Tannin complexation with metal ions and its implication on human health, environment and industry: An overview

Plant Secondary Metabolites-Central Regulators Against Abiotic and Biotic Stresses

As global climates shift, plants are increasingly exposed to biotic and abiotic stresses that adversely affect their growth and development, ultimately reducing agricultural productivity. To counter these stresses, plants produce secondary metabolites (SMs), which are critical biochemical and essential compounds that serve as primary defense mechanisms. These diverse compounds, such as alkaloids, flavonoids, phenolic compounds, and nitrogen/sulfur-containing compounds, act as natural protectants against herbivores, pathogens, and oxidative stress. Despite the well-documented protective roles of SMs, the precise mechanisms by which environmental factors modulate their accumulation under different stress conditions are not fully understood. This review provides comprehensive insights into the recent advances in understanding the functions of SMs in plant defense against abiotic and biotic stresses, emphasizing their regulatory networks and biosynthetic pathways. Furthermore, we explored the unique contributions of individual SM classes to stress responses while integrating the findings across the entire spectrum of SM diversity, providing a comprehensive understanding of their roles in plant resilience under multiple stress conditions. Finally, we highlight the emerging strategies for harnessing SMs to improve crop resilience through genetic engineering and present novel solutions to enhance agricultural sustainability in a changing climate.

Glycine betaine enhances heavy metal phytoremediation via rhizosphere modulation and nitrogen metabolism in king grass-Serratia marcescens strain S27 symbiosis

Microbe-Assisted Phytoremediation (MAP) is an eco-friendly method for remediating soil contaminated with heavy metals such as cadmium (Cd) and chromium (Cr). This study demonstrates the potential of a king grass-Serratia marcescens strain S27 (KS) co-symbiotic system to enhance heavy metal remediation. The KS symbiosis increased the biomass of king grass by 48 % and enhanced the accumulation of Cd and Cr in the whole plant by 2.75-fold and 1.82-fold, respectively. Root exudates like γ-aminobutyric acid (GABA), glycine betaine (GB), and allantoin (Alla) were tested for enhancing the KS symbiotic, with 0.75 mM GB (GB3X-KS) showing the highest removal efficiencies at 15.1 % for Cd and 14.2 % for Cr. Correlation analysis indicated a link between this enhancement and increased soil nitrogen content. Mechanistic studies revealed GB treatment altered the rhizosphere microbial community, promoting denitrifying bacteria and upregulating nitrogen transformation genes (nrfA) by over 7-fold. GB also enhanced nitrogen assimilation enzymes and antioxidant defenses in king grass, facilitating Cd and Cr transport and sequestration. X-ray fluorescence imaging and two-dimensional correlation spectroscopy showed GB promoted Cd and Cr accumulation in the xylem and phloem of king grass, with phenols and alcohols as key functional groups. The study highlights the potential of the GB-KS symbiotic system for effective soil remediation.

Tannic acid-based bio-MOFs with antibacterial and antioxidant properties acquiring non-hemolytic and non-cytotoxic characteristics

Tannic acid (TA) based bio-metal phenolic networks (bio-MPNs) were prepared by using Cu(II), Zn(II), Bi(III), Ce(III), La(III), and Ti(IV) metal ions. TA-based bio-MPNs exhibited wedge-shaped pores between 16.4 and 25.8 nm pore size ranges. The higher gravimetric yield% was achieved for TA-Bi(III), and TA-Ti(IV) bio-MPNs with more than 90 %, and higher surface area was observed for TA-La(IIII) bio-MPNs as 56.2 m2/g with 17.3 nm average pore sizes. All TA-based MPNs are non-hemolytic with less than 5 % hemolysis ratio, whereas TA-based Bio-MPNs do not affect blood clotting with > 90 % blood clotting indexes except for TA-Cu(II) Bio-MPNs at 0.1 mg/mL concentration. Moreover, TA-Bi(III) and TA-Ce(III) Bio-MPNs were found to be safer materials showing no significant toxicity on L929 fibroblast cells at 100 μg/mL concentration, along with TA-based Bio-MPNs prepared with Cu(II), Zn(II), La(III), and Ti(IV) metal ions that could be safely used in in vivo applications at 1 μg/mL concentration. It has been proven by 2 different antioxidant tests that the prepared TA-based Bio-MPNs show antioxidant properties even if their TA-derived antioxidant properties decrease. Furthermore, all types of TA-based Bio-MPNs show great antimicrobial activity depending on the metal ion or microorganism types and the highest antibacterial/antifungal effect was determined for TA-Cu(II), and TA-Zn(II) Bio-MPNs with the lowest MBC/MFC values against Pseudomonas aeruginosa ATCC 10145, Bacillus subtilis ATCC 6633, and Candida albicans ATCC 10231.

Unlocking the structure-activity relationship of mangrove condensed and hydrolysable tannins: Unveiling their potential ecological significance in antioxidant and antibacterial functions

Tannins play key roles in regulating ecological processes within mangrove ecosystems, but the structures of mangrove condensed tannins (CT) and hydrolysable tannins (HT), as well as their antioxidant and antibacterial activities, are not well understood. In this study, MALDI-TOF MS was used to analyze the structural components of oligomers and polymers in phenolic extracts from Kandelia obovata, Aegiceras corniculatum, and Sonneratia apetala. Results identified two primary structural units: procyanidins (PC) and prodelphinidins (PD), with mass-to-charge ratios of 288 Da and 304 Da, respectively, and a 16 Da interval indicating differences in hydroxylation. Thiolysis degradation and acidic hydrolysis, combined with HPLC-ESI-MS, revealed significant variations in the mean degree of polymerization (mDP): oligomers had mDP values of 1.1-1.2, while polymers ranged from 7.8 to 9.1. Antioxidant assays (Folin-Ciocalteu, FRAP, TEAC, and DPPH) showed that PC < PD < HT in antioxidant capacity, with polymers exhibiting stronger activity than oligomers. Antibacterial tests revealed that A. corniculatum exhibited the weakest activity, while K. obovata and S. apetala showed similar efficacy against bacteria from Actinobacteria, Bacteroidetes, and Proteobacteria. This study enhances our understanding of mangrove phenolics' structural characteristics and their ecological roles in maintaining mangrove ecosystem functions.

Therapeutic potential and limitation of condensed and hydrolyzed tannins in Parkinson's disease

Parkinson's disease is a complex neurodegenerative disorder characterized by neuroinflammation, mitochondrial dysfunction, and the accumulation of misfolded proteins such as α-synuclein. This review explores the therapeutic potential of tannins, particularly proanthocyanidins and hydrolyzable tannins from grape seeds, in alleviating Parkinson's disease pathology. Condensed tannins exhibit significant antioxidant properties, can cross the blood-brain barrier, reduce oxidative stress, upregulate antioxidant proteins, and prevent neuronal apoptosis. Hydrolyzable tannins, through their unique chemical structure, further help reduce neuroinflammation and improve mitochondrial function. Both types of tannins can modulate inflammatory responses and enhance mitochondrial integrity, addressing key aspects of Parkinson's disease pathogenesis. Tannins possess excellent neuroprotective effects, representing a promising therapeutic approach. However, due to their chemical nature and structural characteristics, the bioavailability of tannins in the human body remains low. Current methods to enhance their bioavailability are limited. Further exploration is needed to improve their bioavailability and strengthen their potential clinical applications. Based on this, new Parkinson's disease treatment strategies can be developed, warranting in-depth research and clinical validation.

Biosynthesis-Based Spatial Metabolome of Condensed Tannin Reveals Its Role in Salt Tolerance of Non-Salt-Secretor Mangrove Kandelia obovata

An autofluorescent inclusion (AFI) specifically accumulated in mesophyll cells (MCs) of non-salt-secretor mangrove was found to be related to salt, but its biosynthesis and spatial distribution characteristics remain unclear. Here, Kandelia obovata served as the experimental material, and the composition of AFI was identified as condensed tannin (CT). Na contents increased in purified AFIs under NaCl treatment, while Na+ efflux in MCs was lower than the control. In vitro, Na+ addition caused aggregations of AFIs. Proteins related to Na+/H+ and vesicle transport were identified in the purified AFIs by liquid chromatography-mass spectrometry. TEM images revealed the structures involved in CT biosynthesis in chloroplasts and CT accretions in vacuoles were more visible under higher salinity. Spatial metabolomics analysis on flavonoid metabolites involving in CT biosynthesis illustrated those flavonoids and three CT monomers were positively related to salt in MCs. Real-time quantitative PCR verified the genes encoding enzymes for CT biosynthesis were upregulated accordingly. Taken together, CT biosynthesis is positively correlated with Na accumulation in leaves. The CTs synthesized in chloroplasts are transported as shuttles to vacuole via cytoplasm, facilitating the sequestration and compartmentalization of excessive Na+ ions into the vacuole, which confers non-salt-secretor mangrove K. obovata a higher salt tolerance.

Antimicrobial Potential of Polyphenols: Mechanisms of Action and Microbial Responses-A Narrative Review

Polyphenols (PPs) are recognized as bioactive compounds and antimicrobial agents, playing a critical role in enhancing food safety, preservation, and extending shelf life. The antimicrobial effectiveness of PPs has different molecular and biological reasons, predominantly linked to their hydroxyl groups and electron delocalization, which interact with microbial cell membranes, proteins, and organelles. These interactions may reduce the efficiency of metabolic pathways, cause destructive damage to the cell membrane, or they may harm the proteins and nucleic acids of the foodborne bacteria. Moreover, PPs exhibit a distinctive ability to form complexes with metal ions, further amplifying their antimicrobial activity. This narrative review explores the complex and multifaceted interactions between PPs and foodborne pathogens, underlying the correlation of their chemical structures and mechanisms of action. Such insights shed light on the potential of PPs as innovative natural preservatives within food systems, presenting an eco-friendly and sustainable alternative to synthetic additives.

Metal Ions Fortified Tannin-Furanic Rigid Foam: The Impact on the Uniformity and Mechanical Performance

Tannin-furanic foams with excellent properties have attracted increasing interest due to their advantages such as easy preparation, light weight, and thermal insulation. However, unsatisfactory mechanical strength has limited the expansion of their applications. Herein, three different metal ions (Cu2+, Fe3+, and Zn2+) were chosen to enhance the properties of tannin-furanic foam prepared by mechanical stirring provoked a foaming approach. The positive effects originating from the complexation are attributed to the associated connection between tannin molecules and metal ions. The results indicated that the apparent performance was improved, resulting in even foam cell structures. The apparent densities for the tannin-furanic foam modified with metal ions were located in the range of 36.57-47.84 kg/m3, showing the feature of lightweight material. The enhanced mechanical strength was verified by the compression strength (0.097-0.163 MPa) and pulverization ratio (7.57-11.01%) of the modified foams, which increased by 56-163% and decreased by 61-73%, respectively, in comparison with tannin-furanic foam without the metal ions. Additionally, the thermal conductivity of the modified tannin-furanic foams was in the range of 0.0443 to 0.0552 W/m·K. This indicates that they inherited the excellent thermal insulation typically associated with tannin-based foams. Interestingly, higher mechanical performance was obtained by comparison with other bio-sourced foams even with similar densities. In summary, by introducing only a small amount of metal ions, the foam performance was greatly improved, with a moderate cost increase, which reflects a good development prospect.

Free radicals and their impact on health and antioxidant defenses: a review

Free radicals, characterized by the presence of unpaired electrons, are highly reactive species that play a significant role in human health. These molecules can be generated through various endogenous processes, such as mitochondrial respiration and immune cell activation, as well as exogenous sources, including radiation, pollution, and smoking. While free radicals are essential for certain physiological processes, such as cell signaling and immune defense, their overproduction can disrupt the delicate balance between oxidants and antioxidants, leading to oxidative stress. Oxidative stress results in the damage of critical biomolecules like DNA, proteins, and lipids, contributing to the pathogenesis of various diseases. Chronic conditions such as cancer, cardiovascular diseases, neurodegenerative disorders, and inflammatory diseases have been strongly associated with the harmful effects of free radicals. This review provides a comprehensive overview of the characteristics and types of free radicals, their mechanisms of formation, and biological impacts. Additionally, we explore natural compounds and extracts studied for their antioxidant properties, offering potential therapeutic avenues for managing free radical-induced damage. Future research directions are also discussed to advance our understanding and treatment of free radical-associated diseases.

Large Language Modeling to Assist Natural Polyphenols as Green Precipitants for Recycling Spent Batteries

The growing demand for energy storage batteries, driven by the need to alleviate global warming and reduce fossil fuel dependency, has led to environmental concerns surrounding spent batteries. Efficient recycling of these batteries is essential to prevent pollution and recover valuable metal ions such as nickel (Ni2+), cobalt (Co2+), and manganese (Mn2+). Conventional hydrometallurgical methods for battery recycling, while effective, often involve harmful chemicals and processes. Natural polyphenols offer a greener alternative due to their ability to coordinate with metal ions. However, optimizing polyphenol selection for efficient recovery remains a labor-intensive challenge. This study presents a strategy combining natural polyphenols as green precipitants with the power of GPT-4, a large language model (LLM), to enhance the precipitation and recovery of metal ions from spent batteries. By leveraging the capabilities of GPT-4 in natural language processing, we enable a dynamic, iterative collaboration between human researchers and the LLM, optimizing polyphenol selection for different experimental conditions. The results show that tannic acid achieved precipitation rates of 94.8, 96.7, and 96.7% for Ni2+, Co2+, and Mn2+, respectively, outperforming conventional methods. The integration of GPT-4 enhances both the efficiency and accuracy of the process, ensuring environmental sustainability by minimizing secondary pollution and utilizing biodegradable materials. This innovative strategy demonstrates the potential of combining artificial intelligence-driven analysis with green chemistry to address battery recycling challenges, paving the way for more sustainable and efficient methods.

Green Tea Polyphenol Epigallocatechin Gallate Interactions with Copper-Serum Albumin

Epigallocatechin gallate (EGCg), an abundant phytochemical in green tea, is an antioxidant that also binds proteins and complex metals. After gastrointestinal absorption, EGCg binds to serum albumin in the hydrophobic pocket between domains IIA and IIIA and overlaps with the Sudlow I site. Serum albumin also has two metal binding sites, a high-affinity N-terminal site (NTS) site that selectively binds Cu(II), and a low-affinity, less selective multi-metal binding site (MBS). We proposed to determine whether EGCg binds or reacts with Cu(II)-serum albumin using fluorescence, UV-Visible and electron paramagnetic resonance (EPR) spectroscopy. Our results suggest that when serum albumin is loaded with Cu(II) in both sites, EGCg binds to the MBS-Cu(II) and reduces the copper to Cu(I). EGCg does not bind to or react with Cu(II) in the high-affinity NTS site. Potential consequences include changes in copper homeostasis and damage from pro-oxidative Fenton reactions.

Hypersensitive quantification of major astringency markers in food and wine by substoichiometric quenching of silicon-rhodamine conjugates

Tannins are chemically diverse polyphenols in plant-derived products that not only show diverse biological activities but also play a crucial role in determining the sensory attributes of food and beverages. Therefore, their accurate and cost-effective quantification is essential. Here, we identified a novel fluorescence quenching mechanism of different synthetic rhodamine fluorophores, with a high selectivity towards tannic acid (TA) and catechin-3-gallate (C3G) compared to a structurally diverse panel of tannins and polyphenols. Specific chemical conjugates of silicon-rhodamine with alkyl linkers attached to bulky apolar moieties had a limit of detection near 500 pM and a linear range spanning 5-100 nM for TA. We validated the assay on 18 distinct red wine samples, which showed high linearity (R2 = 0.92) with methylcellulose precipitation with no interference from anthocyanins. In conclusion, a novel assay was developed and validated that allows the sensitive and selective quantification of major astringency markers abundant in food and beverages.

Cell Type-Specific Anti- and Pro-Oxidative Effects of Punica granatum L. Ellagitannins

Pomegranate and its by-products contain a broad spectrum of phytochemicals, such as flavonoids, phenolic acids and tannins, having pleiotropic preventive and prophylactic properties in health disorders related to oxidative stress and microbial contamination. Here, we examined the biological effects of a pomegranate peel ellagitannins-enriched (>90%) extract, PETE. In vitro studies revealed that PETE has a strong antiradical action towards synthetic radicals and biologically relevant ROS surpassing or comparable to that of Trolox. In cellular models, it showed concentration-dependent (25-100 µg/mL) yet opposing effects depending on the cell membrane type and exposure conditions. In erythrocytes, PETE protected membrane integrity in the presence of the strong oxidant HClO and restored reduced glutathione levels to up to 85% of the control value while having much weaker acute and long-term intrinsic effects. Such protection persisted even after the removal of the extract from cells, indicating strong membrane interaction. In HeLa cancer cells, and at concentrations lower than those used for red blood cells, PETE induced robust potentiation of ROS production and mitochondrial potential dissipation, leading to autophagy-like membrane morphology changes and cell death. In S. aureus, the growth arrest and bacterial death in the presence of PETE (with MIC = 31.25 µg/mL and MBC = 125 µg/mL, respectively) can be linked to the tripled ROS induction by the extract in the same concentration range. This study indicates a specificity of ROS production by the pomegranate extract depending on the type of cell, the concentration of the extract and the time of incubation. This specificity witnesses a strong potential of the extract components as candidates in antioxidant and pro-oxidant therapy.

The Protective Effect of the Supplementation with an Extract from Aronia melanocarpa L. Berries against Cadmium-Induced Changes of Chosen Biomarkers of Neurotoxicity in the Brain-A Study in a Rat Model of Current Lifetime Human Exposure to This Toxic Heavy Metal

Since even low-level environmental exposure to cadmium (Cd) can lead to numerous unfavourable health outcomes, including damage to the nervous system, it is important to recognize the risk of health damage by this xenobiotic, the mechanisms of its toxic influence, and to find an effective protective strategy. This study aimed to evaluate, in a female Wistar rat model of current human environmental exposure to Cd (1 and 5 mg/kg of diet for 3-24 months), if the low-to-moderate treatment with this element can harm the brain and whether the supplementation with a 0.1% Aronia melanocarpa L. (Michx.) Elliott berries (chokeberries) extract (AE) can protect against this effect. The exposure to Cd modified the values of various biomarkers of neurotoxicity, including enzymes (acetylcholinesterase (AChE), sodium-potassium adenosine triphosphatase (Na+/K+-ATPase), phospholipase A2 (PLA2), and nitric oxide synthase 1 (NOS1)) and non-enzymatic proteins (calmodulin (CAM), nuclear factor erythroid 2-related factor 2 (Nrf2), and Kelch-like ECH-associated protein 1 (KEAP1)) crucial for the functioning of the nervous system, as well as the concentrations of calcium (Ca) and magnesium (Mg) and some metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in the brain tissue. The co-administration of AE, partially or entirely, protected from most of the Cd-induced changes alleviating its neurotoxic influence. In conclusion, even low-level chronic exposure to Cd may adversely affect the nervous system, whereas the supplementation with A. melanocarpa berries products during the treatment seems a protective strategy.

Mechanism of the wine pomace tannin in hyperpigmentation inhibition: Impact on signaling pathways, cell proliferation, and tyrosinase activity

After winemaking, tannins with high polymerization remain in the pomace. Utilizing these tannin fractions is a concern for the wine industry. While tannins show potential in treating hyperpigmentation, their mechanisms in vivo and at the cellular level are unclear. Herein, pomace tannin fractions (PTFs) were isolated post-winemaking. Nuclear magnetic resonance spectroscopy and mass spectrometry analysis showed PTFs were composed of (epi)catechin gallate and (epi)catechin as terminal and extensional units, with polymerization degrees of 10, 16, and 35. In vivo studies demonstrated that PTFs removed ∼76 % of skin melanin, comparable to hydroquinone. The inhibition by PTFs is due to: (1) Inhibition of the Wnt and melanogenesis pathways, downregulating key melanin synthesis proteins (TYR, TYRP1, TYRP2); (2) Inducing cell cycle arrest at the G1/S checkpoint, disrupting DNA, decreasing mitochondrial membrane potential and integrity, and slowing melanocyte proliferation; (3) Superior tyrosinase inhibitory activity by binding to tyrosinase, chelating copper ions, and demonstrating antioxidant properties. These findings suggest that PTFs inhibit melanin synthesis by the combination of the above mentioned ways, supporting the medical use of winemaking tannins.

Aromatic Biobased Polymeric Materials Using Plant Polyphenols as Sustainable Alternative Raw Materials: A Review

In the foreseeable future, the development of petroleum-based polymeric materials may be limited, owing to the gradual consumption of disposable resources and the increasing emphasis on environmental protection policies. Therefore, it is necessary to focus on introducing environmentally friendly renewable biobased materials as a substitute for petroleum-based feed stocks in the preparation of different types of industrially important polymers. Plant polyphenols, a kind of natural aromatic biomolecule, exist widely in some plant species. Benefiting from their special macromolecular structure, high reactivity, and broad abundance, plant polyphenols are potent candidates to replace the dwindling aromatic monomers derived from petroleum-based resources in synthesizing high-quality polymeric materials. In this review, the most related and innovative methods for elaborating novel polymeric materials from plant polyphenols are addressed. After a brief historical overview, the classification, structural characteristics, and reactivity of plant polyphenols are summarized in detail. In addition, some interesting and innovative works concerning the chemical modifications and polymerization techniques of plant polyphenols are also discussed. Importantly, the main chemical pathways to create plant polyphenol-based organic/organic-inorganic polymeric materials as well as their properties and possible applications are systematically described. We believe that this review could offer helpful references for designing multifunctional polyphenolic materials.

Elucidation and reconstitution of hydrolyzable tannin biosynthesis

Hydrolyzable tannins (HTs) are a class of polyphenols produced mostly in core eudicot plants. They accumulate in various plant tissues and are considered to function as defense compounds that protect against herbivory, infections, and toxic metals (specifically aluminum ions). Moreover, HTs have industrial and pharmaceutical uses that benefit humans. Elucidating and reconstituting the biosynthesis of HTs is necessary for genetically engineering in planta functions and for efficiently producing HTs for human use. The biosynthesis of HTs is initiated by the formation of gallic acid from the shikimate pathway intermediate 3-dehydroshikimic acid, which is catalyzed by bifunctional dehydroquinate dehydratase/shikimate dehydrogenases (DQD/SDHs). In the second step, UDP glycosyltransferases (UGTs) esterify gallic acid with glucose to form β-glucogallin (1-O-galloyl-β-D-glucose). β-glucogallin is then converted to 1,2,3,4,6-penta-O-galloyl-β-D-glucose through a series of galloylation steps that are catalyzed by galloyltransferases, using β-glucogallin as a galloyl donor. Laccases subsequently catalyze the oxidative coupling between adjacent galloyl groups to form hexahydroxydiphenoyl (HHDP) groups, which are characteristic components of ellagitannins. Furthermore, monomeric ellagitannins can undergo oligomerization via intermolecular oxidative coupling, which is also catalyzed by laccases. To reconstitute the HT biosynthetic pathway in HT-non-accumulating plants, DQD/SDHs and UGTs from Eucalyptus camaldulensis were heterologously co-expressed in Nicotiana benthamiana leaves, which resulted in the production of gallic acid and β-glucogallin. In future studies, this transgenic system will be used to identify genes encoding galloyltransferases and laccases to further elucidate and reconstitute the HT biosynthetic pathway.

Pomegranate polyphenol punicalagin as a nutraceutical for mitigating mild cognitive impairment: An overview of beneficial properties

Dementia treatment has become a global research priority, driven by the increase in the aging population. Punicalagin, the primary polyphenol found in pomegranate fruit, exhibits a variety of benefits. Today, a growing body of research is showing that punicalagin is a nutraceutical for the prevention of mild cognitive impairment (MCI). However, a comprehensive review is still lacking. The aim of this paper is to provide a comprehensive review of the physicochemical properties, origin and pharmacokinetics of punicalagin, while emphasizing the significance and mechanisms of its potential role in the prevention and treatment of MCI. Preclinical and clinical studies have demonstrated that Punicalagin possesses the potential to effectively target and enhance the treatment of MCI. Potential mechanisms by which punicalagin alleviates MCI include antioxidative damage, anti-neuroinflammation, promotion of neurogenesis, and modulation of neurotransmitter interactions. Overall, punicalagin is safer and shows potential as a therapeutic compound for the prevention and treatment of MCI, although more rigorous randomized controlled trials involving large populations are required.

The physico-chemical and antimicrobial properties of nano ZnO functionalised tannic acid

Tannic acid (TA) has been reported as an efficient plant-based compound with inhibitory activity against viruses and bacteria. The combination of TA with Zinc Oxide (ZnO) nanostructures with ZnO is one of the most widely used nanoparticles for antimicrobial properties, have not yet fully elucidate especially their mechanisms of overall physicochemical and antimicrobial actions. Hence, to observe the influence of TA adsorption on ZnO, the investigations on the TA concentration and the effect of pH towards the physicochemical, optical and antimicrobial properties are demonstrated. The pure ZnO are synthesised via the chemical reduction method and the ZnO-TA nanostructures are further prepared using the dropwise methods to form variations of pH samples, which causes the formation of different mean particle size distribution, d m . The findings reveal that the performance of physicochemical and optical properties of pure ZnO and ZnO-TA are different due to the wrapped layers of TA which change the charged surface of all the particles. The protonation reactions yield strong pH dependence (pH 3 and 5), with uptake performance becoming more dominant at higher TA concentration loading (pH 3). The detailed optical energy bandgap and Urbach energy that concluded the nanoparticle growth and disorder condition of produced particles are presented. For antimicrobial efficiency, ZnO-TA shows improved effectiveness in growth inhibitions of S. aureus 99.69% compared to pure ZnO nanostructure (99.39%). This work reveals that the TA concentration increases the overall performance, and the discussion gives added support to their potential performance related to the field of ZnO compound.

Discovery of procyanidin condensed tannins of (-)-epicatechin from Kratom, Mitragyna speciosa, as virucidal agents against SARS-CoV-2

Kratom, Mitragyna speciosa, is one of the most popular herbs in the West and Southeast Asia. A number of previous works have focused on bioactive alkaloids in this plant; however, non-alkaloids have never been investigated for their biological activities. Antiviral and virucidal assays of a methanol leaf extract of Kratom, M. speciosa, revealed that a crude extract displayed virucidal activity against the SARS-CoV-2. Activity-guided isolation of a methanol leaf extract of Kratom led to the identification of B-type procyanidin condensed tannins of (-)-epicatechin as virucidal compounds against SARS-CoV-2. The fraction containing condensed tannins exhibited virucidal activity with an EC50 value of 8.38 μg/mL and a selectivity index (SI) value >23.86. LC-MS/MS analysis and MALDI-TOF MS identified the structure of the virucidal compounds in Kratom as B-type procyanidin condensed tannins, while gel permeation chromatograph (GPC) revealed weight average molecular weight of 238,946 Da for high molecular-weight condensed tannins. In addition to alkaloids, (-)-epicatechin was found as a major component in the leaves of M. speciosa, but it did not have virucidal activity. Macromolecules of (-)-epicatechin, i.e., procyanidin condensed tannins, showed potent virucidal activity against SARS-CoV-2, suggesting that the high molecular weights of these polyphenols are important for virucidal activity.

Highly efficient removal of tannic acid from wastewater using biomimetic porous materials

To effectively remove tannic acid (TA) from wastewater, using green and natural materials has attracted increasing attention. Inspired by Galla Chinensis (GC) with high content of TA, this study synthesized a biomimetic porous adsorbent to mimic the GC structure using dialdehyde tapioca starch (DTS) and gelatin (GL). The TA adsorption performance and mechanism of synthetic porous material were investigated. Results revealed that the porous material exhibited a maximum TA adsorption capacity of 1072.01 mg/g, along with a high removal rate of 95.16% under the conditions of a DTS-GL mass ratio of 1:1, DTS aldehyde content of 48.16%, a solid content of 5%, and a pH of 2 at 25 °C. The adsorption of TA by DTS was not affected by water-soluble cationic and anion. The adsorption kinetics of TA on the porous material followed the pseudo-second-order model, and this Langmuir adsorption model (R2 = 0.9954) which were well described the adsorption of TA by the material, indicating that the adsorption primarily occurred in a monolayer. FTIR, XRD, DSC, TG, XPS, and SEM-EDS were employed to characterize the structure characteristics of the porous material. The cross-linking between DTS and GL by Schiff base reaction imparted a chemical structure could absorb TA by hydrogen bonding. The TA desorption rates of in 30% acetone and 40% ethanol solutions were 88.76% and 91.03%, respectively. The porous material prepared by the GC-inspired approach holds promise as an ideal choice for loading polyphenolic compounds and provides a new perspective for the design and application of bioinspired engineering materials.

Removal of Cu (II) by ion exchange resin and its re-utilization of the residual solution from the distilled Lycium barbarum wine

In order to re-utilize the residual from the distillation of the Chinese wolfberry wine and reduce the environmental pollution, the residual is firstly filtered by the ceramic membrane of 50 nm, then the Cu (II) has transferred from the distillation is removed using the ion exchange resin, and the treated solution is recombined with the distilled liquor to make the Chinese wolfberry brandy and the comparison has conducted on the physicochemical properties, antioxidant activity and flavor compounds between the recombined brandy and the finished brandy. The results indicate that the Cu (II) was effectively removed by ceramic membrane combined with the D401 resin. Compared with finished brandy, the recombined brandy contains high contents of polysaccharides, phenols and flavonoids, thus contributing to the improvement of antioxidant capacity. The gas chromatography-ion mobility spectrometry (GC-IMS) reveals that 25 volatile compounds like esters and alcohols have identified in the brandy samples, and the differences are significant between the recombined and the finished brandy. In summary, the distilled residual from the Chinese wolfberry wine might be re-used after the appropriate treatment so as to reduce the discharge and environmental pollution.

Comparative Study of Condensed and Hydrolysable Tannins during the Early Stages of Zebrafish Development

In this study, we present data on the effects of condensed tannins (CTs) and hydrolysable tannins (HTs), polyphenols extracted from plants, at different concentrations on zebrafish development to identify the range of concentrations with toxic effects. Zebrafish embryos were exposed to CTs and HTs at two different concentration ranges (5.0-20.0 μgL-1 and 5.0-20.0 mgL-1) for 72 h. The toxicity parameters were observed up to 72 h of treatment. The uptake of CTs and HTs by the zebrafish larvae was assessed via HPLC analysis. A qRT-PCR analysis was performed to evaluate the expressions of genes cd63, zhe1, and klf4, involved in the hatching process of zebrafish. CTs and HTs at 5.0, 10.0, and 20.0 μgL-1 were not toxic. On the contrary, at 5.0, 10.0, and 20.0 mgL-1, HTs induced a delay in hatching starting from 48 h of treatment, while CTs showed a delay in hatching mainly at 48 h. The analysis of gene expression showed a downregulation in the group exposed to HTs, confirming the hatching data. We believe that this study is important for defining the optimal doses of CTs and HTs to be employed in different application fields such as the chemical industry, the animal feed industry, and medical science.

Combination of Hydrolysable Tannins and Zinc Oxide on Enterocyte Functionality: In Vitro Insights

The management of gastrointestinal disease in animals represents a significant challenge in veterinary and zootechnic practice. Traditionally, acute symptoms have been treated with antibiotics and high doses of zinc oxide (ZnO). However, concerns have been raised regarding the potential for microbial resistance and ecological detriment due to the excessive application of this compound. These concerns highlight the urgency of minimizing the use of ZnO and exploring sustainable nutritional solutions. Hydrolysable tannins (HTs), which are known for their role in traditional medicine for acute gastrointestinal issues, have emerged as a promising alternative. This study examined the combined effect of food-grade HTs and subtherapeutic ZnO concentration on relevant biological functions of Caco-2 cells, a widely used model of the intestinal epithelial barrier. We found that, when used together, ZnO and HTs (ZnO/HTs) enhanced tissue repair and improved epithelial barrier function, normalizing the expression and functional organization of tight junction proteins. Finally, the ZnO/HTs combination strengthened enterocytes' defense against oxidative stress induced by inflammation stimuli. In conclusion, combining ZnO and HTs may offer a suitable and practical approach for decreasing ZnO levels in veterinary nutritional applications.

A Comprehensive Analysis of Diversity, Structure, Biosynthesis and Extraction of Biologically Active Tannins from Various Plant-Based Materials Using Deep Eutectic Solvents

This paper explores the emerging subject of extracting tannins from various plant sources using deep eutectic solvents (DESs). Tannins are widely used in the food and feed industries as they have outstanding antioxidant qualities and greatly enhance the flavor and nutritional content of a wide range of food products. Organic solvents are frequently used in traditional extraction techniques, which raises questions about their safety for human health and the environment. DESs present a prospective substitute because of their low toxicity, adaptability, and environmental friendliness. The fundamental ideas supporting the application of DESs in the extraction of tannins from a range of plant-based materials frequently used in daily life are all well covered in this paper. Furthermore, this paper covers the impact of extraction parameters on the yield of extracted tannins, as well as possible obstacles and directions for future research in this emerging subject. This includes challenges such as high viscosity, intricated recovery of compounds, thermal degradation, and the occurrence of esterification. An extensive summary of the diversity, structure, biosynthesis, distribution, and roles of tannins in plants is given in this paper. Additionally, this paper thoroughly examines various bioactivities of tannins and their metabolites.

Radiocarbon Flux Measurements Provide Insight into Why a Pyroligneous Acid Product Stimulates Plant Growth

Agriculture in the 21st century faces many formidable challenges with the growing global population. Increasing demands on the planet's natural resources already tax existing agricultural practices. Today, many farmers are using biochemical treatments to improve their yields. Commercialized organic biostimulants exist in the form of pyroligneous acid generated by burning agricultural waste products. Recently, we examined the mechanisms through which a commercial pyroligneous acid product, Coriphol™, manufactured by Corigin Solutions, Inc., stimulates plant growth. During the 2023 growing season, outdoor studies were conducted in soybean to examine the effects of different Coriphol™ treatment concentrations on plant growth. Plant height, number of leaves, and leaf size were positively impacted in a dose-dependent manner with 2 gallon/acre soil treatments being optimal. At harvest, this level of treatment boosted crop yield by 40%. To gain an understanding of why Coriphol™ improves plant fitness, follow-up laboratory-based studies were conducted using radiocarbon flux analysis. Here, radioactive 11CO2 was administered to live plants and comparisons were made between untreated soybean plants and plants treated at an equivalent Coriphol™ dose of 2 gallons/acre. Leaf metabolites were analyzed using radio-high-performance liquid chromatography for [11C]-chlorophyll (Chl) a and b components, as well as [11C]-β-carotene (β-Car) where fractional yields were used to calculate metabolic rates of synthesis. Altogether, Coriphol™ treatment boosted rates of Chl a, Chl b, and β-Car biosynthesis 3-fold, 2.6-fold, and 4.7-fold, respectively, and also increased their metabolic turnover 2.2-fold, 2.1-fold, and 3.9-fold, respectively. Also, the Chl a/b ratio increased from 3.1 to 3.4 with treatment. Altogether, these effects contributed to a 13.8% increase in leaf carbon capture.

The Protective Impact of Aronia melanocarpa L. Berries Extract against Prooxidative Cadmium Action in the Brain-A Study in an In Vivo Model of Current Environmental Human Exposure to This Harmful Element

Cadmium (Cd) is a prooxidant that adversely affects human health, including the nervous system. As exposure of the general population to this heavy metal is inevitable, it is crucial to look for agents that can prevent the effects of its toxic action. An experimental model on female rats of current lifetime human exposure to cadmium (3-24-months' treatment with 1 or 5 mg Cd/kg diet) was used to test whether low-level and moderate intoxication can exert a prooxidative impact in the brain and whether supplementation with a 0.1% extract from the berries of Aronia melanocarpa L. (Michx.) Elliott (AE; chokeberry extract) can protect against this action. Numerous parameters of the non-enzymatic and enzymatic antioxidative barrier, as well as total antioxidative and oxidative status (TAS and TOS, respectively), were determined and the index of oxidative stress (OSI) was calculated. Moreover, chosen prooxidants (myeloperoxidase, xanthine oxidase, and hydrogen peroxide) and biomarkers of oxidative modifications of lipids, proteins, and deoxyribonucleic acid were assayed. Cadmium dysregulated the balance between oxidants and antioxidants in the brain and led to oxidative stress and oxidative injury of the cellular macromolecules, whereas the co-administration of AE alleviated these effects. To summarize, long-term, even low-level, cadmium exposure can pose a risk of failure of the nervous system by the induction of oxidative stress in the brain, whereas supplementation with products based on aronia berries seems to be an effective protective strategy.