected chiral (10,3)-a type.
| S-EPMC2790048 | biostudies-literature
Project description:Bioaerosols are the biological materials in the air, which may cause a continuous threat to human health. However, there are many challenges in monitoring bioaerosols such as lack of sensitivity and selectivity. Herein, we synthesized a series of nanohybrids containing zeolitic imidazolate frameworks (ZIFs) and covalent organic frameworks (COFs) to construct an electrochemical aptasensor for detecting adenosine triphosphate (ATP), a biomarker for bioaerosols. The synthesized nanohybrids can not only improve the selectivity of aptasensor because of the original crystal and chemical features of ZIF-67, but also boost its sensitivity due to the excellent conductivity of COFs. After optimizing the nanohybrids, the novel developed sensing platform achieved highly selective detection of ATP with an excellent detection limit of 0.11 nM in a wide linear range from 0.1 nM to 100 nM. Furthermore, this assay was applied to detect bioaerosols in real air samples, and the result showed a positive correlation with that of the culturing-based method, suggesting its potential applicability.
| S-EPMC9496278 | biostudies-literature
Project description:Background and purposeCatechins, biologically active polyphenols in green tea, are known to have a protective effect against cardiovascular diseases. In this study, we investigated direct actions of green tea catechins on cardiac muscle function to explore their uses as potential drugs for cardiac muscle disease.Experimental approachThe effects of catechins were systematically investigated on the force-pCa relationship in skinned cardiac muscle fibres to determine their direct effects on cardiac myofilament contractility. The mechanisms of action of effective catechins were investigated using troponin exchange techniques, quartz crystal microbalance, nuclear magnetic resonance and a transgenic mouse model.Key results(-)-Epicatechin-3-gallate (ECg) and (-)-epigallocatechin-3-gallate (EGCg), but not their stereoismers (-)-catechin-3-gallate and (-)-gallocatechin-3-gallate, decreased cardiac myofilament Ca(2+) sensitivity probably through its interaction with cardiac troponin C. EGCg restored cardiac output in isolated working hearts by improving diastolic dysfunction caused by increased myofilament Ca(2+) sensitivity in a mouse model of hypertrophic cardiomyopathy.Conclusions and implicationsThe green tea catechins, ECg and EGCg, are Ca(2+) desensitizers acting through binding to cardiac troponin C. These compounds might be useful compounds for the development of therapeutic agents to treat the hypertrophic cardiomyopathy caused by increased Ca(2+) sensitivity of cardiac myofilaments.
| S-EPMC2998685 | biostudies-literature
Project description:BackgroundPrevious in vitro studies have reported the inhibitory effect of green tea on p-glycoprotein (p-gp) encoded by ABCB1. This study aimed to investigate the effect of green tea on the pharmacokinetics of digoxin, a typical probe drug of p-gp.MethodsSixteen healthy volunteers participated in this study. At Day 1, 0.5 mg of digoxin was administered via oral route. After a 14-day washout period, 630 mg of green tea catechins (GTC) was administered via oral route, followed by 0.5 mg of digoxin 1 hour later. From Day 16 through Day 28, 630 mg of GTC was administered alone. At Day 29, 630 mg of GTC and 0.5 mg of digoxin were administered in the same way as Day 15. Blood samples for the pharmacokinetic assessments of digoxin were collected up to 8 hours after each dose. Pharmacokinetic parameters were estimated by noncompartmental analysis. Area under the curve (AUC) and peak plasma concentration (Cmax) were compared using mixed effect model between digoxin alone and digoxin with GTC. ABCB1 was genotyped to determine whether its polymorphism affects digoxin-GTC interaction.ResultsFifteen subjects completed the study. Compared to digoxin alone, the concomitant administration of digoxin and GTC significantly reduced the systemic exposure of digoxin: geometric mean ratios (GMR) and 90% confidence intervals (CI) of area under the concentration-time curve from time 0 to the last measurable time (AUClast) and Cmax were 0.69 (0.62-0.75) and 0.72 (0.61-0.85), respectively. The concomitant administration of digoxin and GTC following pretreatment of GTC (Day 29) similarly reduced the AUClast (GMR [90% CI]: 0.67 [0.61-0.74]) and Cmax (GMR [90% CI]: 0.74 [0.63-0.87]). In the comparison of the percentage changes from Day 1 (digoxin single administration) of AUClast between genotypes, C1236T variant type showed a significant difference to wild-type on Day 15 (concomitant administration of digoxin and GTC) (P=0.005).ConclusionThis study demonstrates that the coadministration of GTC reduces the systemic exposure of digoxin regardless of pretreatment of GTC.
| S-EPMC6044363 | biostudies-literature
Project description:Influenza is one of the most serious respiratory viral infections worldwide. Although several studies have reported that green tea catechins (GTCs) might prevent influenza virus infection, this remains controversial. We performed a systematic review and meta-analysis of eight studies with 5,048 participants that examined the effect of GTC administration on influenza prevention. In a random-effects meta-analysis of five RCTs, 884 participants treated with GTCs showed statistically significant effects on the prevention of influenza infection compared to the control group (risk ratio (RR) 0.67, 95%CIs 0.51-0.89, P = 0.005) without evidence of heterogeneity (I2= 0%, P = 0.629). Similarly, in three cohort studies with 2,223 participants treated with GTCs, there were also statistically significant effects (RR 0.52, 95%CIs 0.35-0.77, P = 0.001) with very low evidence of heterogeneity (I2 = 3%, P = 0.358). Additionally, the overall effect in the subgroup analysis of gargling and orally ingested items (taking capsules and drinking) showed a pooled RR of 0.62 (95% CIs 0.49-0.77, P = 0.003) without heterogeneity (I2= 0%, P = 0.554). There were no obvious publication biases (Egger's test (P = 0.138) and Begg's test (P = 0.103)). Our analysis suggests that green tea consumption is effective in the prophylaxis of influenza infections. To confirm the findings before implementation, longitudinal clinical trials with specific doses of green tea consumption are warranted.
| S-EPMC8272076 | biostudies-literature
Project description:Preclinical, epidemiologic, and prior clinical trial data suggest that green tea catechins (GTC) may reduce prostate cancer risk. We conducted a placebo-controlled, randomized clinical trial of Polyphenon E (PolyE), a proprietary mixture of GTCs, containing 400 mg (-)-epigallocatechin-3-gallate (EGCG) per day, in 97 men with high-grade prostatic intraepithelial neoplasia (HGPIN) and/or atypical small acinar proliferation (ASAP). The primary study endpoint was a comparison of the cumulative one-year prostate cancer rates on the two study arms. No differences in the number of prostate cancer cases were observed: 5 of 49 (PolyE) versus 9 of 48 (placebo), P = 0.25. A secondary endpoint comparing the cumulative rate of prostate cancer plus ASAP among men with HGPIN without ASAP at baseline, revealed a decrease in this composite endpoint: 3 of 26 (PolyE) versus 10 of 25 (placebo), P < 0.024. This finding was driven by a decrease in ASAP diagnoses on the Poly E (0/26) compared with the placebo arm (5/25). A decrease in serum prostate-specific antigen (PSA) was observed on the PolyE arm [-0.87 ng/mL; 95% confidence intervals (CI), -1.66 to -0.09]. Adverse events related to the study agent did not significantly differ between the two study groups. Daily intake of a standardized, decaffeinated catechin mixture containing 400 mg EGCG per day for 1 year accumulated in plasma and was well tolerated but did not reduce the likelihood of prostate cancer in men with baseline HGPIN or ASAP.
| S-EPMC4596745 | biostudies-literature
Project description:Green tea polyphenols may contribute to the prevention of cancer and other diseases. To learn more about the pharmacokinetics and interindividual variation of green tea polyphenols after oral intake in humans we performed a population nutrikinetic study of standardized green tea extract. 84 healthy participants took green tea extract capsules standardized to 150 mg epigallocatechin-gallate (EGCG) twice a day for 5 days. On day 5 catechin plasma concentrations were analyzed using non-compartmental and population pharmacokinetic methods. A strong between-subject variability in catechin pharmacokinetics was found with maximum plasma concentrations varying more than 6-fold. The AUCs of EGCG, EGC and ECG were 877.9 (360.8-1576.5), 35.1 (8.0-87.4), and 183.6 (55.5-364.6) h*μg/L respectively, and the elimination half lives were 2.6 (1.8-3.8), 3.9 (0.9-10.7) and 1.8 (0.8-2.9) h, respectively. Genetic polymorphisms in genes of the drug transporters MRP2 and OATP1B1 could at least partly explain the high variability in pharmacokinetic parameters. The observed variability in catechin plasma levels might contribute to interindividual variation in benefical and adverse effects of green tea polyphenols. Our data could help to gain a better understanding of the causes of variability of green tea effects and to improve the design of studies on the effects of green tea polyphenols in different health conditions.Trial registrationClinicalTrials.gov: NCT01360320.
| S-EPMC5821365 | biostudies-literature