A deep insight into mechanism for inclusion of 2R,3R-dihydromyricetin with cyclodextrins and the effect of complexation on antioxidant and lipid-lowering activities

Preparation and characterization of fennel (Foeniculum vulgare miller) essential oil/hydroxypropyl-β-cyclodextrin inclusion complex and its application for chilled pork preservation

Fennel essential oil (FEO) a natural spice that has versatile biological activities. However, the direct use of FEO is limited due to its water insolubility and poor stability. Chilled pork is prone to spoilage during storage. To solve these problems, this study aimed to prepare an inclusion complex (IC) of FEO with hydroxypropyl-β-cyclodextrin via co-precipitation and apply it to the preservation of chilled pork. Results indicated that the optimal parameters were encapsulating temperature 37 °C, wall-core ratio 14:1 g/mL, stirring speed 600 r/min, and encapsulating time 240 min, obtaining an encapsulation efficiency of 83.75%. The results of scanning electron microscopy, Fourier transform infra-red spectroscopy, and nuclear magnetic resonance demonstrated the successful preparation of IC. The release of FEO from IC was controllable through adjusting the different temperatures and relative humidities. Furthermore, IC effectively delayed the spoilage of chilled pork and extended its shelf life by 6 days at 4 °C.

Development of pectin/chitosan-based electrospun biomimetic nanofiber membranes loaded with dihydromyricetin inclusion complexes for wound healing application

Accidents and surgical procedures inevitably lead to wounds, presenting clinical challenges such as inflammation and microbial infections that impede the wound-healing process. This study aimed to address these challenges by developing a series of novel wound dressings known as electrospun biomimetic nanofiber membranes. These membranes were prepared using electrostatic spinning technique, incorporating hydroxypropyl-β-cyclodextrin/dihydromyricetin inclusion complexes. The prepared electrospun biomimetic nanofiber membranes exhibited randomly arranged fiber morphology with average fiber diameters ranging from 200 to 400 nm, resembling the collagen fibers in the native skin. These membranes demonstrated excellent biocompatibility, hemocompatibility, surface hydrophilicity, and wettability, while also releasing dihydromyricetin in a sustained manner. In vitro testing revealed that these membranes, loaded with hydroxypropyl-β-cyclodextrin/dihydromyricetin inclusion complexes, displayed higher antioxidant potential and inhibitory effects against Staphylococcus aureus and Escherichia coli. Furthermore, these membranes significantly reduced the M1 phenotypic transition in RAW264.7 cells, even when stimulated by lipopolysaccharides, effectively restoring M2 polarization, thereby shortening the inflammatory period. Additionally, the in vivo wound healing effects of these membranes were validated. In conclusion, this study introduces a promising nanofiber membrane with diverse biological properties that holds promise for addressing various crucial aspects of the wound-healing process.

Encapsulation of 4-terpineol with β-cyclodextrin: Inclusion mechanism, characterization and relative humidity-triggered release

4-Terpineol (4-TA), a typical monocyclic monoterpene essential oil compound with important biological activities, poor stability and solubility severely hamper its biological activities. To date, β-cyclodextrin (β-CD) encapsulating essential oil to form inclusion complexes (ICs) is considered as a satisfactory treatment. Nevertheless, the detailed inclusion mechanism of β-CD for 4-TA especially the behavior of 4-TA during inclusion formation have not available yet. Herein, 4-TA/β-CD ICs were successfully synthesized by the co-precipitation method, and hydrogen bonds and hydrophobic interactions played a key role in the formation of ICs, and the isopropyl of 4-TA entered the cavity through the wide rim of β-CD. Moreover, the release profile demonstrated that high RH (85 % and 99 %) triggered the release of TA from ICs. This study suggests the great potential of cyclodextrin inclusion strategy for improving the stability and sustained release of 4-TA in food preservation application.

Advancements in application of chitosan and cyclodextrins in biomedicine and pharmaceutics: recent progress and future trends

The global community is faced with numerous health concerns such as cancer, cardiovascular and neurological diseases, diabetes, joint pain, osteoporosis, among others. With the advancement of research in the fields of materials chemistry and medicine, pharmaceutical technology and biomedical analysis have entered a new stage of development. The utilization of natural oligosaccharides and polysaccharides in pharmaceutical/biomedical studies has gained significant attention. Over the past decade, several studies have shown that chitosan and cyclodextrin have promising biomedical implications in background analysis, ongoing development, and critical applications in biomedical and pharmaceutical research fields. This review introduces different types of saccharides/natural biopolymers such as chitosan and cyclodextrin and discusses their wide-ranging applications in the biomedical/pharmaceutical research area. Recent research advances in pharmaceutics and drug delivery based on cyclodextrin, and their response to smart stimuli, as well as the biological functions of cyclodextrin and chitosan, such as the immunomodulatory effects, antioxidant, and antibacterial properties, have also been discussed, along with their applications in tissue engineering, wound dressing, and drug delivery systems. Finally, the innovative applications of chitosan and cyclodextrin in the pharmaceutical/biomedicine were reviewed, and current challenges, research/technological gaps, and future development opportunities were surveyed.

Opportunities and challenges in enhancing the bioavailability and bioactivity of dietary flavonoids: A novel delivery system perspective

Flavonoids have multiple favorable bioactivities including antioxidant, anti-inflammatory, and antitumor. Currently, flavonoid-containing dietary supplements are widely tested in clinical trials for the prevention and/or treatment of multiple diseases. However, the clinical application of flavonoids is largely compromised by their low bioavailability and bioactivity, probably due to their poor aqueous solubility, intensive metabolism, and low systemic absorption. Therefore, formulating flavonoids into novel delivery systems is a promising approach for overcoming these drawbacks. In this review, we highlight the opportunities and challenges in the clinical use of dietary flavonoids from the perspective of novel delivery systems. First, the classification, sources, and bioactivity of dietary flavonoids are described. Second, the progress of clinical research on flavonoid-based dietary supplements is systematically summarized. Finally, novel delivery systems developed to improve the bioavailability and bioactivity of flavonoids are discussed in detail to broaden the clinical application of dietary flavonoids.

L-histidine-assisted ultrasound improved physicochemical properties of myofibrillar proteins under reduced-salt condition - Investigation of underlying mechanisms

The effects of the L-hisdine (L-His)-assisted ultrasound on physicochemical characteristics and conformation of myofibrillar protein (MP) under reduced-salt condition were investigated using spectroscopic analysis, and the binding mechanism between L-His and MP was further elucidated through molecular docking and molecular dynamics (MD) simulations. UV second derivative spectra and intrinsic Try fluorescence spectra revealed that L-His formed a complex with MP and altered the microenvironment of MP. After L-His-assisted ultrasound treatment, MP showed smaller particle size, higher solubility, and more uniform atomic force microscopy image due to the decrease of α-helix content and the subsequent increase in zeta potential, active sulfhydryl content, and surface hydrophobicity. Molecular docking and MD simulations demonstrated the optimal docking pose (minimum binding affinity of -6.78 kcal/mol) and revealed hydrophobic interactions and hydrogen bonds as the main interaction forces between L-His and MP, with several residues (ILE-464, ILE-480, THR-483, ASN-484, GLY-466, ASP-463, PHE-246) identified as binding sites.

Molecular dynamics simulation and in vitro digestion to examine the impact of theaflavin on the digestibility and structural properties of myosin

In this study, the interaction mechanism between theaflavin and myosin was explored to confirm the potential application of theaflavin in the meat protein system. A series of theaflavin and myosin solutions were prepared for spectroscopic studies. Spectroscopy results showed that theaflavins formed complexes with myosin and affected the microenvironment of myosin. And that addition of theaflavin cause static quenching of the myosin solution. Theaflavin and bovine myosin combined through hydrophobic interaction to form a complex, and gradually increasing the temperature was conducive to the binding of theaflavin and bovine myosin. This interaction results in a decrease in the α -helix content of myosin. Molecular dynamics simulation results confirmed that hydrophobic interactions and hydrogen bonds made the protein structure more compact and stable. And the in vitro digestion process was simulated. The results showed that the addition of theaflavin could significantly reduce the digestibility of myosin.

Extract of Pfaffia glomerata Ameliorates Paroxetine-Induced Sexual Dysfunction in Male Mice and the Characterization of Its Phytoconstituents by UPLC-MS

Pfaffia glomerata extract (PGE) has a variety of biological activities. However, its ameliorative effect on and exact working mechanism in male sexual dysfunction are still poorly understood. This study aims to evaluate the ameliorative effect of PGE on paroxetine (PRX)-induced sexual dysfunction in male mice and uses molecular docking technology to investigate its underlying mechanism. In this work, PRX-induced sexual dysfunction was caused and PGE was gavaged in mice for 28 days. The results show that PGE significantly improved the sexual performance of mice and reduced the damage to testicular tissues. Further studies showed that PGE restored serum sex hormones to normal levels and increased nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) levels as well as nitric oxide synthase (NOS) activity in penile tissues, while also decreasing phosphodiesterase-5 (PDE-5) activity, thereby maintaining normal penile erection in mice. In addition, PGE improved the activities of enzymes (LDH, ACP, and ALP) related to energy metabolism in the testis and significantly increased sperm count and viability in mice. Furthermore, the molecular docking results show that all eight compounds in PGE could form a stable complex with PDE-5 and inhibit the activity of PDE-5. In conclusion, PGE had an ameliorative effect on PRX-induced sexual dysfunction, suggesting that PGE has a potential protective effect on male sexual health.

Probing the mechanism of interaction between capsaicin and myofibrillar proteins through multispectral, molecular docking, and molecular dynamics simulation methods

The interaction between myofibrillar proteins (MPs) and capsaicin (CAP) was investigated using multispectral, molecular docking, and molecular dynamics simulation methods. The resulting complex increased the hydrophobicity of the tryptophan and tyrosine microenvironment as revealed by fluorescence spectral analysis. The fluorescence burst mechanism study indicated that the fluorescence burst of CAP on the MPs was a static one (Kq = 1.386 × 10¹² m^-1s^-1) and that CAP could bind with MPs well (Ka = 3.31 × 10⁴ L/mol, n = 1.09). The analysis of circular dichroism demonstrated that the interaction between CAP and MPs caused a decrease in the α-helical structure of MPs. The complexes formed exhibited lower particle size and higher absolute ζ potential. Furthermore, hydrogen bonding, van der Waals forces, and hydrophobic interactions were found to be the primary factors facilitating the interaction between CAP and MPs, as suggested by molecular docking models and molecular dynamics simulations.

Recent Advances in the Pharmaceutical and Biomedical Applications of Cyclodextrin-Capped Gold Nanoparticles

The real problem in pharmaceutical preparation is drugs' poor aqueous solubility, low permeability through biological membranes, and short biological t_1/2. Conventional drug delivery systems are not able to overcome these problems. However, cyclodextrins (CDs) and their derivatives can solve these challenges. This article aims to summarize and review the history, properties, and different applications of cyclodextrins, especially the ability of inclusion complex formation. It also refers to the effects of cyclodextrin on drug solubility, bioavailability, and stability. Moreover, it focuses on preparing and applying gold nanoparticles (AuNPs) as novel drug delivery systems. It also studies the uses and effects of cyclodextrins in this field as novel drug carriers and targeting devices. The system formulated from AuNPs linked with CD molecules combines the advantages of both CD and AuNPs. Cyclodextrins benefit in increasing aqueous drug solubility, loading capacity, stability, and size control of gold NPs. Also, AuNPs are applied as diagnostic and therapeutic agents because of their unique chemical properties. Plus, AuNPs possess several advantages such as ease of detection, targeted and selective drug delivery, greater surface area, high loading efficiency, and higher stability than microparticles. In the present article, we tried to present the potential pharmaceutical applications of CD-derived AuNPs in biomedical applications including antibacterial, anticancer, gene-drug delivery, and various targeted drug delivery applications. Also, the article highlighted the role of CDs in the preparation and improvement of catalytic enzymes, the formation of self-assembling molecular print boards, the fabrication of supramolecular functionalized electrodes, and biosensors formation.

Comparative study of encapsulated cannabidiol ternary solid dispersions prepared by different techniques: The application of a novel technique jet milling

Jet milling is a common technique in ultrafine powder preparation field. It has never been used to design delivery systems. Cannabidiol (CBD) is an important cannabinoid of hemp but poor aqueous solubility limited its applications. In this study, solid dispersion (SD) technique was combined with cyclodextrin complexation technique, and jet milling was used for the first time to prepare SDs for improving CBD solubility. Different characterizations demonstrated that the dispersion effect and complexation structure of CBD SD3 prepared by jet milling were comparable to that of CBD SD2 prepared by spray drying (a common solution-based method), and were better than that of CBD SD1 prepared by cogrinding. The water solubility of CBD was increased to 20.902 μg/mL (909-fold) in CBD SD3. Besides, the antioxidant activity and cytotoxicity to tumor cells of CBD were enhanced by dispersion. This work indicated that jet milling, as a new technique with low cost and excellent applicability, could be further developed for the delivery of food functional factors or bioactive molecules.

Preparation and characterization of inclusion complex of Myristica fragrans Houtt. (nutmeg) essential oil with 2-hydroxypropyl-β-cyclodextrin

Nutmeg essential oil (NEO) is a natural condimentwith versatile biological activities. However, the application of NEO in food has several limitations due to its poor stability and low aqueous solubility. To overcome the shortcomings, this paper focused on the preparation of the inclusion complex (IC) of NEO with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) by the coprecipitation method. The optimal condition was inclusion temperature 36 ℃, time 247 min, stirring speed 520 r/min, and wall-core ratio 12:1, resulting in a recovery of 80.63%. The formation of IC was verified by various methods such as scanning electron microscopy, Fourier transform infrared spectroscopy and nuclear magnetic resonance. The improvement of thermal stability, antioxidant, and nitrite scavenging activities of NEO after encapsulation was proven. Moreover, the controlled release of NEO from IC can be implemented by regulating the temperature and relative humidity. Overall, NEO/HP-β-CD IC has great application potential in food industries.

Interactions between plant-derived antioxidants and cyclodextrins and their application for improving separation, detection, and food quality issues

Plant-derived antioxidants (PD-AOs) are important for food preservation, as well as for human health and nutrition. However, the poor chemical stability and water solubility of many PD-AOs currently limit their application as functional ingredients in foods and pharmaceuticals. Moreover, it is often difficult to isolate and detect specific antioxidants in multi-component systems, which again limits their potential in the food and medical industries. In this review, we highlight recent advances in the use of cyclodextrins (CDs) to overcome these limitations by forming simple, modified and competitive host-guest interactions with PD-AO. The host-guest properties of CDs can be used to enhance the separation efficiency of PD-AOs, as well as to improve their dispersion and stability in food systems. Moreover, the competitive complexation properties of CDs with target molecules can be used to selectively isolate PD-AOs from multi-component systems and develop detection technologies for PD-AOs. Overall, CD-antioxidant interactions have great potential for addressing isolation, detection, and food quality issues.

Preparation, Characterization and Molecular Dynamics Simulation of Rutin-Cyclodextrin Inclusion Complexes

Rutin is a natural flavonoid that carries out a variety of biological activities, but its application in medicine and food is limited by its water solubility. One of the classical methods used to enhance drug solubility is encapsulation with cyclodextrins. In this paper, the encapsulation of different cyclodextrins with rutin was investigated using a combination of experimental and simulation methods. Three inclusions of rutin/beta-cyclodextrin (β-CD), rutin/2-hydroxypropyl beta-cyclodextrin (HP-β-CD) and rutin/2,6-dimethyl beta-cyclodextrin (DM-β-CD) were prepared by the freeze-drying method, and the inclusions were analyzed using Fourier infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC) and ultraviolet-visible spectroscopy (UV) to characterize and demonstrate the formation of the inclusion complexes. Phase solubility studies showed that rutin formed a 1:1 stoichiometric inclusion complex and significantly increased its solubility. β-CD, HP-β-CD, DM-β-CD, rutin and the three inclusion complexes were modeled by using MS2018 and AutoDock 4.0, and molecular dynamics simulations were performed to calculate the solubility parameters, binding energies, mean square displacement (MSD), hydrogen bonding and radial distribution functions (RDF) after the equilibration of the systems. The results of simulation and experiment showed that rutin/DM-β-CD had the best encapsulation effect among the three cyclodextrin inclusion complexes.

Binding of Licochalcone A to Whey Protein Enhancing Its Antioxidant Activity and Maintaining Its Antibacterial Activity

Incorporating LA into whey protein by forming whey protein isolate-LA (WPI-LA) and polymerized whey protein-LA (PWP-LA) complexes is a good way to maintain its bioactivity and improve its functional performance within food matrices. Herein, we found that WPI and PWP were able to interact with LA as suggested by multi-spectroscopy, molecular docking, and molecular dynamics simulations. The interaction between whey protein and LA was a spontaneous non-covalent binding process, while PWP had a higher affinity for LA than WPI, resulting from its more negatively binding free energy with LA. Hydrogen bonds, van der Waals forces, and electrostatic interactions were responsible for WPI-LA interactions. Hydrophobic forces, van der Waals, and hydrogen bonds positively accounted for PWP-LA interactions. The antioxidant activity of LA was improved by complexation with whey proteins as identified by DPPH and ABTS. The antimicrobial efficiency of LA was partially screened by complexation with whey protein with MIC values increased by seven-fold compared to free LA but successfully recovered to its original efficiency upon isolating it from the complex. This work demonstrates the promising antioxidant and antibacterial activities of the whey protein-LA complex and provides a good candidate for developing a new class of natural functional ingredients for food systems.

Strategic developments in the drug delivery of natural product dihydromyricetin: applications, prospects, and challenges

Dihydromyricetin (DHM) is an important natural flavonoid that has attracted much attention because of its various functions such as protecting the cardiovascular system and liver, treating cancer and neurodegenerative diseases, and anti-inflammation effect, etc. Despite its great development potential in pharmacy, DHM has some problems in pharmaceutical applications such as low solubility, permeability, and stability. To settle these issues, extensive research has been carried out on its physicochemical properties and dosage forms to produce all kinds of DHM preparations in the past ten years. In addition, the combined use of DHM with other drugs is a promising strategy to expand the application of DHM. However, although invention patents for DHM preparations have been issued in several countries, the current transformation of DHM research results into market products is insufficient. To date, there is still a lack of deep research into the pharmacokinetics, pharmacodynamics, toxicology, and action mechanism of DHM preparations. Besides, preparations for combined therapy of DHM with other drugs are scarcely reported, which necessitates the development of dosage forms for this application. Apart from medicine, the development of DHM in the food industry is also of great potential. Due to its multiple effects and excellent safety, DHM preparations can be developed for functional drinks and foods. Through this review, we hope to draw more attention to the development potential of DHM and the above challenges and provide valuable references for the research and development of other natural products with a similar structure-activity relationship to this drug.

Computational Methods for the Interaction between Cyclodextrins and Natural Compounds: Technology, Benefits, Limitations, and Trends

Cyclodextrins (CDs) have a hollow structure with a hydrophobic interior and hydrophilic exterior. Forming inclusion complexes with CDs will maximize the bioavailability of natural compounds and enable active components to be processed into functional foods, medicines, additives, and so forth. However, experimental methods cannot explain CD-guest binding at the atomic level. Different models have been recently developed to simulate the interaction between CDs and guests to study the binding conformation and analyze noncovalent forces. This review paper summarizes modeling methods of CD-natural compound complexes. The methods include quantitative structure-activity relationships, molecular docking, molecular dynamics simulations, and quantum-chemical calculations. The applications of these methods to enhance the solubility and bioactivities of guest molecules, assist material transportation, and promote compound extraction are also discussed. The purpose of this review is to explore interaction mechanisms of CDs and guests and to help expand new applications of CDs.

Application of starch-based nanoparticles and cyclodextrin for prebiotics delivery and controlled glucose release in the human gut: a review

Starches are a major constituent of staple foods and are the main source of energy in the human diet (55-70%). In the gastrointestinal tract, starches are hydrolyzed into glucose by α-amylase and α-glucosidase, which leads to a postprandial glucose elevation. High levels of blood glucose levels over sustained periods may promote type 2 diabetes mellitus (T2DM) and obesity. Increasing consumption of starchy foods with a lower glycemic index may therefore contribute to improved health. In this paper, the preparation and properties of several starch-based nanoparticles (SNPs) and cyclodextrins (CDs) derivatives are reviewed. In particular, we focus on the various mechanisms responsible for the ability of these edible nanomaterials to modulate glucose release and the gut microbiome in the gastrointestinal tract. The probiotic functions are achieved through encapsulation and protection of prebiotics or bioactive components in foods or the human gut. This review therefore provides valuable information that could be used to design functional foods for improving human health and wellbeing.

Cannabidiol/hydroxypropyl-β-cyclodextrin inclusion complex: structure analysis, release behavior, permeability, and bioactivity under in vitro digestion

The inclusion complex of CBD greatly improved its release performance and bioactivity.

Recent development in zebrafish model for bioactivity and safety evaluation of natural products

The zebrafish is a species of freshwater fish, popular in aquariums and laboratories. Several advantageous features have facilitated zebrafish to be extensively utilized as a valuable vertebrate model in the lab. It has been well-recognized that natural products possess multiple health benefits for humans. With the increasing demand for natural products in the development of functional foods, nutraceuticals, and natural cosmetics, the zebrafish has emerged as an unprecedented tool for rapidly and economically screening and identifying safe and effective substances from natural products. This review first summarized the key factors for the management of zebrafish in the laboratory, followed by highlighting the current progress on the establishment and applications of zebrafish models in the bioactivity evaluation of natural products. In addition, the zebrafish models used for assessing the potential toxicity or health risks of natural products were involved as well. Overall, this review indicates that zebrafish are promising animal models for the bioactivity and safety evaluation of natural products, and zebrafish models can accelerate the discovery of novel natural products with potential health functions.

Dihydromyricetin Acts as a Potential Redox Balance Mediator in Cancer Chemoprevention

Dihydromyricetin (DHM) is a flavonoid extracted from the leaves and stems of the edible plant Ampelopsis grossedentata that has been used for Chinese Traditional Medicine. It has attracted considerable attention from consumers due to its beneficial properties including anticancer, antioxidative, and anti-inflammatory activities. Continuous oxidative stress caused by intracellular redox imbalance can lead to chronic inflammation, which is intimately associated with the initiation, promotion, and progression of cancer. DHM is considered a potential redox regulator for chronic disease prevention, and its biological activities are abundantly evaluated by using diverse cell and animal models. However, clinical investigations are still scanty. This review summarizes the current potential chemopreventive effects of DHM, including its properties such as anticancer, antioxidative, and anti-inflammatory activities, and further discusses the underlying molecular mechanisms of DHM in cancer chemoprevention by targeting redox balance and influencing the gut microbiota.

Dihydromyricetin incorporated active films based on konjac glucomannan and gellan gum

Active composite films were developed by incorporating different concentration of dihydromyricetin (DMY) into konjac glucomannan (KGM)/gellan gum (GG) matrix. Physicochemical, mechanical, released behaviour, antioxidant and antimicrobial properties of composite films were investigated. The results from the Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) indicated that DMY which well-dispersed in the KGM/GG matrix interacted with matrix through hydrogen bonds. The obtained films presented predominant thermostability, good water resistance property, excellent ultraviolet light barrier ability and sustained controlled release behaviour. In particular, the incorporation of DMY remarkably enhanced the antioxidant and antimicrobial activities of the films. Overall, the fabricated KGM/GG-DMY composite films have a promising application in the fields of food packaging.

Eco-Friendly and Facile Synthesis of Antioxidant, Antibacterial and Anticancer Dihydromyricetin-Mediated Silver Nanoparticles

Background

Dihydromyricetin (DMY), a natural flavonoid, has reportedly antibacterial, antioxidant, anticancer and other properties. In the present study, DMY was used as a reducing agent and stabilizer to synthesize silver nanoparticles (AgNPs), and the optimal conditions for its synthesis were studied. The DMY-AgNPs were investigated for their DPPH scavenging properties and their potential against human pathogenic and food-borne bacteria viz. Escherichia coli (E. coli), and Salmonella. In addition, DMY-AgNPs also showed excellent inhibitory effects on cancer Hela, HepG2 and MDA-MB-231 cell lines.

Methods

The dihydromyricetin-mediated AgNPs (DMY-AgNPs) were characterized by ultraviolet-visible spectrophotometer (UV-Vis spectra), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). Antioxidant activity of DMY-AgNPs was determined by 1.1-diphenyl-2-picrylhydrazyl (DPPH) scavenging. The antibacterial activity was determined by 96-well plate (AGAR) gradient dilution, while anticancer potential was determined by MTT assay.

Results

The results showed that the dispersion of AgNPs had the maximum UV-visible absorption at about 410 nm. The synthesized nanoparticles were almost spherical. FTIR was used to identify functional groups that may lead to the transformation of metal ions into nanoparticles. The results showed that the prepared AgNPs were coated with biological molecules in the extraction solution. The biosynthesized DMY-AgNPs exhibited good antioxidant properties, at various concentrations (0.01-0.1mg/mL), the free radical scavenging rate was about 56-92%. Furthermore, DMY-AgNPs possessed good antibacterial properties against Escherichia coli (E. coli), and Salmonella at room temperature. The minimum inhibitory concentrations (MIC) were 10^-6 g/L, and 10^-4 g/L, respectively. The bioactivity of DMY-mediated AgNPs was studied using MTT assay against Hela, HepG2 and MDA-MB-231 cancer cell lines, and all showed good inhibitory effects.

Conclusion

The present study provides a green approach for the synthesis of DMY-AgNPs which exhibited stronger antioxidant, antibacterial and anticancer properties compared to the dihydromyricetin. DMY-AgNPs can serve as an economical, efficient, and effective antimicrobial material for its applications in food and pharmaceutical fields.

Evaluation of General Synthesis Procedures for Bioflavonoid-Metal Complexes in Air-Saturated Alkaline Solutions

The general synthesis methods of bioflavonoid-metal complexes are considered to be unreliable due to the instability of flavonoids in air-saturated alkaline solutions. In this study, dihydromyricetin (DHM), as a representative bioflavonoid, was selected for complexation with various transition metal ions in an air-saturated alkaline solution to form DHM-metal(II) complexes, following the general synthetic procedure. After characterization, the metal complexes were hydrolyzed to observe the stability of DHM under acidic conditions via HPLC. The effects of synthetic conditions (metal ion, alkalinity, and reflux time) on DHM stability were then investigated by UV-vis spectroscopy and HPLC. Finally, using electron paramagnetic resonance, DHM and its analogs were observed with DMPO (5,5-dimethyl-1-pyrroline-N-oxide) to form a relatively stable free radical adduct. Multiple peaks corresponding to unknown compounds appeared in the LC spectra of the DHM-metal(II) complexes after hydrolysis, indicating that some DHM reacted during synthesis. Subsequently, the transition metal ion and solution alkalinity were found to have notable effects on the stability of free DHM. Furthermore, DHM and several of its analogs generated the superoxide-anion radical in air-saturated alkaline solutions. Their capacities for generating the superoxide anion seemed to correspond to the number and/or location of hydroxyl groups or their configurations. Interestingly, DHM can react with the superoxide anion to transform into myricetin, which involves the abstraction of a C3-H atom from DHM by O₂ ^-. Therefore, the general synthetic procedure for bioflavonoid-metal complexes in air-saturated alkaline solutions should be improved.

Novel amino-β-Cyclodextrins containing polymers: Fabrication, characterization, and biological evaluation

In this study, poly (mPEGMA-co-MAA) (PA) based on monomers of mPEGMA and MAA were synthesized, and different amino-β-Cyclodextrins with various alkyl chains were conjugated to PA through carbodiimide-mediated coupling reactions. The obtained poly (mPEGMA-co-MAA-g-amino-β-CD) (PA-g-amino-β-CD) was characterized by FTIR, NMR and TGA. The fluorescence technique was used to investigate the micellization of PA-g-amino-β-CDs. The results indicated that these polymers could self-assemble into nano-micelles in water, and PA-g-HDA-β-CD possessed the lowest CMC value due to its long alkyl chains. In addition, the PA-g-HDA-β-CD micelles were in spherical shapes with the diameter of 78.5 ± 0.6 nm.The release of the model drug from PA-g-HDA-β-CD micelles was increased as the pH reduced from 7.4-5.5 at 37 °C. Cytotoxicity and cellular uptake experiments were performed in HepG2, which showed that the cargo-free PA-g-HDA-β-CD micelles did not have obvious cytotoxicity and were mainly distributed in the cytoplasm of HepG2 cells by endocytosis. Moreover, the study about in vivo distribution of the experimental rats indicated that the accumulation of PA-g-HDA-β-CD micelles mainly happened in the liver. Therefore, the novel amino-β-CD containing polymers exhibit good potential applications in drug delivery system.