An efficient small intestine-targeted curcumin delivery system based on the positive-negative-negative colloidal interactions

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.

Design and Characterization of a Novel Core-Shell Nano Delivery System Based on Zein and Carboxymethylated Short-Chain Amylose for Encapsulation of Curcumin

Curcumin is a naturally occurring hydrophobic polyphenolic compound with a rapid metabolism, poor absorption, and low stability, which severely limits its bioavailability. Here, we employed a starch-protein-based nanoparticle approach to improve the curcumin bioavailability. This study focused on synthesizing nanoparticles with a zein "core" and a carboxymethylated short-chain amylose (CSA) "shell" through anti-solvent precipitation for delivering curcumin. The zein@CSA core-shell nanoparticles were extensively characterized for physicochemical properties, structural integrity, ionic stability, in vitro digestibility, and antioxidant activity. Fourier-transform infrared (FTIR) spectroscopy indicates nanoparticle formation through hydrogen-bonding, hydrophobic, and electrostatic interactions between zein and CSA. Zein@CSA core-shell nanoparticles exhibited enhanced stability in NaCl solution. At a zein-to-CSA ratio of 1:1.25, only 15.7% curcumin was released after 90 min of gastric digestion, and 66% was released in the intestine after 240 min, demonstrating a notable sustained release effect. Furthermore, these nanoparticles increased the scavenging capacity of the 1,1-diphenyl-2-picrylhydrazyl (DPPH•) free radical compared to those composed solely of zein and were essentially nontoxic to Caco-2 cells. This research offers valuable insights into curcumin encapsulation and delivery using zein@CSA core-shell nanoparticles.

Delivery of encapsulated bioactive compounds within food matrices to the digestive tract: recent trends and future perspectives

Encapsulation technologies have achieved encouraging results improving the stability, bioaccessibility and absorption of bioactive compounds post-consumption. There is a bulk of published research on the gastrointestinal behavior of encapsulated bioactive food materials alone using in vitro and in vivo digestion models, but an aspect often overlooked is the impact of the food structure, which is much more complex to unravel and still not well understood. This review focuses on discussing the recent findings in the application of encapsulated bioactive components in fabricated food matrices. Studies have suggested that the integration of encapsulated bioactive compounds has been proven to have an impact on the physicochemical characteristics of the finished product in addition to the protective effect of encapsulation on the fortified bioactive compound. These products containing bioactive compounds undergo further structural reorganization during digestion, impacting the release and emptying rates of fortified bioactive compounds. Thus, by manipulation of various food structures and matrices, the release and delivery of these bioactive compounds can be altered. This knowledge provides new opportunities for designing specialized foods for specific populations.

Novel pH-responsive alginate-stabilized curcumin-selenium-ZIF-8 nanocomposites for synergistic breast cancer therapy

In this study, a novel selenium@zeolitic imidazolate framework core/shell nanocomposite stabilised with alginate was used to improve the anti-tumour activity of curcumin. The developed alginate-stabilised curcumin-loaded selenium@zeolitic imidazolate framework (Alg@Cur@Se@ZIF-8) had a mean diameter of 159.6 nm and polydispersity index < 0.25. The release of curcumin from the nanocarrier at pH 5.4 was 2.69 folds as high as at pH 7.4. The bare nanoparticles showed haemolytic activity of about 12.16% at a concentration of 500 µg/mL while covering their surface with alginate reduced this value to 5.2%. By investigating cell viability, it was found that Alg@Cur@Se@ZIF-8 caused more cell death than pure curcumin. Additionally, in vivo studies showed that Alg@Cur@Se@ZIF-8 dramatically reduced tumour growth compared to free curcumin in 4T1 tumour-bearing mice. More importantly, the histological study confirmed that the developed drug delivery system successfully inhibited lung and liver metastasis while causing negligible toxicity in vital organs. Overall, due to the excellent inhibitory activity on cancerous cell lines and tumour-bearing animals, Alg@Cur@Se@ZIF-8 can be considered promising for breast cancer therapy.

Co-delivery of hydrophobic β-carotene and hydrophilic riboflavin by novel water-in-oleic acid-in-water (W/OA/W) emulsions

Hydrophobic β-carotene and hydrophilic riboflavin offer a wide range of health benefits, but their limited stability and bioaccessibility pose challenges to their use in the food industry. This study developed a water-in-oleic acid-in-water (W/OA/W) emulsion. The effects of internal/external water phase emulsifiers were investigated on their microstructure, encapsulation efficiency, and stability. Only 0.05 wt% soybean-derived phosphatidylcholine was required as a lipophilic emulsifier to produce W/OA/W emulsions that can encapsulate both hydrophobic β-carotene and hydrophilic riboflavin. Compared to the commercial pea protein isolate (PPI), the PPI-xylooligosaccharide conjugate demonstrated superior performance as hydrophilic emulsifiers in stabilizing W/OA/W emulsions. The W/OA/W emulsion co-delivery system improved the thermal stability, light stability, and bioaccessibility of β-carotene, as well as the light stability of riboflavin. Overall, the W/OA/W emulsion holds great promise for application in natural food and for co-delivering hydrophobic and hydrophilic bioactive ingredients.

Evaluation of curcumin nanoemulsion effect to prevent intestinal damage

Curcumin has gained great prominence for the prevention and treatment of inflammatory bowel disease. However, studies have reported the low bioavailability of orally administered curcumin. This work aimed to evaluate the characteristics, stability and effects of a curcumin-carrying nanoemulsion in preventing intestinal damage induced by indomethacin. Nanoemulsions containing curcumin were prepared by spontaneous emulsification method and it was characterized by dynamic light scattering (DLS), zeta potential and the morphology was evaluated by scanning electron microscopy (SEM). Its stability was tested under different conditions of pH, temperature at 0, 7, 14, 21 and 28 days. In animal experimentation, 36 male mice of the Mus musculus lineage (C57BL/6) were used. The intestinal inflammation was evaluated based on macroscopic, histopathological and metagenomic analysis. It was found a stable nanoemulsion with a size of 409.8 nm, polydispersion index (PDI) of 0.132 and zeta potential of -18.8 mV. However, these lost charge in pH2, showing instability in acidic media (p < 0.05). In animal experiments, the nanoemulsion did not significantly improve intestinal inflammation. However, the group treated with curcumin nanoemulsion showed a higher relative abundance of the genus Lactobacillus (p < 0.05). In conclusion, the curcumin nanoemulsion was relevant in the modulation of the intestinal microbiota.

The impact of differently structured starch gels on the gastrointestinal fate of a curcumin-containing nanoemulsion

In this study, we focused on the in vitro gastrointestinal digestion of curcumin-nanoemulsion-loaded corn starch gels formed using starches with different amylose contents, i.e. waxy (WCS), normal (NCS) and high amylose (HACS) corn starches and their impact on the release and bioaccessibility of curcumin. Curcumin nanoemulsion (CNE) loading significantly increased the storage modulus of the WCS and NCS gels by interspersing in the gelatinized continuous phase, whereas it decreased in the HACS gel due to the formation of a weak network structure as a result of the incomplete gelatinized amylose granules. During the gastric digestion, the disintegration and emptying of the WCS + CNE gel from the stomach was the slowest compared to the other two gels. The changes in the stomach, influenced the emptying of total solids (HACS + CNE > NCS + CNE > WCS + CNE) into the gastric digesta, which further affected the rate of starch and lipid digestion during the intestinal phase. The HACS + CNE and NCS + CNE gels showed a higher and faster release of curcumin compared to the WCS + CNE gel that showed a slower and sustained release during the intestinal digestion. This study demonstrated that the oral-gastric digestion of these starch gels was more dependent on the gel structures rather than on the molecular properties of the starches. The dynamic gastric environment resulted in the formation of distinct gel structures, which significantly influenced the composition and microstructure of the emptied digesta, further affecting starch hydrolysis and curcumin bioaccessibility in the small intestine.

The bioavailability, metabolism and microbial modulation of curcumin-loaded nanodelivery systems

Curcumin (Cur), the major bioactive component of turmeric (Curcuma longa) possesses many health benefits. However, low solubility, stability and bioavailability restricts its applications in food. Recently, nanocarriers such as complex coacervates, nanocapsules, liposomes, nanoparticles, nanomicelles, have been used as novel strategies to solve these problems. In this review, we have focused on the delivery systems responsive to the environmental stimuli such as pH-responsive, enzyme-responsive, targeted-to-specific cells or tissues, mucus-penetrating and mucoadhesive carriers. Besides, the metabolites and their biodistribution of Cur and Cur delivery systems are discussed. Most importantly, the interaction between Cur and their carriers with gut microbiota and their effects of modulating the gut health synergistically were discussed comprehensively. In the end, the biocompatibility of Cur delivery systems and the feasibility of their application in food industry is discussed. This review provided a comprehensive review of Cur nanodelivery systems, the health impacts of Cur nanocarriers and an insight into the application of Cur nanocarriers in food industry.

Enhancement of the chemical stability of nanoemulsions loaded with curcumin by unsaturated mannuronate oligosaccharide

Unsaturated mannuronate oligosaccharide (MOS) is an acidic oligosaccharide prepared from alginate-derived polymannuronate by enzymatic depolymerization, followed by double bond formation between C-4 and C-5 at the nonreducing end. In this study, MOS was used as a stabilizer to fabricate O/W nanoemulsions loaded with curcumin (MOS-CUR) for the first time. The results revealed that the MOS-CUR showed small droplet sizes and narrow size distributions and was slightly more stable than normal oil-in-water (O/W) curcumin nanoemulsions (water-CUR). Additionally, MOS can improve the superoxide anion scavenging ability and iron ion reducing ability of the curcumin nanoemulsion system. Although the digestion behaviour of MOS-CUR and water-CUR was similar, the bioavailability of curcumin in MOS-CUR was significantly higher than that in water-CUR. All these results indicated that MOS could be used as a stabilizer for preparing nanoemulsions to easily encapsulate labile nutrients and to enhance the bioavailability and antioxidant capacity of these nutrients.

Designing Gastric-Stable Adsorption Layers by Whey Protein-Pectin Complexation at the Oil-Water Interface

This work aims to design gastric-stable emulsions with food-grade biopolymers using a novel multiscale approach. The adsorption layer formation at the oil-water interface was based on opposite charge interactions between whey proteins and pectin (with different esterification levels) at pH 3.0 by a sequential adsorption method. The interfacial assembly and disassembly (interfacial complexation, proteolysis, lipolysis) during in vitro gastric digestion were evaluated using a quartz crystal microbalance with dissipation monitoring, ζ-potential, dynamic interfacial tension, and interfacial dilatational rheology. Besides, the evolution of the particle size and microstructure of bulk emulsions during the digestion was investigated by static light scattering and light microscopy. Compared with whey protein isolate (WPI)-stabilized emulsions, the presence of an additional pectin layer can prevent or at least largely delay gastric destabilization (giving rise to coalescence or/and oiling off). Especially, the esterification degree of the pectin used was found to largely affect the emulsion stability upon gastric digestion.

Assessment of Various Food Proteins as Structural Materials for Delivery of Hydrophobic Polyphenols Using a Novel Co-Precipitation Method

In this study, sodium caseinate (NaCas), soy protein isolate (SPI), and whey protein isolate (WPI) were used as structural materials for the delivery of rutin, naringenin, curcumin, hesperidin, and catechin. For each polyphenol, the protein solution was brought to alkaline pH, and then the polyphenol and trehalose (as a cryo-protectant) were added. The mixtures were later acidified, and the co-precipitated products were lyophilized. Regardless of the type of protein used, the co-precipitation method exhibited relatively high entrapment efficiency and loading capacity for all five polyphenols. Several structural changes were seen in the scanning electron micrographs of all polyphenol-protein co-precipitates. This included a significant decrease in the crystallinity of the polyphenols, which was confirmed by X-ray diffraction analysis, where amorphous structures of rutin, naringenin, curcumin, hesperidin, and catechin were revealed after the treatment. Both the dispersibility and solubility of the lyophilized powders in water were improved dramatically (in some cases, >10-fold) after the treatment, with further improvements observed in these properties for the powders containing trehalose. Depending on the chemical structure and hydrophobicity of the tested polyphenols, there were differences observed in the degree and extent of the effect of the protein on different properties of the polyphenols. Overall, the findings of this study demonstrated that NaCas, WPI, and SPI can be used for the development of an efficient delivery system for hydrophobic polyphenols, which in turn can be incorporated into various functional foods or used as supplements in the nutraceutical industry.

Targeted delivery of food functional ingredients in precise nutrition: design strategy and application of nutritional intervention

With the high incidence of chronic diseases, precise nutrition is a safe and efficient nutritional intervention method to improve human health. Food functional ingredients are an important material base for precision nutrition, which have been researched for their application in preventing diseases and improving health. However, their poor solubility, stability, and bad absorption largely limit their effect on nutritional intervention. The establishment of a stable targeted delivery system is helpful to enhance their bioavailability, realize the controlled release of functional ingredients at the targeted action sites in vivo, and provide nutritional intervention approaches and methods for precise nutrition. In this review, we summarized recent studies about the types of targeted delivery systems for the delivery of functional ingredients and their digestion fate in the gastrointestinal tract, including emulsion-based delivery systems and polymer-based delivery systems. The building materials, structure, size and charge of the particles in these delivery systems were manipulated to fabricate targeted carriers. Finally, the targeted delivery systems for food functional ingredients have gained some achievements in nutritional intervention for inflammatory bowel disease (IBD), liver disease, obesity, and cancer. These findings will help in designing fine targeted delivery systems, and achieving precise nutritional intervention for food functional ingredients on human health.

The presence of propylene glycol alginate increased the stability and intestine-targeted delivery potential of carboxymethyl starch-stabilized emulsions

Propylene glycol alginate (PGA) was added to improve the stability and delivery performance of carboxymethyl starch (CMS)-stabilized emulsion. In the first instance, the CMS/PGA complexes were characterized, which proved that the formation of CMS/PGA complexes mainly depended on hydrogen bonding, and the CMS/PGA complexes showed porous networks. The CMS/PGA complexes were more hydrophobic than CMS, and the interaction of CMS with PGA enhanced the thermal stability of CMS. Next, the effects of CMS/PGA complexes on the properties of emulsions were investigated, and the intestine-targeted delivery potential of emulsions was evaluated through the in vitro release study as well. The droplet size of CMS/PGA complex-stabilized emulsions gradually decreased and the encapsulation efficiency (EE) improved with increasing the PGA content in CMS/PGA complexes. The addition of PGA also greatly improved the physical stability of emulsions, including anti-flocculation and anti-coalescence stabilities. All emulsions exhibited non-Newtonian pseudoplastic properties. Furthermore, the emulsions stabilized by CMS/PGA complexes showed reduced curcumin (Cur) release in the simulated gastric fluid (SGF), whereas exhibited sustained release in the α-amylase-containing simulated intestinal fluid (SIF). These results demonstrated that the emulsion stabilized by CMS/PGA complex was able to control and modulate the release of Cur in the gastrointestinal tract, and was therefore a promising intestine-targeted delivery system for Cur.

Impact of Recombined Milk Systems on Gastrointestinal Fate of Curcumin Nanoemulsion

Milk powder is an important ingredient in various foods and pediatric formulations. The textural and digestion properties of the formulations depend on the preheat treatment of the milk powder during manufacture. Thus, it is interesting to know how these modifications can influence on the release of fortified bioactive compounds during digestion with a milk matrix. In this study, a curcumin nanoemulsion was incorporated into milks reconstituted from low-heat, medium-heat and high-heat skim milk powders (SMPs) and the milks were subjected to semi dynamic in vitro digestion. All the recombined milk systems formed a curd under gastric conditions, which reduced the gastric emptying of protein and curcumin-loaded oil droplets. Because of the formation of heat-induced casein/whey protein complexes, the open fragmented curd formed by the high-heat-treated reconstituted powder resulted in higher protein and oil droplets emptying to the intestine and higher curcumin bioaccessibility. This study provides useful information for how protein ingredients can govern the fate of added health-promoting compounds during digestion.

Progress in Colloid Delivery Systems for Protection and Delivery of Phenolic Bioactive Compounds: Two Study Cases-Hydroxytyrosol and Curcumin

Insufficient intake of beneficial food components into the human body is a major issue for many people. Among the strategies proposed to overcome this complication, colloid systems have been proven to offer successful solutions in many cases. The scientific community agrees that the production of colloid delivery systems is a good way to adequately protect and deliver nutritional components. In this review, we present the recent advances on bioactive phenolic compounds delivery mediated by colloid systems. As we are aware that this field is constantly evolving, we have focused our attention on the progress made in recent years in this specific field. To achieve this goal, structural and dynamic aspects of different colloid delivery systems, and the various interactions with two bioactive constituents, are presented and discussed. The choice of the appropriate delivery system for a given molecule depends on whether the drug is incorporated in an aqueous or hydrophobic environment. With this in mind, the aim of this evaluation was focused on two case studies, one representative of hydrophobic phenolic compounds and the other of hydrophilic ones. In particular, hydroxytyrosol was selected as a bioactive phenol with a hydrophilic character, while curcumin was selected as typical representative hydrophobic molecules.

Dual-modified starch nanospheres encapsulated with curcumin by self-assembly: Structure, physicochemical properties and anti-inflammatory activity

Pullulanase debranching and subsequent hydroxypropylation were applied to prepare a series of dual-modified starches (Hydroxypropylated debranched starch, HPDS) with different degrees of hydroxypropyl substitution. Their structural and physicochemical properties varied with the degree of hydroxypropyl substitution, and all HPDS exhibited the ability to self-assemble into well-shaped nanospheres (100-150 nm, PDI < 0.2). These HPDS nanospheres were attempted to encapsulate curcumin with the aim of improving the bioavailability, solubility and stability of curcumin. Their structural characteristics, thermal stability, iodine staining, morphology, safety, encapsulation efficiency, in vitro gastrointestinal release behavior, and anti-inflammatory activity were evaluated. The results showed that curcumin could be effectively encapsulated into the HPDS nanospheres, and the encapsulation efficiency, water solubility and physical stability were positively correlated with the degree of hydroxypropyl substitution. After encapsulation, the water solubility and physical stability of curcumin could be increased up to 226-fold and 6-fold, respectively. The HPDS nanospheres also exhibited good safety (including hemolysis and cytotoxicity) and sustainable release of curcumin. Evaluation of anti-inflammatory activity showed that the activity of curcumin-encapsulated HPDS was enhanced by 170% compared to unencapsulated curcumin. These suggest that HPDS nanospheres encapsulation may be a more suitable option for the development of functional foods containing bioactive compounds.

Curcumin-Loaded Hybrid Nanoparticles: Microchannel-Based Preparation and Antitumor Activity in a Mouse Model

Purpose

To develop microchannel-based preparation of curcumin (Cur)-loaded hybrid nanoparticles using enzyme-targeted peptides and star-shaped polycyclic lipids as carriers, and to accomplish a desirable targeted drug delivery via these nanoparticles, which could improve the bioavailability and antitumor effects of Cur.

Methods

The amphiphilic tri-chaintricarballylic acid-poly (ε-caprolactone)-methoxypolyethylene glycol (Tri-CL-mPEG) and the enzyme-targeted tetra-chain pentaerythritol-poly (ε-caprolactone)-polypeptide (PET-CL-P) were synthesized. The Cur-loaded enzyme-targeted hybrid nano-delivery systems (Cur-P-NPs) were prepared by using the microfluidic continuous granulation technology. The physicochemical properties, release behavior in vitro, and stability of these Cur-P-NPs were investigated. Their cytotoxicity, cellular uptake, anti-proliferative efficacy in vitro, biodistribution, and antitumor effects in vivo were also studied.

Results

The particle size of the prepared Cur-P-NPs was 146.1 ± 1.940 nm, polydispersity index was 0.175 ± 0.014, zeta potential was 10.1 ± 0.300 mV, encapsulation rate was 74.66 ± 0.671%, and drug loading capacity was 5.38 ± 0.316%. The stability of Cur-P-NPs was adequate, and the in vitro release rate increased with the decrease of the environmental pH. Seven days post incubation, the cumulative release values of Cur were 52.78%, 67.39%, and 98.12% at pH 7.4, pH 6.8 and pH 5.0, respectively. Cur-P-NPs exhibited better cell entry and antiproliferation efficacy against U251 cells than the Cur-solution and Cur-NPs and were safe for use. Cur-P-NPs specifically targeted tumor tissues and inhibited their growth (78.63% tumor growth inhibition rate) with low toxic effects on normal tissues.

Conclusion

The enzyme-targeted hybrid nanoparticles prepared in the study clearly have the tumor-targeting ability. Cur-P-NPs can effectively improve the bioavailability of Cur and have potential applications in drug delivery and tumor management.