Physicochemical properties and bioavailability comparison of two quercetin loading zein nanoparticles with outer shell of caseinate and chitosan

Co-encapsulation of curcumin and fucoxanthin in solid-in-oil-in-water multilayer emulsions: Characterization, stability and programmed sequential release

To enhance the bioavailability of bioactives with varying efficacy in the gastrointestinal tract (GIT), a co-delivery system of solid-in-oil-in-water (S/O/W) emulsion was designed for the co-encapsulation of two bioactives in this paper. S/O/W emulsions were fabricated utilizing fucoxanthin (FUC)-loaded nanoparticles (NPs) as the solid phase, coconut oil containing curcumin (Cur) as the oil phase, and carboxymethyl starch (CMS)/propylene glycol alginate (PGA) complex as the aqueous phase. The high entrapment efficiency of Cur (82.3-91.3%) and FUC (96.0-96.1%) was found in the CMS/PGA complex-stabilized S/O/W emulsions. Encapsulation of Cur and FUC within S/O/W emulsions enhanced their UV and thermal stabilities. In addition, S/O/W emulsions prepared with CMS/PGA complexes displayed good stability. More importantly, the formed S/O/W emulsion possessed programmed sequential release characteristics, delivering Cur and FUC to the small intestine and colon, respectively. These results contributed to designing co-delivery systems for the programmed sequential release of two hydrophobic nutrients in the GIT.

Development of quercetin-loaded electrospun nanofibers through shellac coating on gelatin: Characterization, colon-targeted delivery, and anticancer activity

Quercetin possesses multiple biological activities. To achieve efficient colon-specific release of quercetin, new composite nanofibers were developed by coating pH-responsive shellac on hydrophilic gelatin through coaxial electrospinning. These composite nanofibers contained bead-like structures. The encapsulation efficiency (87.6-98.5 %) and loading capacity (1.4-4.1 %) varied with increasing the initial quercetin addition amount (2.5-7.5 %). FTIR, XRD, and TGA results showed that the quercetin was successfully encapsulated in composite nanofibers in an amorphous state, with interactions occurring among quercetin, gelatin, and shellac. Composite nanofibers had pH-responsive surface wettability due to the shellac coating. In vitro digestion experiments showed that these composite nanofibers were highly stable in the upper gastrointestinal tract, with quercetin release ranging from 4.75 % to 12.54 %. In vivo organ distribution and pharmacokinetic studies demonstrated that quercetin could be sustainably released in the colon after oral administration of composite nanofibers. Besides, the enhanced anticancer activity of composite nanofibers was confirmed against HCT-116 cells by analyzing their effect on cell viability, cell cycle, and apoptosis. Overall, these novel composite nanofibers could deliver efficiently quercetin to the colon and achieve its sustained release, thus potential to regulate colon health. This system is also helpful in delivering other bioactives to the colon and exerting their functional effects.

Fabrication and characterization of TPGS-modified chlorogenic acid liposomes and its bioavailability in rats

Chlorogenic acid (CGA), a polyphenol compound, exhibits excellent anti-oxidative, anti-hypoxic, antibacterial, antiviral, and anti-inflammatory activities, however the bioactivity of it has not been fully utilized in vivo due to its instability and low bioavailability. To address these issues, we prepared and characterized CGA-TPGS-LP, which is a TPGS-modified liposome loaded with CGA. The pharmacokinetics of CGA-TPGS-LP were studied in rats after oral administration. CGA-TPGS-LP was fabricated using a combination of thin film dispersion and ion-driven methods. The liposomes were observed to be uniformly small and spherical in shape. Their membranes were composed of lecithin, cholesterol, and TPGS lipophilic head with a TPGS hydrophilic tail chain coating on its surface. The loading efficiency and encapsulation efficiency were found to be 11.21% and 83.22%, respectively. The physicochemical characterisation demonstrated that the CGA was present in an amorphous form and retained its original structural state within the liposomal formulation. The stability of CGA was significantly improved by fabricating TPGS-LP. CGA-TPGS-LP exhibited good sustained-release properties in both simulated gastric and intestinal fluids. Following oral administration, ten metabolites were identified in rat plasma using UPLC-QTOF-MS. UPLC-QqQ-MS/MS quantitative analysis demonstrated that the oral bioavailability of CGA encapsulated in TPGS-modified liposomes was enhanced by 1.52 times. In addition, the three main metabolites of CGA had higher plasma concentrations and slower degradation rate. These results demonstrate that TPGS-modified liposomes could be a feasible strategy to further enhance the oral bioavailability of CGA, facilitating its clinical use.

Enhanced oral bioavailability of cannabidiol by flexible zein nanoparticles: in vitro and pharmacokinetic studies

Introduction

Cannabidiol (CBD) has a variety of pharmacological effects including antiepileptic, antispasmodic, anxiolytic and anti-inflammatory among other pharmacological effects. However, since CBD is a terpene-phenolic compound, its clinical application is limited by its poor water solubility, low stability, and low bioavailability.

Methods

In this study, we used several strategies to address the above problems. Hydrochloric acid was used to modify zein to improve the molecular flexibility. Flexible zein nanoparticles (FZP-CBD) loaded with CBD was prepared to improve the stability and bioavailability of CBD. The parameters were evaluated in terms of morphology, particle size (PS), polydispersity index (PDI), zeta potential (ZP), entrapment efficiency (EE%), loading capacity (LC%), and storage stability. Simulated gastrointestinal fluid release experiment and bioavailability assay were applied in the evaluation.

Results

The simulated gastrointestinal fluid experiment showed that the release rates of FZP-CBD and natural zein nanoparticles (NZP-CBD) loaded with CBD were 3.57% and 89.88%, respectively, after digestion with gastric fluid for 2 h, 92.12% and 92.56%, respectively, after intestinal fluid digestion for 2 h. Compared with NZP-CBD, the C max of FZP-CBD at 3 different doses of CBD was increased by 1.7, 1.3 and 1.5 times respectively, and AUC0-t was increased by 1.4, 1.1 and 1.7 times respectively, bioavailability (F) was increased by 135.9%, 114.9%, 169.6% respectively.

Discussion

The experimental results showed that FZP-CBD could protect most of the CBD from being released in the stomach, and then control its release in the intestines, promote the absorption of CBD in the small intestine, and increase the bioavailability of CBD. Therefore, FZP-CBD could improve the utilization value of CBD and provide a new idea for the application of CBD in medicine and pharmacy.

Preparation, characterization, stability, and controlled release of chitosan-coated zein/shellac nanoparticles for the delivery of quercetin

Quercetin, an essential flavonoid compound, exhibits diverse biological activities including anti-inflammatory and antioxidant effects. Nevertheless, due to its inadequate solubility in water and vulnerability to degradation, pure quercetin is constrainedly utilized in pharmaceutical formulations and functional foods. Considering the existing scarcity of nanoparticles consisted of zein and hydrophobic biopolymers, this study developed a quercetin-loaded nanoencapsulation based on zein, shellac, and chitosan (QZSC). When the mass ratio of zein to chitosan was 4:1, the encapsulation efficiency of QZSC reached 74.95%. The ability of QZSC for scavenging DPPH radicals and ABTS radicals increased from 59.2% to 75.4% and from 47.0% to 70.2%, respectively, compared to Quercetin. For QZSC, the maximum release amount of quercetin reached 59.62% in simulated gastric fluid and 81.64% in simulated intestinal fluid, achieving controlled and regulated release in vitro. In summary, this study offers a highly promising encapsulation strategy for hydrophobic bioactive substances that are prone to instability.

Nanoemulsions Based on Soluble Chenopodin/Alginate Complex for Colonic Delivery of Quercetin

Inflammatory bowel disease (IBD) is an autoimmune disorder caused by uncontrolled immune activation and the subsequent destruction of the colon tissue. Quercetin (Qt) is a natural antioxidant and anti-inflammatory agent proposed as an alternative to mitigate IBD. However, its use is limited by its low oral bioavailability. This study aimed to develop nanoemulsions (NEs) based on a soluble chenopodin/alginate (QPA) complex and Tween 80 (T80), intended for the colonic release of Qt, activated by the pH (5.4) and bacteria present in the human colonic microbiota. NEs with different ratios of QPA/Tw80 (F1-F6) were prepared, where F4Qt (60/40) and F5Qt (70/30) showed sizes smaller than 260 nm, PDI < 0.27, and high encapsulation efficiency (>85%). The stability was evaluated under different conditions (time, temperature, pH, and NaCl). The DSC and FTIR analyses indicated hydrophobic and hydrogen bonding interactions between QPA and Qt. F4Qt and F5Qt showed the greater release of Qt in PBS1X and Krebs buffer at pH 5.4 (diseased condition), compared to the release at pH 7.4 (healthy condition) at 8 h of study. In the presence of E. coli and B. thetaiotaomicron, they triggered the more significant release of Qt (ƒ2 < 50) compared to the control (without bacteria). The NEs (without Qt) did not show cytotoxicity in HT-29 cells (cell viability > 80%) and increased the antioxidant capacity of encapsulated Qt. Therefore, these NEs are promising nanocarriers for the delivery of flavonoids to the colon to treat IBD.

Oral Delivery of Liraglutide-Loaded Zein/Eudragit-Chitosan Nanoparticles Provides Pharmacokinetic and Glycemic Outcomes Comparable to Its Subcutaneous Injection in Rats

Liraglutide (LIRA) is a glucagon-like peptide-1 (GLP-1) receptor agonist renowned for its efficacy in treating type 2 diabetes mellitus (T2DM) and is typically administered via subcutaneous injections. Oral delivery, although more desirable for being painless and potentially enhancing patient adherence, is challenged by the peptide's low bioavailability and vulnerability to digestive enzymes. This study aimed to develop LIRA-containing zein-based nanoparticles stabilized with eudragit RS100 and chitosan for oral use (Z-ERS-CS/LIRA). These nanoparticles demonstrated a spherical shape, with a mean diameter of 238.6 nm, a polydispersity index of 0.099, a zeta potential of +40.9 mV, and an encapsulation efficiency of 41%. In vitro release studies indicated a prolonged release, with up to 61% of LIRA released over 24 h. Notably, the nanoparticles showed considerable resistance and stability in simulated gastric and intestinal fluids, suggesting protection from pH and enzymatic degradation. Pharmacokinetic analysis revealed that orally administered Z-ERS-CS/LIRA paralleled the pharmacokinetic profile seen with subcutaneously delivered LIRA. Furthermore, in vivo tests on a diabetic rat model showed that Z-ERS-CS/LIRA significantly controlled glucose levels, comparable to the results observed with free LIRA. The findings underscore Z-ERS-CS/LIRA nanoparticles as a promising approach for oral LIRA delivery in T2DM management.

Insights into the preparation of zein nanoparticles by continuous membrane nanoprecipitation

Nanoparticles (NPs) preparation is limited to an exclusive use in batch processes and small-scale formulations. The use of membranes as high-performance micromixers is expected to open new scenarios to overcome limitations of conventional nanoprecipitation system such as stirred tank (ST) nanoprecipitation. The ability of the porous membrane to add uniformly one phase to another and govern their mixing at the membrane interface seems to be an important parameter for obtaining uniform NPs. Inorganic membranes (pore size of 1 μm) were used to carry out membrane nanoprecipitation (MN) to form Zein nanoparticles (ZNPs) at pores level by non-solvent induced phase separation. A systematic study of the preparation of ZNPs in the ST and MN systems was carried out to establish the Ouzo diagram. The influence of zein concentration and solvent to non-solvent ratio on the size and size distribution of ZNPs was also investigated. A wider stable Ouzo zone was obtained with MN than with the ST process. ZNPs size increased from 100 nm up to 700 nm, while maintaining low polydispersity index (PDI < 0.2). The results demonstrate the suitability of MN for the continuous production of ZNPs and open the possibility of scaling up the nanoprecipitation process.

Fabrication of resveratrol-loaded soy protein isolate-glycyrrhizin nanocomplex for improving bioavailability via pH-responsive hydrogel properties

Resveratrol (RES) is a functional polyphenol that suffers from low water solubility and poor bioavailability. A novel RES-loaded soy protein isolate-dipotassium glycyrrhizinate (SPI-DG) nanocomplex (RES@SPI-DG) was designed and evaluated in this study. RES@SPI-DG was prepared using a simple but novel self-assembly ultrasonic-assisted pH-driven method. The interactions between RES and SPI-DG were non-covalent bonds, including hydrophobic interactions, hydrogen bonds, and van der Waals interactions. RES@SPI-DG exhibited high encapsulation efficiency (97.60 ± 0.38 %) and loading capacity (8.74 ± 0.03 %) of RES with a uniform small size (68.39 ± 1.10 nm). RES in RES@SPI-DG was in an amorphous state and demonstrated a 24-h apparent solubility 482.53-fold higher than bare RES. RES@SPI-DG also showed strong in vitro antioxidant properties. The pH-responsive hydrogel character of SPI-DG makes it an effective intestine-targeted delivery system that could retard the release of RES in a simulated stomach and accelerate it in a simulated intestine. In animal experiments, the bioavailability of RES@SPI-DG was 5.17 times higher than that of bare RES, and the biodistribution was also significantly improved. RES@SPI-DG demonstrated a strong hepatoprotective effect against overdose acetaminophen-induced liver injury. The SPI-DG complex might be a promising nano-platform for enhancing the bioavailability and efficacy of hydrophobic polyphenols such as RES.

The role of polysaccharides in improving the functionality of zein coated nanocarriers: Implications for colloidal stability under environmental stresses

Zein has gained popularity over the past few years as an incredible food and bio-based materials. The potential functions and health benefits of zein microcapsules or micro-/nanoparticles in bioactive components delivery, structured emulsion, etc., have received great attention. However, the development has been limited by colloidal destabilization, especially when thermal processing is involved. There is a recent trend in developing zein-polysaccharide complexes (ZPCs), which has tremendously improved the performance of zein-based colloidal carrier systems or emulsions. Increasing our understanding of zein interactions and their contribution to the structure of various macromolecules can help us to develop novel biomaterials that can be used in food, agriculture, biomedicine, and cosmetics. In addition, these nanocarriers are suitable for the encapsulation and delivery of bioactive compounds which have positive perspective in food industry. Therefore, this article aimed to review recent advances in the ZPCs that can be applied to functional or health-promoting foods, with a focus on the characteristics of different ZPCs, factors and mechanisms affecting the stability (especially thermal stability) of these complexes, and their application in food industry as a carrier for BCs. Further, the stability of ZPCs based emulsions under processing and physiological environments, as well some typical effective methods are introduced. Also, the principal challenges and prospects were enumerated and discussed.

Fabrication of Luteolin Loaded Zein-Caseinate Nanoparticles and its Bioavailability Enhancement in Rats

Luteolin loaded zein nanoparticles (Lut-ZNP) were prepared by using sodium caseinate as an electrostatic stabilizer. The formulation of the nanoparticles was optimized. Lut-ZNP were spray-dried, and the physicochemical properties were characterized by SEM, XRD, FT-IR and DSC. Then, the bioavailability of luteolin in rats was determined. Under the formulation of luteolin, zein and sodium caseinate with mass ratio of 1:5:15, the particle size, ζ-potential, encapsulation efficiency and loading efficiency of Lut-ZNP were 171.8 nm, -49.05 mV, 85.85% and 3.15%, respectively. Luteolin existed in the nanoparticles with amorphous form. Lut-ZNP exhibited good redispersibility in water after drying. Compared with free luteolin, the solubility, stability and release of luteolin in Lut-ZNP were greatly improved. Besides, the fecal excretion of luteolin in rats was significantly reduced after oral administration of Lut-ZNP. In addition to native luteolin, its metabolites including sulfate, glucuronidate and methylated glucuronidate were found in rat plasma. Lut-ZNP significantly increased the plasma concentrations of luteolin and its metabolites, and the bioavailability of luteolin was enhanced by 2.92 times.

The Commonly Used Stabilizers for Phytochemical-Based Nanoparticles: Stabilization Effects, Mechanisms, and Applications

Phytochemicals, such as resveratrol, curcumin, and quercetin, have many benefits for health, but most of them have a low bioavailability due to their poor water solubility and stability, quick metabolism, and clearance, which restricts the scope of their potential applications. To overcome these issues, different types of nanoparticles (NPs), especially biocompatible and biodegradable NPs, have been developed. NPs can carry phytochemicals and increase their solubility, stability, target specificity, and oral bioavailability. However, NPs are prone to irreversible aggregation, which leads to NP instability and loss of functions. To remedy this shortcoming, stabilizers like polymers and surfactants are incorporated on NPs. Stabilizers not only increase the stability of NPs, but also improve their characteristics. The current review focused on discussing the state of the art in research on synthesizing phytochemical-based NPs and their commonly employed stabilizers. Furthermore, stabilizers in these NPs were also discussed in terms of their applications, effects, and underlying mechanisms. This review aimed to provide more references for developing stabilizers and NPs for future research.

Encapsulation of quercetin into zein-ethyl cellulose coaxial nanofibers: Preparation, characterization and its anticancer activity

In order to efficiently improve the colon-targeted delivery of quercetin, the hydrophobic core-shell nanofibers were fabricated to encapsulate quercetin using ethyl cellulose as the shell and zein as the core by coaxial electrospinning. The encapsulation efficiency of coaxial nanofibers reached >97 %. FTIR and XRD results revealed the interactions between quercetin and wall materials and quercetin was encapsulated in an amorphous state. The thermal stability and surface hydrophobicity of coaxial nanofibers were improved compared to the uniaxial zein fibers. After in vitro gastrointestinal digestion, the quercetin release from core-shell nanofibers was <12.38 %, while the corresponding value for zein fibers was 36.24 %. DPPH and FRAP assays showed that there was no significant difference in the antioxidant activity of quercetin before and after encapsulation. Furthermore, the encapsulated quercetin exhibited similar anti-proliferative activity against HCT-116 cells compared to the free form. The results suggest these coaxial nanofibers have potential applications in functional foods.

Zein-based nanospheres and nanocapsules for the encapsulation and oral delivery of quercetin

In this study, the ability of zein nanospheres (NS) and zein nanocapsules containing wheat germ oil (NC) to enhance the bioavailability and efficacy of quercetin was evaluated. Both types of nanocarriers had similar physico-chemical properties, including size (between 230 and 250 nm), spherical shape, negative zeta potential, and surface hydrophobicity. However, NS displayed a higher ability than NC to interact with the intestinal epithelium, as evidenced by an oral biodistribution study in rats. Moreover, both types of nanocarriers offered similar loading efficiencies and release profiles in simulated fluids. In C. elegans, the encapsulation of quercetin in nanospheres (Q-NS) was found to be two twice more effective than the free form of quercetin in reducing lipid accumulation. For nanocapsules, the presence of wheat germ oil significantly increased the storage of lipids in C. elegans; although the incorporation of quercetin (Q-NC) significantly counteracted the presence of the oil. Finally, nanoparticles improved the oral absorption of quercetin in Wistar rats, offering a relative oral bioavailability of 26% and 57% for Q-NS and Q-NC, respectively, compared to a 5% for the control formulation. Overall, the study suggests that zein nanocarriers, particularly nanospheres, could be useful in improving the bioavailability and efficacy of quercetin.

Preparation of core-shell hordein/pectin nanoparticles as quercetin delivery matrices: Physicochemical properties and colon-specific release analyses

Quercetin (Que) is a hydrophobic flavanol that has the potential to prevent colon diseases. This study aimed to design hordein/pectin nanoparticle as a colon-specific delivery system for quercetin. The encapsulation efficiency, physicochemical stability and release properties of the nanoparticles were estimated. The FTIR and secondary structure analysis indicated that hydrogen bonds, hydrophobic interactions and electrostatic attractions were formed in the quercetin-loaded hordein/pectin nanoparticles (Que-hordein/pectin NPs). In comparison to Que-hordein NPs, Que-hordein/pectin NPs exhibited better colloidal stability (physical, UV light, heating and salt). Furthermore, the release properties studies showed that pectin coating restrained the premature release of Que from hordein NPs in gastric fluid and intestinal fluid. In-vitro release, when the Que-hordein/pectin NPs were exposed to simulated colonic fluid (SCF) for 6 h, quercetin was greatly released from the hordein/pectin NPs (15.29 ± 1.17% - 80.60 ± 1.78%). In-vivo release, the concentration of Que (μg/g) in Que-hordein/pectin NPs was 2.18 times higher than Que-hordein NPs in colon tissue after 6 h of oral administration. This study suggests that Que-hordein/pectin NPs have promising applications in the specific delivery and release of quercetin to the colon.

Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry Estimation of Quercetin-Loaded Nanoemulsion in Rabbit Plasma: In Vivo-In Silico Pharmacokinetic Analysis Using GastroPlus

In the present study, we developed and validated a rapid, specific, sensitive, and reproducible liquid chromatography-electrospray ionization tandem mass spectrometry method for quantifying quercetin (QT) in rabbit plasma using hydrochlorothiazide as the internal standard. Animals were orally administered with optimized QT-loaded nanoemulsion (QTNE) and QT suspension (QTS), equivalent to 30 mg/kg, to the test and control group, respectively. The blood samples were collected at pre-determined time points up to 48 h. The linearity range was from 5 to 5000 ng mL^-1 with R ² = 0.995. Further, we analyzed the various pharmacokinetic parameters and established the in vitro-in vivo correlation (IVIVC) of QTNE using GastroPlus software. The method was successfully developed and validated, and when applied for the determination of QT in rabbit plasma, it exhibited an increase in C _max from 122.56 ng mL^-1 (QTS) to 286.51 ng mL^-1 (QTNE) (2.34-fold) and AUC_0-48 from 976 ng h mL^-1 (QTS) to 4249 ng h mL^-1 (QTNE) (4.35-fold), indicating improved oral bioavailability QT when administered as QTNE. Statistical analysis revealed that the Loo-Riegelman method (two-compartmental method) best fitted the deconvolution approach (R ² = 0.998, SEP = 4.537, MAE = 2.759, and AIC = 42.38) for establishing the IVIVC. In conclusion, the established bioanalytical method and IVIVC studies revealed that QTNE is a potential carrier for the effective delivery of QT with enhanced oral bioavailability.

Interactions between zein and anthocyanins at different pH: Structural characterization, binding mechanism and stability

Zein-anthocyanin nanoparticles (ZACNPs) at different pH values were successfully developed to stabilize anthocyanins based on the self-assembly properties of zein. The structural characterization by the Fourier infrared spectroscopy, fluorescence spectroscopy, differential scanning calorimetry and molecular docking analysis showed that the interactions between anthocyanins and zein were driven by the hydrogen bonds formed between the hydroxyl and carbonyl oxygen groups on anthocyanin glycoside groups and the amino acid residues (glutamine and serine), as well as the hydrophobic interactions from the A or B ring of anthocyanins and the amino acid residues of zein. The binding energy of zein to two anthocyanin monomers cyanidin 3-O-glucoside and delphinidin 3-O-glucoside was 8.2 and 7.4 kcal/mol. Further property examinations of ZACNPs showed that the thermal stability of anthocyanins at a ratio of zein:ACN = 1:0.3 was improved by 56.64 % (90 °C, 2 h), and the storage stability increased by up to 31.11 % at pH 2. In addition, the antioxidant activity of ZACNPs (zein:ACN = 1:0.3) was significantly enhanced, and the DPPH, ABTS radical scavenging activities, FRAP and ORAC value reached 87.73 %, 87.89 %, 435.5 μg/mL, 90.58 μmol/mL at pH 4, respectively. These results suggested that combining zein to anthocyanins is a feasible method to stabilize anthocyanins.

Fabrication, characterization, and lipid-lowering effects of naringenin-zein-sodium caseinate-galactosylated chitosan nanoparticles

Naringenin is a natural flavonoid that is widely distributed in citrus fruits and pharmacologically demonstrated to licit lipid-lowering activity. However, the clinical relevance of naringenin is limited due to its poor water solubility and inefficient absorption. In this study, we designed and developed naringenin-zein-sodium caseinate-galactosylated chitosan nanoparticles (GC-NPs) for hepatocyte-specific targeting, with naringenin-zein-sodium caseinate-chitosan nanoparticles (CS-NPs) as a control. Electrostatic adsorption was the primary binding mode in the GC-NPs and CS-NPs. Moreover, the particle size and zeta potential of GC-NPs were larger than those of CS-NPs and both types of nanoparticles had similar encapsulation rates. In vitro study experiments demonstrated that GC-NPs aggregated inside and outside of the cell membrane and significantly inhibited total triglyceride and cholesterol levels in oleic acid-induced HepG2 cells (p < 0.05). In high-fat diet-fed C57BL/6J mice, GC-NPs administration visibly improved the body weight, total cholesterol, and triglyceride content in the serum and liver, and high-density lipoprotein cholesterol levels improved, which corresponded to liver histological results. Additionally, in vitro and in vivo assays demonstrated that GC-NPs exhibited higher lipid-lowering activity than CS-NPs and naringenin monomers. These results suggest that GC-NPs are effective for oral delivery of naringenin in lipid-lowering therapies.

Enhanced oral bioavailability from food protein nanoparticles: A mini review

The oral route is the most desirable drug administration path. The oral bioavailability is always compromised from the poor physicochemical and/or biopharmaceutical properties of the active pharmaceutical ingredients. Food protein nanoparticles show promise for oral drug delivery, with improved biosafety and cost-effectiveness compared to polymeric nanoparticles. More importantly, diverse food proteins provide "choice and variety" to meet the challenges faced by different drugs in oral delivery resulting from low solubility, poor permeability, and gastrointestinal stability. The abundance of hydroxyl, amino, and carboxyl groups in food proteins allows easy surface modification of the nanoparticles to impart unique functions. Albeit being in its infancy, food protein nanoparticles exhibit high capability to enhance oral bioavailability of a wide range of drugs from small molecules to biomacromolecules. Considering the rapid growth of the field, the achievements and mechanisms of food protein nanoparticles in enhancing oral bioavailability are reviewed. Factors affecting the performance of food protein nanoparticles are discussed with the purpose to inspire the development of food protein nanoparticle-based oral drug delivery systems.

Enhanced Bioavailability and Pharmacokinetics of a Natural Self-Emulsifying Reversible Hybrid-Hydrogel System of Quercetin: A Randomized Double-Blinded Comparative Crossover Study

Despite the vast array of health beneficial pharmacological effects, the bioavailability of the dietary flavonoid quercetin was found to be poor due to insolubility, incompatibility, and rapid biotransformation. Herein, we investigated the solubility, morphology, particle size, stability, in vitro release, and human pharmacokinetics of a hybrid-hydrogel formulation of quercetin (FQ-35) using fenugreek galactomannans as the hydrogel scaffold. Physicochemical characterization revealed that the crystalline quercetin was well encapsulated in the hydrogel matrix to form translucent microgel particles of FQ-35 with enhanced solubility (96-fold). The mean particle size was found to be 183.6 ± 42.7 nm with a zeta potential of 35.1 ± 3.8 mV. Pharmacokinetic investigation on healthy volunteers (N = 16) employing tandem mass spectrometric (ultra-performance liquid chromatography-electrospray tandem mass spectrometry) measurements of the concentration of free (unconjugated) and conjugated quercetin metabolites revealed an 18.6-fold improvement in free (unconjugated) quercetin bioavailability and 62-fold improvement in total quercetin (sum of free and conjugated) bioavailability, compared to the unformulated quercetin extracted from Sophora japonica. In summary, the natural self-emulsifying reversible hybrid-hydrogel delivery system was found to offer significant solubility, stability, and bioavailability of quercetin upon single-dose oral administration.

Encapsulation of vitexin-rhamnoside based on zein/pectin nanoparticles improved its stability and bioavailability

To improve the solubility, stability, and bioavailability of vitexin-rhamnoside (VR) isolated from hawthorn, it was encapsulated by the zein-pectin nanoparticles system. When the mass ratio of zein to pectin was 1:4, the particle size of nanoparticles was 222.7 nm, and the encapsulation efficiency of VR was 67%. Analysis with the scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) revealed that the zein-VR-pectin nanoparticles were spherical and uniformly distributed. The hydrogen bonding and electrostatic interactions were the main forces to assemble the nanoparticles. The nanoparticle had good stability at pH 3-8.5 with particle sizes ranging from 234 to 251 nm, and the nanoparticles were able to resist the relatively lower ionic strength. In vitro simulated digestion and rat in vivo intestinal perfusion experiments showed that the nanoparticles exhibited significant slow-release properties and the highest absorption rate in the duodenal segment of rats, with Ka and Papp of 0.830 ± 0.11 and 17.004 ± 1.09. These results provided a theoretical and technological approach for the construction of flavonoids delivery system with slow-release properties and improved bioavailability.

Properties of curcumin-loaded zein-tea saponin nanoparticles prepared by antisolvent co-precipitation and precipitation

The properties of nutraceutical-loaded biopolymer nanoparticles fabricated by antisolvent co-precipitation (ASCP) and precipitation (ASP) were compared. Curcumin-loaded zein-tea saponin nanoparticles were fabricated using both methods and then their structural and physicochemical properties were characterized. The diameter of the nanoparticles prepared by ASCP were smaller (120-130 nm) than those prepared by ASP (140-160 nm). The encapsulation efficiency of the ASCP-nanoparticles (80.0%) was higher than the ASP-ones (71.0%) at a zein-to-curcumin mass ratio of 3:1, which was also higher than previous studies. The storage and light stability of curcumin was higher in zein-saponin nanoparticles than in zein nanoparticles. All nanoparticles had good water dispersibility after freeze-drying and rehydration. This study shows that nanoparticles produced by antisolvent co-precipitation have superior properties to those produced by antisolvent precipitation. The co-precipitation method leads to a higher encapsulation efficiency, smaller particle size, and greater storage stability, which may be advantageous for some applications.

Synthesis and evaluation of glycosylated quercetin to enhance neuroprotective effects on cerebral ischemia-reperfusion

Quercetin (Que), a polyphenolic flavonoid compound with antioxidant properties has been explicated to have neuroprotective effects on neuronal injury/neurodegenerative diseases. However, low water-solubility, instability and inability to cross the blood-brain barrier (BBB) imped its application. To enhance the neuroprotective effects and improve the potential application of quercetins as a nutraceutical or medicine, we designed and synthesized two types of glycosylated quercetins--Glu-Que and 2Glu-Que through click reaction. Glu-Que and 2Glu-Que improved the water solubility and stability of quercetin, as well as alleviating H₂O₂-induced neurotoxicity by increasing the cell viability of PC12 cells and reducing the ROS generation. What's more, glycosylated quercetins enhanced neuroprotective effects on cerebral ischemia-reperfusion (I/R). Among the two types of glycosylated quercetin, 2Glu-Que displayed higher neuroprotective potential than Glu-Que. In conclusion, the glycosylated quercetin 2Glu-Que, with better water solubility, bioavailability and brain-targeting ability, significantly enhanced the neuroprotective effects of quercetin, making it a promising nutraceutical or candidate drug in neuroprotection.

A review of factors affecting the stability of zein-based nanoparticles loaded with bioactive compounds: from construction to application

Zein-based nanoparticles loaded with bioactive compounds have positive prospects in the food industry, but an important limiting factor for development is colloidal instability. Currently, extensive researches are focused on solving the instability of zein nanoparticles, but since the beginning of the studies, there has not been a summary of the factors affecting the stability of zein-based nanoparticles. In the present work, the factors were reviewed comprehensively from the perspective of carrier construction and application evaluation. The former mainly includes type, quantity, and characteristics of biopolymer, the mass ratio of biopolymer/bioactive compound to zein, blending sequence of biopolymer, and location of encapsulated bioactive compounds. The latter mainly includes pH, heating, ionic strength, storage, freeze-drying, and gastrointestinal digestion. The former is the prerequisite for the success of the latter. The challenge is that stability research is limited to the laboratory level, and it is difficult to ensure that the stability results are suitable for commercial food matrices due to their complexity. At the laboratory level, the future trends are the influence of external energy and the cross-complexity and uniformity of stability research. The review is expected to provide systematic understanding and guidance for the development of zein-based nanoparticles stability.

Enhanced Stability and Oral Bioavailability of Cannabidiol in Zein and Whey Protein Composite Nanoparticles by a Modified Anti-Solvent Approach

Wide applications of cannabidiol (CBD) in the food and pharmaceutical industries are limited due to its low bioavailability, sensitivity to environmental pressures and low water solubility. Zein nanoparticles were stabilized by whey protein (WP) for the delivery of cannabidiol (CBD) using a modified anti-solvent approach. Particle size, surface charge, encapsulation efficiency, and re-dispersibility of nanoparticles were influenced by the zein to WP ratio. Under optimized conditions at 1:4, zein–WP nanoparticles were fabricated with CBD (200 μg/mL) and further characterized. WP absorbed on zein surface via hydrogen bond, hydrophobic forces, and electrostatic attraction. The zein–WP nanoparticles showed excellent storage stability (4 °C, dark) and effectively protected CBD degradation against heat and UV light. In vivo pharmacokinetic study demonstrated that CBD in zein–WP nanoparticles displayed 2-times and 1.75-fold enhancement in maximum concentration (C max) and the area under curve (AUC) as compared to free-form CBD. The data indicated the feasibility of developing zein–WP based nanoparticles for the encapsulation, protection, and delivery of CBD.

Enhancing the stability of zein/fucoidan composite nanoparticles with calcium ions for quercetin delivery

In this study, zein and fucoidan-based composite nanoparticles were prepared by the antisolvent precipitation method. The effects of different calcium ion (Ca²⁺, 0-3.0 mM) concentrations on the stability of the composite nanosystems loaded with quercetin were studied under different conditions (pH, temperature, salt concentration, and ultraviolet light irradiation), and the composite nanoparticles were characterized. Electrostatic interactions, hydrogen bonding, and hydrophobic interactions are the main forces underlying the formation of composite nanoparticles. The addition of Ca²⁺ led to improved release of the active substances from the composite nanoparticles in simulated digestive solutions (especially when the Ca²⁺ concentration was 1.5 mM). The composite nanosystems based on alcohol-soluble proteins and anionic polysaccharides with added Ca²⁺ can be potentially applied for the delivery of active substances.

Fabrication and characterization of quercetin loaded casein phosphopeptides-chitosan composite nanoparticles by ultrasound treatment: Factor optimization, formation mechanism, physicochemical stability and antioxidant activity

Ultrasound treatment was used to successfully prepare Quercetin (Qu)-loaded Casein phosphopeptides (CPP)/chitosan (CS) nanoparticles. Compared with the control, the above ternary nanoparticles with the smallest size (241.27 nm, decreased by 34.32%), improved encapsulation efficiency of Qu (78.55%, increased by 22.12%) when prepared under following conditions: ultrasonic frequency, 20/35/50 kHz; the power density, 80 W/L; the time, 20 min, and the intermittent ratio, 20 s/5s. Electrostatic interactions, hydrogen bonding, and hydrophobic interactions were the main driving forces for nanoparticles formulation, which were strengthened by ultrasound treatment. The compact, homogeneous and spherical composite nanoparticles obtained by sonication were clearly observed by scanning electron microscope and atomic force microscope. The environmental stability (NaCl, pH, exposure time, storage time, and simulated gastrointestinal digestion) and antioxidant activity of the ternary nanoparticles were remarkably enhanced after ultrasonic treatment. Furthermore, the ternary nanoparticles prepared by ultrasound exhibited excellent stability in simulated gastrointestinal digestion. The above results indicate that ultrasound not only increases the loading of the nanoparticles on bioactive substances but also improves the environmental stability and antioxidant activity of the formed nanoparticles. Ultrasound-assisted preparation of nanoparticles loaded with bioactive substances could be well used in the functional food and beverage industry.

Recent Advancement in Chitosan-Based Nanoparticles for Improved Oral Bioavailability and Bioactivity of Phytochemicals: Challenges and Perspectives

The excellent therapeutic potential of a variety of phytochemicals in different diseases has been proven by extensive studies throughout history. However, most phytochemicals are characterized by a high molecular weight, poor aqueous solubility, limited gastrointestinal permeability, extensive pre-systemic metabolism, and poor stability in the harsh gastrointestinal milieu. Therefore, loading of these phytochemicals in biodegradable and biocompatible nanoparticles (NPs) might be an effective approach to improve their bioactivity. Different nanocarrier systems have been developed in recent decades to deliver phytochemicals. Among them, NPs based on chitosan (CS) (CS-NPs), a mucoadhesive, non-toxic, and biodegradable polysaccharide, are considered the best nanoplatform for the oral delivery of phytochemicals. This review highlights the oral delivery of natural products, i.e., phytochemicals, encapsulated in NPs prepared from a natural polymer, i.e., CS, for improved bioavailability and bioactivity. The unique properties of CS for oral delivery such as its mucoadhesiveness, non-toxicity, excellent stability in the harsh environment of the GIT, good solubility in slightly acidic and alkaline conditions, and ability to enhance intestinal permeability are discussed first, and then the outcomes of various phytochemical-loaded CS-NPs after oral administration are discussed in detail. Furthermore, different challenges associated with the oral delivery of phytochemicals with CS-NPs and future directions are also discussed.

In vivo and in vitro comparison of three astilbin encapsulated zein nanoparticles with different outer shells

Three shell materials, lecithin (ZNP-L), chitosan (ZNP-CH) and sodium caseinate (ZNP-SC), were used to prepare core-shell zein nanoparticles. Astilbin was encapsulated as a model flavonoid to compare the influence of the shell materials on zein nanoparticles both in vitro and in vivo. The particle size was moderately increased by lecithin and sodium caseinate, but notably increased by chitosan. All the shell materials provided good redispersibility for the nanoparticles and significantly improved the colloidal stability. Chitosan and sodium caseinate significantly delayed and decreased the feces excretion of astilbin in rats, while lecithin exhibited a very weak effect. The results may be attributed to the difference in mucoadhesive properties between the shell materials. As a consequence, the bioavailability values of astilbin in rats were 18.2, 9.3 and 1.89 times increased through ZNP-CH, ZNP-SC and ZNP-L compared with that of free astilbin, respectively.