Multivariate analysis of the composition of bioactive in tea of the species Camellia sinensis

Total and bioaccessible contents of phenolic bioactives in nutritious flours exposed to consumption in Salvador, Bahia, Brazil using in vitro gastrointestinal digestion (INFOGEST protocol)

There is growing interest in quantifying phenolic bioactives (PBs) in food matrices, including a variety of nutritious flours. The objective of this study apply a factorial design to determine the total (TT) and bioaccessible (TB) levels of PBs in 26 nutritious flours, using the INFOGEST in vitro digestion method. Acids (gallic, protocatechuic, chlorogenic, caffeic, syringic, p-coumaric, sinapic and ellagic) and flavonoids (catechin, rutin, quercetin and kaempferol) were determined by high performance liquid chromatography with diode array detector (HPLC-DAD). TT ranged, in μg g-1, from 3.16 ± 0.27 (p-coumaric acid) to 3803 ± 217 (rutin). TB, in μg g-1, ranged from <0.17 to 1.37 ± 0.07 (ellagic acid) to <0.16 to 88.83 ± 0.72 (catechin). Significant concentrations of CP in nutritious flours - eggplant (FBJ), orange (FLJ) and grape seed (FSU) - are relevant to profile these samples and help consumers incorporate them into their daily diets.

Alkaloids in food: a review of toxicity, analytical methods, occurrence and risk assessments

Alkaloids have been utilized by humans for years. They have diverse applications in pharmaceuticals. They have been proven to be effective in treating a number of diseases. They also form an important part of regular human diets, as they are present in food items, food supplements, diet ingredients and food contaminants. Despite their obvious importance, these alkaloids are toxic to humans. Their toxicity is dependent on a range of factors, such as specific dosage, exposure time and individual properties. Mild toxic effects include nausea, itching and vomiting while chronic effects include paralysis, teratogenicity and death. This review summarizes the published studies on the toxicity, analytical methods, occurrence and risk assessments of six major alkaloid groups that are present in food, namely, ergot, glycoalkaloids, purine, pyrrolizidine, quinolizidine and tropane alkaloids.

Discriminative Chemical Profiles of Shan Tuyet Tea (Camellia sinensis var. Shan) and Sinensis Tea (Camellia sinensis var. sinensis) Collected in Ta Xua, Son La, Vietnam and Their Correlation With Antioxidant Activity

Chè Shan Tuyet ( Camellia sinensis var. Shan) is one of the precious tea resources of Vietnam; however, there is little research on its chemical composition. The purpose of this study was to characterize the main quality components, such as free amino acids and catechins, in Camellia sinensis var. Shan and Camellia sinensis var. sinensis collected in the high mountain of Ta Xua, Son La, Vietnam by using an amino acid analyzer and liquid chromatography coupled with tandem mass spectrometry, respectively. Principal component analysis (PCA) discrimination analysis of chemical profiles revealed a clear metabolic difference between the young leaves of Shan Tuyet tea and mature leaves of the same variety and of sinensis tea. The amino acids serine, glutamic acid, arginine, ornithine, and aspartic acid contributed mainly to the discrimination and could be considered biomarkers for Shan Tuyet tea. The levels of caffeine and 7 catechins, catechin, catechin 3-gallate, epicatechin, epicatechin-3-gallate, epigallocatechin 3-gallate, gallocatechin, and gallocatechin 3-gallate, in young leaves of Shan Tuyet tea were significantly higher than in the other types. Notably, the pair correlation among catechins revealed strong coefficients of the epistructures and non-epistructures, which suggested that these compounds can be converted naturally to each other. The strong correlation between epicatechin-3-gallate and catechin 3-gallate with antiradical ABTS activity of Shan Tuyet tea leaves indicates that these 2 catechins are mainly responsible for the antioxidant activity. This is the first report on the bioactive compounds of Shan Tuyet tea, as well as its potential for the production of health supplements.

The Effect of In Vitro Digestion on Matcha Tea (Camellia sinensis) Active Components and Antioxidant Activity

This study investigates the effects of in vitro digestion on the antioxidant activity and release of phenolics, xanthine alkaloids, and L-theanine contents of matcha. It establishes digestibility values between 61.2–65.8%. Considering native matcha, the rutin content (303–479 µg/g) reached higher values than catechin (10.2–23.1 µg/g). Chlorogenic acid (2090–2460 µg/g) was determined as predominant. Rutin, quercetin, ferulic, ellagic, and caffeic acid were the least-released phenolics, and their remaining residues reached 76–84%. Protocatechuic, hydroxybenzoic acid, epigallocatechin, and epigallocatechin-3-gallate were the best-released phenolics, with the remaining residues under 1%. Caffeine, L-theanine, and theobromine contents in native matcha reached 16.1, 9.85, and 0.27 mg/g, respectively. Only caffeine (3.66–5.26 mg/g) and L-theanine (0.09–0.15 mg/g) were monitored in the undigested residue, representing 13 and 0.1% of the remaining part, respectively. A chemiluminescence assay showed that water-soluble antioxidants showed significant antioxidant activity in native matcha, while lipid-soluble compounds showed higher antioxidant activity in the undigested samples. Cinnamic and neochlorogenic acids were determined as the main contributors to the ACW values in the undigested matcha, epicatechin, and quercetin in the ACL fraction. The application of the digestion process reduced the antioxidant activity by more than 94%. SEM has proved specific digestion patterns of in vitro digestibility of matcha.

Processing, chemical signature and food industry applications of Camellia sinensis teas: An overview

The plant Camellia sinensis is the source of different teas (white, green, yellow, oolong, black, and pu-ehr) consumed worldwide, which are classified by the oxidation degree of their bioactive compounds. The sensory (taste, aroma, and body of the drink) and functional properties of teas are affected by the amount of methylxanthines (caffeine and theobromine), amino acids (l-theanine) and reducing sugars in their composition. Additionally, flavan-3-ols, mainly characterized by epicatechins, catechins, and their derivatives, represent on average, 60% of the bioactive compounds in teas. These secondary metabolites from teas are widely recognized for their antioxidant, anti-cancer, and anti-inflammatory properties. Thus, Camellia sinensis extracts and their isolated compounds have been increasingly used by the food industry. However, bioactive compounds are very susceptible to the oxidation caused by processing and degradation under physiological conditions of gastrointestinal digestion. In this context, new approaches/technologies have been developed for the preservation of these compounds. This review presents the main stages involved in production of Camellia sinensis teas following a description of their main bioactive compounds, biological properties, stability and bioaccessibility. Besides, and updated view of Camellia sinensis teas in the field of food science and technology was provided by focusing on novel findings and innovations published in scientific literature over the last five years.

Capillary electrophoresis-UV analysis using silica-layer coated capillary for separation of seven phenolic acids and caffeine and its application to tea analysis

Abstract

This work presents an innovative silica-layer coated capillary with comparison study of the silica-layer coated capillary and the fused-silica capillary for the separation of seven phenolic acids viz. p-hydroxyphenylacetic acid (PHPA), p-coumaric acid (PCA), p-hydroxybenzoic acid (PHBA), caffeic acid (CFA), (3,4-dihydroxyphenyl)acetic acid (DHPA), gallic acid (GLA), and 2,3,4-trihydroxybenzoic acid (THBA), together with caffeine (CF), by capillary electro-chromatography (CEC) and micellar electrokinetic chromatography (MEKC), respectively. The running buffer was 25.0 mM borate at pH 9.0, with addition of 50.0 mM sodium dodecyl sulfate for the MEKC mode. The non-coated capillary could not separate all seven phenolic acids by CEC or MEKC. This was achieved using the coated capillary for both CEC and MEKC. The innovative coated capillary with CEC had plate number N ≥ 2.0 × 104 m−1 and resolution Rs ≥ 1.6 for all adjacent pairs of peaks. The capillary was also able to separate GLA and THBA which are structural isomers. Although MEKC mode provided comparable efficiency and selectivity, the reduced EOF of the coated capillary led to longer separation time. The linear calibration range of the seven phenolic acids and caffeine were different but the coefficients of determinations (r2) were all > 0.9965. The precisions of the relative migration times and peak area ratios of analyte to internal standard were 0.1–1.8% and 1.8–6.8%, respectively. There were no statistical differences in the efficiency of separation of the phenolic acids and caffeine for three coated capillaries. It was applied to the analysis of caffeine and phenolic acids in brewed tea using tyramine as the internal standard. The tea samples were diluted prior to analysis by CEC. The separation was less than 15 min. Caffeine, gallic acid and p-coumaric acid were detected and quantified. Caffeine and gallic acid contents were 10.8–15.0 and 2.6–4.8 mg g−1 dry tea leaves, respectively. p-Coumaric acid was detected in only one of the samples with a content of 0.4 mg g−1. Percent recoveries of spiked diluted samples were 90 ± 9 to 106 ± 13%, respectively.

Article highlights

Graphical abstract

Potential role of tea extract in oocyte development

Tea is the second most popular beverage in the world and beneficial to health. It has been demonstrated that tea polyphenols can reduce the risk of diseases, such as cancers, diabetes, obesity, Alzheimer's disease, etc. But the knowledge of tea extract on the female germline is limited. Folliculogenesis is a complicated process and prone to be affected by ROS. Tea polyphenols can reduce the accumulation of ROS in folliculogenesis and affect oocyte maturation. Tea extract also influences granulosa cell proliferation and expansion during oocyte growth and maturation. However, the studies about the benefits of tea extract on female germline are few, and the underlying mechanisms are obscure. In the present study, we will mainly discuss the effects of tea extract on ovarian function, oocyte maturation, and the underlying possible mechanisms, and according to the discussion, we suggest that tea extract may have benefits for oocytes at an appropriate dose.

Phenolic content and antioxidant capacity of infusions herbs: Optimization of phenolic extraction and HPLC-DAD method

The aim of this work was to investigate the phenolic content and antioxidant capacity of infusions of commercial herb samples (fennel, anise, peppermint, lemon grass and lemon balm) popularly consumed in Brazil. The infusion preparation for phenolic extraction was optimized using multivariate planning. Spectrophotometric methods were used to determine in vitro antioxidant activity and total phenolic and flavonoid content. Peppermint infusions had higher phenolic content and antioxidant potential. It was developed and validated a method by HPLC-DAD for the determination of caffeine, phenolic acids and flavonoids and applied for the analysis of the composition of the infusions. Higher concentrations were obtained for chlorogenic and p-coumaric phenolic acids and for flavonoids rutin and catechin. Principal Components Analysis and Hierarchical Cluster Analysis were applied for the comparative evaluation of the phenolic composition of the infusions. The multivariate analyzes indicate that the phenolic profile for the samples of the same species tend to present greater similarities in relation to other herbs and one of the analyzed samples, commercialized as anise, does not belong to the P. anisum species.

Arabica and Conilon coffee flowers: Bioactive compounds and antioxidant capacity under different processes

This study presents innovative research for comparison of the effect of the different dehydration techniques and methods of extraction on the antioxidant potential and bioactive compounds of Conilon and Arabica coffee flowers. The compounds were analyzed by high performance liquid chromatography and the antioxidant capacity evaluated by the 2,2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide assays. Among the compounds evaluated, trigonelline, gallic acid, chlorogenic acid, and caffeine were identified, with trigonelline and caffeine being those with the highest concentration. The investigated factors significantly influenced the profile of the bioactive compounds identified, and the antioxidant capacity. The 92 °C infusion of freeze-dried Conilon coffee flowers, in general, showed greater antioxidant capacity by ABTS and DPPH assays, as well as total phenolic content. Lyophilization had a positive influence on maintaining the content of phenolic compounds and antioxidant capacity of the samples. Coffee flowers proved to be a potential raw material for making tea-like drinks.

Extraction and characterization of phytochemical compounds from araçazeiro (Psidium cattleianum) leaf: Putative antioxidant and antimicrobial properties

Underexplored species have phytochemical potential for pharmacological and nutraceutical applications. The fruits of such species, including aracá (Psidium cattleianum Sabine), are rich in specialized metabolites with putative antioxidant and antimicrobial activity; therefore, the leaves of these species are also a potential source of bioactive compounds. In this study, araçazeiro leaves were extracted using an aqueous infusion (Al) and a pressurized liquid extraction system with water (PLE-W), ethanol (PLE-E), and 1:1 water:ethanol ratio combination (PLE-W:E). PLE-W:E yielded a greater diversity of extracted compounds. Nonetheless, all extracts showed inhibitory activity against pathogenic Gram-positive and Gram-negative bacteria and antioxidant activity in the in vitro thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS) assays with rat brain and yeast model systems. Thus, araçazeiro leaves can be exploited as a promising source of bioactive compounds.

Multivariate analysis applied in dataset of Poison Control Center of São Paulo, Brazil

Multivariate analysis techniques could be used to identify possible intercorrelations in intoxications cases. The statistical analyses used were a multiple logistic regression, multiple correspondence analysis, principal component and hierarchical cluster analysis. Of the 320 samples analysed, 192 samples were positive for some of the investigated toxic agents, of which 100 were positive for ethanol and 131 were positive for other substances. It was possible to group the patients into 3 clusters, which appears 66.5% of this information in the three first factorial axes. On the first axis, the male patients were separated from the female patients. Patients exposed to drugs, between 30 and 39 years old were grouped in the same cluster. On the second factorial axis, patients who were intoxicated with ethanol and who became intoxicated with diazepam were grouped. This work contributed to the mapping of intoxication cases at the Poison Control Centre of the São Paulo city, Brazil (CCI-SP) and serves as an initial study for the creation of a database that could be updated constantly and thus could provide a toxicovigilance system for educational policies.

Pseudorivibacter rhizosphaerae gen. nov., sp. nov., isolated from rhizosphere soil of Camellia sinensis (L.) O. Ktze and emended description of the genus Rivibacter

A Gram-stain-negative, facultative anaerobic, motile and straight rod-shaped bacterium, designated strain C1-9^T, was isolated from rhizosphere soil of Camellia sinensis (L.) O. Ktze collected from a tea garden in Huize, south-western PR China. Cells were oxidase-positive and catalase-negative. Growth occurred at 20-40 °C and pH 6.0-10.0, with an optimal growth at 30 °C and pH 7.0. The respiratory quinone was detected as ubiquinone-8 (Q-8). The major fatty acids were identified as summed feature 3 (C_16 : 1ω7c and/or C_16 : 1ω6c), C_16 : 0 and summed feature 8 (C_18 : 1ω7c or C_18 : 1ω6c). The cellular polar lipids contained phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, three unidentified phospholipids, two unidentified lipids, one unidentified aminophospholipid and one unidentified aminolipid. The polyamine types were detected as 1,8-diaminooctane and 2-hydroxyputrescine. The genomic DNA G+C content was 68.6 mol%. Based on the results of 16S rRNA gene sequence analysis, strain C1-9^T (MF687442) showed highest sequence similarity to Rivibacter subsaxonicus DSM 19570^T (97.1 %). The phylogenetic tree based on 16S rRNA gene sequences showed that strain C1-9^T clustered close to R. subsaxonicus DSM 19570^T, Methylibium petroleiphilum CCTCC AB 2014193^T and species belonging to the genera Rhizobacter and Piscinibacter. The phylogenomic tree indicated that strain C1-9^T formed a clade with R. subsaxonicus. The average nucleotide identity value was 76.0 % between strain C1-9^T and R. subsaxonicus DSM 19570^T, which is lower than the prokaryotic species delineation threshold of 95.0-96.0 %. The polyphasic taxonomic characteristics indicated that strain C1-9^T represents a novel species of a new genus within the order Burkholderiales, for which the name Pseudorivibacter rhizosphaerae gen. nov., sp. nov. (type strain C1-9^T = KCTC 62325^T=CGMCC 1.13864^T) is proposed.

Vibrational (FT-IR, Raman) analysis of tea catechins based on both theoretical calculations and experiments

Structural investigations, based on density functional theory (DFT) calculations, are performed on tea catechins, including 4-aminobutyric acid (GABA), L-theanine (Thea), caffeine (CAF), theobromine (TB), theophylline (TP), catechin (C), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), catechin gallate (CG), epicatechin gallate (ECG), gallocatechin gallate (GCG) and epigallocatechin gallate (EGCG). With an identified lowest energy conformer of investigated molecules, FTIR and FT-Raman spectra have been assigned according to DFT calculations in the way of B3LYP/6-31 + G (d, p). Normal spectra of these catechin powders are also measured by Raman spectrometers. There is a kind of everlasting correlation between experimental results and theoretical data. And our research has also obtained a clear evidence for reliable assignments of vibrational bands, bringing great feasibility to the rapid tea catechin detection.

Understanding Camellia sinensis using Omics Technologies along with Endophytic Bacteria and Environmental Roles on Metabolism: A Review

Camellia sinensis is the most consumed beverage worldwide. It contains a wide variety of secondary metabolites, such as alkaloids, saponins, tannins, catechins, and polyphenols, generated through a condensation reaction of cinnamic acid with three malonyl-CoA groups. In addition to the metabolic processes occurring within this plant, there are also some plant-associated bacterial endophytes. These bacteria reside in the living tissues of the host plants without causing any harmful effect to them, thereby stimulating secondary metabolite production with a diverse range of biological effects. Omics technologies reveal understanding of the biological phenomena of transcriptomics, proteomics, and metabolomics. In this sense, the present review aims to provide a comprehensive review of various methods used to identify distinct plant compounds, namely transcriptomic, proteomic, and metabolomic analysis. The role of endophytic bacteria in C. sinensis metabolism, and C. sinensis antioxidant and antimicrobial effects, are also carefully highlighted.

Determination of Vitamin B2 Content in Black, Green, Sage, and Rosemary Tea Infusions by Capillary Electrophoresis with Laser-Induced Fluorescence Detection

Vitamin B2, also known as riboflavin (RF) is an essential micronutrient for human health and must be obtained from dietary sources. Plants biosynthesize riboflavin and are important dietary sources of vitamin B2 for humans. Our present study reports sensitive detection of vitamin B2 in widely consumed tea infusions, namely black, green, sage and rosemary tea infusions, by a capillary electrophoresis method combined with laser induced fluorescence detection. Moreover, the correlation between the vitamin B2 content of tea plants with their total phenolics (TPs) and antioxidant capacity are evaluated in this study. Whereas green teas have the highest TPs and antioxidant capacity, the highest RF content is in sage infusions. The RF content ranged between 0.34 and 10.36 µg/g for all tea samples studied. Comparing the RF content of tea samples found in this study to the RF content of known RF sources, tea infusions are proposed as important dietary sources of vitamin B2.