Catechin Extract Research Articles

Ultrasonic assisted aqueous extraction of catechin and gallic acid from Syzygium cumini seed kernel and evaluation of total phenolic, flavonoid contents and antioxidant activity

Present work reported ultrasonic-assisted aqueous extraction (UAE) of bioactives from Syzygium cumini seed kernels powder (SCSKP) as an alternative to conventional, soxhlet and stirred batch techniques. The yield of catechin, gallic acid, TPC (Total phenolic contents), TFC (Total flavonoid contents) and IC50 value obtained was 2.2, 54.5 mg/g, 100.07 mg of gallic acid equivalent (GAE)/g of SCSKP, 10.11 mg of catechin equivalent (CE)/g of SCSKP and 10.59 μg/mL respectively in 12 min. extraction time when other optimum parameters were used asSCSKP to the water ratio 1:15, temperature 35°C, power 125 W, and duty cycle 60 % (1.2 min. ON and 0.8 min. OFF). TPC, TFC and antioxidant activity of the extract were determined by using Folin Ciocalteu (FC), AlCl3 and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. The optimized stirred batch technique was used for sequential batch extraction till 5 stages giving catechin and gallic acid yield of 1.05 mg/g and 53.3 mg/g, respectively. UAE technique not only enhanced the yield of catechin, gallic acid, TPC, TFC by 3.6, 1.5, 1.3, 1.4 times respectively and antioxidant activity by 1.2 times but also reduced the extraction time, amount of solvent and temperature by 8.8, 1.3 and1.4 times respectively as compared to conventional stirred batch technique.

Solid-Phase Extraction of Catechins from Green Tea with Deep Eutectic Solvent Immobilized Magnetic Molybdenum Disulfide Molecularly Imprinted Polymer.

A type of molecular-imprinted polymer with magnetic molybdenum disulfide as a base and deep eutectic solvent as a functional monomer (Fe3O4@MoS2@DES-MIP) was prepared with surface molecular imprinting method. It was applied as the adsorbent for the selective recognition and separation of (+)-catechin, (−)-epicatechin, (−)-epigallocatechin, (−)-epicatechin gallate, and (−)-epigallocatechin gallate in green tea in the process of magnetic solid-phase extraction (MSPE) combined with high-performance liquid chromatography (HPLC). The structure of Fe3O4@MoS2@DES-MIP was characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The adsorption properties and selective recognition ability on (−)-epigallocatechin gallate and the other four structural analogues were examined and compared. The results show that the polymer has excellent selective recognition ability for (−)-epigallocatechin gallate, and its adsorption capacity was much higher than that of structural analogues. The Fe3O4@MoS2@DES-MIP not only has the special recognition ability to template a molecule, but also can be separated by magnets with high separation efficiency and can be used in MSPE.

Black tea classification based on its electrophoretic profile

The problem of food authenticity control is relevant from both a theoretical and a practical point of view. Various approaches are applied to product identification, for example, the search for marker substances and pattern recognition methods. The latter considers profiles of various nature as a single characteristic feature of the product, which allows one to obtain a classification model of objects. Another way to compare profiles is to build and visually compare the petal diagrams. This paper is aimed at studying the electrophoretic profile of black tea and identifying characteristics which make it possible to classify tea according to the geographical origin, without considering the technology of its manufacture. The methodology for the determination of caffeine, catechin, epigallocatechin gallate, epicatechin and gallic acid in tea extracts was tested by micellar electrokinetic chromatography method. The range of determination linearity was established and amounted to 0.5-200 μg / ml for all the components under study, the error in the analytes determination did not exceed 15%, the standard deviation of the peak area on the electrophoregram was less than 10%. We have examined the electrophoretic profiles of black tea extracts of various origins and observed nine characteristic peaks that were satisfactorily reproduced, were legal, and were present in all the samples. An array of data was generated based on the characteristic peaks areas on the electrophoregrams recorded for extracts of Assamese, Ceylon and “original” Krasnodar tea. To level the influence of values spread of the characteristic peaks areas, they were related to each other. The application to the matrix of data, which included the ratio of the characteristic peak areas, of the variance analysis with subsequent processing of its results using the principal component method, made it possible to establish the ratios most influencing the sample reference to a certain tea group. Based on the selected area ratios, a graphic model for classifying black tea by origin was constructed. It was verified, and satisfactory results were obtained. “Visual images”, built on the medians of the characteristic peaks areas ratio, clearly show the differences in the tea sample groups of Ceylon, Assamese and Krasnodar origin. Key words : polyphenols, black tea, micellar electrokinetic chromatography method, electrophoretic profiles, principal component method DOI: http://dx.doi.org/10.15826/analitika.2020.24.3.001 K.S. Gushchaeva, T.G. Tsiupko, O.B. Voronova Kuban State University, Stavropolskaia ul.,149, Krasnodar, 350040, Russian Federation

Determination of polyphenols in Schinus terebinthifolius Raddi bark extracts and chemometric analysis

This work describes a comparison of HPLC and spectrophotometric methods to determine the variation of the polyphenolics catechin, gallic acid, epicatechin, rutin, quercetin and chlorogenic acid in bark extracts of Schinus terebinthifolius Raddi (Anacardiaceae).

Extraction, Isolation, Characterisation and Antioxidant Activity Assay of Catechin Gambir (Uncaria gambir (Hunter). Roxb

Catechins are one of polyphenol compounds which reported have antioxidant properties. This study aims to extraction, isolation, characterization, and determine the antioxidant activity of catechin compounds from gambier powder(Uncaria gambir (Hunter). The extraction method used was maceration extraction with three types of solvents (70% ethanol, 70% methanol, and ethyl acetate). The process of purifying catechins is carried out with water, ethyl acetat, and n-hexane. Catechins were characterized by FTIR (Fourier Transform Infra Red) and UV-Vis spectrophotometer and tested for antioxidant activity using the DPPH (2.2 Difenyl -1-Pikrilhidrazil) method. The results showed that the extracted gambier using 70% ethanol solvent resulted in more catechins (51.20 g) than the 70% methanol solvent (40.35 g) and ethyl acetate (16.40 g). Characterization of catechin using UV-Vis spectrophotometer showed that purity content of catechins obtained from the extract ethanol 70% had purity 70.76%, methanol 70% 70.86%, and ethyl acetate 70.35%. Analysis using FTIR showed catechin has functional groups such as hydroxy (-OH), vibration C = C alkene, C-H, CH2 and C-O, so that the compound isolated has the basic structure of the catechin. The result of antioxidant activity from showed IC50 value are 2.72 ppm; 3.04 ppm and 3.06 ppm for extract catechin of etanol 70%, methanol 70% and ethyl acetate, so that can be said that catechins have antioxidant activity levels in a very strong category.

Effects of leaf extracts of Protium spruceanum against adult and larval Rhipicephalus microplus.

Rhipicephalus microplus is the ectoparasite responsible for large economic losses in cattle herds. The aim of this study was to investigate the in vitro action of leaf extracts of Protium spruceanum on resistant strains of this tick. Ethanolic extracts (EE) and ethyl acetate extracts (EAE) of P. spruceanum leaves were used against engorged females and larvae by biocarrapaticidogram and larval package (TPL) tests. Chromatographic analyses were performed using a gas chromatograph and showed the presence of the flavonoid catechin in both extracts and the terpenoid β-amirine only in EAE. EE and EAE were not effective in altering the mortality of engorged females; however, 92% of females treated with the extracts reduced the postures and > 90% of larval hatching was inhibited at 100mg/ml of extracts. Acaricidal efficacies were > 80% for 100mg/ml EE and > 90% for EAE at 50mg/ml. In TPL tests, EE and EAE promoted larval mortality > 88% at 100mg/ml. In this study, EAE was more effective against adult females and larvae than EE, representing an alternative agent for the integrated control of R. microplus.

Sequential Green Extraction of Caffeine and Catechins from Green Tea

Separation of caffeine and catechins from tea extracts usually requires conventional liquid-liquid extraction employing chloroform. This work was planned to improve a green extraction technique to distunguish these important chemicals from green tea. Extraction of caffeine and catechins from Turkish green tea firstly employing MAE, and then to separate these compounds from each other using a SFE method were purpose of this study. Microwave assisted extraction was applied to extract tea components from green tea then i) conventional liquid-liquid extraction or ii) supercritical carbon dioxide fluid extraction (SFE) method was charged with the effective separation of caffeine and catechins. Initially, an ethanol: water mixture was used in a close microwave system under the particuler extraction situations of green tea samples (fresh, frozen or dried) picked up in three collection periods (first, second and third collection periods). MAE of tea samples was exerted under a controlled 600 W microwave power for 4 min irradiation time at 80 oC temperature. Then MAE crude aqueous extract was divided in to two portions. The first portion was fractionated first with chloroform to distunguish caffeine then ethyl acetate for catechins. Caffeine and catechins were successfully separated. Second portion was freeze-dried and obtained lyophilized solid was used for SFE. Caffeine (3.68% extract yield) was successfully separated from catechins with SFE at 250 bar and 60°C for 180 min. Constituents of the extracts were determined (caffeine and four catechins namely EGC, EC, C, EGCG) by HPLC to evaluate the effectiveness of the separation.

Application of amino-based chitosan cyclodextrin derivatives for the extraction of catechins in green tea with high-performance liquid chromatography.

Chitosan derivatives have been studied widely, but poor solubility in water restricts their applications. In this study, four types of amine-based chitosan derivatives were prepared and modified further with beta-cyclodextrin. The sequential microextraction of catechins ((+)-catechin and (-)-epigallocatechin gallate) from green tea powder by an optimized solid-phase extraction method using these four derivatives was investigated. The optimal conditions for the extraction of catechins were 60°C for a 40min extraction period. The purity and amount of each catechin were determined by high-performance liquid chromatography. The different amines strengthened the extraction capacity of chitosan. Among the four types of amines, ethylene diamine grafted chitosan beta-cyclodextrin had the highest extraction capacity to catechins. Therefore, this material was used in the extraction assay, and the standard curves of (+)-catechin and (-)-epigallocatechin gallate were linear over the concentration range, 0.25-500µg/mL, after assaying five data points in duplicate. Solid-phase extraction with the amino-based chitosan beta-cyclodextrin system is a new application of chitosan, which has potential applications in the extraction of bioactive compounds from plant materials or the removal of different impurities from specific extracts.

Bioactivities of catechin from gambir (Uncaria gambir Roxb.) against wood-decaying fungi

Gambir is one of the most economically important natural products of Indonesia. Indonesia accounts for 80% of the global exports of this product. The product contains catechin, a phenolic compound of the flavonoid group, which has demonstrated bioactivity against horticulture-destroying fungi. However, its bioactivity in controlling wood-decaying fungi has not yet been reported. A laboratory study was conducted to examine the characteristics of the catechin of gambir and its bioactivity against the wood-decaying fungi Schizophylum commune Fr. Extraction of catechin from gambir was conducted via a gradual maceration process using hot water (70 °C, 3 h) followed by ethyl acetate (1:10 w/v, 4 h). The chemical components of catechin were analyzed by gas chromatography mass spectrometry (GCMS), while its bioactivity against S. commune was examined according to EN 113 (1986). The results showed that there were five chemical components in catechins, i.e., 1,2-benzenediol, catechol, 1,3,5-benzenetriol, dimethyl terephphtalate, and terephthalic acid. These compounds demonstrated the ability to remarkably inhibit the growth of S. commune.

Direct and Fast Electrochemical Determination of Catechin in Tea Extracts using SWCNT‐Subphthalocyanine Hybrid Material

AbstractIn this study, single walled carbon nanotubes (SWCNTs) were covalently functionalized by terminal ethynyl bearing subphthalocyanine (SubPc) to obtain a new hybrid material, viz. SWCNT‐SubPc (CS), via “click” reaction for the first time. The structural characterization and study of the electrochemical sensor properties of the CS hybrid material to catechin were carried out. A convenient and fast analytical method was offered for the determination of catechin. It was shown that the deposition of CS on the surface of a glassy carbon electrode (GCE) led to a 2.2 and 8‐fold increase in the differential pulse voltammetry (DPV) responses to catechin in Britton‐Robinson (BR) buffer solution (a pH of 3) in comparison with SWCNT‐modified and bare GCE, respectively. The dynamic range, detection and quantification limits of catechin were determined to be 0.1–1.5 μM, 13 nM and 43 nM, respectively. Selectivity of the suggested CS/GCE sensor was investigated on addition of a number of interfering metal ions, antioxidants and biomolecules. The applicability of the modified electrode for the detection of catechin in real tea samples such as green, rosehip fruit, Turkish and Indian black tea was demonstrated with the standard addition method. Along with the ease in fabrication and low prices, the proposed CS/GCE sensor was reproducible, selective, stable and sensitive to catechin in major types of tea samples.

Green tea extract catechin improves cardiac function in pediatric cardiomyopathy patients with diastolic dysfunction

BackgroundOur previous studies have demonstrated that Ca2+ desensitizing catechin could correct diastolic dysfunction in experimental animals with restrictive cardiomyopathy. In this study, it is aimed to assess the effects of green tea extract catechin on cardiac function and other clinical features in pediatric patients with cardiomyopathies.MethodsTwelve pediatric cardiomyopathy patients with diastolic dysfunction were enrolled for the study. Echocardiography, ECG, and laboratory tests were performed before and after the catechin administration for 12 months. Comparison has been made in these patients before and after the treatment with catechin. Next Generation Sequencing was conducted to find out the potential causative gene variants in all patients.ResultsA significant decrease of isovolumetric relaxation time (115 ± 46 vs 100 ± 42 ms, P = 0.047 at 6 months; 115 ± 46 vs 94 ± 30 ms, P = 0.033 at 12 months), an increase of left ventricle end diastolic volume (40 ± 28 vs 53 ± 28 ml, P = 0.028 at 6 months; 40 ± 28 vs 48 ± 33 ml, P = 0.011 at 12 months) and stroke volume (25 ± 16 vs 32 ± 17 ml, P = 0.022 at 6 months; 25 ± 16 vs 30 ± 17 ml, P = 0.021 at 12 months) were observed with echocardiography in these patients 6-month after the treatment with catechin. Ejection fraction, left ventricular wall thickness, biatrial dimension remained unchanged. No significant side effects were observed in the patients tested.ConclusionsThis study indicates that Ca2+ desensitizing green tea extract catechin, is helpful in correcting the impaired relaxation in pediatric cardiomyopathy patients with diastolic dysfunction.

Antioxidant Activity, Anti-Inflammatory and Analgesic Effects of Caralluma europaea (Eddaghmouss) in Mice

The aim of the current study is to evaluate the anti-inflammatory, antioxidant and analgesic properties of ethanolic (100 and 200 mg/kg, p.o.) and ethyl acetate extracts (100 and 200 mg/kg, p.o.) of Caralluma europaea. Formalin-induced paw licking test, Acetic Acid induced Writhing Test and Hot-PlateTest were used to assess the analgesic activity. Xylene-induced ear edema test was used to evaluate anti-inflammatory activity of those extracts. In this work, the High-Performance Liquid Chromatography technique (HPLC), allowed us to identify and quantify the main phenolic compounds present in ethanolic and ethyl acetate extracts. In vitro anti-oxidant propriety was evaluated using two methods, the 2,2-Diphenyl-1Picrylhydrazyl (DPPH) radical scavenging method and reducing power methods. The main phenols identified were Catechin (24%) and quercetin (18%) in ethanolic extract, while in the ethyl acetate extract, they were quercetin (36%), P-coumaric (30%) and 2-hydroxycinnamic (25%). Analysis of our results had shown that Caralluma europaea extracts had exhibited a very potent analgesic activity. Percentage of Pain Inhibition (PPI) in the writhing test, 63.60±4.24% for the Ethanolic Extract (EE) (200 mg/kg, p.o.) and 65.39±3.27% for the Ethyl Acetate Extract (EAE). The PPI of early and late phase in the formalin test were respectively, 41% and 73% for EAE (200 mg/kg; p.o), 28% and 75% for EE. In the hotplate test, latency to the thermal stimuli was increased in a dose dependent manner after the administration of EE and EAE. However, the analgesic potential of EAE seems to be higher than EE. Both EE and EAE presented a significant in vitro redox potential and high anti-inflammatory activity. Our results have shown that Caralluma europaea is rich in phenolic compounds and possesses an important antinociceptive, anti-inflammatory and anti-oxidant activity.

Green Tea Catechin Extract Supplementation Does Not Influence Circulating Sex Hormones and Insulin-Like Growth Factor Axis Proteins in a Randomized Controlled Trial of Postmenopausal Women at High Risk of Breast Cancer

Consumption of green tea has been associated with reduced risk of breast cancer. Hormonal modulation has been suggested as one of the potential underlying mechanisms; however, it has yet to be fully elucidated in large, long-term human clinical trials. We investigated the effects of decaffeinated green tea extract (GTE) on circulating sex hormones and insulin-like growth factor (IGF) proteins. We conducted a placebo-controlled double-blind randomized clinical trial recruiting from 8 clinical centers in Minnesota. Participants were 538 healthy postmenopausal women randomly assigned to the GTE group (463 completed the study; mean age=60.0 y) and 537 to the placebo group (474 completed; mean age=59.7 y). Women in the GTE group orally took 4 decaffeinated capsules containing 1315 mg total catechins including 843 mg epigallocatechin-3-gallate daily for 1 y, whereas women in the placebo group took similar capsules containing no tea catechins. Blood sex hormones (estrone, estradiol, androstenedione, testosterone, and sex hormone-binding globulin) and IGF proteins (IGF-1 and IGF binding protein-3) were quantified at baseline and months 6 (for IGF proteins only) and 12, and were assessed as secondary outcomes of the study using a mixed-effect repeated-measures ANOVA model. Women in the GTE group had significantly higher blood total estradiol (16%; P=0.02) and bioavailable estradiol (21%; P=0.03) than in the placebo group at month 12. There was a statistically significant interaction between GTE supplementation and duration of treatment on estradiol and bioavailable estradiol (both Ps for interaction=0.001). The catechol-O-methyltransferase genotype did not influence blood sex hormones before or after GTE supplementation. The circulating concentrations of IGF proteins were comparable between GTE and placebo groups at all 3 time points. These results suggest that a 12-mo GTE supplementation significantly increases circulating estradiol concentrations in healthy postmenopausal women. This trial was registered at clinicaltrials.gov as NCT00917735.

Determination of the catechin contents of bioactive plant extracts using disposable screen-printed carbon electrodes in a batch injection analysis (BIA) system

This work presents an analytical study of the determination of catechin, extracted from the Brazilian plants Rhizophora mangle, Arrabidaea brachypoda, and Lippia origanoides, using disposable screen-printed carbon electrodes (C-SPE) coupled to a batch injection analysis (BIA) system. Preliminary cyclic voltammetry experiments in acetate buffer solution (pH 4.5) containing catechin revealed reversible redox processes, with anodic and cathodic peak potentials located at ~0.16 V and ~0.10 V vs. Ag/AgCl, respectively, and an irreversible peak at ~0.49 V. Under optimized conditions, the repeatability for direct amperometric determination of catechin, performed at +0.3 V with the C-SPE in the BIA system, using successive injections of 50 μmol L−1 of catechin, was RSD = 1.03% (n = 30). The sampling throughput was 120 injections per hour. The amperometric response showed a linear range from 1 to 150 μmol L−1 (R = 0.999), with detection and quantification limits of 0.021 and 0.070 μmol L−1, respectively. Application of the proposed methodology for the determination of catechin in extracts of the medicinal plants provided quantitative results similar to those obtained by high performance liquid chromatography (HPLC), at a confidence level of ~95%.

The Influence of Water Composition on Flavor and Nutrient Extraction in Green and Black Tea.

Tea is made from the processed leaves of the Camellia sinensis plant, which is a tropical and subtropical evergreen plant native to Asia. Behind water, tea is the most consumed beverage in the world. Factors that affect tea brewing include brewing temperature, vessel, and time, water-to-leaf ratio, and, in some reports, the composition of the water used. In this project, we tested if the water used to brew tea was sufficient to influence perceived flavor to the everyday tea drinker. Black and green tea were brewed with bottled, tap, and deionized water, with brewing temperature, vessel, time, and the water-to-leaf ratio matched. The samples were analyzed with a human consumer sensory panel, as well as instrumentally for color, turbidity, and Epigallocatechin Gallate (EGCG) content. Results showed that the type of water used to brew tea drastically affected sensory properties of green tea (and mildly also for black tea), which was likely driven by a much greater degree of extraction of bitter catechins in teas brewed with more purified bottled or deionized water. For the everyday tea drinker who drinks green tea for health, the capability to double the EGCG content in tea by simply brewing with bottled or deionized water represents a clear advantage. Conversely, those drinking tea for flavor may benefit from instead brewing tea with tap water.

Optimization of HIB Value Combination of Tween 60 and Span 80 on Cream Formulation of Ethanol Extract of Green Tea Leaves (Camellia Sinensis L.)

Green tea (Camellia sinensis L.) is known to have ability to protect skin against free radicals. This is supported by polyphenol compound catechin. This research aims to determine the optimum Hydrophilic-Lipophilic Balance (HLB) value of Tween 60 and Span 80 compositions on the optimum cream formula of ethanol extract of green tea leaves. Tea leaves are extracted by macerating using 70% ethanol. Catechin in extract is known from Thin Layer Chromatography (TLC) test with silica gel 60 F254 as stationary phase and ethyl acetate:aquadest:formic acid (18:1:1 v/v) as mobile phase. Antioxidant activity is determined by 2,2-Diphenyl-1-picryhydrazyl (DPPH) method and value of Inhibition Concentration 50% (IC50) is then calculated. Formula optimization using Design Expert® version 7.1.5 (DX 7) software, Simplex Lattice Design (SLD) method with two components Tween 60 and Span 80. Cream is characterized according to physical properties organoleptic, homogeneity, viscosity, pH, spreadability, adhesiveness, and cream type. The optimum formula obtained is then tested for physical stability for 4 weeks at room temperature (28±2°C) and data are statistically analyzed using one-way ANOVA. The extract contains catechin proved with Retention factor (Rf) value 0.8 and has antioxidant activity with IC50 value 56.35 ppm. 6.4% Tween 60 and 3.6% Span 80 result an optimum HLB value 11.1. It has viscosity 2897.50±35.94 mPa.s, spreadability 18.44±0.06 cm2, adhesiveness 0.85±0.05 seconds, and pH 4.530±0.002. Statistical test shows that the cream is significantly altered at pH, but does not significantly change in viscosity, spreadability, and adhesiveness after being stored for 4 weeks.

The in Vivo Antioxidant Effects of (-)-Epigallocatechin-3-Gallate Consumption in Healthy Postmenopausal Women Measured by Urinary Excretion of Secondary Lipid Peroxidation Products.

The present study was carried out to determine whether the consumption of epigallocatechin (EGCG), the major bioactive green tea catechin, exerts a positive effect on lowering in vivo lipid peroxidation, a measure of oxidative stress, in healthy postmenopausal women. Urinary excretion of secondary lipid peroxidation products, a measure of in vivo lipid peroxidation, was determined in 40 participants randomly assigned to consume a green tea catechin extract (843.0 ± 44.0 mg EGCG/d) or placebo capsules for 12 months. Urine samples were analyzed for individual polar and nonpolar lipophilic aldehydes and related carbonyl compounds by high-performance liquid chromatography (HPLC) at the beginning and at the end of the 12-month intervention period. Results show that two nonpolar aldehydes, nonanal and decatrienal, were both 48% lower (p < 0.005) following consumption of EGCG. These results indicate that a modest degree of in vivo antioxidant activity exists with long-term EGCG consumption, which could slightly limit oxidative damage associated with lipid peroxidation and the onset and progression of chronic diseases.

Investigation of (+)‐catechin stability under ultrasonic treatment and its degradation kinetic modeling

Abstract(+)‐Catechin (CA) is extremely difficult to be extracted using ultrasound‐assisted extraction technique as CA is unstable under high temperature and oxidation condition. Thus, the stability of CA under various ultrasonic treatment conditions was properly investigated in the present study. The degradation ratio of CA gradually increased with the increase in either the ultrasonic frequency or the input power when the ultrasonic frequency was below 135 kHz or the ultrasonic power was below 0.45 W/cm2. Additionally, the primary degradation product of CA was identified as epicatechin (EC) that was epimerized by CA. Reaction kinetics analysis confirmed that the degradation of CA under ultrasonic treatment followed first‐order kinetics. In addition, ultrasonic treatment induced the increase in kinetic constant (k) and frequency factor (A), while the apparent activation energies (Ea) of CA degradation only decreased at 135 kHz. A mathematical model was established to accurately predict the degradation level of CA under various ultrasonic conditions. The results are of great significance for the ultrasonic extraction of CA from plants without sacrificing the recovery rate.Practical applications(+)‐Catechin (CA), which is sensitive to many environmental factors, possesses many physicochemical properties and biological activities. However, due to limited investigations about using ultrasound to extract CA, the stability of CA under ultrasonic treatment was not well studied and no appropriate ultrasound‐assisted extraction method for CA has been developed. Hence, it is essential to understand the stability of CA under ultrasonic treatment. In the present work, the stability of CA under various ultrasonic treatment conditions was properly investigated. A mathematical model was established to accurately predict the degradation level of CA under various ultrasonic conditions. The results are of great significance for the ultrasonic extraction of CA from plants without sacrificing the recovery rate.

Adsorption of Catechin in Green-Tea Extracts Using &lt;i&gt;N&lt;/i&gt;-Vinylacetamide-Grafted Fiber

Adsorption of Catechin in Green-Tea Extracts Using &lt;i&gt;N&lt;/i&gt;-Vinylacetamide-Grafted Fiber

Carbon molecular sieve based micro-matrix-solid-phase dispersion for the extraction of polyphenols in pomegranate peel by UHPLC-Q-TOF/MS.

A rapid, simple, and efficient sample extraction method based on micro-matrix-solid-phase dispersion (micro-MSPD) was applied to the extraction of polyphenols from pomegranate peel. Five target analytes were determined by ultra-HPLC coupled with Q-TOF/MS. Carbon molecular sieve (CMS) was firstly used as dispersant to improve extraction efficiency in micro-MSPD. The major micro-MSPD parameters, such as type of dispersant, amount of dispersant, grinding time, and the type and the volume of elution solvents, were studied and optimized. Under optimized conditions, 26 mg of pomegranate peel was dispersed with 32.5 mg of CMS, the grinding time was selected as 90 s, the dispersed sample was eluted with 100μL of methanol. Results showed that the proposed method was of good linearity for concentrations of analytes against their peak areas (coefficient of determination r2 > 0.990), the LOD was as low as 3.2ng/mL, and the spiking recoveries were between 88.1 and 106%. Satisfactory results were obtained for the extraction of gallic acid, punicalagin A, punicalagin B, catechin, and ellagic acid from pomegranate peel sample, which demonstrated nice reliability and high sensitivity of this approach.