Identification and characterization of silver nanoparticles from Erythrina indica and its antioxidant and Uropathogenic antimicrobial properties.

The plant Erythrina indica comes under Fabaceae family, mainly used for used in traditional medicine as nervine sedative, antiepileptic, antiasthmatic, collyrium in opthalmia, antiseptic. Current study focused synthesize of silver nanoparticles (AgNPs) by E. indica leaf ethanol extract. The green-synthesized AgNPs underwent characterization using multiple analytical techniques, including UV-visible, FTIR, DLS, SEM, TEM, XRD, and EDX, and estimation of their antioxidant activity and antimicrobial activity. Phytochemical analysis identified alkaloids, tannins, saponins, flavonoids, and phenols as secondary metabolites. The Total Phenol Content (TPC) was determined to be 237.35 ± 2.02 mg GAE-1, indicating a substantial presence of phenolic compounds. The presence of AgNPs was verified through UV-Visible analysis at 420 nm, and FT-IR revealed characteristic phenolic functional groups. DLS analysis indicated a narrow size distribution (polydispersity index - PDI: 3.47%), with SEM revealing spherical AgNPs of approximately 20 nm. TEM showed homogeneous, highly polycrystalline AgNPs with lattice spacing at 0.297. XRD analysis demonstrated crystallinity and purity, with distinct reflection peaks corresponding to miller indices of JCPDS card no. 01 087 1473. In vitro, AgNPs exhibited robust antioxidant activity like; DPPH, ABTS, and H2O2, surpassing E. indica-assisted synthesis. ABTS assay indicated higher antioxidant activity (81.94 ± 0.05%) for AgNPs at 734 nm, while E. indica extraction showed 39.67 ± 0.07%. At 532 nm, both E. indica extraction (57.71 ± 0.11%) and AgNPs (37.41 ± 0.17%) exhibited H2O2 scavenging. Furthermore, AgNPs displayed significant antimicrobial properties, inhibiting Staphylococcus aureus (15.7 ± 0.12 mm) and Candida albicans (10.7 ± 0.17 mm) byfor the concentration of 80 µg/mL. Through the characterizations underscore of the potential of Erythrina indica-synthesized AgNPs, rich in polyphenolic compounds, for pharmacological, medical, biological applications and antipyretic properties.

Biomimetic Platelet-Cloaked Nanoparticles for the Delivery of Anti-Inflammatory Curcumin in the Treatment of Atherosclerosis.

Atherosclerosis still represents a major driver of cardiovascular diseases worldwide. Together with accumulation of lipids in the plaque, inflammation is recognized as one of the key players in the formation and development of atherosclerotic plaque. Systemic anti-inflammatory treatments are successful in reducing the disease burden, but are correlated with severe side effects, underlining the need for targeted formulations. In this work, curcumin is chosen as the anti-inflammatory payload model and further loaded in lignin-based nanoparticles (NPs). The NPs are then coated with a tannic acid (TA)- Fe (III) complex and further cloaked with fragments derived from platelet cell membrane, yielding NPs with homogenous size. The two coatings increase the interaction between the NPs and cells, both endothelial and macrophages, in steady state or inflamed status. Furthermore, NPs are cytocompatible toward endothelial, smooth muscle and immune cells, while not inducing immune activation. The anti-inflammatory efficacy is demonstrated in endothelial cells by real-time quantitative polymerase chain reaction and ELISA assay where curcumin-loaded NPs decrease the expression of Nf-κb, TGF-ß1, IL-6, and IL-1ß in lipopolysaccharide-inflamed cells. Overall, due to the increase in the cell-NP interactions and the anti-inflammatory efficacy, these NPs represent potential candidates for the targeted anti-inflammatory treatment of atherosclerosis.

[Dynamic Chemistry of Tannins].

Tannins are a group of polyphenols that possess the ability to precipitate proteins, causing an undesirable astringent taste by interacting with salivary peptides. This interaction deactivates the digestive enzymes; therefore, tannins are considered as plant defense substances. The health benefits of tannins and related polyphenols in foods and beverages have been demonstrated by biological and epidemiological studies; however, their metabolism in living plants and the chemical changes observed during processing of foods and medicinal herbs raises some questions. This review summarizes our studies concerning dynamic changes observed in tannins. Ellagitannins present in the young leaves of Camellia japonica and Quercus glauca undergo oxidative degradation as the leaves mature. Similar oxidative degradation is also observed in whiskey when it is kept for aging in oak barrels, and in decaying wood caused by fungi in natural forests. In contrast, ellagitannins have been observed to undergo reduction in the leaves of Carpinus, Castanopsis, and Triadica species as the leaves mature. This phenomenon of reductive metabolism in leaves enabled us to propose a new biosynthetic pathway for the most fundamental ellagitannin acyl groups, which was also supported by biomimetic synthetic studies. Polyphenols undergo dynamic changes during the process of food processing. Catechin in tea leaves undergo oxidation upon mechanical crushing to generate black tea polyphenols. Though detailed production mechanisms of catechin dimers have been elucidated, structures of thearubigins (TRs), which are complex mixtures of oligomers, remain ambiguous. Our recent studies suggested that catechin B-ring quinones couple with catechin A-rings during the process of oligomerization.

Plant polyphenol surfactant construction with strong surface activity and chelation properties as efficient decontamination of UO22+ on cotton fabric.

Chemically synthesized surfactants have promising applications in the treatment of uranium, however, their hazardous environmental effects, non-biodegradability, and numerous drawbacks prevent them from being widely used in practice. Herein, we successfully synthesized a green chelating and foaming integrated surfactant (BTBS) by Mannich reaction and acylation of bayberry tannin for the effective removal of UO22+ from aqueous environments or solid surfaces. The as-prepared surfactant was systematically characterized by FT-IR, showing that the hydrophobic groups were successfully grafted onto tannin. The modified material showed better foaming and emulsifying properties, which proved this method could improve the amphiphilicity of tannin. Moreover, for the first time, a foam fractionation method in conjunction with a tannin-based surfactant was applied for UO22+ removal from water. This surfactant was used as a co-surfactant and could readily remove 90 % of UO22+ (20 mg L-1) from water. The removal of UO22+ could be completed in a short time (30 min), and the maximum adsorption capacity was determined as 175.9 mg g-1. This surfactant can also be used for efficient decontamination of uranium-contaminated cotton cloth with a high removal rate of 94.55 %. In addition, the mechanism studies show that the adsorption of BTBS for UO22+ can be mainly attributed to a chelating mechanism between UO22+ and the adjacent phenolic hydroxyls. The novel biomass-derived BTBS with advantages such as high capture capacity, environmental friendliness, and cost-effectiveness suggests that it plays an important role in the remediation of radionuclide pollution.

Why is it important to understand the nature and chemistry of tannins to exploit their potential as nutraceuticals?

Tannins comprise a large group of polyphenols that can differ widely in chemical composition and molecular weight. The use of tannins dates back to antiquity, but it is only in recent years that their potential use as nutraceuticals associated with the human diet is beginning to be exploited. Although the biological effects of these phytocomplexes have been studied for many years, there are still several open questions regarding their chemistry and biotransformation. The vastness of the molecules that make up the class of tannins has made their characterisation, as well as their nomenclature and classification, a daunting task. This review has been written with the aim of bringing order to the chemistry of tannins by including aspects that are sometimes still overlooked or should be updated with new research in order to understand the potential of these phytocomplexes as active ingredients or technological components for nutraceutical products. Future trends in tannin research should address many questions that are still open, such as determining the exact biosynthetic pathways of all classes of tannins, the actual biological effects determined by the interaction of tannins with other molecules, their metabolization, and the best extraction methods, but with a view to market requirements.

Affinity of Tannins to Cellulose: A Chromatographic Tool for Revealing Structure-Activity Patterns.

Food, feed and beverage processing brings tannins into contact with macromolecules, such as proteins and polysaccharides, leading to different chemical and physical interactions. The interactions of tannins with proteins are well known but less is known about the affinity of tannins to polysaccharides. We used bacterial cellulose from nata de coco as a model compound to investigate how tannins and cellulose interact by adsorption measurements using UPLC-DAD. We also explored how the structure of tannins influences these interactions. The model tannins included nine individual structurally different hydrolysable tannins (HTs) and eight well-defined proanthocyanidin (PA) fractions with different monomeric units, mean degree of polymerization and both A- and B-type linkages. Tannins were found to have both strong and weak interactions with bacterial cellulose, depending on the exact structure of the tannin. For HTs, the main structural features affecting the interactions were the structural flexibility of the HT molecule and the number of free galloyl groups. For PAs, prodelphinidins were found to have a higher affinity to cellulose than procyanidins. Similarly to HTs, the presence of free galloyl groups in galloylated PAs and the flexibility of the PA molecule led to a stronger interaction. Adsorption measurements by UPLC-DAD proved to be a sensitive and rapid tool to evaluate the affinity of tannins to cellulose.

Tannins Can Have Direct Interactions with Anthelmintics: Investigations by Isothermal Titration Calorimetry.

Plant tannins are known for their anthelmintic and antiparasitic activities and have been increasingly studied to battle the ever-growing problem of anthelmintic resistance. While tannins have been shown to exhibit these activities on their own, one approach would be to use them as complementary nutrients alongside commercial anthelmintics. So far, research on the interactions between tannins and anthelmintics is limited, and few studies have reported both synergistic and antagonistic effects depending on the type of tannin and the method used. These interactions could either strengthen or weaken the efficacy of commercial anthelmintics, especially if tannin-rich diets are combined with anthelmintics used as oral drenches. To study these interactions, a series of hydrolysable tannins (HTs) was selected, and their direct interactions with thiabendazole (TBZ) were evaluated by isothermal titration calorimetry (ITC), which allowed the detection of the exothermic interaction but also the roles and significances of different structural features of HTs in these interactions. Our results show that HTs can have a direct interaction with the benzimidazole anthelmintic TBZ and that the interaction is strengthened by increasing the number of free galloyl groups and the overall molecular flexibility of HTs.

Investigation of Chemical Constituents and Antioxidant Activity of Biologically Active Plant-Derived Natural Products.

The aim of this publication is to present rapid screening methods (visual/colorimetric) that will enable quick identification of the presence of biologically active compounds in aqueous solutions. For this reason, 26 plant extracts obtained by ultrasound-assisted extraction were analysed for the content of these compounds. Higher plants, used as a raw material for extraction, are common in Europe and are easily available. The article proposes a comparison of various protocols for the identification of various compounds, e.g., phenolic compounds (phenols, tannins, anthocyanins, coumarins, flavones, flavonoids), vitamin C, quinones, quinines, resins, glycosides, sugars. Initial characterisation of the composition of plant extracts using fast and inexpensive methods allows you to avoid the use of time-consuming analyses with the use of advanced research equipment. In addition, the antioxidant activity of plant extracts using spectrophotometric methods (DPPH, ABTS, FRAP assay) and quantitative analysis of plant hormones such as abscisic acid, benzoic acid, gibberellic acid, indole acetic acid, jasmonic acid, salicylic acid, zeatin, zeatin riboside, and isipentenyl adenine was performed. The obtained results prove that the applied visual methods show different sensitivity in detecting the sought chemical compounds. Therefore, it is necessary to confirm the presence or absence of bioactive substances and their concentration using modern analytical methods.

Activity and potential mechanisms of action of persimmon tannins according to their structures: A review.

One distinguishing feature of the persimmon, that differentiates it from other fruits, is its high proanthocyanidins content, known as persimmon tannin (PT). Despite the poor absorption of PT in the small intestine, results from animal studies demonstrate that PT has many health benefits. Our goal in this review is to summarize the literature that elucidates the relationship between PT structure and activity. In addition, we also summarize the potential mechanisms underlying the health benefits that result from PT consumption; this includes the hypolipidemic, hypoglycemic, antioxidant, anti-inflammatory, antiradiation, antibacterial and antiviral, detoxification effects on snake venom, and the absorption of heavy metals and dyes. Studies show that PT is a structurally distinct proanthocyanidins that exhibits a high degree of polymerization. It is galloylation-rich and possesses unique A-type interflavan linkages in addition to the more common B-type interflavan bonds. Thus, PT is converted into oligomeric proanthocyanidins by depolymerization strategies, including the nucleophilic substitution reaction, acid hydrolysis, and hydrogenolysis. In addition, multiple health benefits exerted by PT mainly involve the inactivation of lipogenic and intracellular inflammatory signaling pathways, activation of the fatty acid oxidation signaling pathway, regulation of gut microbiota, and highly absorptive properties.

Protein aggregation model to explain the bioactivity of condensed tannins.

Tannins are involved in the taste of foods and multi bioactivity of traditional herbal medicines. The characteristics of tannins are believed to derive from their connectivity with proteins. However, the mode of interaction between proteins and tannins is not yet understood because of the complexity of the tannin structure. Then this study aimed to elucidate the detail binding mode of tannin and protein by the 1H-15N HSQC NMR method using the 15N-labeled MMP-1that have not been used so far. The HSQC results suggested cross-link sites between MMP-1s, which cause protein aggregation and inhibit MMP-1 activity. This study presents the first 3D protein aggregation model of condensed tannins, which is important for understanding the bioactivity of polyphenols. Furthermore, it can broaden the understanding of the range of interactions between other proteins and polyphenols.

New Type of Tannins Identified from the Seeds of Cornus officinalis Sieb. et Zucc. by HPLC-ESI-MS/MS.

There is a lack of information on the compound profile of Cornus officinalis Sieb. et Zucc. seeds. This greatly affects their optimal utilization. In our preliminary study, we found that the extract of the seeds displayed a strong positive reaction to the FeCl3 solution, indicating the presence of polyphenols. However, to date, only nine polyphenols have been isolated. In this study, HPLC-ESI-MS/MS was employed to fully reveal the polyphenol profile of the seed extracts. A total of 90 polyphenols were identified. They were classified into nine brevifolincarboxyl tannins and their derivatives, 34 ellagitannins, 21 gallotannins, and 26 phenolic acids and their derivatives. Most of these were first identified from the seeds of C. officinalis. More importantly, five new types of tannins were reported for the first time: brevifolincarboxyl-trigalloyl-hexoside, digalloyl-dehydrohexahydroxydiphenoyl (DHHDP)-hexdside, galloyl-DHHDP-hexoside, DHHDP-hexahydroxydiphenoyl(HHDP)-galloyl-gluconic acid, and peroxide product of DHHDP-trigalloylhexoside. Moreover, the total phenolic content was as high as 79,157 ± 563 mg gallic acid equivalent per 100 g in the seeds extract. The results of this study not only enrich the structure database of tannins, but also provide invaluable aid to its further utilization in industries.

Antioxidant and chemotherapeutic efficacies of seaweed-derived phlorotannins in cancer treatment: A review regarding novel anticancer drugs.

The ineffectiveness of traditional cancer therapies due to drug resistance, nontargeted delivery, and chemotherapy-associated adverse side effects has shifted attention to bioactive phytochemicals. Consequently, research efforts toward screening and identification of natural compounds with anticancer properties have increased in recent years. Marine seaweed-derived bioactive compounds, such as polyphenolic compounds, have exhibited anticancer properties. Phlorotannins (PTs), a major group of seaweed-derived polyphenolic compounds, have emerged as powerful chemopreventive and chemoprotective compounds, regulating apoptotic cell death pathways both in vitro and in vivo. In this context, this review focuses on the anticancer activity of polyphenols isolated from brown algae, with a special reference to PTs. Furthermore, we highlight the antioxidant effects of PTs and discuss how they can impact cell survival and tumor development and progression. Moreover, we discussed the potential therapeutic application of PTs as anticancer agents, having molecular mechanisms involving oxidative stress reduction. We have also discussed patents or patent applications that apply PTs as major components of antioxidant and antitumor products. With this review, researcher may gain new insights into the potential novel role of PTs, as well as uncover a novel cancer-prevention mechanism and improve human health.

Biological and pharmacological aspects of tannins and potential biotechnological applications.

Secondary metabolites are divided into three classes: phenolic, terpenoid, and nitrogenous compounds. Phenolic compounds are also known as polyphenols and include tannins, classified as hydrolysable or condensed. Herein, we explored tannins for their ROS reduction characteristics and role in homeostasis. These activities are associated with the numbers and degree of polymerisation of reactive hydroxyl groups present in the phenolic rings of tannins. These characteristics are associated with anti-inflammatory, anti-aging, and anti-proliferative health benefits. Tannins can reduce the risk of cancer and neurodegenerative diseases, such as cardiovascular diseases and Alzheimer's, respectively. These biomolecules may be used as nutraceuticals to maintain good gut microbiota. Industrial applications include providing durability to leather, anti-corrosive properties to metals, and substrates for 3D printing and in bio-based foam manufacture. This review updates regarding tannin-based research and highlights its biological and pharmacological relevance and potential applications.

Encapsulation of tannins and tannin-rich plant extracts by complex coacervation to improve their physicochemical properties and biological activities: A review.

As a major class of dietary polyphenols, tannins are demonstrated to have various health-promoting properties. Although tannins have been widely utilized in food, pharmaceutical and many other industries, the applications of tannins are quite limited due to their poor stability, sensory attributes and bioavailability. Encapsulation helps improve all of these properties. Complex coacervation, one of the most effective encapsulation techniques, is known for its simplicity, low cost, scalability and reproducibility in encapsulation of functional components. In recent years, complex coacervation has been successfully used for encapsulation of tannins and tannin-rich plant extracts. In this article, the research progress in encapsulating tannins and tannin-rich plant extracts by complex coacervation to improve their physicochemical properties and biological activities is critically reviewed for the first time. Encapsulation of tannins and tannin-rich plant extracts can effectively improve their sensory characteristics, stabilities, bioavailability, anti-hypercholesterolemia, anti-diabetic, antioxidant, anticancer and antimicrobial activities. In particular, the enhancement of biological activities of tannins and tannin-rich plant extracts is usually correlated to their improved physicochemical properties imparted by the encapsulation technique. Moreover, we introduce the issues that need to be further resolved in future studies on encapsulation of tannins and tannin-rich plant extracts by complex coacervation.

Sustainable extraction of antioxidants from out-of-caliber kiwifruits.

Valorisation of discarded kiwifruits is proposed by extracting bioactive compounds using sustainable solvents namely deep eutectic solvents (DES). A screening of fifteen DES and several hydrogen bonding donor solvents was carried out. Extraction efficiency was measured in terms of antioxidant activity using DPPH and FRAP tests. The influence of solvents characteristics in particular DES structure, presence of ethanol or water, and pH of DES/water mixture on the antioxidant properties of the extracts was studied. Results show that kiwi peels extracts obtained with DES based on carboxylic acids exhibit enhanced antioxidant activity compared to conventional solvents and alcohol-based DES with a maximum DPPH scavenging activity of 42.0 mg TE/g DW. Glycerol or ethylene glycol are also efficient at extracting antioxidant compounds with DPPH scavenging activity of 33.1 and 36.7 mg TE/g DW. Finally, a chemical analysis of extracts using HPTLC revealed that most active compounds extracted are polyphenolic compounds, presumably tannins.

Development of Zein/tannic acid nanoparticles as antioxidants for oxidation inhibition of blackberry seed oil emulsions.

The zein-tannic acid nanoparticles (ZTNPs) were developed as antioxidants for oxidation inhibition of blackberry seed oils. These particles were spherical with an average diameter below 200 nm. The results of structural characterization indicated that tannic acid was bound to zein by electrostatic, hydrophobic, and hydrogen bonding interactions, resulting in the conformational changes of zein. The antioxidant capacity of zein was significantly improved by binding of tannic acid, which suggested ZTNPs had a 2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-Oxide (PTIO) radical scavenging rate as high as 77.5 % at pH 4. Moreover, ZTNPs at pH 7 exhibited a higher thermal stability and better resistance to emulsion lipid oxidation. They inhibited the formation of ROOH and TBARS of blackberry seed oil emulsions during storage by covering at the oil-water interface with an adsorption rate of approximately 100 %, forming a dense particle film to reduce the oxygen content and prevent the continuation of the oxidation process.

Overview of Phlorotannins' Constituents in Fucales.

Fucales are an order within the Phaeophyceae that include most of the common littoral seaweeds in temperate and subtropical coastal regions. Many species of this order have long been a part of human culture with applications as food, feedand remedies in folk medicine. Apart from their high nutritional value, these seaweeds are also a well-known reservoir of multiple bioactive compounds with great industrial interest. Among them, phlorotannins, a unique and diverse class of brown algae-exclusive phenolics, have gathered much attention during the last few years due to their numerous potential health benefits. However, due to their complex structural features, combined with the scarcity of standards, it poses a great challenge to the identification and characterization of these compounds, at least with the technology currently available. Nevertheless, much effort has been taken towards the elucidation of the structural features of phlorotannins, which have resulted in relevant insights into the chemistry of these compounds. In this context, this review addresses the major contributions and technological advances in the field of phlorotannins extraction and characterization, with a particular focus on Fucales.

Antimicrobial Resistance of Tannin Extract against E. coli Isolates from Sheep.

Plants have been long valuable sources of natural materials that have served to preserve human and animal health; as a result, pharmacological purposes have arisen from the use of plant compounds in most countries, according to a World Health Organization report. The present study aimed to assess the antimicrobial resistance of tannin extract against Escherichia coli (E. coli) isolates in sheep. A total of 100 samples from sheep were used to isolate E. coli and treated with tannin extract (90% purity) to investigate the in vitro effect, as compared to some antibiotics (Clindamycin, Cephalexin, Kanamycin, Tetracycline, and Vancomycin). The bacterial samples were cultured in a selective and differential medium, and Gram staining was used to examine them. The biochemical assays were performed to purify and expose these cultures; moreover, the API 20E system and RapidTM ONE kits were utilized to confirm the bacterial strain. Based on the findings, 50% of the samples showed a positive result for the presence of E. coli. The well diffusion technique was used to investigate the antibacterial activity to confirm the antibacterial action of tannin extract (from pomegranate peel) in different concentrations against E. coli. The highest zone of inhibition for the bacteria ranged from 12±0.5 to 30.3±0.2 at 50% concentrations, proving that tannins extract was significantly effective against E. coli. The presence of E. coli was detected in 50 % of the samples. The well-diffusion technique was used to evaluate the antimicrobial property of tannin extract through various concentrations with the highest zone of inhibition for the bacteria ranging from 12.5 to 30.30.2 at 50%, demonstrating that tannin extract was significantly effective on E. coli.

Effects of Saignée and Bentonite Treatment on Phenolic Compounds of Marquette Red Wines.

To improve the phenolic extraction and color stability of red wine made from cold-hardy grapes, two winemaking practices, saignée and bentonite, were applied separately and in combination on Marquette grapes at crushing. The effects of these winemaking strategies on Marquette wine's basic chemical properties, monomeric and polymeric phenolic compounds were studied, as well as the development of color characteristics from crushing to 5 months of aging. The saignée (9% juice run-off) treatment showed little impact on the phenolic content of the finished wine, but showed an increase in color intensity. A hue shift towards an orange-yellow tone was observed in the bentonite-treated wines, which was associated with a loss of monomeric anthocyanins. The combination of saignée and bentonite showed less impact on removing anthocyanins and wine color, and increased phenolics content, therefore improving the extraction of non-anthocyanins monomeric phenolics. Although this combination treatment led to the highest concentration of tannin content after pressing, this difference between the control and other treatments disappeared over time. These results suggested that the interactions between tannins and other wine compounds still occur after removing proteins in Marquette wines.

Quinoa protein extract: an effective alternative for the fining of wine phenolics.

BACKGROUND: Lately, there has been an increasing interest in using plant-derived proteins for wine phenolic fining. Proteins extracted from cereals, potatoes, and legumes have been proposed as effective fining agents, but only those from pea, wheat, and potatoes have been approved for their use in wine. This work aimed at determining the fining ability of quinoa (Chenopodium quinoa Willd.) protein extracts (QP), compared to commercial fining agents, on red wines. RESULTS: The trials compared the performance of QP (30 and 50 g/hL), two potato protein extracts and gelatin, at two different contact times (48 and 96 h), using Petit Verdot, Malbec, and Cabernet Sauvignon wines. Turbidity, total phenolics, precipitable tannins, catechins, and color characteristics were determined. QP reduced the turbidity of all wines in a similar way to commercial fining agents. Both doses of QP significantly reduced tannins and other phenolic measures, including color intensity reductions, in a similar way to commercial fining agents. CONCLUSION: QP behaved as an effective fining agent that deserves further studies in order to improve its performance and advance its characterization. © 2022 Society of Chemical Industry.