Pectin from steam explosion-treated citrus peel exhibits good emulsion properties and bioavailability-promoting effect in vitro of nobiletin

Steam explosion (SE) is a potential method to modify pectin structure, which might be connected to its emulsifying characteristics and the bioavailability of encapsulated polymethoxyflavone like nobiletin. However, the relationship between SE-modified pectin and the bioavailability of encapsulated nobiletin is still unclear. In this study, nobiletin-loaded emulsion was fabricated using citrus pectin modified with SE (0.15-0.9 MPa, 3 min) as emulsifier for in vitro digestion study, and the transport and absorption of nobiletin in Caco-2 cells to investigate the bioavailability-promoting effect. The results showed that SE treatment lowered the droplet size of emulsion from 21.38 ± 2.30 μm to 2.14 ± 0.12 μm, enhanced the nobiletin encapsulation efficiency from 23.73 ± 0.78% to 86.27 ± 3.81%, improved the nobiletin bioaccessibility in vitro from 2.48 ± 0.10% to 25.42 ± 0.10% and increased the intracellular accumulation of nobiletin by over 10 times, even higher than that of Tween 80. In conclusion, pectin from SE-treated citrus peel exhibited good emulsion properties and bioavailability-promoting effect in vitro of nobiletin.

Natural product nobiletin-loaded Pickering emulsion stabilized by bovine serum albumin/carboxymethyl inulin complexes: preparation and digestive characteristics

To expand the application of nobiletin (NOB) in semi-solid functional foods, bovine serum albumin (BSA)/carboxymethyl inulin (CMI) complexes-stabilized Pickering emulsion (BCPE) (φoil = 60%, v/v) was fabricated, and the swallowing index and bioavailability of the NOB-loaded Pickering emulsion was evaluated. Confocal laser scanning microscope (CLSM) and cryo-scanning electron microscopy (cryo-SEM) images revealed that BSA/CMI complexes attached to the oil-water interface. NOB-loaded BCPE exhibited a viscoelastic and shear-thinning behavior. Fork drip test results suggested that the textural value of unloaded and NOB-loaded emulsions was International Dysphagia Diet Standardisation Initiative Level 4, which could be swallowed directly without chewing. The in vitro lipolysis model suggested that NOB had a faster digestive profile and a higher bioaccessibility in the BCPE than in the oil suspension. The in vivo rat model revealed that the oral bioavailability of NOB was increased by 2.07 folds in BCPE compared to its bioavailability in unformulated oil. Moreover, BCPE led to a higher plasma concentration of the major demethylated metabolite of NOB (4'-demethylnobiletin) than the unformulated oil. Accordingly, BCPE enhanced the oral bioavailability of NOB by improving bioaccessibility, absorption, and biotransformation.

Influence of 1,3-diacylglycerol on physicochemical and digestion properties of nanoemulsions and its enhancement of encapsulation and bioaccessibility of hydrophobic nobiletin

Lipid-based delivery systems are commonly used to encapsulate hydrophobic bioactive compounds for enhancing their bioaccessibility and bioavailability, especially for triacylglycerol (TAG) oil-based delivery systems. However, studies on the development of 1,3-diacylglycerol (DAG) oil-based delivery systems are rather limited. Herein, the influence of 1,3-DAG oil as a carrier oil on the properties of nanoemulsions and the bioaccessibility of encapsulated hydrophobic nobiletin (NOB) were investigated. High-purity 1,3-DAG (over 93% pure) was prepared by a combination of enzymatic esterification and ethanol crystallization. 1,3-DAG oil as a carrier oil could be used to formulate nanoemulsions with smaller droplet size, narrower size distribution and similar stability compared to TAG oil. Importantly, 1,3-DAG oil could efficiently encapsulate high-loading NOB (1.45 mg g-1) in nanoemulsions and significantly improve the bioaccessibility of NOB (above 80%), which is attributable to its massive lipolysis and higher encapsulation capacity than TAG oil. Moreover, the addition of the 1,3-DAG component in TAG oil significantly improved the properties of nanoemulsions and the loading and bioaccessibility of NOB, especially as the 1,3-DAG content was not less than 50%. The structure of lipids (DAG versus TAG) influenced the nanoemulsion properties and the bioaccessibility of encapsulated NOB. Based on the good properties of 1,3-DAG oil coupled with its health benefits, 1,3-DAG oil-based nanoemulsion delivery systems have great prospects for improving and extending emulsion properties and bioactivity as well as bioaccessibility enhancement.

Zein/pullulan complex colloidal particle-stabilized Pickering emulsions for oral delivery of polymethoxylated flavones: protection effect and in vitro digestion

BACKGROUND

Polymethoxylated flavones (PMFs) show multiple biological functions, while their high hydrophobicity leads to a low bioaccessibility and limits their wide applications. The design of a reasonable food-grade drug delivery system is an effective strategy to improve the low bioaccessibility of PMFs. In this study, sinensetin, tangeretin and nobiletin were encapsulated in Pickering emulsions stabilized by zein/pullulan complex colloidal particles (ZPPs), and the protection effect and in vitro digestion were characterized.

RESULTS

Rheological analysis revealed that ZPP-Pickering emulsion loading with PMFs maintained a strong gel-like network structure. Moreover, the ability to scavenge free radicals of PMFs was improved by the emulsion delivery system. The antioxidant activity of PMFs encapsulated in Pickering emulsion was positively correlated with the oil volume fraction (φ). ZPP-Pickering emulsion loading with PMFs can effectively delay lipid oxidation, and the φ (70%) of Pickering emulsion showed the most pronounced effects, in which the lipid hydroperoxide content and malondialdehyde content decreased by 64.3% and 38.3% after 15 days of storage, compared with the bulk oil group, respectively. The bioaccessibility of the three PMFs has been increased by ZPP-Pickering emulsion simultaneously and it presented the highest values as its φ was 50%, in which the bioaccessibility of sinensetin, tangeretin and nobiletin increased by 2.5, 3.2 and 3.9 times, compared with the bulk oil group, respectively.

CONCLUSION

Pickering emulsion stabilized by ZPPs is an excellent nutrient delivery system for delivering three PMFs simultaneously and imparting functional properties to bioactive delivery systems. © 2022 Society of Chemical Industry.

Coordination-driven Metal-polyphenolic Nanoparticles toward Effective Anticancer Therapy

Stabilization of bioactive components, especially for hydrophobic functional factors, is a promising approach for improving their biological activity. Here, a metal-phenolic coordination chemistry that synthesizes biocompatible and biodegradable thin-film based on tannic acid (TA) and trivalent metal ion (Fe³⁺ or Al³⁺ ) is addressed, and the results also demonstrate its use for encapsulating a hydrophobic drug (Nobiletin, NOB) and triggering drug release for cancer treatment both in vitro and in vivo. This assembled system provides drug-loaded nanoparticles (NPs) with small, but uniform, size (∼200 nm). It displays beneficial potential in enhancing colloidal stability and preventing premature drug leakage. Moreover, the metal-phenolic coating is found to possess high cell biocompatibility as a delivery vector for controlled drug delivery, while the final fabricated drug NPs have effective anti-tumor activity by both inducing higher tumor apoptosis and inhibiting tumor metastasis, which is superior to naked drug formulations. Overall, our findings propose an effective and straightforward way for coating hydrophobic drugs employing interfacial adhesion and assembly, which could be a highly promising vehicle for controlled-release biomedical applications for cancer therapy. This article is protected by copyright. All rights reserved.

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

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

Co-encapsulation of probiotic Lactobacillus acidophilus and Reishi medicinal mushroom (Ganoderma lingzhi) extract in moist calcium alginate beads

Probiotic L. acidophilus La-14 cells were co-encapsulated with Ganoderma lingzhi extract to prolong the viability of the cells under simulated gastrointestinal (SGI) condition and to protect the active ingredients of Reishi mushroom during the storage period. Combinations of distinctive reagents (sodium alginate, chitosan, maltose, Hydroxyethyl-cellulose (HEC), hydroxypropyl methylcellulose (HPMC), and calcium lactate) were tested. Optimal double layer Ca-alginate hydrogel beads were fabricated with significantly improved characteristics. The incorporation of maltose significantly decreases the release rate of mushrooms' phenolics, antioxidants, and β-glucan during the storage time. Significant improvement in probiotic cells viability under SGI condition has been found and confirmed by confocal laser microscopy in maltose containing double layer coated calcium alginate beads variants. The encapsulation of newly formulated prebiotic Reishi extract and probiotic L. acidophilus is creating a new potential food application for such medicinal mushrooms and natural products with unpleasant taste upon oral consumption.

Recent Developments in the Formulation and Use of Polymers and Particles of Plant-based Origin for Emulsion Stabilizations

The main scope of this Review was the recent progress in the use of plant-based polymers and particles for the stabilization of Pickering and non-Pickering emulsion systems. Due to their availability and promising performance, it was discussed how the source, modification, and formulation of cellulose, starch, protein, and lignin-based polymers and particles would impact their emulsion stabilization. Special attention was given toward the material synthesis in two forms of polymeric surfactants and particles and the corresponding formulated emulsions. Also, the effects of particle size, degree of aggregation, wettability, degree of substitution, and electrical charge in stabilizing oil/water systems and micro- and macro-structures of oil droplets were discussed. The wide range of applications using such plant-based stabilizers in different technologies as well as their challenge and future perspectives were described.

Development of organogel-based emulsions to enhance the loading and bioaccessibility of 5-demethylnobiletin

5-Demethylnobiletin (5-DMN), identified in the aged citrus peels, has received increasing attentions due to its outstanding bioactivity among citrus polymethoxyflavones (PMFs). However, the poor water solubility and high crystallinity limit its oral bioavailability. Besides, the solubility of 5-DMN in the oil is very limited, which restricts its loading capacity in emulsions for bioavailability enhancement. In this study, an organogel formulation was developed to improve the solubility of 5-DMN in medium-chain triacylglycerols by 3.5 times higher without crystal formation during 5-day storage at room temperature. Increasing the gelator (i.e., sugar ester) concentration led to the increase of viscosity and a gel-like structure of the organogel. The ternary phase diagram of organogel-based emulsions was explored, and 40% organogel was selected as the oil phase for emulsion preparation. Increasing the concentration of Tween 80 from 0% to 6% decreased the droplet size and viscoelasticity of the emulsions. Two in vitro models, the pH-stat lipolysis model and TNO gastro-intestinal model (TIM-1), were applied to investigate the bioaccessibility of 5-DMN in different delivery systems. Compared with the conventional emulsion and oil suspension, the pH-stat lipolysis demonstrated that the organogel-based emulsion was the most efficient tool to enhance 5-DMN bioacccessibility. Moreover, TIM-1 digestive study indicated that 5-DMN bioaccessibility delivered by organogel-based emulsions was about 3.26-fold higher than that of oil suspension. Our results suggested that the organogel-based emulsion was an effective delivery route to enhance the loading and bioaccessibility of lipophilic compounds of high crystallinity.

Biopolymer Additives Enhance Tangeretin Bioavailability in Emulsion-Based Delivery Systems: An In Vitro and In Vivo Study

The oral bioavailability of tangeretin, a poly(methoxyflavone) found in citrus fruits, is typically very low because of its extremely limited solubility. In this research, tangeretin was encapsulated within whey protein-stabilized emulsions containing ingredients that may alter their behavior under gastrointestinal conditions and enhance the bioavailability of tangeretin after oral administration: cinnamaldehyde (CA), gum arabic (GA), or hydroxypropyl methylcellulose (HPMC). The presence of these ingredients altered the size, aggregation state, and encapsulation efficiency of tangeretin in the emulsions. In vitro studies demonstrated that the bioaccessibility of the encapsulated tangeretin was much higher than that of a crude tangeretin oil suspension. Particularly, the addition of HPMC increased the bioaccessibility of tangeretin from around 36 to 90%. In vivo pharmacokinetics results using rats indicated that tangeretin concentration in the plasma increased from 4- to 20-fold after encapsulation, especially in the presence of HPMC. HPMC also prolonged the release of tangeretin to 22 h. Tangeretin preferentially accumulated within the liver and kidney of the animals. Overall, the knowledge confirmed that structured emulsion-based delivery systems could be used to improve the oral bioavailability of hydrophobic functional ingredients.

Assessment of Oral Bioavailability and Biotransformation of Emulsified Nobiletin Using In Vitro and In Vivo Models

Nobiletin has received much attention for its promising biological activities. Owing to its limited solubility, various encapsulation strategies have been developed to enhance nobiletin bioavailability. However, the understanding of the bioavailability and biotransformation of nobiletin in vivo and the correlation between in vitro and in vivo data remains limited. This study developed a high-loading nobiletin (1%) emulsion. The in vitro models, which combined pH-stat lipolysis with a Franz cell, showed very good correlation with in vivo data for the relative bioavailability. Rat studies showed that nobiletin had a high absolute bioavailability (≈20% for oil suspension). Besides, the emulsification improved the amount of bioavailable nobiletin and its major metabolite in the blood by about two times, as compared to an oil suspension. This work provides scientific insights into a rapid screening method for delivery systems and a better understanding of the biological fate of nobiletin in vivo.

Nobiletin as a Molecule for Formulation Development: An Overview of Advanced Formulation and Nanotechnology-Based Strategies of Nobiletin

Approximately 40% of compounds in clinical drug development suffer from solubility and bioavailability challenges. Evidence from literature demonstrates the growing interest to utilize flavonoids as potential compounds owing to their widespread therapeutic utility in various ailments. Nobiletin (NOB), one such dietary polymethoxylated flavonoid found in citrus fruits, has multiple pharmacological effects such as antioxidant, anti-microbial, anti-cancer, and anti-inflammatory. It is useful in cancer, inflammatory bowel diseases, atherosclerosis, obesity, and Alzheimer's disease. Although preclinical studies demonstrate the therapeutic utility of NOB, it suffers from serious biopharmaceutical limitations such as low aqueous solubility (below 1 μg/ml), poor permeability across biological barriers, and low bioavailability. To overcome these biopharmaceutical challenges associated with NOB, the use of advanced formulations and nanotechnology-based strategies appears to be a promising approach to potentiate its therapeutic action. Multiple reviews cover the various therapeutic benefits of NOB in various diseases; however, there is an absence of a comprehensive review that focuses on the formulation development strategies of NOB. The purpose of this review is to provide a concise perspective on NOB as a candidate molecule for formulation development. The manuscript covers various aspects related to NOB, such as its chemistry, physicochemical properties, and pharmacological effects. This is also a thorough review of various formulation development strategies with advances made in the past years to improve the solubility, bioavailability, and therapeutic efficacy of NOB. The review also contains information related to toxicity and patents involving NOB and its formulation.