Total Catechin Content Research Articles

Isolation and Functional Characterization of Multiple NADPH-Cytochrome P450 Reductase Genes from Camellia sinensis in View of Catechin Biosynthesis.

Catechins are critical constituents for the sensory quality and health-promoting benefits of tea. Cytochrome P450 monooxygenases are required for catechin biosynthesis and are dependent on NADPH-cytochrome P450 reductases (CPRs) to provide reducing equivalents for their activities. However, CPRs have not been identified in tea, and their relationship to catechin accumulation also remains unknown. Thus, three CsCPR genes were identified in this study, all of which had five CPR-related conserved domains and were targeted to the endoplasmic reticulum. These three recombinant CsCPR proteins could reduce cytochrome c using NADPH as an electron donor. Heterologous co-expression in yeast demonstrated that all the three CsCPRs could support the enzyme activities of CsC4H and CsF3'H. Correlation analysis indicated that the expression level of CsCPR1 (or CsCPR2 or CsCPR3) was positively correlated with 3',4',5'-catechin (or total catechins) content. Our results indicate that the CsCPRs are involved in the biosynthesis of catechins in tea leaves.

UHPLC analysis and in vitro biological activities of Areca triandra Roxb. ex Buch.-Ham.: a substitute of areca nut

Areca triandra Roxb. ex Buch.-Ham. (Arecaceae) distributed in Assam, North Bengal plains, Meghalaya andaman and Nicobar Islands is used as a substitute for A. catechu L. (Areca Nut). A. catechu is widely used as masticator in South Asia. The present study was conducted to find out the phenolic acids present in A. triandra and potential of it in inhibiting the reactive oxygen species (ROS). Plant extracts obtained from leaf and nut were analyzed qualitatively, quantitatively and phenolic acids were identified and quantified using reverse phase chromatography method developed on through Hypersil Gold aQ C18 column in Thermo Scientific Dionex Ultimate 3000 UHPLC. Three antioxidant assays viz. DPPH, ABTS and reducing power assay were performed to assess the potential of A. triandra as an antioxidant. Antifungal susceptibility test was performed by Clinical Laboratory Standard Institute (CLSI) recommended broth microdilution assay and disk diffusion susceptibility assay using Tinidazole as standard. Total catechin content was 19.51% of total phenolic content in NME. The antioxidant property was observed in NME only for DPPH, ABTS and RPA assays. In antifungal activity, minimum effective concentration (MEC) was observed in NME at the concentration of 1.0mg/ml and above whereas in LME, no MEC was observed up to tested concentrations. A. triandra possesses high catechin content and has promising potential as an antioxidant agent.

Light control of catechin accumulation is mediated by photosynthetic capacity in tea plant (Camellia sinensis)

BackgroundCatechins are crucial in determining the flavour and health benefits of tea, but it remains unclear that how the light intensity regulates catechins biosynthesis. Therefore, we cultivated tea plants in a phytotron to elucidate the response mechanism of catechins biosynthesis to light intensity changes.ResultsIn the 250 μmol·m− 2·s− 1 treatment, the contents of epigallocatechin, epigallocatechin gallate and total catechins were increased by 98.94, 14.5 and 13.0% respectively, compared with those in the 550 μmol·m− 2·s− 1 treatment. Meanwhile, the photosynthetic capacity was enhanced in the 250 μmol·m− 2·s− 1 treatment, including the electron transport rate, net photosynthetic rate, transpiration rate and expression of related genes (such as CspsbA, CspsbB, CspsbC, CspsbD, CsPsbR and CsGLK1). In contrast, the extremely low or high light intensity decreased the catechins accumulation and photosynthetic capacity of the tea plants.The comprehensive analysis revealed that the response of catechins biosynthesis to the light intensity was mediated by the photosynthetic capacity of the tea plants. Appropriately high light upregulated the expression of genes related to photosynthetic capacity to improve the net photosynthetic rate (Pn), transpiration rate (Tr), and electron transfer rate (ETR), which enhanced the contents of substrates for non-esterified catechins biosynthesis (such as EGC). Meanwhile, these photosynthetic capacity-related genes and gallic acid (GA) biosynthesis-related genes (CsaroB, CsaroDE1, CsaroDE2 and CsaroDE3) co-regulated the response of GA accumulation to light intensity. Eventually, the epigallocatechin gallate content was enhanced by the increased contents of its precursors (EGC and GA) and the upregulation of the CsSCPL gene.ConclusionsIn this study, the catechin content and photosynthetic capacity of tea plants increased under appropriately high light intensities (250 μmol·m− 2·s− 1 and 350 μmol·m− 2·s− 1) but decreased under extremely low or high light intensities (150 μmol·m− 2·s− 1 or 550 μmol·m− 2·s− 1). We found that the control of catechin accumulation by light intensity in tea plants is mediated by the plant photosynthetic capacity. The research provided useful information for improving catechins content and its light-intensity regulation mechanism in tea plant.

Determination of catechins in green tea leaves by HPLC compared to spectrophotometry

Aim. To study the qualitative composition, the quantitative content of catechins in green tea leaves and compare the data obtained with those evaluated by spectrophotometry.Materials and methods. Green tea leaves used for the analysis were collected in Anhui Province, China. The extract for the HPLC analysis was obtained by the maceration method with 60 % ethanol twice in the raw material/extractant ratio of 1 : 20. In the case of the spectrophotometric analysis, green tea leaves were extracted with 70 % ethanol twice by the maceration method in the raw material/extractant ratio of 1 : 20. The analysis of the extract from green tea leaves was performed by high performance liquid chromatography using a Prominence LC-20 Shimadzu chromatographic system (Japan) with a SPD-20AV spectrophotometric detector, an Agilent Technologies Microsorb-MV-150 column (reversed phase, C18 modified silica gel, length – 150 mm, diameter – 4.6 mm, particles size – 5 μm). Substances in the extract were identified by comparing the retention time and the spectral characteristics of the test substances with the same characteristics of the reference standards. Spectrophotometric measurements were carried out using a UV-1000 single beam spectrophotometer (China) with the pair of S90-309Q quartz square cells.Results and discussion. Using high performance liquid chromatography 5 catechins were identified. Among them epigallocatechin-3-O-gallate (10.85 %) predominated, while catechin (0.61 %) had the lowest concentration. The total amount of catechins in green tea leaves was 30.56 and 24.79 % by HPLC and spectrophotometry, respectively. The F- and t-tests showed that there was no significant difference between the results of HPLC and spectrophotometry.Conclusions. The qualitative composition and the quantitative content of catechins have been determined in the extract from green tea leaves by high performance liquid chromatography and spectrophotometry. Both HPLC and spectrophotometric methods can be used to determine the total catechin content in green tea leaves. The high content of catechins makes the extract promising for further study and creation of new herbal medicinal products and dietary supplements. The results obtained will be used for standardization of green tea leaves and for future pharmacological research of its extract.

Increasing of Phenolic Compounds by Brassinosteroid Applications in Immobilized Cell Suspension Cultures of Vitis vinifera L. cv. Cinsault

In this paper, the effects on secondary metabolite accumulation of brassinosteroid (BR) (24-epibrassinolide (24-eBL) on immobilized cells that were obtained from Vitis vinifera cv. Cinsault was investigated. 24-eBL was treated to immobilized cells covered calcium alginate beads at concentrations of 0, 0.25, 0.50, 0.75 and 1.0 mg L-1 for one month. As a result of this study, it was found that 24-eBL applications modified secondary metabolite accumulation and had positive effects on secondary metabolite production when the suitable concentration was used. While the highest total phenolic, catechin, p-coumaric acid and chlorogenic acid contents were found in immobilized cells treated 0.75 mg L-1 24-eBL, the highest epicatechin, quercetin, trans-resveratrol contents were obtained in immobilized cells treated 0.50 mg L-1 24-eBL and the highest gallic acid content was determined in immobilized cells treated 0.25 mg L-1 24-eBL. Moreover, the highest 24-eBL concentration (1 mg L-1) decreased the content of secondary metabolite compared to the control (0 mg L-1 24-eBL) except total phenolic and catechin content. To conclude, 0.50 and 0.75 mg L-1 24-eBL concentrations were the most suitable concentrations for immobilized cell culture to provide the highest secondary metabolite accumulation.

Effect of fermentation time and temperature on the of polyphenol compounds change of different Congou black tea

This study evaluated the effects of fermentation time and temperature on the content of high molecular weight polyphenol mitochondrial activation factors (MAFs) and other polyphenols in Congou black tea using high-performance liquid chromatography (HPLC). There were two broad chromatographic peaks in the HPLC spectra of MAFs: MAFs-1 (16.163 min) and MAFs-2 (34.31 min); MAFs-2 was satisfactorily analyzed by HPLC, with separation by paper chromatography. The MAFs-2 contents increased gradually in different varieties of Congou black tea as the fermentation time and temperature increased; the maximum MAFs-2 content was 5.11% in Xiaoxianghong 21-3 after 8 hr of fermentation. The total polyphenols and catechins contents decreased, whereas the theabrownins contents increased as the fermentation time and temperature increased; the theaflavins and thearubigins contents in different Congou black teas showed different variation tendencies. Therefore, studies regarding changes in polyphenols during fermentation will help improve the quality of Congou black tea and enhance its health benefits. Novelty impact statement A new method for the determination of MAFs-2 by high-performance liquid chromatography combined with paper chromatography was established. The content of MAFs-2 increased initially and then stabilized as fermentation was continued from 2 to 8 hr, it increased gradually as the fermentation temperature was increased from 23 to 37°C. These results provide a new analytical method for MAFs in black tea and a theoretical basis and technical guidance for improving the quality of Congou black tea.

Comparison of the effects of raw and cooked adzuki bean on glucose/lipid metabolism and liver function in diabetic mice

AbstractBackground and objectivesDiabetes is a serious metabolic disease. The present study investigated the ability of diets supplemented with raw and cooked adzuki bean to mitigate the effects of diabetes and related metabolic disorders in type 2 diabetic mice induced by a high‐fat diet combined with streptozotocin (STZ).FindingsCompared with untreated diabetic mice, raw adzuki bean (RAB) supplementation significantly reduced food intake, glycated serum protein (GSP), and fasting blood glucose (FBG) and improved glucose tolerance. Cooked adzuki bean (CAB) supplementation cannot effectively improve FBG, but significantly reduce weight loss and GSP. In addition, adzuki bean supplementation significantly reduced low‐density lipoprotein cholesterol (LDL‐C) and total cholesterol (TC) levels. Histological observations confirmed the ability of adzuki bean supplementation to prevent pancreatic and liver damage. The content of total flavonoids and catechins in adzuki bean decreased significantly after processing.ConclusionsAlthough RAB and CAB supplementation showed many beneficial impacts on type 2 diabetic mice, the lower efficacy of CAB is likely caused by a loss of bioactive substances from processing.Significance and noveltyThese findings may contribute to a better understanding of the benefits of adzuki bean as a dietary supplement to prevent type 2 diabetes mellitus (T2DM) and related metabolic disorders.

The catechins profile and antioxidant activity in different types of green tea bags

Tea and mainly green tea as a rich source of antioxidants has been widely known for some time. The antioxidant capacity of tea including green tea is mainly due to its catechins content. The objective of this study was to determine the relationship between the ORAC value and the catechins content. Regular and decaffeinated commercial green tea bags commonly consumed in the United Kingdom (UK) have been examined using Reversed-Phase High-pressure Liquid Chromatography (RP-HPLC). Teabags were purchased from different local supermarkets in the UK and extracted with natural mineral water at temperature 100°C for 9 minutes at the pre-adjusted pH 4. The level of four catechins (Epi-structured) for the thirteen types of green tea were separated and determined by HPLC analysis, i.e. ()-epigallocatechin (EGC), ()-epicatechin (EC), ()-epigallocatechin-3-gallate (EGCG) and ()-epicatechin gallate (ECG). The standard graphs were validated using certified reference catechins supplied by the Laboratory of the Government Chemist (LGC). The levels of total catechins and oxygen radical absorbance capacity (ORAC) values varied from 34.61to 204.55 mg/g, 830.19- 4197.81 Trolox equivalents/g tea bags for thirteen types of green teas respectively. It was clear from the results of this study that there was a significant linear and positive correlation (r = 0.951, df = 12, p < 0.05) is found to exist between the total catechins contents and ORAC values. It can be concluded that the results of catechins measurements coupled to this; the well-known ORAC assay was successfully modified to measure the antioxidant capacity of the green tea extracts throughout this study. Furthermore, the higher the level of catechins the higher is the antioxidant capacity of the tea. This may stimulus consumers in selecting the type of tea and tea brewing times, exhibiting more health benefits. Nevertheless, the differences between the studied brands are owing to shelf life, production and storage conditions.
 

A comparative study to investigate the effects of addition of milk and sugar on total polyphenol, flavonoid, catechin and tannin contents of green and black teas consumed in India

A comparative study to investigate the effects of addition of milk and sugar on total polyphenol, flavonoid, catechin and tannin contents of green and black teas consumed in India

Black Tea Quality is Highly Affected during Processing by its Leaf Surface Microbiome.

Microbiomes can greatly affect the quality of fermented food and beverages, including tea. In this study, microbial populations were characterized during black and green tea manufacturing, revealing that tea processing steps can drive both the bacterial and fungal community structure. Tea leaves were found to mostly harbor Proteobacteria, Bacteriodetes, Firmicutes, and Actinobacteria among bacteria and Ascomycetes among fungi. During processing, tea microbial populations changed especially between sterilized and unsterilized samples. The surface sterilization of fresh leaves before processing can remove many microbes, especially the bacteria of the genera Sphingomonas and Methylobacteria, indicating that these are mostly phylloplane microbes on tea leaves. The surface sterilization removed most fungi, except the Debaryomyces. We also observed a fluctuation in the content of several tea quality-related metabolites during processing. Caffeine and theanine were found in the same quantities in green tea with or without leaf surface sterilization. However, the sterilization process dramatically decreased the content of total catechins and theanine in black tea, indicating that microbes on the surface of tea leaf may be involved in maintaining the formation of these important metabolites during black tea processing.

Analysis of inbreeding depression in the tea plant (Camellia sinensis) based on the self-compatible cultivar ‘Ziyan’

Most tea plants (Camellia sinensis) are considered self-incompatible (SI). It is difficult to identify self-compatible (SC) tea mutants through controlled hand-pollination. ‘Ziyan’ (ZY), a purple tea cultivar, was previously found to be SC by pedigree relationship reconstruction of its offspring using DNA markers. To assess the inbreeding depression in C. sinensis, in this study we identified 29 selfing progeny plants (SP) of ZY and compared their fitness traits and contents of secondary metabolites with the out-crossing progeny (OP, n = 38 plants) and the clonal mother ZY (n = 3 plants). The results showed that fitness traits, including root-collar diameter, matured leaf area, and fruit number of SP, were significantly lower than those of OP and ZY. Notably, the average fruit number of SP was only 9.0 % of ZY and 7.3 % of OP. The spring bud flush time of SP was also significantly later than the OP as indicated by the sprouting index on March 30th, 2020. However, the average content of anthocyanin of SP was 3.67 times that of OP. The total catechin and caffeine contents in SP were lower than those in OP and ZY, but less significantly. Together, the results indicated a strong inbreeding depression of fitness traits in the first selfing generation of ZY, while the impacts on secondary metabolites were not consistent. In addition, a possible homozygous lethal allele was found on LG03. The findings of this study have useful implications for inbred line-based breeding and researches in C. sinensis.

Volatile profiles and antioxidant activity of different cultivars of Camellia sinensis var. assamica grown in Thailand

Tea is considered as the most consumed drink in the world containing high antioxidant capacity. In this study, the volatile compounds, the phenolic content, catechins and caffeine including antioxidant activities of 22 Camellia sinensis var. assamica (Assam tea) cultivars were investigated. The volatile compounds were investigated by GC-MS. At least forty-five volatile compounds representing 94.99-99.65% of all cultivars were identified. Limonene, trans-linalool oxide, cis-linalool oxide, linalool, and furfural were detected as the major components among these cultivars. Varied ranges were found in all Assam tea cultivars for the contents of phenolics (113.45-245.55 mg gallic acid/g dry weight), total catechins (170.03-355.59 mg/g dry weight), caffeine (0.92-3.40 mg/g dry weight), and antioxidant activities (1418.68-2728.46 µmol Trolox/g dry weight and 1448.98-2864.17 µmol Trolox/g dry weight for DPPH and ABTS assay, respectively). The antioxidant activity was correlated with phenolic compounds such as epigallocatechin gallate, epicatechin gallate, and catechin gallate. The specific differences among Assam tea cultivars are dependent on the tea cultivar and altitude which may play a significant role in breeding Assam tea cultivars in Thailand for providing its potential health benefits.

Effects of GABA on the polyphenol accumulation and antioxidant activities in tea plants (Camellia sinensis L.) under heat-stress conditions

Polyphenols are important active components in tea plants, which have strong biological activity and antioxidant activity. A certain degree of stress or exogenous substances can significantly increase the content of polyphenols in plants. γ-Aminobutyric acid (GABA), a natural functional amino acid, was used to study whether exogenous GABA can increase the content of polyphenols and enhance antioxidant activity in tea plants under heat-stress conditions. The results showed that the content of GABA was positively correlated with the content of polyphenols (r = 0.649), especially with the content of total catechins (r = 0.837). Most of the related genes encoding flavonoid metabolism (PAL, C4H, 4CL, CHS, CHI, F3H, F3′H, F3′5′H, DFR, LAR, ANS, ANR and FLS) as well as enzyme activities (PAL, C4H and 4CL) were upregulated. In addition, the activities of antioxidant enzymes were induced under heat-stress conditions. However, 3-mercaptopropionic acid (3-MPA), an inhibitor of GABA synthesis, exhibited opposite results under heat-stress conditions compared with GABA treatment. These results indicated that GABA plays a key role in the accumulation of polyphenols and the upregulation of the antioxidant system in tea plants under heat-stress conditions.

Characterizing relationship between chemicals and in vitro bioactivities of teas made by six typical processing methods using a single Camellia sinensis cultivar, Meizhan

ABSTRACT Processing method is considered as a major factor that affects biotransformation of phytochemicals in tea and leads to diverse flavor and bioactivity of tea. In the present work, six typical tea manufacturing processings were employed to compare the effect on chemical composition of teas through using leaves of the single tea cultivar – – Camellia sinensis var. Meizhan. And in vitro antioxidant activity, inhibition against α-glucosidase and three lipid metabolism enzymes of these teas were also investigated, the relationships among them were analyzed further. As fresh leaves were processed into six categories of teas, the content of total catechins (TCs) has decreased in varying degrees while theaflavins (TFs) has increased. The antioxidant capacity composite index (ACCI) from high to low were green tea, yellow tea, oolong tea, white tea, dark tea, and black tea with the range from 98.44 to 58.38, which dominated by the content of TCs. Furthermore, all categories of teas possessed an inhibition effect on the pancreatic lipase (PL), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-COA reductase), lecithin cholesterol acyltransferase (LCAT), and α-glucosidase. The inhibition rate of PL and α-glucosidase appears to be positively influenced by TFs content (r =0.863, r =0.857, p < 0.05) while that of LCAT showed significant positive correlations with the content of tea polyphonels (TPs) (r = 0.902, p < 0.01). These results provide a better understanding of the relationships between processing method and chemical components of tea. It is suggested that various tea categories possess potential healthy effects which could serve as promising nutritional supplements.

Phytochemical characterization and biological activities of green tea (Camellia sinensis) produced in the Azores, Portugal

BackgroundGreen tea is not only one of the most widely consumed beverages worldwide, but is also known for its health promoting and therapeutic effects. Green tea is cultivated in areas with high humidity and acidic soils in China, Indonesia and Japan. Those places have well-marked dry and rainy seasons. In opposite, Azores have a climate with constant average annual rainfall and, unlike eastern regions, relatively constant air humidity throughout the year. While a brand implemented on the Portuguese market, the quality of green tea produced in Azores must be guaranteed. Quality control measures based on phytochemical determination of the chemical composition and biological activities are needed in order to address whenever climate changes interferes significantly with composition and biological effects. PurposeMake the phytochemical characterization of various extracts of green tea leaves coming from Azores and evaluate the anti-cancer activities of the extracts in order to compare the obtained results with those of teas coming from eastern regions. MethodsPhytochemical characterization (catechins, oxyaromatic acids, flavonols, alkaloids and theanine) and total catechins contents (TCC) was performed by using HPLC-DAD analysis, in infusions (5–7 min and 30 min), maceration and methanolic extracts of Camellia sinensis samples coming from Azores, Portugal. The antioxidant activity of extracts was measured by the DPPH assay and the total phenolics contents (TPC) were estimated using the Folin-Ciocalteu colorimetric method. The cytotoxic activity towards drug sensitive and multidrug-resistant leukemia cell lines was determined by the resazurin assay. ResultsThe TCC was higher in methanolic extracts and lower in maceration, as epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) concentrations were significantly higher in methanolic extracts and were only residual in maceration extracts. Maceration extracts showed the highest content of gallic acid, indicating that methanol extracts contained more flavonols of higher molecular weight and/or that maceration may lead to the degalloylation of catechins. The amount of o-caffeoylquinic acid extracted was significantly higher in methanolic samples. Short-term extraction at high temperatures resulted in high amounts of neochlorogenic acid. The contents of glycosylated quercitin-3-d-galactoside and kaempferol-3-glucoside were small in maceration samples and high in methanolic samples. Caffeine was easily extracted by methanol (99%) compared with water, while extraction of the amino-acid l-theanine was unattainable with methanol. TPC values correlated linearly with DPPH•IC50, with infusion samples showing the best antioxidant capacities. The aqueous and the methanol/water extracts were active in multidrug-resistant and drug sensitive cancer cells. ConclusionDespite these climatic differences, the phytochemical characterization revealed that tea coming from the Azores compares well with those from China and Japan. In addition, tea can be produced without fungicides and pesticides to control pests that appear during rainy seasons. This allows the production of high-quality bioorganic tea. Aqueous and methanol/water extracts of the Azorean tea showed to be useful targeting sensitive and drug-resistant tumor cells.

Multi-stage block freeze-concentration of green tea (Camellia sinensis) extract

Tea is the third most consumed beverage in the world. It has bioactive compounds that provide health benefits; for that reason, concentrating this product is a good alternative for different industries. Block freeze-concentration is a technology with the potential to be used to concentrate food solutions, preserving functional compounds. The aim of this work was to study the effect of block freeze-concentration on the total solids content, catechin content, polyphenol content, antioxidant activity and sensorial profile of green tea. Green tea extract at a 4% (w/w) solid mass fraction was freeze-concentrated in three successive stages at −25 °C. The effects of some parameters were evaluated, such as the concentration index, solid recovery yield, and concentration efficiency. After three stages, the solution was concentrated from 4% (w/w) to 14.1% (w/w) with a distribution coefficient of 0.43 and a total concentration efficiency of 81.6%. The efficiency of concentration decreased with the number of stages. The levels of catechins and polyphenols were increased by 4.5- and 3.4-fold in the final liquid fraction, respectively. The antioxidant activity was preserved after three stages of freeze concentration. The physicochemical parameters were maintained: of the 27 sensory attributes evaluated, 18 of them were retained. The results demonstrated that block freeze-concentration is a useful technique for preserving and enhancing the bioactive compound content and the functional properties of green tea extracts. • Green tea extract was freeze-concentrated by the block technique. • The content of bioactive compounds was increased after the concentration. • The technique preserved the functional properties of the green tea extract. • The sensory attributes of the extract were preserved.

Co-regulation of catechins biosynthesis responses to temperature changes by shoot growth and catechin related gene expression in tea plants (Camellia sinensis L.)

ABSTRACT Catechins are the major compounds in tea (Camellia sinenesis L.) and are responsible for its sensory qualities and health benefits. The study investigated the response of catechins biosynthesis to temperature changes in the controlled conditions and the possible mechanisms. The low-temperature treatment inhibited the growth of young shoots, suppressed the expression of catechins biosynthesis-related genes (except CsCHS3, CsDFR2, CsLAR2), and decreased the content of total esterified catechins but increased the content of total non-esterified catechins in tea plants. When the temperature increased from 15°C to 30°C, the young shoots grew faster, and the contents of total catechins, total esterified catechins and epigallocatechin gallate in tea plants increased by 87.7%, 92.5% and 53.6%, respectively. Meanwhile, the expression of growth-related genes was upregulated in the higher temperature treatment and was consistent with the response of catechins biosynthesis-related genes to temperature. The positive correlation and the cubic function (R2 > 90%) were noted between the growth of young shoots and catechins content. In brief, the response of catechins biosynthesis to temperature changes coordinately regulated by shoot growth and catechins genes expression of tea plants. Our findings provide the reference for improving tea quality by increasing its catechin contents.

Polyphenols Content in Capsicum chinense Fruits at Different Harvest Times and Their Correlation with the Antioxidant Activity.

The aim of this work was to investigate the changes of the content of polyphenols in fruits of Capsicum chinense Jacq. at different harvest times and their correlation with the antioxidant activity. Habanero pepper plants grown in black soil (Mayan name: Box lu’um) and harvested at 160, 209, 223, 237 and 252 post-transplant days (PTD) were analyzed. The results indicated that subsequent harvesting cycles decreased the content of total polyphenols, catechin, chlorogenic acid and ellagic acid, while the content of gallic and protocatechuic acid increased. The antioxidant activity determined by DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical scavenging and ABTS (2,2′-azino-di-3-ethylbenzthiazoline sulfonic acid) assay decreased through the harvest days. Linear correlation analysis between total polyphenol content and antioxidant activity in peppers resulted in a correlation of r2DPPH = 0.8999 and r2ABTS = 0.8922. Additionally, a good correlation of the antioxidant activity was found with catechin (r2DPPH = 0.8661 and r2ABTS = 0.8989), chlorogenic acid (r2DPPH = 0.8794 and r2ABTS = 0.8934) and ellagic acid (r2DPPH = 0.8979 and r2ABTS = 0.9474), indicating that these polyphenols highly contributed to the antioxidant activity in Habanero peppers. This work contributes to understanding the changes that take place during the development of Capsicum chinense, indicating that fruit harvested at earlier PTD showed the highest concentrations of total polyphenols and antioxidant activity, obtaining the best results at 160 PTD.

Catechin and caffeine content of tea (Camellia sinensis L.) leaf significantly differ with seasonal variation: A study on popular cultivars in North East India

Two thirds of the tea growing area of North East India is covered by Tocklai vegetative (TV) cultivars. The present study investigates the principal catechins [(−)-epigallocatechin gallate (EGCG), (−)-epicatechin gallate (ECG), (−)-epigallocatechin (EGC), (−)-epicatechin (EC), and (+)-catechin (+C)], total catechin (TC) and caffeine content in thirty-one TV cultivars (TV1-TV31) and four popular cultivars, viz. Betjan, Kharijan, S.3A/3, and T.3E/3 in three harvesting seasons i.e., pre-monsoon, monsoon and autumn, along with their genetic diversity. The monsoon harvested crop showed the highest average content of TC, EGCG, ECG, and caffeine. The TC levels varied from 129 ± 0.03 to 214 ± 4.72, 151 ± 4.21 to 238 ± 8.41, and 121 ± 4.45 to 181 ± 5.82 mg g-1 in pre-monsoon, monsoon and autumn, respectively. The most predominant catechin EGCG varied from 52.2 ± 1.07 to 111 ± 1.24, 70.4 ± 1.03 to 141 ± 1.35, and 58.4 ± 2.47 to 108 ± 2.15 mg g-1in pre-monsoon, monsoon and autumn, respectively. Caffeine content varied from 27.1 ± 0.32 to 48.7 ± 0.50, 35.3 ± 1.56 to 55.0 ± 1.34 and 27.6 ± 1.11 to 40.7 ± 0.42 mg g-1 in pre-monsoon, monsoon and autumn, respectively. TC contents in cultivars TV23, TV17 and TV15; and EGCG contents in TV10, TV11, and TV9 were significantly higher (p ≤ 0.05) than for other cultivars. Environmental factors, viz. day length, sunlight, temperature across seasons might have induced seasonal variation in phenolic composition.

Analytical strategy coupled to chemometrics to differentiate Camellia sinensis tea types based on phenolic composition, alkaloids, and amino acids.

Catechins, amino acids, and alkaloids are primary chemical components of tea and play a crucial role in determining tea quality. Their composition and content largely vary among different types of tea. In this study, a convenient chemical classification method was developed for six Camellia sinensis tea types (white, green, oolong, black, dark, and yellow) based on the quantification of their major components. Twenty-one free amino acids, 6 catechins, 2 alkaloids, and gallic acid in 24 teas were quantified using ultra-high-performance liquid chromatography (UHPLC). The total catechin contents in these tea samples ranged from 10.96 to 95.67 mg/g, while total free amino acid content ranged from 2.63 to 25.89 mg/g. Theanine (Thea) was the most abundant amino acid in all tea varieties. Catechin and amino acid levels in tea were markedly reduced upon fermentation of tea. Furthermore, high-temperature processing (roasting) during tea production induced degradation and epimerization of catechins, yielding epimerized catechins, simple catechins, and gallic acid. Principal component analysis revealed that major ester-catechins (EGCG and ECG), major amino acids (Thea), and major alkaloids (caffeine) are potential factors for distinguishing different types of tea. Linear discriminant analysis showed that 100% of teas were correctly classified in which (+)-catechin, ECG, EGC, gallic acid, GABA, cysteine, lysine, and threonine were the most discriminating compounds. This study shows that quantification of the major tea components combined with chemometric analysis, can serve as a simple, convenient, and reliable approach for classifying tea according to fermentation level. PRACTICAL APPLICATION: Different Camellia sinensis tea types can be produced worldwide but it is still challenging to know which chemical markers can be used to trace their production. in this paper we used a targeted methodology to classify six tea types (white, green, oolong, black, dark, and yellow) based on phenolic composition, alkaloids, and amino acids. The main chemical markers responsible for the discrimination were pinpointed with the use of chemometric tools.