Catechin Derivatives Research Articles

Enzyme Inhibitory Activities, Phenolic Profile, and In Silico Studies of Sorbus torminalis Tree Bark Methanol Extract.

The different parts of Sorbus torminalis (L.) Crantz are used in traditional medicine for various conditions such as cardiac diseases, cough, and diabetes, indicating its significant medicinal potential. Therefore, the current investigation aimed to reveal the phenolic composition of the poorly studied S. torminalis methanol extract of the bark, as well as its capacity to inhibit enzymes relevant to cardiovascular, neurodegenerative, and metabolic diseases. A total of 28 phenolic components, including 20 procyanidins aglycones (A- and B-type), four procyanidin glycosides, catechin and its glycoside, and two (epi)catechin derivatives, were detected using LC-MS. The contents of total polyphenols (6.22 %), total tannins (3.04 %), condensed tannins (0.70 %), and total flavonoids (0.24 %) were determined spectrophotometrically, highlighting the considerable phenolic richness of the examined plant material. The concentration-dependent ability to inhibit α-amylase (IC50=130 μg /mL), α-glucosidase (IC50=312.13 μg /mL), acetylcholinesterase (IC50=156.46 μg /mL), butyrylcholinesterase (IC50=217.68 μg /mL), and angiotensin-converting enzyme (IC50=36.77 μg /mL) was demonstrated in vitro. The in silico approach showed that catechin, procyanidin B2 and C1, S. torminalis bark constituents, can form stable complexes with the target enzymes but with different binding affinity. The results supported the medicinal potential of S. torminalis bark and significantly expanded our knowledge of its chemistry, justifying further research.

Green and miniaturized ultrasonic-assisted extraction using natural deep eutectic solvents to extract phenolic compounds from tea samples

Natural deep eutectic solvents (NADES) have emerged as promising green solvents, particularly useful in sample treatment procedures. For the first time, different types of NADES were prepared and evaluated as potential phenolic extraction solvents from tea samples (Camellia sinensis). The NADES, composed of lactic acid:glycerol:water in a molar ratio of 1:1:3, provided the best results for the simultaneous extraction of the target phenolic compounds. This NADES was also characterized by using nuclear magnetic resonance (NMR), and the presence of nuclear Overhauser enhancement effects confirmed its supramolecular structure. The experimental conditions affecting the miniaturized ultrasonic-assisted extraction (UAE) were optimized to maximize extraction efficiency by performing a design of experiments. The proposed sample treatment was combined with ultra-high performance liquid-chromatography coupled to tandem mass spectrometry detection (UHPLC-MS/MS) to determine 21 phenolic compounds including catechin derivatives and other minor compounds. The UAE-UHPLC-MS/MS method was successfully characterized and applied to the analysis of various commercial green, black, white and red tea samples. In all cases, 18 phenolic compounds were determined with concentrations ranging from 0.3 to 29,125 mg kg−1. The proposed sample treatment is a high-throughput, easy, fast and robust alternative to conventional procedures, which reduces organic solvent consumption and costs, aligned with green sample preparation principles.

Medicinal Plants and Natural Products to Treat Obesity through Inhibiting Pancreatic Lipase: A Review (2020-2022)

: Pancreatic lipase is an enzyme that catalyzes the hydrolysis of triglycerides to monoglycerides and free fatty acids which promote and accelerate their absorption by the intestine, thus leading to obesity. Drugs that have numerous side effects explain the beneficial medicinal effect of plants resulting from their Phyto molecules that exhibit strong anti-lipase activity. The present review reveals the medical treatment and consequently the associated side effects. It also represents an update of various medicinal plants and their metabolites that act as lipase inhibitors published between (2020-2022). We have discussed 93 species belonging to 48 different plant families and numerous bioactive molecules exerting this activity. We have compared 29 species for their anti-lipase potential. Fabaceae and Lamiaceae were the most dominant with 7 species, and the highest percentage (95%) for pancreatic lipase inhibitory activity was recorded by “Filipendula kmtaschatia” from Rosaceae family while “Piper betle” from Piperaceae family showed the lowest percentage (15.9%). The medical treatments with low dose effect were liraglutide saxenda (3mg/day), also flavonoids, in particular catechin derivatives, which were the most potent in terms of pancreatic lipase inhibitory activity with the lowest IC50s. This study summarized medical and natural treatments that are used to treat obesity through inhibiting pancreatic lipase and delaying fat assimilation in the intestines. So far, more studies are needed for the use of these as herbal medicine for obesity. Conclusion: This study summarized medical and natural treatments that are used to treat obesity through inhibiting pancreatic lipase and delaying fat assimilation in the intestines. So far, more studies are needed for the use of these as herbal medicine for obesity.

Exploring the potential mechanisms of the ethyl acetate fraction of Hippophae rhamnoides L. seeds as a natural healing agent for wound repair

Ethnopharmacological relevanceSea buckthorn (Hippophae rhamnoides L.) has been designated a "medicine food homology" fruit by the National Health Commission of China due to its nutritional value. In traditional Chinese ethnomedicine, Hippophae rhamnoides L. is commonly used to treat nonhealing wounds such as burns, sores, and gastric ulcers. The aim of this study was to explore the healing effects of the ethyl acetate extract of sea buckthorn seeds (SBS-EF) on burn wounds. Aim of the studyThe primary objectives of this research were to determine the most effective medicinal site of action for treating burns with sea buckthorn seeds (SBS) and to investigate the underlying material basis and mechanisms of their therapeutic effects. Materials and methodsThe effects of different components of SBS-EF on the proliferation and migration of human skin fibroblasts (HSFs) were evaluated via MTT assays, scratch assays, transwell assays, and hydroxyproline secretion analysis. SBS-EF displayed the greatest activity amongst the extracts. Subsequent analyses included network pharmacology methodology, molecular docking studies, ultraperformance liquid chromatography UPLC-Orbitrap-Exploris-120-MS and a severe second-degree burn rat model to investigate the chemical constituents and potential therapeutic mechanisms of the SBS-EF. ResultsIn vitro studies demonstrated the efficacy of SBS-EF in promoting HSF growth and migration. UPLC-Orbitrap-Exploris-120-MS analysis revealed that SBS-EF had ten major constituents, with flavonoids being the predominant compounds, especially catechin, quercetin, and kaempferol derivatives. Network pharmacology and molecular docking analyses indicated that SBS-EF may exert its healing effects by modulating the Wnt/β-catenin signalling pathway. Subsequent in vivo experiments demonstrated that SBS-EF accelerated burn wound healing in rats, increased hydroxyproline expression in skin tissue, facilitated skin structure repair, and enhanced collagen production and organisation over a 21 d period. Additionally, exposure to SBS-EF upregulated WNT3a and β-catenin while downregulating GSK-3β levels in rat skin tissue. ConclusionsThe wound healing properties of SBS-EF were attributed to its ability to enhance HSF growth and migration, increase hydroxyproline levels in the skin, promote collagen accumulation, reduce scarring, and decrease the skin water content. SBS-EF may also provide therapeutic benefits for burns by modulating the Wnt/β-catenin signalling pathway, as evidenced by its effective site and likely mechanism of action in the treatment of burned rats.

Children of Nature: Thoughts on Targeted and Untargeted Analytical Approaches to Decipher Polyphenol Reactivity in Food Processing and Metabolism.

Following 25 years of polyphenol research in our laboratory, the astonishing chemical and metabolic reactivity of polyphenols resulting in considerable chemical diversity has emerged as the most remarkable attribute of this class of natural products. To illustrate this concept, we will present selected data from black tea and coffee chemistry. In black tea chemistry, enzymatic fermentation converts six catechin derivatives into an estimated 30 000 different polyphenolic compounds via a process we have termed the oxidative cascade process. In coffee roasting, around 45 chlorogenic acids are converted into an estimated 250 novel derivatives following a series of diverse chemical transformations. Following ingestion by humans, these dietary polyphenols, whether genuine secondary metabolites or food processing products, encounter the microorganisms of the gut microbiota, converting them into a myriad of novel structures. In the case of coffee, only two out of 250 chlorogenic acids are absorbed intact, with most others being subject to gut microbial metabolism. Modern mass spectrometry (MS) has been key in unravelling the true complexity of polyphenols subjected to food processing and metabolism. We will accompany this assay with a short overview on analytical strategies developed, including ultrahigh-resolution MS, tandem MS, multivariate statistics, and molecular networking that allow an insight into the fascinating chemical processes surrounding dietary polyphenols. Finally, experimental results studying biological activity of polyphenols will be presented and discussed, highlighting a general promiscuity of this class of compounds associated with nonselective protein binding leading to loss of enzymatic function, another noteworthy general property of many dietary polyphenols frequently overlooked.

Chemical composition, antioxidant and antimicrobial activities of Vaccinium macrocarpon (Ericaceae) and Camellia sinensis (Theaceae) extracts

In the modern scientific community, considerable attention is given to studying the pharmacological activity of catechin and anthocyanin derivatives. However, a comparative analysis of the antioxidant and antimicrobial activities of extracts rich in anthocyanins and catechins has not been previously conducted. So, the purpose of this work was to study and compare phytochemical composition, antimicrobial and antioxidant potential of Vaccinium macrocarpon L., Ericaceae fruit thick and Camellia sinensis L., Theaceae leaf liquid extracts. The quantification of biologically active substances (BAS) was accomplished with spectrophotometric, titrimetric and HPLC methods of analysis; antioxidant activity was determined by the potentiometric method; antimicrobial and anti-fungi effects was evaluated by the well method and minimum inhibition concentration. The total content of phenolic compounds was 0.47% and 10.10%, organic acids – 4.27% and 1.60% for V. macrocarpon fruit thick and C. sinensis leaf extract. The total content of catechins in the C. sinensis leaf extract was 105,000 mg/kg, where epicatechin-3-O-gallate dominated (37300 mg/kg). The total content of anthocyanins in the V. macrocarpon fruit thick extract was 1280 mg/kg, where peonidin-3-O-galactoside dominated (408 mg/kg). Both extracts possessed a high antioxidant potential, and effective antimicrobial and anti-fungi effects. The antioxidant, antimicrobial and anti-fungi activity of V. macrocarpon fruit extract was higher than C. sinensis leaf extract. In addition, we assumed that anthocyanins had higher antioxidant, antimicrobial and anti-fungi properties than catechins. These findings would promote application of V. macrocarpon fruits extract as pharmaceuticals and nutraceuticals.

Pruned tea biomass plays a significant role in functional food production: A review on characterization and comprehensive utilization of abandon-plucked fresh tea leaves.

Tea is the second largest nonalcoholic beverage in the world due to its characteristic flavor and well-known functional properties in vitro and in vivo. Global tea production reaches 6.397 million tons in 2022 and continues to rise. Fresh tea leaves are mainly harvested in spring, whereas thousands of tons are discarded in summer and autumn. Herein, pruned tea biomass refers to abandon-plucked leaves being pruned in the non-plucking period, especially in summer and autumn. At present, no relevant concluding remarks have been made on this undervalued biomass. This review summarizes the seasonal differences of intrinsic metabolites and pays special attention to the most critical bioactive and flavor compounds, including polyphenols, theanine, and caffeine. Additionally, meaningful and profound methods to transform abandon-plucked fresh tea leaves into high-value products are reviewed. In summer and autumn, tea plants accumulate much more phenols than in spring, especially epigallocatechin gallate (galloyl catechin), anthocyanins (catechin derivatives), and proanthocyanidins (polymerized catechins). Vigorous carbon metabolism induced by high light intensity and temperature in summer and autumn also accumulates carbohydrates, such as soluble sugars and cellulose. The characteristics of abandon-plucked tea leaves make them not ideal raw materials for tea, but suitable for novel tea products like beverages and food ingredients using traditional or hybrid technologies such as enzymatic transformation, microbial fermentation, formula screening, and extraction, with the abundant polyphenols in summer and autumn tea serving as prominent flavor and bioactive contributors.

Extraction and Purification of Catechins from Tea Leaves: An Overview of Methods, Advantages, and Disadvantages

This review study explores the complex methods involved in the extraction and purification of polyphenols, specifically catechins, prominent compounds that are bioactive and found in plant-based extracts and foods like tea. This study also addresses the challenges that may arise from the complex chemical structure of catechins and their inherent variability across botanical sources. Despite these shortcomings and obstacles, catechins and catechin derivatives present significant potential, particularly in healthcare but also in the food industry. Their enhanced antioxidant properties have been exhaustively investigated and associated with countless health benefits, making them promising agents with numerous applications, most notably in healthcare against chronic diseases. Furthermore, catechins have numerous applications across various industries, including food and beverage, cosmetics, agriculture, and materials science. This review is a compilation of the most notable and recent research found in the literature and emphasizes the importance of continued research and innovation in catechin separation, extraction, and utilization, which hold promise for advancing human health and technological progress across multiple domains.

Impact of Drying Method and Solvent Extraction on Ethiopian Verbascum sinaiticum (Qetetina) Leaves: Metabolite Profiling and Evaluation of Antioxidant Capacity

The aim of this study was to evaluate the effects of different drying methods on bioactive compounds and to analyze their composition in Verbascum sinaiticum (V. sinaiticum) leaf extracts using UHPLC-ESI-QTOF-MS/MS. V. sinaiticum is traditionally used as an herbal medicine, yet it has undergone limited scientific investigations regarding its secondary metabolites. V. sinaiticum leaves were dried using oven dryers at 50 °C, 60 °C, and 70 °C, as well as a freeze dryer. The leaves were then extracted using 50% and 70% aqueous ethanol and 100% aqueous solutions. The results showed that the highest contents of TPC and TFC were observed when 70% aqueous ethanol was used during freeze drying, reaching 181.73 mg GAE/g dw and 78.57 mg CE/g dw, respectively. The strongest correlations were observed between the TFC and DPPH radical scavenging activity (0.9082), followed by TPC and ABTS assays (0.8933) and TPC and DPPH (0.8272). In the FTIR analysis, freeze drying exhibited a lower intensity of the phenolic -OH functional groups, contrasting with significant denaturation observed during oven drying at 70 °C. Metabolite analysis identified 29 compounds in V. sinaiticum leaves, further confirming the presence of 14 phenolic and flavonoid compounds, including kaempferol, catechin, gallic acid, and myricetin derivatives, consistent with the experimentally observed antioxidant capacity. This study highlights the impact of drying methods on the bioactive composition of V. sinaiticum and underscores its potential as a source of antioxidants for food, nutraceutical, and pharmaceutical applications.

Unraveling the transcriptional regulators of polyphenolic variation in Thymus daenensis Celak

Due to its economic value and antioxidant phenolic compositions, there is a growing interest for Thymus daenensis in the food, cosmetic, and pharmaceutical industries. The current study was motivated by the paucity of studies on the molecular regulation of polyphenols and flavonoids in T. daenensis. From breeding materials, we selected and explored the transcriptome profiles of two chemotypes (‘Zagheh-11’ and ‘Malayer-21’). Tandem mass spectrometry identified 14 phenolic and flavonoid compounds in T. daenensis. Quantitative HPLC-PDA also revealed that ‘Zagheh-11’ contains higher amounts of flavonoids (luteolin, apigenin, kaempferol, quercetin, and catechin derivatives), while ‘Malayer-21’ was a rich source of rosmarinic acid. RNA-seq data mining indicated that 1840 unigenes have differential expression (DE) patterns between these chemotypes. Mapping of unigenes in flavonoids and phenylpropanoids pathways identified a total of 74% and 45% of structural genes, respectively. Four out of 15 DE unigenes in the aforementioned pathways played a key role in the metabolic divergence of these genotypes. RNA-seq and qRT-PCR indicated that the richness of flavonoids in ‘Zagheh-11’ was driven by higher expression of chalcone isomerase (CHI) and flavonoid 3′-hydroxlase (F3′H). In contrast, overexpression of phenylalanine ammonia lyase (PAL) and rosmarinic acid synthase (RAS) coincided with enhanced accumulation of rosmarinic acid in ‘Malayer-21’. To further understanding of these four key genes, we performed bioinformatic and structural analysis on their complete coding sequences. These findings should improve knowledge on how specialized metabolites are governed by transcriptional regulators and which are suitable for targeted metabolic engineering.

Assessing the stability of polyphenol content in red rooibos herbal tea using traditional methods and high-resolution mass spectrometry: Implications for studying dietary interventions in preclinical rodent studies

Preclinical rodent models are used to examine the relationship between tea consumption and bone health, where tea is available for rodents and typically replaced weekly. However, the extent to which the tea polyphenols change over time remains uncertain, despite its importance in preparing tea during preclinical rodent trials. Using an untargeted molecular approach, we applied a liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOFMS) system to assess the molecular profile of red rooibos teas throughout a 6-day aging period. We found a significant, 3-fold decrease of polyphenols involved in bone metabolism, including m-coumaric acid, catechin derivatives and courmaroyl tartaric acid over 6 days, likely due to photochemical decomposition and autooxidation within tea extracts. Using a novel untargeted workflow for polyphenol characterization, our findings revealed the complexity of polyphenols in red rooibos teas that can inform the evidence-based decisions of how often to change teas during in vivo rodent trials.

Targeted Offline Two-Dimensional HPLC and UHPLC-Orbitrap-MS Combined with Molecular Networking Reveal the Effect of Processing on Chemical Constituents of Xuetong (the Stem of Kadsura heteroclita)

Xuetong, the dried stem of Kadsura heteroclita (Roxb.) Craib, is a traditional Tujia medicine extensively used to treat rheumatoid arthritis (RA). All traditional Chinese medicines (TCMs) necessitate a processing stage called “Paozhi” before clinical application. However, there is a dearth of research concerning the processing methods employed for Xuetong. To investigate the impact of vinegar and wine processing on the chemical constituents of Xuetong, this study devised a targeted offline two-dimensional (2D) high-performance liquid chromatography (HPLC) and ultra-high-performance liquid chromatography-orbitrap mass spectrometry (UHPLC-orbitrap-MS) method. By incorporating various MS data-processing techniques, such as molecular networking technology, fragment-ion similarity searching (FISh), online and offline database matching, and fragmentation pattern analysis, a total of 158 components were identified in Xuetong. Among them, 14 were verified by comparison with the reference standards. Notably, aside from triterpenoids and lignans, catechin derivatives were found to be the predominant constituents of Xuetong, and their levels exhibited a significant decrease following processing. This method significantly improved peak capacity and resolution, overcoming the limitations of 1D LC in simultaneously analyzing highly polar catechin derivatives and less polar triterpenoids and lignans. Moreover, the developed method shows promise for Xuetong’s quality control.

Processing of Reynoutria multiflora: transformation of catechin and gallic acid derivatives and their identification.

Introduction: The root of Reynoutria multiflora (Thunb.) Moldenke (RM) has been used widely in formulations of herbal medicines in China for centuries. Raw R. multiflora (RRM) should be processed before use to reduce toxicity and increase efficacy. However, detailed regulation of the processing endpoint is lacking, and the duration of processing can vary considerably. We conducted in-depth research on stilbene glycosides in RM at different processing times. Previously, we discovered that 219 stilbene glycosides changed markedly in quantity and content. Therefore, we proposed that processing causes changes in various chemical groups. Methods: To better explain the mechanism of RM processing for toxicity reduction and efficacy enhancement, we used a method of tandem mass spectrometry described previously to research gallic acid based and catechin based metabolites. Results: A total of 259 metabolites based on gallic acid and 112 metabolites based on catechins were identified. Among these, the peak areas of 157 gallic acid and 81 catechins gradually decreased, those of another 71 gallic acid and 30 catechins first increased and then decreased, those of 14 gallic acid and 1 catechin gradually increased. However, 17 of the gallic acids showed no significant changes. We speculate that many gallic acid metabolites hydrolyze to produce gallic acid; moreover, the dimers/trimers of catechins, after being cleaved into catechins, epicatechin, gallic acid catechins, and epicatechin monomers, are cleaved into gallic acid and protocatechualdehyde under high temperature and high humidity, subsequently participating in the Maillard reaction and browning reactions. Discussion: We showed that processing led to changes in chemical groups, clarification of the groups of secondary metabolites could provide a basis for research on the pharmacological and toxic mechanisms of RM, as well as the screening of related markers.

A randomized placebo-controlled clinical trial of oral green tea epigallocatechin 3-gallate on erythropoiesis and oxidative stress in transfusion-dependent β-thalassemia patients.

β-Thalassemia patients suffer from ineffective erythropoiesis and increased red blood cell (RBC) hemolysis. Blood transfusion, erythropoietic enhancement, and antioxidant supplementation can ameliorate chronic anemia. Green tea extract (GTE) is comprised of catechin derivatives, of which epigallocatechin-3-gallate (EGCG) is the most abundant, presenting free-radical scavenging, iron-chelating, and erythropoiesis-protective effects. The present study aimed to evaluate the effects of GTE tablets on the primary outcome of erythropoiesis and oxidative stress parameters in transfusion-dependent β-thalassemia (TDT) patients. Twenty-seven TDT patients were randomly divided into placebo and GTE tablet (50 and 100mg EGCG equivalent) groups and assigned to consume the product once daily for 60days. Blood was collected for analysis of hematological, biochemical, and oxidative stress parameters. Accordingly, consumption of GTE tablets improved blood hemoglobin levels when compared with the placebo; however, there were more responders to the GTE tablets. Interestingly, amounts of nonheme iron in RBC membranes tended to decrease in both GTE tablet groups when compared with the placebo. Importantly, consumption of GTE tablets lowered plasma levels of erythroferrone (p < 0.05) and reduced bilirubin non-significantly and dose-independently. Thus, GTE tablets could improve RBC hemolysis and modulate erythropoiesis regulators in transfusion-dependent thalassemia patients.

Inhibition of pancreatic lipase by coffee leaves-derived polyphenols: A mechanistic study

The suppression of pancreatic lipase has been employed to mitigate obesity. This study explored the mechanism of coffee leaf extracts to inhibit pancreatic lipase. The ethyl acetate fraction derived from coffee leaves (EAC) exhibited the highest inhibitory capacity with a half-maximal inhibitory concentration (IC50) of 0.469 mg/mL and an inhibitor constant (Ki) of 0.185 mg/mL. This fraction was enriched with 3,5-dicaffeoylquinic acid (3,5-diCQA, 146.50 mg/g), epicatechin (87.51 mg/g), and isoquercetin (48.29 mg/g). EAC inhibited lipase in a reversible and competitive manner, and quenched its intrinsic fluorescence through a static mechanism. Molecular docking revealed that bioactive compounds in EAC bind to key amino acid residues (HIS-263, PHE-77, and SER-152) located within the active cavity of lipase. Catechin derivatives play a key role in the lipase inhibitory activity within EAC. Overall, our findings highlight the promising potential of coffee leaf extract as a functional ingredient for alleviating obesity through inhibition of lipase.

A potential antiviral against COVID-19 obtained from Byrsonima coccolobifolia leaves extract

In this study, we specifically focused on the crude methanolic leaf extract of Byrsonima coccolobifolia, investigating its antifungal potential against human pathogenic fungi and its antiviral activity against COVID-19. Through the use of high-performance liquid chromatography coupled with electrospray ionization ion trap tandem mass spectrometry, direct infusion electrospray ionization ion trap tandem mass spectrometry, and chromatographic dereplication procedures, we identified galloyl quinic acid derivatives, catechin derivatives, proanthocyanidins, and flavonoid glycosides. The broth dilution assay revealed that the methanolic leaf extract of B. coccolobifolia exhibits antifungal activity against Cryptococcus neoformans (IC50 = 4 μg/mL). Additionally, docking studies were conducted to elucidate the interactions between the identified compounds and the central residues at the binding site of biological targets associated with COVID-19. Furthermore, the extract demonstrated an in vitro half-maximum effective concentration (EC50 = 7 μg/mL) and exhibited significant selectivity (>90%) toward SARS-CoV-2.

Bioactive agents from Parkia biglobosa (Jacq.) R.Br. ex G. Don bark extracts for health promotion and nutraceutical uses.

Parkia biglobosa stem bark extracts were prepared using methanol, methanol 80%, water and ethyl acetate to investigate their phytochemical contents, as well as antioxidant and enzyme inhibitory properties. Liquid chromatography (LC) quadrupole time-of-flight mass spectrometry (MS) and LC-MSn revealed the presence of flavonoids, hydroxycinnamic acid derivatives and gallotannins. Particularly, the water extract contained rutin (480 μg per 100 mg) and 3-caffeoylquinic acid (1109 μg per 100 mg) in higher amounts, whereas the 80% methanol extract contains methoxyluteolin-7-O-rutinoside and catechin derivatives as major compounds. Total phenolic and flavonoid contents of the extracts were yielded in the range of 32.26-119.88 mg gallic acid equivalents g-1 and 0.60-2.39 mg rutin equivalents g-1 , respectively. Total antioxidant capacity was also displayed in the range of 0.53-6.34 mmol Trolox equivalents (TE) g-1 . Both the methanolic extracts showed higher total antioxidant capacity that could be related to the total phenolic contents. Radical scavenging capacity in DPPH (2,2-diphenyl-2-picryl-hydrazyl) (37.21-508.30 mg TE g-1 ) and ABTS [2,2-azinobis(3-ethylbenzothiazoline- 6-sulfonic acid)] (60.95-1068.06 mg TE g-1 ) assays, reducing power in cupric ion reducing antioxidant capacity (54.23-1002.78 mg TE g-1 ) and ferric ion reducing antioxidant power (33.18-558.68 mg TE g-1 ) assays, as well as metal chelating activity (2.45-11.28 mg EDTA equivalents g-1 ), were exhibited by all extracts. All extracts were found to inhibit acetylcholinesterase [0.23-2.47 mg galanthamine equivalents (GALAE) g-1 ], tyrosinase [27.20-83.33 mg kojic acid equivalents g-1 ], amylase [mmol acarbose equivalents (ACAE) g-1 ]. On the other hand, all extracts, except the water extract, inhibited butyrylcholinesterase (5.38-6.56 mg GALAE g-1 ), whereas only the water and ethyl acetate extract showed glucosidase inhibitory potential (1.96 and 1.82 mmol ACAE g-1 ). In general, the water extract was found to be a weaker enzyme inhibitor suggesting that water is not the preferrable extraction solvent to obtain active products. The present study demonstrated that the stem bark extracts of P. biglobosa contains good amount of phytochemical and extracts present significant antioxidant, as well as reasonable enzyme inhibitory effects. Hence, these findings suggest that further studies can be performed on more specific biological targets and models of bioactivity to determine their safe usage as a nutraceutical or for the preparation functional foods. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Green tea extracts and substantial catechin derivatives: Evaluation of their potential against breast cancer

Breast cancer is one of the most predominant types of cancer. Although assorted treatment options are available to cope with breast cancer (e.g. chemotherapy, radiotherapy, surgery, hormone therapy, targeted therapy), chemotherapy regimens still hold vital importance. Studies on the discovery of drug-candidate molecules that can create an alternative in the treatment of breast cancer continue at full speed. At this point, nature has a substantial place offering great diversity. Natural products may exhibit anticancer properties directly through molecular targets such as genes or indirectly through metabolic pathways. Moreover, they may be adjuvant agents and contribute to conventional therapy, and thus, they can enhance the efficacy of chemotherapeutics or even ease their side effects. Green tea, a critical dietary source of polyphenols and flavonoids, is obtained from the minimally fermented or unfermented leaves of the Camellia sinensis L. plant and is used in traditional Chinese medicine for many important conditions, including cancer. The phytochemical content of green tea is extremely rich, including (-)-epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC); (-)-epicatechin-3-gallate (ECG) and (-)-epicatechin (EC) as the main catechins in the composition of green tea. Within the scope of our study, we proposed the cytotoxicity and toxicity comparison of the water and 80% ethanolic extract of the green tea extracts as well as of (-)-epicatechin (EC) and (-)-epigallocatechin (EGC) in terms of their cytotoxicity and toxicity based on the structure-activity relationship on breast cancer. Therefore, we tested aqueous and 80% ethanolic extracts of green tea and EGC and EC on MDA-MB-231, MDA-BMB-468, MCF-7 and SK-BR-3 breast cancer cells. Their toxicity on healthy rat myoblastoma H9c2 cells was further examined. Resazurin reduction assay was used to detect cytotoxicity and toxicity. Both water and 80% ethanolic extract of green tea exhibited remarkable cytotoxicity on MCF-7 cancer cells deserving further investigation, including phytochemical characterization of the extract. Epigallocatechin was also cytotoxic on MCF-7 cells with an IC50 value of 20.07 µM. The possible therapeutic potentials of green tea extracts and their substantial catechin derivatives were assessed for breast cancer therapy.

Real-time monitoring of the amyloid β1-42 monomer-to-oligomer channel transition using a lipid bilayer system.

This study describes the observation of the transformation of monomeric amyloid β1-42 (Aβ42) into oligomers in a lipid membrane utilizing a lipid bilayer system for electrophysiological measurement. The relevance of oligomers and protofibrils in Alzheimer's disease (AD) is underscored given their significant neurotoxicity. By closely monitoring the shift of Aβ42 from its monomeric state to forming oligomeric channels in phospholipid membranes, we noted that this transformation transpired within a 2-h frame. We manipulated the lipid membrane's constitution with components such as glycerophospholipid, porcine brain total lipid extract, sphingomyelin (SM), and cholesterol (Chol.) to effectively imitate nerve cell membranes. Interesting findings showcased Chol.'s ability to foster stable oligomeric channel formation in the lipid membrane, with SM and GM1 lipids potentially enhancing channel formation as well. Additionally, the study identified the potential of a catechin derivative, epigallocatechin gallate (EGCG), in obstructing oligomerization. With EGCG present in the outer solution of the Aβ42-infused membrane, a noteworthy reduction in channel current was observed, suggesting the successful inhibition of oligomerization. This conclusion held true in both, prior and subsequent, stages of oligomerization. Our findings shed light on the toxicity of oligomers, promising invaluable information for future advancements in AD treatment strategies.

“Green” synthesized versus chemically synthesized zinc oxide nanoparticles: In vivo antihyperglycemic activity and pharmacokinetics

Zinc is one of the most studied trace elements, commonly used as supplement in diabetes treatment. By its involvement in the synthesis, secretion of insulin, promotion of insulin sensitivity and its multiple enzymatic functions it is known to contribute to reduce hyperglycemia. Researchers have shown that zinc administered under the form of zinc oxide nanoparticles (ZnONPs) is more effective than under its ionic form. Studies evaluating the antihyperglycemic activity of these nanocarriers include both ZnONPs synthesised using plants (i.e. green synthesized) or chemically synthesized. The present work aims to compare green synthesized ZnONPs with the marketed chemically synthesized ones. Green ZnONPs were synthesized using the aqueous extract of the stem bark of the medicinal plant Panda oleosa and zinc nitrate hexahydrate. Both nanocarriers were compared in terms of optical properties, morphology, composition, chemical functions, resistance to oxidation, in vivo antihyperglycemic activity via oral glucose tolerance test (OGTT) and pharmacokinetics in relation to zinc in C57BL/6J mice. A UV absorption peak was observed at 354 nm and 374 nm for the green and marketed ZnONPs, respectively. The shape and hydrodynamic diameters were anisotropic and of 228.8 ± 3.0 nm for the green ZnONPs and spherical and of 225.6 ± 0.9 nm for the marketed ZnONPs. Phenolic compounds accounted for 2.58 ± 0.04% of the green ZnONPs and allowed them to be more stable and unaffected by an oxidizing agent during the experiment, while the marketed chemically synthesized ZnONPs aggregated with or without contact with an oxidizing agent. No significant differences were observed on the amounts of zinc absorbed when comparing green ZnONPs, chemically synthesized ZnONPs and zinc sulfate in a pharmacokinetics study in normoglycemic mice. When evaluating the in vivo hypoglycemic activity of the nanocarriers in obese/diabetic mice, green synthesized ZnONPs displayed a significant hypoglycemic effect compared with the chemically synthesized nanoparticles following an OGTT. Altogether, these data indicate that phytocompounds, as catechin derivatives and polyphenols, attached to the green synthesized ZnONPs’ surface, could contribute to their hypoglycemic activity. The comparison thus demonstrated that green synthesized ZnONPs are significantly more efficient than chemically ones at reducing hyperglycemia regardless of their absorption.