Stimuli-Responsive Tannin-FeIII Hybrid Microcapsules Demonstrated by the Active Release of an Anti-Tuberculosis Agent

Recent progress in tannin and lignin blended metal oxides and metal sulfides as smart materials for electrochemical sensor applications

Our technologically advanced civilization has made sensors an essential component. They have potential uses in the pharmaceutical sector, clinical analysis, food quality control, environmental monitoring, and other areas. One of the most active fields of analytical chemistry research is the fabrication of electrochemical sensors. An intriguing area of electroanalytical chemistry is the modification of electrodes using polymeric films. Due to their benefits, which include high adhesion to the electrode surface, chemical stability of the coating, superior selectivity, sensitivity, and homogeneity in electrochemical deposition, polymer-modified electrodes have attracted a great deal of interest in the electroanalytical sector. Conducting polymers are an important material for sensing devices because of their fascinating features, which include high mechanical flexibility, electrical conductivity, and the capacity to be electrochemically converted between electronically insulating and conducting states. Tannin or lignin nanomaterials can be an inter-linker leading to flexible and functional polymeric networks. There is a continuing demand for fast and simple analytical methods for the determination of many clinically important biomarkers, food additives, environmental pollutants etc. This review in a comprehensive way summarizes and discusses the various metal oxide and sulfide-incorporated tannin and lignin scaffolds using electrochemical sensing and biosensing.

Novel strategies based on natural products and synthetic derivatives to overcome resistance in Mycobacterium tuberculosis

One of the biggest health challenges of today's world is the emergence of antimicrobial resistance (AMR), which renders conventional therapeutics insufficient and urgently demands the generation of novel antimicrobial strategies. Mycobacterium tuberculosis (M. tuberculosis), the pathogen causing tuberculosis (TB), is among the most successful bacteria producing drug-resistant infections. The versatility of M. tuberculosis allows it to evade traditional anti-TB agents through various acquired and intrinsic mechanisms, rendering TB among the leading causes of infectious disease-related mortality. In this context, researchers worldwide focused on establishing novel approaches to address drug resistance in M. tuberculosis, developing diverse alternative treatments with varying effectiveness and in different testing phases. Overviewing the current progress, this paper aims to briefly present the mechanisms involved in M. tuberculosis drug-resistance, further reviewing in more detail the under-development antibiotics, nanotechnological approaches, and natural therapeutic solutions that promise to overcome current treatment limitations.

Metal-polyphenol microgels for oral delivery of puerarin to alleviate the onset of diabetes

Puerarin (Pue) is a naturally bioactive compound with many potential functions in regulating blood glucose and lipid metabolism. However, the low bioavailability and rapid elimination in vivo limit the application of Pue in diabetic treatment. Here, we developed a metal-polyphenol-functionalized microgel to effectively deliver Pue in vivo and eventually alleviate the onset of diabetes. Pue was initially encapsulated in alginate beads through electrospray technology, and further immersed in Fe3+ and tannic acid solution from tannic acid (TA)-iron (Fe) coatings (TF). These constructed Pue@SA-TF microgels exhibited uniform spheres with an average size of 367.89 ± 18.74 µm and high encapsulation efficiency of Pue with 61.16 ± 1.39%. In vivo experiments proved that compared with free Pue and microgels without TF coatings, the biological distribution of Pue@SA-TF microgels specifically accumulated in the small intestine, prolonged the retention time of Pue, and achieved a high effectiveness in vivo. Anti-diabetic experimental results showed that Pue@SA-TF microgels significantly improved the levels of blood glucose, blood lipid, and oxidative stress in diabetic mice. Meanwhile, histopathological observations indicated that Pue@SA-TF microgels could significantly alleviate the damage to the liver, kidney, and pancreas in diabetic mice. Our study provided an effective strategy for oral delivery of Pue and achieved high anti-diabetic efficacy.

Mass Spectrometry-Based Untargeted Metabolomics Reveals the Importance of Glycosylated Flavones in Patterned Lentil Seed Coats

Lentil seed coats are rich in antioxidant polyphenols that are important for plant defense and have potential as valorized byproducts. Although biochemical differences among lentil seed coat colors have been previously studied, differences among seed coat patterns remain largely unexplored. This study used mass spectrometry-based untargeted metabolomics to investigate polyphenol differences among lentil seed coat patterns to search for biochemical pathways potentially responsible for seed coat pattern differences. Comparing patterned with non-patterned green lentil seed coats, 28 significantly upregulated metabolites were found in patterned seed coats; 19 of them were identified as flavones. Flavones were virtually absent in non-patterned seed coats, thereby strongly suggesting a blockage in their flavone biosynthetic pathway. Although the black pattern is not readily discernible on black seed coats, many of the same flavones found in green marbled seed coats were also found in black seed coats, indicating that black seed coats likely have a marbled pattern.

Self-Assembled Integrative Nutrient Carrier Platform Containing Green Tea Catechin for Short Bowel Syndrome Treatment

Extensive resection of the small intestine leads to the development of short bowel syndrome (SBS), which reduces the effective absorptive surface area of the intestine and predisposes patients to emaciation, malnutrition, and other severe symptoms. Herein, green tea catechin (-)-epigallocatechin gallate (EGCG) and ferrous ions (Fe²⁺ ) are utilized to construct a nutrient carrier platform that self-assembles with nutrients to form phenolic-based nutrient complexes (PNCs). PNCs effectively prolong the residence and absorption time of nutrients in the intestine. Further this platform is applied to integrate full nutrient formula, an enteral nutrition (EN) preparation containing a range of full nutrient components. In an SBS rat model, the prepared phenolic-based integrative nutrient complexes (PINCs) enhance nutritional status, improve anemia and immune function, as well as facilitate the growth of remaining intestinal villi and crypts, and maintain the integrity of the intestinal barrier. In addition, PINCs enable the modulation of gut microbial dysbiosis, enrich the abundance of beneficial bacteria, and have no toxic effects after the long-term ingestion. These results provide a proof of principle for the use of polyphenol-based nanocomplexes as EN preparation, offering a feasible strategy for both nutritional support and therapeutic perspectives for SBS treatment.

One-Pot Synthesis of Customized Metal-Phenolic-Network-Coated AIE Dots for In Vivo Bioimaging

The integration of aggregation-induced emission luminogens (AIEgens) and inorganic constituents to generate multifunctional nanocomposites has attracted much attention because it couples the bright aggregate-state fluorescence of AIEgens with the diverse imaging modalities of inorganic constituents. Herein, a facile and universal strategy to prepare metal-phenolic-network (MPN)-coated AIE dots in a high encapsulation efficiency is reported. Through precise control on the nucleation of AIEgens and deposition of MPNs in tetrahydrofuran/water mixtures, termed as coacervation, core-shell MPN-coated AIE dots with bright emission are assembled in a one-pot fashion. The optical properties of MPN-coated AIE dots can be readily tuned by varying the incorporated AIEgens. Different metal ions, such as Fe³⁺ , Ti⁴⁺ , Cu²⁺ , Ni²⁺ , can be introduced to the nanoparticles. The MPN-coated AIE dots with a red-emissive AIEgen core are successfully used to perform magnetic resonance/fluorescence dual-modality imaging in a tumor-bearing mouse model and blood flow visualization in a zebrafish larva. It is believed that the present study provides a tailor-made nanoplatform to meet the individual needs of in vivo bioimaging.

Ultrasound-based one-step fabrication of nobiletin particle: A facile stabilization strategy

As a typical representative of polymethoxylated flavones, nobiletin (NOB) is beneficial to health but hard to be processed, stored, and absorbed, due to its hydrophobicity and crystallinity. Herein, we developed a stabilization system based on an efficient manufacturing procedure of NOB nanocrystal by anti-solvent method combined with ultrasonic treatment. Metal-phenolic networks composed of tannic acid and metal ions were introduced to conformally coat on formed nanocrystal for further stabilization. From the results, the size and morphology of the prepared particles could be altered by the amount, ratio, and kind of the coating materials. The optimized samples could be redispersed after centrifugation, and keep stable at 4 ℃ for at least 120 days. Moreover, they possessed higher acid stability and more effective release than the control sample during the in vitro digestion experiment. Therefore, this work provided a promising idea for overcoming storage and delivery obstacle of hydrophobic crystalline bioactive components.

Study on the stability and oral bioavailability of curcumin loaded (-)-epigallocatechin-3-gallate/poly(N-vinylpyrrolidone) nanoparticles based on hydrogen bonding-driven self-assembly

The biological activity and absorption of curcumin (Cur) is limited in application due to its low water solubility, poorstabilityand rapid metabolism. In this work, Cur loaded (-)-epigallocatechin-3-gallate (EGCG)/poly(N-vinylpyrrolidone) (PVP) nanoparticles (CEP-NPs) was successfully fabricated via self-assembly driven by hydrogen bonding, providing with desirable Cur-loading efficiency, high stability, strong antioxidant capacity, and pH-triggered intestinal targeted release properties. Molecular dynamics simulations further indicated the Cur was coated with EGCG and PVP in CEP-NPs and high acid prolonged release property was attribute to low ionization degree of EGCG. Besides, the enhanced intestinal absorption of Cur was related to inhibition of Cur metabolism by EGCG, enhancement of cellular uptake and higher Caco-2 monolayer permeation. Pharmacokinetic study showed that the oral bioavailability presented nearly 12-fold increment. Therefore, this study provides a new horizon for improving the Cur utilization in food and pharmaceutical fields.

Chemical Derivatization of Commercially Available Condensed and Hydrolyzable Tannins

Novel valorization routes for tannins were opened by the development of a simple, straightforward, robust, and flexible approach to the selective functionalization of condensed and hydrolyzable tannins. Irrespective of the different degrees of polymerization, different commercial tannins were efficiently functionalized by the generation of an ether linkage bound to a short linker carrying the desired functional group. Functionalizations could be realized at varying degrees of technical loadings, i.e., amounts of introduced tannin-alien functionalities per number of phenolic hydroxyl groups. The same strategy was found suitable for the synthesis of polyethylene glycol-functionalized tannin copolymers. Condensed tannins functionalized with carboxylic acid moieties could be converted into a tannin-oligopeptide hybrid.

An Untargeted Metabolomics Approach for Correlating Pulse Crop Seed Coat Polyphenol Profiles with Antioxidant Capacity and Iron Chelation Ability

Pulse crop seed coats are a sustainable source of antioxidant polyphenols, but are typically treated as low-value products, partly because some polyphenols reduce iron bioavailability in humans. This study correlates antioxidant/iron chelation capabilities of diverse seed coat types from five major pulse crops (common bean, lentil, pea, chickpea and faba bean) with polyphenol composition using mass spectrometry. Untargeted metabolomics was used to identify key differences and a hierarchical analysis revealed that common beans had the most diverse polyphenol profiles among these pulse crops. The highest antioxidant capacities were found in seed coats of black bean and all tannin lentils, followed by maple pea, however, tannin lentils showed much lower iron chelation among these seed coats. Thus, tannin lentils are more desirable sources as natural antioxidants in food applications, whereas black bean and maple pea are more suitable sources for industrial applications. Regardless of pulse crop, proanthocyanidins were primary contributors to antioxidant capacity, and to a lesser extent, anthocyanins and flavan-3-ols, whereas glycosylated flavonols contributed minimally. Higher iron chelation was primarily attributed to proanthocyanidin composition, and also myricetin 3-O-glucoside in black bean. Seed coats having proanthocyanidins that are primarily prodelphinidins show higher iron chelation compared with those containing procyanidins and/or propelargonidins.

Sulfited Tannin Capsules: Novel Stimuli-Responsive Delivery Systems

Microcapsules of sulfited Acacia mearnsii tannin (AmST-MCs) were generated for the first time via the sonochemical method. Their stability profile was assessed and set in the general context of tannin microcapsules (TMCs) generated under the same experimental conditions. The analytical data gathered in this work indicate an excellent stability of TMCs over time as well as under high temperature and pressure, which is a major milestone toward the meaningful applications of TMCs in industrial, pharmaceutical, and biomedical applications in which sterilization of TMCs might be a prerequisite. Active release is shown to be efficiently triggered by varying pH and/or salinity, with different profiles for TMCs from sulfited and nonsulfited species. Surfactants also affect the stability of TMCs significantly, with effects eventually amplifiable by pH and the inherent kosmotropic and chaotropic characteristics of salt components in solutions.

Chitosan coated pH-responsive metal-polyphenol delivery platform for melanoma chemotherapy

The safe and effective drug delivery system is important for cancer therapy. Here in, we first constructed a delivery system Cabazitaxel(Cab)@MPN/CS between metal-polyphenol (MPN) and chitosan (CS) to deliver Cab for melanoma therapy. The preparation process is simple, green, and controllable. After introducing CS coating, the drug loading was improved from 7.56 % to 9.28 %. Cab@MPN/CS NPs released Cab continuously under acid tumor microenvironment. The zeta potential of Cab@MPN/CS NPs could be controlled by changing the ratio of Cab@MPN and CS solutions. The positively charged Cab@MPN/CS accelerate B16F10 cell internalization. After internalized, Cab@MPN/CS NPs could escape from lysosomes via the proton sponge effect. The permeability of CS promotes the penetration of Cab@MPN/CS to the deeper B16F10 tumor spheroids. In vivo results showed that Cab@MPN/CS NPs have a longer retention time in tumor tissues and significantly inhibit tumor growth by up-regulating TUNEL expression and down-regulating KI67 and CD31 expression. Thus, this delivery system provides a promising strategy for the tumor therapy in clinic.

A Review on Recent Trends in Green Synthesis of Gold Nanoparticles for Tuberculosis

Tuberculosis (TB) is a contagious disease that has affected mankind. The anti-TB treatment has been used from ancient times to control symptoms of this disease but these medications produced some serious side effects. Herbal products have been successfully used for the treatment of TB. Gold is the most biocompatible metal among all available for biomedical purposes so Gold nanoparticles (GNPs) have sought attention as an attractive biosynthesized drug to be studied in recent years for bioscience research. GNPs are used as better catalysts and due to unique small size, physical resemblance to physiological molecules, biocompatibility and non-cytotoxicity extensively used for various applications including drug and gene delivery. Greenly synthesized GNPs have much more potential in different fields because phytoconstituents used in GNP synthesis itself act as reducing and capping agents and produced more stabilized GNPs. This review is devoted to a discussion on GNPs synthesis with herbs for TB. The main focus is on the role of the natural plant bio-molecules involved in the bioreduction of metal salts during the GNPs synthesis with phytoconstituents used as antitubercular agents.

Tannin-Based Hybrid Materials and Their Applications: A Review

Tannins are eco-friendly, bio-sourced, natural, and highly reactive polyphenols. In the past decades, the understanding of their versatile properties has grown substantially alongside a continuously broadening of the tannins' application scope. In particular, recently, tannins have been increasingly investigated for their interaction with other species in order to obtain tannin-based hybrid systems that feature advanced and/or novel properties. Furthermore, in virtue of the tannins' chemistry and their high reactivity, they either physicochemically or physically interact with a wide variety of different compounds, including metals and ceramics, as well as a number of organic species. Such hybrid or hybrid-like systems allow the preparation of various advanced nanomaterials, featuring improved performances compared to the current ones. Consequently, these diverse-shaped materials have potential use in wastewater treatment or catalysis, as well as in some novel fields such as UV-shielding, functional food packaging, and biomedicine. Since these kinds of tannin-based hybrids represent an emerging field, thus far no comprehensive overview concerning their potential as functional chemical building blocks is available. Hence, this review aims to provide a structured summary of the current state of research regarding tannin-based hybrids, detailed findings on the chemical mechanisms as well as their fields of application.

Lignosulfonate Microcapsules for Delivery and Controlled Release of Thymol and Derivatives

Thymol and the corresponding brominated derivatives constitute important biological active molecules as antibacterial, antioxidant, antifungal, and antiparasitic agents. However, their application is often limited, because their pronounced fragrance, their poor solubility in water, and their high volatility. The encapsulation of different thymol derivatives into biocompatible lignin-microcapsules is presented as a synergy-delivering remedy. The adoption of lignosulfonate as an encapsulating material possessing relevant antioxidant activity, as well as general biocompatibility allows for the development of new materials that are suitable for the application in various fields, especially cosmesis. To this purpose, lignin microcapsules containing thymol, 4-bromothymol, 2,4-dibromothymol, and the corresponding O-methylated derivatives have been efficiently prepared through a sustainable ultrasonication procedure. Actives could be efficiently encapsulated with efficiencies of up to 50%. To evaluate the applicability of such systems for topical purposes, controlled release experiments have been performed in acetate buffer at pH 5.4, to simulate skin pH: all of the capsules show a slow release of actives, which is strongly determined by their inherent lipophilicity.