Preventing the thermal degradation of astaxanthin through nanoencapsulation

Recent advancement in protected delivery methods for carotenoid: a smart choice in modern nutraceutical formulation concept

Carotenoids are fat-soluble bio pigments often responsible for red, orange, pink and yellow coloration of fruits and vegetables. They are commonly referred as nutraceutical which is an alternative to pharmaceutical drugs claiming to have numerous physiological benefits. However their activity often get disoriented by photonic exposure, temperature and aeration rate thus leading to low bioavailability and bio accessibility. Most of the market value for carotenoids revolves around food and cosmetic industries as supplement where they have been continuously exposed to rigorous physico-chemical treatment. Though several encapsulation techniques are now in practice to improve stability of carotenoids, the factors like shelf life during storage and controlled release from the delivery vehicle always appeared to be a bottleneck in this field. In this situation, different technologies in nanoscale is showing promising result for carotenoid encapsulation and delivery as they provide greater mass per surface area and protects most of their bioactivities. However, safety concerns related to carrier material and process must be evaluated crucially. Thus, the aim of this review was to collect and correlate technical information concerning the parameters playing pivotal role in characterization and stabilization of designed vehicles for carotenoids delivery. This comprehensive study predominantly focused on experiments carried out in past decade explaining how researchers have fabricated bioprocess engineering in amalgamation with nano techniques to improve the bioavailability for carotenoids. Furthermore, it will help the readers to understand the cognisance of carotenoids in nutraceutical market for their trendy application in food, feed and cosmeceutical industries in contemporary era.

Solubilization of Hydrophobic Astaxanthin in Water by Physical Association with Phytoglycogen Nanoparticles

Astaxanthin (AXT) is a xanthophyll carotenoid with reported health benefits. Realizing its potential as a bioactive is challenging because of its extremely poor solubility in water. We describe a method to improve the effective solubility of AXT in water through its physical association with phytoglycogen (PG), which is produced in sweet corn as compact, highly branched nanoparticles. We combine PG in water with AXT in acetone, evaporate the acetone, and lyophilize. The result is an AXT-PG complex that can be readily redispersed in water, resulting in stable aqueous dispersions. By characterizing the UV-vis absorbance due to different aggregation states of AXT in the AXT-PG complex, we determined the maximum loading of AXT onto PG to be ∼10% by mass. Our results demonstrate the promise of using PG as a solubilizing agent for hydrophobic compounds in water.

Production and therapeutic use of astaxanthin in the nanotechnology era

Astaxanthin (AXT) is a red fat-soluble pigment found naturally in aquatic animals, plants, and various microorganisms and can be manufactured artificially using chemical catalysis. AXT is a xanthophyll carotenoid with a high potential for scavenging free radicals. Several studies have investigated AXT efficacy against diseases such as neurodegenerative, ocular, skin, and cardiovascular hypertension, diabetes, gastrointestinal and liver diseases, and immuno-protective functions. However, its poor solubility, low stability to light and oxygen, and limited bioavailability are major obstacles hindering its wide applications as a therapeutic agent or nutritional supplement. Incorporating AXT with nanocarriers holds great promise in enhancing its physiochemical properties. Nanocarriers are delivery systems with several benefits, including surface modification, bioactivity, and targeted medication delivery and release. Many approaches have been applied to enhance AXT's medicinal effect, including solid lipid nanoparticles, nanostructured lipid carriers (NLCs) and polymeric nanospheres. AXT nano-formulations have demonstrated a high antioxidant and anti-inflammatory effect, significantly affecting cancer in different organs. This review summarizes the most recent data on AXT production, characterization, biological activity, and therapeutic usage, focusing on its uses in the nanotechnology era.

Preparation and evaluation of astaxanthin-loaded 2-hydroxypropyl-beta-cyclodextrin and Soluplus® nanoparticles based on electrospray technology

BACKGROUND

Astaxanthin is a type of food-derived active ingredient with antioxidant, antidiabetic and non-toxicity functions, but its poor solubility and low bioavailability hinder further application in food industry. In the present study, through inclusion technologies, micellar solubilization and electrospray techniques, we prepared astaxanthin nanoparticles before optimizing the formulation to regulate the physical and chemical properties of micelles. We accomplished the preparation of astaxanthin nanoparticle delivery system based on single needle electrospray technology through use of 2-hydroxypropyl-β-cyclodextrin and Soluplus® to improveme the release behavior of the nanocarrier.

RESULTS

Through this experiment, we successfully prepared astaxanthin nanoparticles with a particle size of approximately 80 nm, which was further verified with scanning electron microscopy and transmission electron microscopy. Furthermore, the encapsulation of astaxanthin molecules into the carrier nanoparticles was verified via the results of attenuated total reflectance intensity and X-ray powder diffraction techniques. The in vitro release behavior of astaxanthin nanoparticles was different in media that contained 0.5% Tween 80 (pH 1.2, 4.5 and 6.8) buffer solution and distilled water. Also, we carried out a pharmacokinetic study of astaxanthin nanoparticles, in which it was observed that astaxanthin nanoparticle showed an effect of immediate release and significant improved bioavailability.

CONCLUSION

2-hydroxypropyl-β-cyclodextrin and Soluplus® were used in the present study as a hydrophilic nanocarrier that could provide a simple way of encapsulating natural function food with repsect to improving the solubility and bioavailability of poorly water-soluble ingredients. © 2023 Society of Chemical Industry.

Improving the Bioaccessibility and Bioavailability of Carotenoids by Means of Nanostructured Delivery Systems: A Comprehensive Review

Carotenoids are bioactive compounds provided by the diet playing a key role in maintaining human health. Therefore, they should be ingested daily in an adequate amount. However, even a varied and well-balanced diet does not guarantee an adequate intake, as both the bioaccessibility and bioavailability of the compounds significantly affect their absorption. This review summarizes the main results achieved in improving the bioaccessibility and bioavailability of carotenoids by means of nanostructured delivery systems, discussing in detail the available lipid-based and biopolymeric nanocarriers at present, with a focus on their formulation and functional efficiency. Although the toxicity profile of these innovative delivery systems is not fully understood, especially for long-term intake, these systems are an effective and valuable approach to increase the availability of compounds of nutritional interest.

Chitosan-Tripolyphosphate Nanoparticles Prepared by Ionic Gelation Improve the Antioxidant Activities of Astaxanthin in the In Vitro and In Vivo Model

The present study aimed to investigate the effects of chitosan (CS)-tripolyphosphate (TPP) nanoparticles (NPs) on the stability, antioxidant activity, and bioavailability of astaxanthin (ASX). ASX-loaded CS-TPP NPs (ACT-NPs) prepared by ionic gelation between CS (0.571 mg/mL) and TPP (0.571 mg/mL) showed 505.2 ± 184.8 nm, 20.4 ± 1.2 mV, 0.348 ± 0.044, and 63.9 ± 3.0% of particle size, zeta potential, polydispersity index and encapsulation efficiency, respectively. An in vitro release study confirmed that the release of ASX in simulated gastric (pH 1.2) and intestinal (pH 6.8) fluid was prolonged within ACT-NPs. The in vitro antioxidant activities of ACT-NPs were significantly improved compared with free ASX (FA) (p < 0.05). Furthermore, the cellular and in vivo antioxidant analysis verified that ACT-NPs could enhance the cytoprotective effects on the BHK-21 cell line and demonstrate sustained release properties, leading to prolonged residence time in the rat plasma. The results suggest that the stability, antioxidant properties, and bioavailability of ASX can be effectively enhanced through encapsulation within CS-TPP NPs.

Microalgae Xanthophylls: From Biosynthesis Pathway and Production Techniques to Encapsulation Development

In the last 20 years, xanthophylls from microalgae have gained increased scientific and industrial interests. This review highlights the essential issues that concern this class of high value compounds. Firstly, their chemical diversity as the producer microorganisms was detailed. Then, the use of conventional and innovative extraction techniques was discussed. Upgraded knowledge on the biosynthetic pathway of the main xanthophylls produced by photosynthetic microorganisms was reviewed in depth, providing new insightful ideas, clarifying the function of these active biomolecules. In addition, the recent advances in encapsulation techniques of astaxanthin and fucoxanthin, such as spray and freeze drying, gelation, emulsification and coacervation were updated. Providing information about these topics and their applications and advances could be a help to students and young researchers who are interested in chemical and metabolic engineering, chemistry and natural products communities to approach the complex thematic of xanthophylls.

Recent research advances in astaxanthin delivery systems: Fabrication technologies, comparisons and applications

Astaxanthin (AST) is classified as a kind of carotenoid with bright red color, powerful antioxidant activity as well as a range of health benefits. AST-based functional foods present a new thought of healthy diets with both the enhancement of food color and incorporation of nutrients. However, the poor water solubility, easy oxidation, light instability, thermal instability and peculiar smell excessively restrict its application in the food industry. In this review, common bio-based materials for various AST delivery systems suitable for different food products are highlighted. Moreover, characteristics of different delivery systems and current applications in food products are also compared and summarized. This review provides some ideas on the research trends and applications of AST delivery systems in food. The joint use of two or more materials can significantly enhance the stability of delivery systems. All of the encapsulation systems slow down the degradation of AST to a certain extent and can be applied to different food systems. However, studies and applications are still focused on emulsions and microcapsules with unsatisfactory odor masking effects. In the future, diverse AST-loaded delivery systems with high encapsulation efficacy, good stability, odor masking effects and cost-effective preparation technologies will be the major research trends.

An integration study of microalgae bioactive retention: From microalgae biomass to microalgae bioactives nanoparticle

Microalgae metabolites include biologically active compounds with therapeutic effects such as anticancer, anti-inflammatory and immunomodulation effects. One of the most recent focuses is on utilizing microalgae lipid-based biologically active compounds in food applications. However, most microalgae biological active compounds in their natural forms have common drawbacks like low solubility, low physicochemical stability and strong susceptibility to degradation, which significantly limits their application in foods, therefore, it is important to find solutions to retain their functional properties. In the present work, a comprehensive review on multi-product biorefinery was carried out from upstream processing stage to downstream processing stage, and identify critical processes and factors that impact bioactive material acquisition and retention. Furthermore, since nanoencapsulation technology emerges as an effective solution for microalgae nutraceutical product's retention, this work also focus on the nanoparticle perspective and comprehensively reviews the current nanoencapsulation solutions of the microalgae bioactive extract products. The aim is to depict advances in the formulations of microalage bioactive nanoparticles and provide a critical analysis of the reported nanoparticle formation. Overall, through the investigation of microalgae from biomass to bioactive nanoparticles, we aim to facilitate microalgae nutraceuticals incorporation as high value-added ingredients in more functional food that can improve human health.

Astaxanthin Delivery Systems for Skin Application: A Review

Astaxanthin (AST) is a biomolecule known for its powerful antioxidant effect, which is considered of great importance in biochemical research and has great potential for application in cosmetics, as well as food products that are beneficial to human health and medicines. Unfortunately, its poor solubility in water, chemical instability, and low oral bioavailability make its applications in the cosmetic and pharmaceutical field a major challenge for the development of new products. To favor the search for alternatives to enhance and make possible the use of AST in formulations, this article aimed to review the scientific data on its application in delivery systems. The search was made in databases without time restriction, using keywords such as astaxanthin, delivery systems, skin, cosmetic, topical, and dermal. All delivery systems found, such as liposomes, particulate systems, inclusion complexes, emulsions, and films, presented peculiar advantages able to enhance AST properties, among which are stability, antioxidant potential, biological activities, and drug release. This survey showed that further studies are needed for the industrial development of new AST-containing cosmetics and topical formulations.

Integrated Structural Studies for Elucidating Carotenoid-Protein Interactions

Carotenoids are ancient pigment molecules that, when associated with proteins, have a tremendous range of functional properties. Unlike most protein prosthetic groups, there are no recognizable primary structure motifs that predict carotenoid binding, hence the structural details of their amino acid interactions in proteins must be worked out empirically. Here we describe our recent efforts to combine complementary biophysical methods to elucidate the precise details of protein-carotenoid interactions in the Orange Carotenoid Protein and its evolutionary antecedents, the Helical Carotenoid Proteins (HCPs), CTD-like carotenoid proteins (CCPs).

Astaxanthin for the Food Industry

Xanthophyll astaxanthin, which is commonly used in aquaculture, is one of the most expensive and important industrial pigments. It is responsible for the pink and red color of salmonid meat and shrimp. Due to having the strongest anti-oxidative properties among carotenoids and other health benefits, natural astaxanthin is used in nutraceuticals and cosmetics, and in some countries, occasionally, to fortify foods and beverages. Its use in food technology is limited due to the unknown effects of long-term consumption of synthetic astaxanthin on human health as well as few sources and the high cost of natural astaxanthin. The article characterizes the structure, health-promoting properties, commercial sources and industrial use of astaxanthin. It presents the possibilities and limitations of the use of astaxanthin in food technology, considering its costs and food safety. It also presents the possibilities of stabilizing astaxanthin and improving its bioavailability by means of micro- and nanoencapsulation.

Effect of CO2 Flow Rate on the Extraction of Astaxanthin and Fatty Acids from Haematococcus pluvialis Using Supercritical Fluid Technology

Haematococcus pluvialis is the largest producer of natural astaxanthin in the world. Astaxanthin is a bioactive compound used in food, feed, nutraceutics, and cosmetics. In this study, astaxanthin extraction from H. pluvialis by supercritical fluid extraction was evaluated. The effects of temperature (40 and 50 °C), pressure (40 and 50 MPa), and CO₂ flow rate (2 and 4 L/min) were investigated. The results showed that the highest astaxanthin recovery was obtained at 50 °C/50 MPa and the CO₂ flow rates evaluated had no significant effect. It was possible to achieve astaxanthin recoveries of 95% after 175 min for a CO₂ flow rate of 2 L/min, and 95 min for CO₂ flow rate of 4 L/min. The ω-6/ω-3 ratios obtained were similar in all conditions, reaching 0.87, demonstrating that the extracts from H. pluvialis by SFE are rich in unsaturated fatty acids (UFA) which increases their positive effects when used as a functional ingredient in food.

Microalgae Encapsulation Systems for Food, Pharmaceutical and Cosmetics Applications

Microalgae are microorganisms with a singular biochemical composition, including several biologically active compounds with proven pharmacological activities, such as anticancer, antioxidant and anti-inflammatory activities, among others. These properties make microalgae an interesting natural resource to be used as a functional ingredient, as well as in the prevention and treatment of diseases, or cosmetic formulations. Nevertheless, natural bioactives often possess inherent chemical instability and/or poor solubility, which are usually associated with low bioavailability. As such, their industrial potential as a health-promoting substance might be severely compromised. In this context, encapsulation systems are considered as a promising and emerging strategy to overcome these shortcomings due to the presence of a surrounding protective layer. Diverse systems have already been reported in the literature for natural bioactives, where some of them have been successfully applied to microalgae compounds. Therefore, this review focuses on exploring encapsulation systems for microalgae biomass, their extracts, or purified bioactives for food, pharmaceutical, and cosmetic purposes. Moreover, this work also covers the most common encapsulation techniques and types of coating materials used, along with the main findings regarding the beneficial effects of these systems.

Potential Antioxidant and Wound Healing Effect of Nano-Liposol with High Loading Amount of Astaxanthin

Background

Astaxanthin (ASTA), a carotenoid, is a strong antioxidant. However, its application in functional foods, pharmaceuticals, and cosmetics remains limited due to its low aqueous solubility and stability. Several different encapsulating materials have been used to improve the stability and bioavailability of ASTA; however, the currently investigated nano-carriers for ASTA require additional improvements with regard to their loading capacity and stability.

Methods

In this study, we developed lecithin nano-liposol (Lec NS) as a novel carrier of ASTA using a simple emulsion evaporation method. The physicochemical characteristics including hydrodynamic diameter, polydispersity index, surface charge and morphology were analyzed by DLS and TEM. The antioxidant activity of the ASTA-loaded Lec NS (ASTA@Lec NS) was evaluated using a DPPH radical scavenging assay and in vitro antioxidant assay. The study of in vitro wound healing efficacy was carried out to observe the beneficial effect of antioxidant activity of ASTA@Lec NS on cell migration.

Results

ASTA@Lec NS showed improved stability and efficacy owing to improved aqueous solubility of ASTA inside Lec NS. Both in situ and in vitro antioxidant activities of ASTA@Lec NS were higher than that of bare ASTA and Lec NS. It also exhibited strong wound healing efficacy by regulation of ROS level in in vitro cell model.

Conclusion

This study revealed that the encapsulation of ASTA into Lec NS using a wet phase transfer enhanced its physiological stability and bioavailability for effective scavenging of reactive oxygen species.

Astaxanthin and other Nutrients from Haematococcus pluvialis-Multifunctional Applications

Bioactive compounds of natural origin are gaining increasing popularity. High biological activity and bioavailability, beneficial effects on health and safety of use are some of their most desirable features. Low production and processing costs render them even more attractive. Microorganisms have been used in the food, medicinal, cosmetic and energy industries for years. Among them, microalgae have proved to be an invaluable source of beneficial compounds. Haematococcus pluvialis is known as the richest source of natural carotenoid called astaxanthin. In this paper, we focus on the cultivation methods of this green microalga, its chemical composition, extraction of astaxanthin and analysis of its antioxidant, anti-inflammatory, anti-diabetic and anticancer activities. H. pluvialis, as well as astaxanthin can be used not only for the treatment of human and animal diseases, but also as a valuable component of diet and feed.

Morphology and microstructural analysis of bioactive-loaded micro/nanocarriers via microscopy techniques; CLSM/SEM/TEM/AFM

Efficient characterization of the physicochemical attributes of bioactive-loaded micro/nano-vehicles is crucial for the successful product development. The introduction of outstanding science-based strategies and techniques makes it possible to realize how the characteristics of the formulation ingredients affect the structural and (bio)functional properties of the final bioactive-loaded carriers. The important points to be solved, at a microscopic level, are investigating how the features of the formulation ingredients affect the morphology, surface, size, dispersity, as well as the particulate interactions within bioactive-comprising nano/micro-delivery systems. This review presents a detailed description concerning the application of advanced microscopy techniques, i.e., confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) in characterizing the attributes of nano/microcarriers for the efficient delivery of bioactive compounds. Furthermore, the fundamental principles of these approaches, instrumentation, specific applications, and the strategy to choose the most proper technique for different carriers has been discussed.

Improving the efficiency of natural antioxidant compounds via different nanocarriers

Encapsulation technology, as a promising approach, has been employed for the protection and controlled release of different bioactive compounds including natural antioxidants; there are restrictions for applying these valuable ingredients in real food products, pharmaceuticals, and cosmetics such as low solubility, low shelf life, difficultly in their packaging and handling, losses due to environmental stresses and food processes, undesirable flavors and odors, untargeted release and instability in various conditions during digestion in gastrointestinal tract. Nanocarriers can be employed to overcome these challenges. There are five groups of nanocarriers based on the principal mechanism/ingredient used to make them for the encapsulation of natural antioxidants titled biopolymeric nanoparticles, lipid-based and surfactant-based nanocarriers, nanocarriers made with specially designed equipment, nature-inspired nanocarriers, and miscellaneous ones. The main goal of this study is to have an overview of role of different nanocarriers in improving the efficiency of natural antioxidant compounds for different purposes. It has been verified that antioxidant-loaded nanocarriers can be applied in many formulations with a higher and controlled release antioxidant activity, which would meet the current needs of consumers' expectations towards clean label products.

Effects of Astaxanthin from Shrimp Shell on Oxidative Stress and Behavior in Animal Model of Alzheimer's Disease

This study aimed to investigate the effect of astaxanthin (ASX) extracted and ASX powder from shrimp (Litopenaeus vannamei) shells on Wistar rats with Alzheimer's disease, induced by amyloid-β (1-42) peptides. In this task, the rats were divided into eight groups: (1) Control, (2) sham operate, (3) negative control (vehicle) + Aβ_1-42, (4) ASX extract+Aβ_1-42, (5) commercial ASX + Aβ_1-42, (6) ASX powder + Aβ_1-42, (7) blank powder + Aβ_1-42, and (8) vitamin E + Aβ_1-42. All treatments were orally administrated for 30 days. At 14- and 29-days post injection, animals were observed in behavioral tests. On the 31st day, animals were sacrificed; the hippocampus and cortex were collected. Those two brain areas were then homogenized and stored for biochemical and histological analysis. The results showed that the Aβ_1-42 infused group significantly reduced cognitive ability and increased memory loss, as assessed by the Morris water maze test, novel object recognition test, and novel object location test. Moreover, the Aβ_1-42 infused group exhibited a deterioration of oxidative markers, including glutathione peroxidase enzymes (GPx), lipid peroxidation (MDA), products of protein oxidation, and superoxide anion in the cortex and the hippocampus. Meanwhile, ASX powder (10 mg/kg body weight) showed a significant reduction in cognitive and memory impairments and oxidative stress which is greater than ASX extract in the same dose of compound or vitamin E (100 mg/kg body weight). Our study indicates the beneficial properties of ASX in alleviation of cognitive functions and reducing neurodegeneration in Wistar rats induced by amyloid-β (1-42) peptides.

Development and Characterization of Astaxanthin-Containing Whey Protein-Based Nanoparticles

Astaxanthin (ASX) is a carotenoid of great interest due to its potential health benefits. However, its use in the food, feed, and pharmaceutical fields is limited due to low bioavailability, poor stability during thermochemical treatments, susceptibility to oxidation, and poor organoleptic characteristics. The aim of this work was to develop a method to stabilize astaxanthin extracted from the microalgae Haematococcus pluvialis (H.p.) and to improve its nutritional and functional properties through nanoencapsulation. Nanoparticles (NPs) were produced by emulsification–solvent evaporation technique starting from H.p. oleoresin using whey proteins concentrate (WPC) as stabilizer. The efficiency of encapsulation was 96%. The particle size (Z-average) was in the range of 80–130 nm and the superficial charge (measured as zeta-potential) was negative (−20 to −30 mV). The stability of the NPs upon resuspension in water was assayed through a panel of stress tests, i.e., extreme pH, UV radiation, Fe³⁺ exposition, and heating at 65 °C, that always showed a superior performance of encapsulated ASX in comparison to oleoresin, even if NPs tended to precipitate at pH 3.5–5.5. Simulated gastroenteric digestion was conducted to study the release of ASX in physiological conditions, and showed a maximum bioaccessibility of 76%, with 75% ASX converted into the more bioavailable free form. The collected data suggest that NPs might have possible future applications as supplements for human and animal diets.

Enhanced proliferation and differentiation of mesenchymal stem cells by astaxanthin-encapsulated polymeric micelles

Astaxanthin is a highly potent antioxidant which can be extracted from Haematococcus pluvialis when cultivated and induced at high stress conditions. Due to astaxanthin's hydrophobicity, methoxypolyethylene glycol-polycaprolactone (mPEG-PCL) copolymer was synthesized to form polymeric micelles for the encapsulation of astaxanthin. Astaxanthin-loaded polymeric micelles were then used to examine the effects on the proliferation and differentiation of human mesenchymal stem cells (MSCs). Dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FT-IR) confirmed astaxanthin was encapsulated into mPEG-PCL micelles. Astaxanthin loading and encapsulation efficiency, determined by UV/Vis spectroscopy, were 3.27% and 96.67%, respectively. After 48 h, a total of 87.31% of astaxanthin was released from the polymeric micelles. The drug release profile was better fit by the Michaelis-Menten type model than the power law model. The MSC culture results showed that culture medium supplemented with 0.5 μg/mL astaxanthin-encapsulated polymeric micelles led to a 26.3% increase in MSC proliferation over an 8-day culture period. MSC differentiation results showed that 20 ng/mL astaxanthin-encapsulated polymeric micelles enhanced adipogenesis, chondrogenesis, and osteogenesis of MSCs by 52%, 106%, and 182%, respectively.

Properties and bioavailability assessment of shrimp astaxanthin loaded liposomes

This study aimed to investigate the effects of phospholipid composition on the properties and bioavailability of astaxanthin-loaded liposomes using cell culture. Two mixtures of phospholipids with different proportions of phosphatidylcholine (PC, 23% and 70%) were used at various concentrations (0.8, 1.6, and 2.0% w/v) to prepare astaxanthin-loaded liposomes, which were investigated for entrapment efficiency (EE), antioxidant activity, morphology and changes in astaxanthin properties during a storage period of 8 weeks at 4 °C. Furthermore, Caco-2 human colon adenocarcinoma cells were employed to examine the cellular uptake of astaxanthin-loaded liposomes. The highest EE was observed with astaxanthin-loaded liposomes containing 70% PC, and used at the concentration of 2.0% w/v. Liposomes maintained the antioxidant activity of astaxanthin. All liposomal preparations were non-toxic. Cellular uptake of astaxanthin-loaded liposomes containing 70% PC was significantly higher than that of 23% PC-containing liposomes (p < 0.05).

Nanoliposomes as Vehicles for Astaxanthin: Characterization, In Vitro Release Evaluation and Structure

Astaxanthin was encapsulated in nanoliposomes by a film dispersion-ultrasonic technique using soybean phosphatidyl choline. The astaxanthin-loaded nanoliposomes displayed advantages in the aspects of high encapsulation efficiency and less particle size with a remarkably homodisperse size distribution. Based on X-ray diffraction and differential scanning calorimetry the analysis, it has been demonstrated that there could be interactions of astaxanthin with the lipid bilayer, resulting in the forming of astaxanthin-loaded nanoliposomes. The thermal gravimetric analysis revealed that the thermal stability of astaxanthin after encapsulation in nanoliposomes was remarkably enhanced as compared to astaxanthin alone. Furthermore, encapsulation could greatly enhance the water dispersibility of astaxanthin. This study also confirmed that encapsulation of astaxanthin in nanoliposomes could be an effective way to supply astaxanthin continuously in the body. The effects of astaxanthin incorporation on structural changes of the liposomal membrane were investigated through steady-state fluorescence measurements. This study revealed that the incorporation of astaxanthin into the lipid bilayer decreased membrane fluidity, but increased micropolarity in the membrane within a certain range of astaxanthin concentrations. Additionally, it indicated that the encapsulation of astaxanthin in the lipid bilayer could be applied to modulate the structural properties of membranes.

Nanoencapsulation of carotenoids: a focus on different delivery systems and evaluation parameters

Different types of nanoparticles have been synthesized to protect carotenoids against exposition of external factors such as light, heat and oxygen; and processing conditions; to increase stability and to improve the bioavailability of nanoencapsulated carotenoid. The type of nanostructure synthesized (nanoemulsions, liposomes, solid lipid nanoparticles, nanostructured lipid carrier, and polymeric nanoparticles) influences on the synthesis and nanoparticles stability, which reflect in physic-chemical characteristics such as polydispersity index, zeta potential, and encapsulation efficiency. Different nanostructures can be used to improve stability of carotenoids; however, currently, polymeric nanocapsules are the nanostructure most utilized due to its stability during storage, high efficiency to encapsulate and to control the release of the carotenoid encapsulated. Due to these considerations, they have been focus of researchers for future studies regarding to application of carotenoids nanoencapsulated by food industries. The focus of this review is the presentation of different carotenoids delivery systems and the use of techniques to evaluate parameters that might limit the application of this innovative and potential technology in cosmetic, pharmaceutical and food industry.

Supercritical Carbon Dioxide Extraction of Astaxanthin, Lutein, and Fatty Acids from Haematococcus pluvialis Microalgae

Haematococcus pluvialis microalgae in the red phase can produce significant amounts of astaxanthin, lutein, and fatty acids (FAs), which are valuable antioxidants in nutraceutics and cosmetics. Extraction of astaxanthin, lutein, and FAs from disrupted biomass of the H. pluvialis red phase using carbon dioxide (CO₂) in supercritical fluid extraction (SFE) conditions was investigated using a bench-scale reactor in a semi-batch configuration. In particular, the effect of extraction time (20, 40, 60, 80, and 120 min), CO₂ flow rate (3.62 and 14.48 g/min) temperature (50, 65, and 80 °C), and pressure (100, 400, and 550 bar.) was explored. The results show the maximum recovery of astaxanthin and lutein achieved were 98.6% and 52.3%, respectively, at 50 °C and 550 bars, while the maximum recovery of FAs attained was 93.2% at 65 °C and 550 bars.

Fabrication and Characterization of β-Lactoglobulin-Based Nanocomplexes Composed of Chitosan Oligosaccharides as Vehicles for Delivery of Astaxanthin

Astaxanthin (Ax), a type of carotenoid, has limited use as a result of its poor water solubility, low bioavailability, and decomposition under harsh conditions. This study reports a delivery system for Ax through a simple affinity binding with β-lactoglobulin and then coated with chitosan oligosaccharides. Ax-loaded β-lactoglobulin nanocomplexes and chitosan oligosaccharide-coated nanocomplexes were successfully prepared. The nanocomplexes exhibited a smooth spherical shape with diameters of about 40 and 60 nm measured by transmission electron microscopy. Spectroscopic techniques (ultraviolet-visible, fluorescence, and Fourier transform infrared spectroscopy) combined with molecular docking were used to determine the binding mechanism of Ax and β-lactoglobulin. In comparison to native Ax, the nanocomplexes maintain the hydroxyl radical scavenging activity of Ax under the treatment of acid, high temperature, and ultraviolet radiation. The release experiment of nanocomplexes revealed that the encapsulation could provide prolonged release of Ax in simulated gastrointestinal juices. This study aimed to fabricate and characterize Ax-β-lactoglobulin nanocomplexes, which can improve the Ax stability and slow release.

Fabrication of aqueous nanodispersion from natural DNA and chitosan as eminent carriers for water-insoluble bioactives

For high-valued application of natural DNA as raw materials, we prepared nanocarriers by using salmon sperm DNA and chitosan to encapsulate water-insoluble bioactives. Here, water dispersible astaxanthin/DNA/chitosan nano-aggregates (ADC-NAs) were prepared by co-assemble evaporation method. The key point for preparing well formed ADC-NAs was specifically discussed. The resultant ADC-NAs were spherical with 100-300 nm diameter measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM), and their homogeneous dispersions were sufficiently stable at room temperature. One important feature of these nanocarriers is enormously high loading amount of cargo (about 40 wt%). According to the UV-Vis spectra of the nanosuspension, we deduced that astaxanthin was encapsulated as uniquely structured J-aggregates. Fourier transform infra-red (FTIR) spectroscopy proved fabrication was successfully and astaxanthin was embedding in DNA/chitosan nanocarriers. Cytotoxicity was examined in vitro using cell culture in L929 cell lines. When necessary, these nano-aggregates can be degraded by DNase I. Homogeneous dispersions of other non-charged guest molecules are also prepared by using DNA/chitosan nanocarriers. These dispersions are cheaply and easily obtainable from naturally occurring DNA and chitosan, and should be useful for versatile applications.

Astaxanthin-antioxidant impact on excessive Reactive Oxygen Species generation induced by ischemia and reperfusion injury

Oxidative stress induced by Reactive Oxygen Species (ROS) was shown to be involved in the pathogenesis of chronic diseases such as cardiovascular pathologies. Particularly, oxidative stress has proved to mediate abnormal platelet function and dysfunctional endothelium-dependent vasodilatation representing a key factor in the progression of ischemic injuries. Antioxidants like carotenoids have been suggested to contribute in their prevention and treatment. Astaxanthin, a xanthophyll carotenoid produced naturally and synthetically, shows interesting antioxidant and anti-inflammatory properties. In vivo studies applying different models of induced ischemia and reperfusion (I/R) injury confirm astaxanthin's protective action after oral or intravenous administration. However, some studies have shown some limitations after oral administration such as low stability, bioavailability and bioefficacy, revealing a need for the implementation of new biomaterials to act as astaxanthin vehicles in vivo. Here, a brief overview of the chemical characteristics of astaxanthin, the carrier systems developed for overcoming its delivery drawbacks and the animal studies showing its potential effect to treat I/R injury are presented.

Formulation and characterization of O/W nanoemulsions encapsulating high concentration of astaxanthin

This study evaluates the effect of modified lecithin (ML) and sodium caseinate (SC) on the formulation, stability and bioaccessibility of astaxanthin (AXT) loaded oil-in-water (O/W) nanoemulsions. These nanoemulsions were formulated using high-pressure homogenization in four passes at 100MPa. The volume mean diameter (d_4,3) of nanoemulsions produced by ML and SC were 163±5 and 144±12 nm, respectively. The physiochemical stability of nanoemulsions was recorded at 25°C. The nanoemulsions prepared by ML were stable for 30 minutes against a wide range of pH and heating temperatures (60-120 °C). However, ML-stabilized nanoemulsions showed droplet growth when treated at high NaCl concentrations. In comparison, droplet growth was observed in SC-stabilized nanoemulsions at pH4 and at high temperature treatment. However, SC-stabilized nanoemulsions were stable at high NaCl concentration (500 mM). The SC-stabilized nanoemulsions showed good physical and chemical stability (>70%) after 30 days of storage. The bioaccessibility of AXT in nanoemulsions was significantly higher in ML (33%) than in SC-stabilized nanoemulsions (6%), indicating a strong influence of emulsifier on bioaccessibility. These findings provide valuable information in designing nutritional products such as aqueous based AXT fortified beverages.

Formulation and characterization of monodisperse O/W emulsions encapsulating astaxanthin extracts using microchannel emulsification: Insights of formulation and stability evaluation

The study used straight-through microchannel emulsification (MCE) to encapsulate different extracts of astaxanthin (AXT) in oil-in-water (O/W) emulsion droplets. We used silicon microchannel plates (WMS 11-1) containing 13,752 discrete 10×104μm microslots, connected to a circular microhole with a diameter of 10μm. Two different AXT extracts (AstaReal (AR) and Zenthin^® (ZR)) based upon concentration and without purification was used as encapsulants in the dispersed phase, while different emulsifiers (1% (w/w) SDS, ML-750, MO-7S, Na-Cs and ML) with different stabilizing mechanisms were used as the continuous phase. The MCE was conducted at a dispersed phase flow rate of 1mLh^-1. Successful emulsification was conducted with a Sauter mean diameter of 35-37μm and relative span factor <0.25. The emulsification was highly depended on the type of emulsifiers and the extract type used during emulsification. Better droplet productivity was achieved with AR extract with 1% (w/w) ML-750 as the optimized emulsifier in Milli-Q Water. The O/W emulsion droplets remained stable at 25°C with encapsulation efficiency of over 98% during 15days of storage period.

Preparation of astaxanthin-loaded DNA/chitosan nanoparticles for improved cellular uptake and antioxidation capability

DNA/chitosan co-assemblies were initially used as nanocarriers for efficient astaxanthin encapsulation and delivery. The obtained astaxanthin-loaded DNA/chitosan (ADC) colloidal system was transparent and homogenous, with astaxanthin content up to 65μg/ml. Compared to free astaxanthin, ADC nanoparticles with an astaxanthin concentration as low as 3.35nM still showed a more powerful cytoprotective effect on H₂O₂-induced oxidative cell damage, and improved cell viability from 49.9% to 61.9%. The ROS scavenging efficiency of ADC nanoparticles was as high as 54.3%, which was 2-fold higher than that of free astaxanthin. Besides this, ADC nanoparticles were easily engulfed by Caco-2 cells in a short time, indicating that the encapsulated astaxanthin could be absorbed through endocytosis by intestinal epithelial cells. The improved antioxidation capability and facilitated cellular uptake enabled the ADC nanoparticles to be good candidates for efficient delivery and absorption of astaxanthin.

Nose to brain delivery of astaxanthin-loaded solid lipid nanoparticles: fabrication, radio labeling, optimization and biological studies

Astaxanthin nanoformulation was found appropriate in all measures with strong antioxidant activity against H₂O₂induced oxidative stress in PC12 cells. Biodistribution and brain delivery was also found to be superior to conventional dosage form.