Gallocatechin Gallate Research Articles

Correlation Analysis Among the Chemical Composition and Cytotoxic and Antioxidative Activities of a Tessaria absinthioides Decoction for Endorsing Its Potential Application in Oncology.

Historically, botanical preparations have been used to improve human health. Their active ingredients are influenced by multiple factors such as intraspecies variations, environmental conditions, collection time and methods, and the part of the plant used. To ensure the efficiency and safety of these herbal drugs, qualitative and quantitative analyses are required. A Tessaria absinthioides decoction (DETa) was reported as having hypocholesterolemic, anti-inflammatory, cytotoxic, antitumor, and antioxidative properties. This work aimed to analyze DETa by correlating its chemical composition with cytotoxic and antioxidative properties, with the aim of promoting research on it as an anticancer agent. DETa collections (2017, 2018, 2019, and 2022) were analyzed by UHPLC-DAD, UHPLC-DAD-FLD, and UPLC-MS/MS; cytotoxicity was assessed on the MCF-7 breast cancer cell line; antioxidative capacity was evaluated by the DPPH and FRAP methods; and correlation analysis was used to determine biological and chemical markers. The results provide evidence that biological activities were consistent across the collections. Among the quantified compounds, apigenin, naringin, gallocatechin gallate, ginnalin A, myricetin, epicatechin, OH-tyrosol, quercetin, and chlorogenic, tessaric, p-coumaric, vanillic, caffeic, caftaric, ellagic, and rosmarinic acids correlated as bioactive and chemical markers. Moreover, tessaric acid could be established as a species marker. Altogether, these findings add relevant information to DETa properties, encouraging further exploration of its potential application as an anticancer botanical.

Influence of Primary Light Exposure on the Morphophysiological Characteristics and Phenolic Compounds Accumulation of a Tea Callus Culture (Camellia sinensis L.).

Tea plant calli (Camellia sinensis L.) are characterized by the accumulation of various phenolic compounds (PC)-substances with high antioxidant activity. However, there is still no clarity on the response of tea cells to light exposure of varying intensity. The purpose of the research was to study tea callus cultures grown under the influence of primary exposure to different light intensities (50, 75, and 100 µmol·m-2·s-1). The cultures' growth, morphology, content of malondialdehyde and photosynthetic pigments (chlorophyll a and b), accumulation of various PC, including phenylpropanoids and flavanols, and the composition of catechins were analyzed. Primary exposure to different light intensities led to the formation of chloroplasts in tea calli, which was more pronounced at 100 µmol·m-2·s-1. Significant similarity in the growth dynamics of cultures, accumulation of pigments, and content of malondialdehyde and various phenolics in tea calli grown at light intensities of 50 and 75 µmol·m-2·s-1 has been established, which is not typical for calli grown at 100 µmol·m-2·s-1. According to data collected using high-performance liquid chromatography, (+)-catechin, (-)-epicatechin, epigallocatechin, gallocatechin gallate, epicatechin gallate, and epigallocatechin gallate were the main components of the tea callus culture's phenolic complex. Its content changed under the influence of primary exposure to light, reaching the greatest accumulation in the final stages of growth, and depended on the light intensity. The data obtained indicate changes in the morphophysiological and biochemical characteristics of tea callus cultures, including the accumulation of PC and their individual representatives under primary exposure to light exposure of varying intensity, which is most pronounced at its highest values (100 µmol·m-2·s-1).

Effects of Microbial Proteins on Qingzhuan Tea Sensory Quality during Pile Fermentation.

To determine the effects of microbial proteins on Qingzhuan tea sensory quality during tea pile fermentation, tea leaf metabolomic and microorganism proteomic analyses were performed. In total, 1835 differential metabolites and 443 differentially expressed proteins of the microorganisms were identified. Correlation analysis between metabolomics and proteomics data revealed that the levels of microbial proteins EG II and CBH I cellulase may play important roles in cell wall construction and permeability, which were crucial for the interaction between tea leaves and microorganisms. Microbial proteins heat shock proteins (HSP), alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), and CuAO related to detoxification and stress responses showed a positive correlation with tea theanine, glutamine, γ-aminobutyric acid, glutamic acid, catechin, (-)-gallocatechin gallate, and (-)-catechin gallate, suggesting their effects on tea characteristic compound accumulation, thus affecting Qingzhuan tea sensory quality.

Metabolomics Analysis of Phenolic Composition and Content in Five Pear Cultivars Leaves.

Phenolic compounds are the predominant chemical constituents in the secondary metabolites of plants and are commonly found in pears. In this study, we focused on the analysis of the phenolic composition and antioxidant activity of leaves from five pear cultivars (Cuiguan, Chaohong, Kuerle, Nanguoli, and Yali) and tea leaves (Fudingdabai as the control) using ultra-performance liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry. The results indicated significant differences in the amount and composition of phenolic metabolites between tea and pear leaves, as well as among the five pear varieties. Only approximately one-third of the metabolites exhibited higher levels in pear leaves compared to that in tea leaves. The total phenol content in the Yali cultivar was higher than that in the other pear cultivars. Furthermore, specific phenolic metabolites with high expression were identified in the leaves of different groups. The levels of delphinidin 3-glucoside, aesculin, prunin, cosmosiin, quercetin 3-galactoside, isorhamnetin-3-O-glucoside, nicotiflorin, narcissin, chlorogenic acid, and cryptochlorogenic acid were relatively high among the five pear cultivars. (-)-Gallocatechin gallate, 6-methylcoumarin, aesculetin, hesperidin, kaempferol, and caftaric acid were identified as specific metabolic substances unique to each type of pear leaf. Most of the differential metabolites showed positive correlations and were primarily enriched in the flavonoid biosynthesis, flavone and flavonol biosynthesis, and phenylpropanoid biosynthesis pathways. DPPH (1,1-Diphenyl-2-picrylhydrazyl radical) analysis indicated that the Yali cultivar exhibited the highest antioxidant activity compared to other varieties. This systematic analysis of the differences in phenolic metabolite composition and antioxidant activity between pear and tea leaves provides a theoretical foundation for the development and utilization of pear leaf resources.

Tea's Characteristic Components Eliminate Acrylamide in the Maillard Model System.

This study investigated the effects of various characteristic components of tea-theaflavins, catechins, thearubigins, theasinensins, theanine, catechin (C), catechin gallate (CG), epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin (GC), and gallocatechin gallate (GCG)-on acrylamide formation. The results revealed that most of tea's characteristic components could significantly eliminate acrylamide, ranked from highest to lowest as follows: GC (55.73%) > EC (46.31%) > theaflavins (44.91%) > CG (40.73%) > thearubigins (37.36%) > ECG (37.03%) > EGCG (27.37%) > theabrownine (22.54%) > GCG (16.21%) > catechins (10.14%) > C (7.48%). Synergistic elimination effects were observed with thearubigins + EC + GC + CG, thearubigins + EC + CG, thearubigins + EC + GC, theaflavins + GC + CG, and thearubigins + theaflavins, with the reduction rates being 73.99%, 72.67%, 67.62%, 71.03%, and 65.74%, respectively. Tea's components reduced the numbers of persistent free radicals to prevent acrylamide formation in the model system. The results provide a theoretical basis for the development of low-acrylamide foods and the application of tea resources in the food industry.

Identification of chemical components of large-leaf yellow tea by ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry

Large-leaf yellow tea, a slightly fermented yellow tea that is unique to China, has a stronger hypoglycemic effect than other tea varieties, such as green and black tea. Research on large-leaf yellow tea has focused on its hypoglycemic effect owing to the lack of comprehensive techniques to characterize its chemical components; thus, its development and further promotion are limited. Therefore, the development of a reliable analytical method to fully characterize the chemical components of large-leaf yellow tea is urgently required. In this study, a reliable strategy based on the data-acquisition technology of ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q TOF/MS) was established to rapidly screen and analyze the main chemical components of large-leaf yellow tea by combining the information of neutral loss groups and characteristic fragment ions. The chromatographic separation experiments were performed on a Waters ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm) with gradient elution using 0.1% formic acid aqueous solution and acetonitrile as the mobile phases. The flow rate was 0.2 mL/min, the sample volume was 2 μL, and the column temperature was 35 ℃. The mass spectral information of the components in a large-leaf yellow tea solution was collected using the full-information tandem MS (MSE) technique in positive and negative ion modes. The specific chemical components of large-leaf yellow tea was identified as follows. First, a self-established database of tea chemical components was constructed based on the literature. The mass spectral cleavage pathways of different types of compounds in large-leaf yellow tea were then sorted using reference substances, and the characteristics of the fragment ions and neutral loss groups were summarized. The precise mass-to-charge ratio of the target chemical components were then obtained based on the mass spectral information. Finally, the structures of the compounds in large-leaf yellow tea were confirmed based on their chromatographic retention times, mass spectral cleavage pathways, characteristic fragment ions, and neutral loss groups. A total of 87 chemical components, including 10 catechins, 32 flavonoids, 16 phenolic acids, 12 tannins, 6 theaflavins, and 11 compounds in other classes, were identified in large-leaf yellow tea. Representative compounds of various classes, including gallocatechin gallate, quercetin, vitexin, gallic acid, chlorogenic acid, 1,3,6-tri-O-galloyl-β-D-glucose, and theaflavin, were selected, and their characteristic fragment ions and neutral loss groups were investigated in detail to reveal the cleavage pathways of different types of compounds in large-leaf yellow tea. The UPLC-Q TOF/MS method established in this study can comprehensively identify the main chemical components of large-leaf yellow tea in a simple, highly sensitive, stable, and reliable manner. This study provides a scientific basis and data support for the discovery of functional ingredients and quality evaluation of large-leaf yellow tea.

Hyperspectral guidance for summer tea processing: Enhancing taste and aroma through short‐term cycled heaping

AbstractTo reduce the unpleasant flavor in tea infusion made from summer fresh leaves and lessen tea resource wastage, a short‐term cycled heaping method, addressing the temperature/moisture variations during prolonged heaping, was introduced to produce high‐quality yellow tea with significantly enhanced taste and aroma. Furthermore, a hyperspectral approach was developed to anticipate such improvements. Specifically, short‐term cycled heaping reduced summer tea's astringency and bitterness while increasing sweetness. Using near‐infrared spectroscopy, the multiplicative scatter correction (MSC)–support vector machine (SVM) model predicted tea umami with 66.25% precision and richness with 77.64% accuracy via standard normal variate (SNV)–SVM, based on epigallocatechin (EGC), epicatechin (EC), and gallocatechin gallate (GCG) variations. Aroma enhancement was forecasted by a hyperspectral–electronic nose regression model, achieving over 81.50% prediction accuracy for summer tea aromas in the visible spectrum and surpassing 73.45% in the near‐infrared domain, primarily attributed to pentanal, propanal, toluene, ethyl propionate, and 2,3‐pentanedione variations. Overall, hyperspectral‐guided summer tea processing, particularly for summer‐harvested leaves, shows potential in offering a valuable screening tool, enhancing quality, and efficiency in the tea industry and promoting sustainable development.

Use of Guazuma ulmifolia Lam. Stem Bark Extracts to Prevent High-Fat Diet Induced Metabolic Disorders in Mice.

This study aimed to evaluate the effects of supplementation with ethanolic and aqueous extracts from the bark of the stem of Guazuma ulmifolia in mice submitted to a high-fat diet as well as to evaluate the chemical composition of these extracts. The chemical composition and antioxidant potential was evaluated in aqueous and ethanolic extracts of the stem bark. The in vivo test consisted of evaluating the effects of the aqueous and ethanolic extracts of the stem bark on C57BL/6 mice receiving a high-fat diet. The animals were evaluated for weight gain, feed consumption, visceral adiposity, serum, and inflammatory and hormonal parameters. The results of the chemical analyses corroborate those obtained by the literature, which reported gallocatechin, epigallocatechin and epigallocatechin gallate. Compared with the ethanolic extract, the aqueous extract showed greater antioxidant capacity. Both extracts resulted in lower feed consumption in the animals, but they did not influence weight gain or visceral adiposity and resulted in varied changes in the lipid profile. In addition, they did not influence glucose tolerance, insulin sensitivity, or fasting blood glucose. Furthermore, the leptin levels increased, which may have contributed to satiety, but this was shown to have a negative impact on other inflammatory and hormonal parameters. Therefore, under the conditions of this study, the biologically active compounds present in the plant species Guazuma ulmifolia were not able to contribute to the treatment of metabolic changes related to the consumption of a high-fat diet.

An efficient method for tracing the geographic origin of Enshi Yulu fresh tea leaves based on near infrared spectroscopy combined with synergy interval PLS and genetic algorithm

This paper applies near-infrared spectroscopy (NIRS) and multiple chemometrics to efficiently distinguish the origins of fresh tea leaves. The key components were obtained using the partial least squares discriminant analysis (PLS-DA) method. PLS, synergy interval PLS (siPLS), principal component analysis (PCA), genetic algorithm (GA), and their combination methods were used to establish NIRS non-destructive discrimination models. Then, the practical application was examined using external samples. The study identified nine key components (variable importance for the projection (VIP) > 1): epigallocatechin, epicatechin, total sugar, water extracts, total catechins, gallocatechin gallate, tea polyphenols, gallocatechin, and epigallocatechin gallate. Of the six NIRS models, the siPLS-GA model that used 37 spectral data points produced the best results (Rp2 = 0.9706, RMSEP = 0.0772, RPD = 6.59). This model had a prediction accuracy of 96.67% for the prediction set samples and 93.33% for the external samples. It offers a rapid, precise, and non-invasive approach to monitor and regulate the illicit trade of fresh tea leaves, thereby guaranteeing the authenticity of Enshi Yulu products from the processing source and fostering the long-term prosperity and stability of the Enshi Yulu tea industry.

Effect of osmanthus hydrolat on the aroma quality and volatile components of osmanthus black tea

Osmanthus fragrans is an evergreen shrub with a pleasant fragrance and a wide range of applications in many fields. The condensed hydrolat obtained during the drying process of its fresh flowers was collected in a low-temperature vacuum environment and its sensory evaluation and volatile components were studied. The main aroma compounds in Osmanthus fragrans were dihydro-β-ionone, nonanal, β-cyclocitral, β-ionone, benzaldehyde, α-ionone, and 6-methyl-5-hepten-2-one, whose contents were used as the main evaluation criteria, and the hydrolats obtained under different scenting and drying times were compared. This process can effectively collect the aroma components in Osmanthus fragrans and the optimal drying conditions were 50 °C for 5 h. The hydrolat was used to provide the scent of osmanthus black tea, which had a fresher and mellower taste, while the fragrance of osmanthus was abundant. These results show that osmanthus hydrolat can be used to provide the scent of floral black tea. Chemical compounds studied in this article(−)-Catechin (PubChem CID: 1203); (−)-epigallocatechin gallate (PubChem CID: 65064); (−)-epicatechin gallate (PubChem CID: 367141); (−)-epigallocatechin (PubChem CID: 72277); (−)-epicatechin (PubChem CID: 72276); (−)-gallocatechin gallate (PubChem CID: 199472); (−)-catechin gallate (PubChem CID: 6419835); (−)-gallocatechin (PubChem CID: 9882981).

(-)-Gallocatechin Gallate: A Novel Chemical Marker to Distinguish Triadica cochinchinensis Honey.

Triadica cochinchinensis honey (TCH) is collected from the nectar of the medicinal plant T. cochinchinensis and is considered the most important honey variety in southern China. TCH has significant potential medicinal properties and commercial value. However, reliable markers for application in the authentication of TCH have not yet been established. Herein, a comprehensive characterization of the botanical origin and composition of TCH was conducted by determining the palynological characteristics and basic physicochemical parameters. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) was used to investigate the flavonoid profile composition of TCH, T. cochinchinensis nectar (TCN) and 11 other common varieties of Chinese commercial honey. (-)-Gallocatechin gallate (GCG) was identified as a reliable flavonoid marker for TCH, which was uniquely shared with TCN but absent in the other 11 honey types. Furthermore, the authentication method was validated, and an accurate quantification of GCG in TCH and TCN was conducted. Overall, GCG can be applied as a characteristic marker to identify the botanical origin of TCH.

Changes in phenolic compounds of Phyllanthus emblica juice during different storage temperature and pH conditions.

The aim of this experiment was to investigate the effect of storage temperature and pH on phenolic compounds of Phyllanthus emblica juice. Juice was stored at different temperatures and pH for 15 days and sampled on 2-day intervals. The browning index (BI, ABS420 nm), pH, centrifugal precipitation rate (CPR), and phenolic compounds were evaluated. The results showed 4°C and pH 2.5 could effectively inhibit browning and slow down pH drop of P. emblica juice. The result of orthogonal partial least square-discriminant analysis showed P. emblica juice stored at 4°C and pH 2.5 still had a similar phenolic composition, but at 20°C, 37°C, and pH 3.5, the score plots were concentrated only in the first 3 days. Additionally, gallic acid (GA) and ellagic acid (EA) were screened out to be the differential compounds for browning of P. emblica juice. The contents of GA, epigallocatechin (EGC), corilagin (CL), gallocatechin gallate (GCG), chebulagic acid (CA), 1,2,3,4,6-O-galloyl-d-glucose (PGG), and EA were more stable at 4°C and pH 2.5. Overall, during storage at 4°C and pH 2.5, it could inhibit the increase of GA and EA and decrease of CL, GCG, CA, and PGG, whereas EGC did not show significant difference between storage conditions. The CPR was higher at 4°C, while pH 2.5 could reduce the CPR. In conclusion, in order to maintain stability of phenolic compounds and extended storage period, the P. emblica juice could be stored at low temperature and adjust the pH to increase the stability of juice system.

(-)-Gallocatechin Gallate Mitigates Metabolic Syndrome-Associated Diabetic Nephropathy in db/db Mice.

Metabolic syndrome (MetS) significantly predisposes individuals to diabetes and is a prognostic factor for the progression of diabetic nephropathy (DN). This study aimed to evaluate the efficacy of (-)-gallocatechin gallate (GCG) in alleviating signs of MetS-associated DN in db/db mice. We administered GCG and monitored its effects on several metabolic parameters, including food and water intake, urinary output, blood glucose levels, glucose and insulin homeostasis, lipid profiles, blood pressure, and renal function biomarkers. The main findings indicated that GCG intervention led to marked improvements in these metabolic indicators and renal function, signifying its potential in managing MetS and DN. Furthermore, transcriptome analysis revealed substantial modifications in gene expression, notably the downregulation of pro-inflammatory genes such as S100a8, S100a9, Cd44, Socs3, Mmp3, Mmp9, Nlrp3, IL-1β, Osm, Ptgs2, and Lcn2 and the upregulation of the anti-oxidative gene Gstm3. These genetic alterations suggest significant effects on pathways related to inflammation and oxidative stress. In conclusion, GCG demonstrates therapeutic efficacy for MetS-associated DN, mitigating metabolic disturbances and enhancing renal health by modulating inflammatory and oxidative responses.

Development of UHPLC-Q-Exactive Orbitrap/MS Technique for Determination of Proanthocyanidins (PAs) Monomer Composition Content in Persimmon.

The main units of persimmon proanthocyanidins (PAs) are composed of flavan-3-ols including epigallocatechin gallate (EGCG) and gallocatechin gallate (GCG). Precise quantification of GCG is challenging due to its trace amounts in persimmon. In this study, to establish the optimal UHPLC-Q-Exactive Orbitrap/MS technique for the determination of PAs monomer composition in persimmon fruit flesh of different astringency types, mass spectrometry and chromatographic conditions were optimized. The results showed that when operating in negative ion mode, using a T3 chromatographic column (a type of C18 column with high-strength silica), acetonitrile as the organic phase, a 0.1% mobile phase acid content, and a mobile phase flow rate of 0.2 mL/min, the chromatographic peak shape and resolution of the PAs monomer composition improved. Additionally, there was no tailing phenomenon observed in the chromatographic peaks. At the same time, the intra-day and inter-day precision, stability, and recovery of the procedure were good. The relative standard deviation (RSD) of stability was less than 5%. The intra-day precision was in the range of 1.14% to 2.36%, and the inter-day precision ranged from 1.03% to 2.92%, both of which were less than 5%. The recovery rate ranged from 94.43% to 98.59% with an RSD less than 5%. The results showed that the UHPLC-Q-Exactive Orbitrap/MS technique established in this study can not only be used for the quantification of EGCG and GCG in persimmon fruit flesh but also be suitable for analyzing other PAs monomer compositions, providing robust support for the related research on persimmon PAs.

Microencapsulation of Grape Pomace Extracts with Alginate-Based Coatings by Freeze-Drying: Release Kinetics and In Vitro Bioaccessibility Assessment of Phenolic Compounds.

The phenols from grape pomace have remarkable beneficial effects on health prevention due to their biological activity, but these are often limited by their bioaccessibility in the gastrointestinal tract. Encapsulation could protect the phenolics during digestion and influence the controlled release in such an intestine where their potential absorption occurs. The influence of freeze-drying encapsulation with sodium alginate (SA) and its combination with gum Arabic (SA-GA) and gelatin (SA-GEL) on the encapsulation efficiency (EE) of phenol-rich grape pomace extract and the bioaccessibility index (BI) of phenolics during simulated digestion in vitro was investigated. The addition of a second coating to SA improved the EE, and the highest EE was obtained with SA-GEL (97.02-98.30%). The release of phenolics followed Fick's law of diffusion and the Korsmeyer-Peppas model best fitted the experimental data. The highest BI was found for the total phenolics (66.2-123.2%) and individual phenolics (epicatechin gallate 958.9%, gallocatechin gallate 987.3%) using the SA-GEL coating were used. This study shows that freeze-dried encapsulated extracts have the potential to be used for the preparation of various formulations containing natural phenolic compounds with the aim of increasing their bioaccessibility compared to formulations containing non-encapsulated extracts.

Impact of Storage Temperature on Green Tea Quality: Insights from Sensory Analysis and Chemical Composition

This study investigated the impact of storage temperatures (−20 °C, room temperature, and 40 °C) on the sensory evaluation, metabolites, and volatile compounds of green tea stored for 12 months. The sensory evaluation revealed that tea samples stored at −20 °C retained their emerald green colour, tender aroma, and refreshing taste. Green tea biochemical constituents, including water extracts and total free amino acids, were measured by Chinese National Standard Methods (GB/T 8305-2013 and GB/T 8314-2013). Tea polyphenols and flavonoids were determined using spectrophotometric methods, while phytochemicals were detected using validated HPLC, and volatile compounds were detected using validated gas chromatography coupled with triple quadrupole mass spectrometry. The analysis showed that tea polyphenols were highest at −20 °C, and flavonoids were significantly reduced at higher temperatures. A similar trend was observed for amino acids, soluble sugar content, and water extracts. Tea catechins, including (-)-epigallocatechin-3-gallate (EGCG) and (-)-gallocatechin gallate (GCG), were highest at −20 °C, showing their susceptibility to temperature. A volatile compound analysis revealed distinct profiles with variations in the abundance of compounds, such as di-methyl sulfide, phenyl ethyl alcohol, indole, and benzaldehyde. This study identifies temperature-sensitive compounds, providing insights into the mechanisms underlying tea quality deterioration during storage.

Exploring Beta-Lactamase Inhibitory Potential of Common Medicinal Plants

The use of ?-Lactam antibiotics improperly has significant negative effects on public safety and health around the world. It causes the disturbance of gut flora, the emergence of multi-drug-resistant bacteria, and environmental contamination. The focus of this investigation was the Gram-negative pathogens Escherichia coli (E. coli), and Pseudomonas aeruginosa (P. aeruginosa). Potent beta-lactamase inhibitors were found among phytochemicals from medicinal plants by in-silico analysis, with Gallocatechin gallate from Green tea and Glycyrrhetinic acid from Licorice being particularly effective against TEM-1 and IMP-1 ?-Lactamases, respectively. In-vitro analysis such as D-zone assay and time-kill assay showed that the methanolic plant extracts improved the effectiveness of antibiotics against these Gram-negative pathogens. This research emphasizes the potential of medicinal plants in combating ?-Lactam antibiotic resistance, offering alternative solutions to address this global health challenge.

Chemical composition and discrimination with volatile profiles of Yongchuan Xiuya green tea with different baking treatments

AbstractThis study aimed to explore the effects of different baking treatments on the quality of Yongchuan Xiuya (YCXY) green tea. It was found that a long time baking at low temperature was beneficial to keep green colour, faint scent, mellow and fresh taste quality, whereas baking under high temperature was adverse to the quality. Baking treatments slightly regulated (−)‐epigallocatechin, (−)‐epicatechin, (−)‐gallocatechin gallate, total chlorophyll and carotenoid. As the baking temperature rose, the content of tea polyphenols, gallic acid, catechins, caffeine, soluble sugar and polyphenols/amino acids ratio obviously decreased. A total of 40 kinds of volatiles were detected in these six tea samples. A model for aroma type discrimination was successfully established based on partial least squares‐discriminant analysis (PLS‐DA). Ten kinds of volatile substances were the key characteristic markers for the faint scent, chestnut aroma and high‐fired aroma types of YCXY green tea. 1‐hexanol, hotrienol and dimethyl sulfide were furtherly used to discriminant aroma type based on Fisher discriminant analysis (FDA).

In silico exploration of phenolics as modulators of penicillin binding protein (PBP) 2× of Streptococcus pneumoniae

Infections caused by multidrug-resistant Streptococcus pneumoniae remain the leading cause of pneumonia-related deaths in children < 5 years globally, and mutations in penicillin-binding protein (PBP) 2 × have been identified as the major cause of resistance in the organism to beta-lactams. Thus, the development of new modulators with enhanced binding of PBP2x is highly encouraged. In this study, phenolics, due to their reported antibacterial activities, were screened against the active site of PBP2x using structure-based pharmacophore and molecular docking techniques, and the ability of the top-hit phenolics to inhibit the active and allosteric sites of PBP2x was refined through 120 ns molecular dynamic simulation. Except for gallocatechin gallate and lysidicichin, respectively, at the active and allosteric sites of PBP2x, the top-hit phenolics had higher negative binding free energy (ΔGbind) than amoxicillin [active site (− 19.23 kcal/mol), allosteric site (− 33.75 kcal/mol)]. Although silicristin had the best broad-spectrum effects at the active (− 38.41 kcal/mol) and allosteric (− 50.54 kcal/mol) sites of PBP2x, the high thermodynamic entropy (4.90 Å) of the resulting complex might suggest the need for its possible structural refinement for enhanced potency. Interestingly, silicristin had a predicted synthetic feasibility score of < 5 and quantum calculations using the DFT B3LYP/6-31G+ (dp) revealed that silicristin is less stable and more reactive than amoxicillin. These findings point to the possible benefits of the top-hit phenolics, and most especially silicristin, in the direct and synergistic treatment of infections caused by S. pneumoniae. Accordingly, silicristin is currently the subject of further confirmatory in vitro research.

Characterization, Bioaccesibility and Antioxidant Activities of Phenolic Compounds Recovered from Yellow pea (Pisum sativum) Flour and Protein Isolate.

This study focused on studying the bioaccesible phenolic compounds (PCs) from yellow pea flour (F) and protein isolate (I). Total phenolic contents (TPC), PCs composition and antioxidant activities were analysed in ethanol 60% extracts obtained by applying ultrasound assisted extraction (UAE, 15min/40% amplitude). The preparation of I under alkaline conditions and the elimination of some soluble components at lower pH produced a change of PCs profile and antioxidant activity. After simulated gastrointestinal digestion (SGID) of both ingredients to obtain the digests FD and ID, notable changes in the PCs concentration and profiles could be demonstrated. FD presented a higher ORAC activity than ID (IC50 = 0.022 and 0.039mg GAE/g dm, respectively), but lower ABTS•+ activity (IC50 = 0.8 and 0.3mg GAE/g dm, respectively). After treatment with cholestyramine of extracts from FD and ID in order to eliminate bile salts and obtain the bioaccesible fractions FDb and IDb, ROS scavenging in H2O2-induced Caco2-TC7 cells was evaluated, registering a greater activity for ID respect to FD (IC50 = 0.042 and 0.017mg GAE/mL, respectively). These activities could be attributed to the major bioaccesible PCs: OH-tyrosol, polydatin, trans-resveratrol, rutin, (-)-epicatechin and (-)-gallocatechin gallate for FD; syringic (the most concentrated) and ellagic acids, trans-resveratrol, and (-)-gallocatechin gallate for ID, but probably other compounds such as peptides or amino acids can also contribute.