Astaxanthin: structural and functional aspects

Investigation of isomerization and oxidation of astaxanthin in ready-to-eat Litopenaeus vannamei during accelerated storage

Astaxanthin (AST), the natural pigment in Litopenaeus vannamei, is susceptible to oxidation and isomerization, leading to the fading of the orange-red color in ready-to-eat (RTE) shrimps. This study specifically investigated the changes mechanism in AST content, including geometric and stereoisomers, as well as oxidation degradation, throughout the storage process of RTE shrimps. The results showed that the total amount of AST decreased by 46.76 % after 45 days of storage at 40 °C. The levels of geometric isomers (all-E, 9-Z, 13-Z) and stereoisomers (3S,3'S, 3S,3'R, 3R,3'R) gradually decreased over time. Notably, 9-Z and 3S,3'S isomers, known for their strong antioxidant activity, were reduced by 83.57 % and 61.64 % respectively. Additionally, AST underwent oxidative degradation, forming short-chain compounds (astaxanthinal or astaxanthinone), with the main products being Apo-14'-astaxanthinal and Apo-7-astaxanthinone DHA ester. These findings provide a theoretical foundation for further research on the degradation mechanism of AST, and offer valuable insights into the color protection of RTE shrimps.

Recent progress in practical applications of a potential carotenoid astaxanthin in aquaculture industry: a review

Astaxanthin is the main natural C40 carotenoid used worldwide in the aquaculture industry. It normally occurs in red yeast Phaffia rhodozyma and green alga Haematococcus pluvialis and a variety of aquatic sea creatures, such as trout, salmon, and shrimp. Numerous biological functions reported its antioxidant and anti-inflammatory activities since astaxanthin possesses the highest oxygen radical absorbance capacity (ORAC) and is considered to be over 500 more times effective than vitamin E and other carotenoids such as lutein and lycopene. Thus, synthetic and natural sources of astaxanthin have a commanding influence on industry trends, causing a wave in the world nutraceutical market of the encapsulated product. In vitro and in vivo studies have associated astaxanthin's unique molecular features with various health benefits, including immunomodulatory, photoprotective, and antioxidant properties, providing its chemotherapeutic potential for improving stress tolerance, disease resistance, growth performance, survival, and improved egg quality in farmed fish and crustaceans without exhibiting any cytotoxic effects. Moreover, the most evident effect is the pigmentation merit, where astaxanthin is supplemented in formulated diets to ameliorate the variegation of aquatic species and eventually product quality. Hence, carotenoid astaxanthin could be used as a curative supplement for farmed fish, since it is regarded as an ecologically friendly functional feed additive in the aquaculture industry. In this review, the currently available scientific literature regarding the most significant benefits of astaxanthin is discussed, with a particular focus on potential mechanisms of action responsible for its biological activities.

Anti-Aging Activity and Modes of Action of Compounds from Natural Food Sources

Aging is a natural and inescapable phenomenon characterized by a progressive deterioration of physiological functions, leading to increased vulnerability to chronic diseases and death. With economic and medical development, the elderly population is gradually increasing, which poses a great burden to society, the economy and the medical field. Thus, healthy aging has now become a common aspiration among people over the world. Accumulating evidence indicates that substances that can mediate the deteriorated physiological processes are highly likely to have the potential to prolong lifespan and improve aging-associated diseases. Foods from natural sources are full of bioactive compounds, such as polysaccharides, polyphenols, carotenoids, sterols, terpenoids and vitamins. These bioactive compounds and their derivatives have been shown to be able to delay aging and/or improve aging-associated diseases, thereby prolonging lifespan, via regulation of various physiological processes. Here, we summarize the current understanding of the anti-aging activities of the compounds, polysaccharides, polyphenols, carotenoids, sterols, terpenoids and vitamins from natural food sources, and their modes of action in delaying aging and improving aging-associated diseases. This will certainly provide a reference for further research on the anti-aging effects of bioactive compounds from natural food sources.

Algal Carotenoids: Chemistry, Sources, and Application

Recently, the isolation and identification of various biologically active secondary metabolites from algae have been of scientific interest, with particular attention paid to carotenoids, widely distributed in various photosynthetic organisms, including algal species. Carotenoids are among the most important natural pigments, with many health-promoting effects. Since the number of scientific studies on the presence and profile of carotenoids in algae has increased exponentially along with the interest in their potential commercial applications, this review aimed to provide an overview of the current knowledge (from 2015) on carotenoids detected in different algal species (12 microalgae, 21 green algae, 26 brown algae, and 43 red algae) to facilitate the comparison of the results of different studies. In addition to the presence, content, and identification of total and individual carotenoids in various algae, the method of their extraction and the main extraction parameters were also highlighted.

Natural Astaxanthin Is a Green Antioxidant Able to Counteract Lipid Peroxidation and Ferroptotic Cell Death

Astaxanthin is a red orange xanthophyll carotenoid produced mainly by microalgae but which can also be chemically synthesized. As demonstrated by several studies, this lipophilic molecule is endowed with potent antioxidant properties and is able to modulate biological functions. Unlike synthetic astaxanthin, natural astaxanthin (NAst) is considered safe for human nutrition, and its production is considered eco-friendly. The antioxidant activity of astaxanthin depends on its bioavailability, which, in turn, is related to its hydrophobicity. In this study, we analyzed the water-solubility of NAst and assessed its protective effect against oxidative stress by means of different approaches using a neuroblastoma cell model. Moreover, due to its highly lipophilic nature, astaxanthin is particularly protective against lipid peroxidation; therefore, the role of NAst in counteracting ferroptosis was investigated. This recently discovered process of programmed cell death is indeed characterized by iron-dependent lipid peroxidation and seems to be linked to the onset and development of oxidative-stress-related diseases. The promising results of this study, together with the "green sources" from which astaxanthin could derive, suggest a potential role for NAst in the prevention and co-treatment of chronic degenerative diseases by means of a sustainable approach.

Pharmaceutical and nutraceutical potential of natural bioactive pigment: astaxanthin

Astaxanthin (3,3'-dihydroxy-β,β-carotene-4,4'-dione) is an orange-red, lipophilic keto-carotenoid pigment. It is majorly found in marine ecosystems particularly in aquatic animals such as salmon, shrimp, trout, krill, crayfish, and so on. It is also synthesized in microalgae Heamatococcus pluvialis, Chlorococcum, Chlorella zofingiensis, red yeast Phaffia rhodozyma and bacterium Paracoccus carotinifaciens. Some aquatic and terrestrial creatures regarded as a primary and secondary sources of the astaxanthin producing and accumulating it through their metabolic pathways. Astaxanthin is the powerful antioxidant, nutritional supplement as well as promising therapeutic compound, observed to have activities against different ravaging diseases and disorders. Researchers have reported remarkable bioactivities of astaxanthin against major non-communicable chronic diseases such as cardiovascular diseases, cancer, diabetes, neurodegenerative, and immune disorders. The current review discusses some structural aspects of astaxanthin. It further elaborates its multiple potencies such as antioxidant, anti-inflammatory, anti-proliferative, anti-cancer, anti-obese, anti-diabetic, anti-ageing, anti-TB, anti-viral, anti-COVID 19, neuro-protective, nephro-protective, and fertility-enhancing properties. These potencies make it a more precious entity in the preventions as well as treatments of prevalent systematic diseases and/or disorders. Also, the review is acknowledging and documenting its powerful bioactivities in relation with the pharmaceutical as well as nutraceutical applicability.

Growth Performance, Immune-Related and Antioxidant Genes Expression, and Gut Bacterial Abundance of Pacific White Leg Shrimp, Litopenaeus vannamei, Dietary Supplemented With Natural Astaxanthin

The current study examines the effect of dietary supplementation of ethanolic extract of Arthrospira platensis NIOF17/003, which is mainly natural astaxanthins (97.50%), on the growth performance, feed utilization, bacterial abundance, and immune-related and antioxidant gene expressions of the Pacific white leg shrimp, Litopenaeus vannamei. A total of 360 healthy L. vannamei postlarvae (0.19 ± 0.003 g) were divided into four groups (0, 2, 4, and 6 g natural astaxanthins/kg diet) each in three replicates, at an initial density of 30 PLs per tank (40 L capacity). The shrimp were fed the tested diets three times a day at a rate of 10% of their total body weight for 90 days. Diets supplemented with different astaxanthin levels significantly improved shrimp growth performance and feed conversion ratio compared to the control diet. No significant differences were observed in survival rates among all experimental groups. The immune-related genes (prophenoloxidase, lysozyme, beta-glucan binding protein, transglutaminase, and crustin) mRNA levels were significantly upregulated in groups fed with different concentrations of the natural astaxanthins in a dose-dependent manner. The prophenoloxidase gene is the highest immune-upregulated gene (14.71-fold change) in response to astaxanthin supplementation. The superoxide dismutase mRNA level was significantly increased with increasing dietary astaxanthin supplementation. In addition, increasing astaxanthin supplementation levels significantly reduced the count of heterotrophic bacteria and Vibrio spp. in the culture water and shrimp intestine. Overall, the current results concluded that diet supplementation with natural astaxanthin, extracted from Arthrospira platensis, enhanced the growth performance, immune response, and antioxidant status of L. vannamei.

Chemical manipulation of mitochondrial function affects metabolism of red carotenoids in a marine copepod (Tigriopus californicus)

The shared-pathway hypothesis offers a cellular explanation for the connection between ketocarotenoid pigmentation and individual quality. Under this hypothesis, ketocarotenoid metabolism shares cellular pathways with mitochondrial oxidative phosphorylation such that red carotenoid-based coloration is inextricably linked mitochondrial function. To test this hypothesis, we exposed Tigriopus californicus copepods to a mitochondrially targeted protonophore, 2,4-dinitrophenol (DNP), to induce proton leak in the inner mitochondrial membranes. We then measured whole-animal metabolic rate and ketocarotenoid accumulation. As observed in prior studies of vertebrates, we observed that DNP treatment of copepods significantly increased respiration and that DNP-treated copepods accumulated more ketocarotenoid than control animals. Moreover, we observed a relationship between ketocarotenoid concentration and metabolic rate, and this association was strongest in DNP-treated copepods. These data support the hypothesis that ketocarotenoid and mitochondrial metabolism are biochemically intertwined. Moreover, these results corroborate observations in vertebrates, perhaps suggesting a fundamental connection between ketocarotenoid pigmentation and mitochondrial function that should be explored further.

Astaxanthin from Crustaceans and Their Byproducts: A Bioactive Metabolite Candidate for Therapeutic Application

In recent years, the food, pharma, and cosmetic industries have shown considerable interest in bioactive molecules of marine origin that show high potential for application as nutraceuticals and therapeutic agents. Astaxanthin, a lipid-soluble and orange-reddish-colored carotenoid pigment, is one of the most investigated pigments. Natural astaxanthin is mainly produced from microalgae, and it shows much stronger antioxidant properties than its synthetic counterpart. This paper aims to summarize and discuss the important aspects and recent findings associated with the possible use of crustacean byproducts as a source of astaxanthin. In the last five years of research on the crustaceans and their byproducts as a source of natural astaxanthin, there are many new findings regarding the astaxanthin content in different species and new green extraction protocols for its extraction. However, there is a lack of information on the amounts of astaxanthin currently obtained from the byproducts as well as on the cost-effectiveness of the astaxanthin production from the byproducts. Improvement in these areas would most certainly contribute to the reduction of waste and reuse in the crustacean processing industry. Successful exploitation of byproducts for recovery of this valuable compound would have both environmental and social benefits. Finally, astaxanthin’s strong biological activity and prominent health benefits have been discussed in the paper.

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.

Evaluating the effects of different processing methods on the nutritional composition of shrimp and the antioxidant activity of shrimp powder

Shrimp is a prevalent food in the Arabian Gulf that is known for its good sensory properties and high nutritional value. The aim of the present work was to assess the effects of diverse processing methods on the nutritional composition of shrimp and the antioxidant activity of shrimp powder. Shrimp (Penaeus semisulcatus) flesh was treated using four processes (salting, frying, grilling, and boiling), following which its macronutrient content, fatty acid profile, vitamins and mineral contents were measured. Also, the antioxidant activity of all shrimp powder extracts was assessed using the 2, 2 diphenyl 1 picrylhydrazyl (DPPH), linoleic acid oxidation inhibition, and reducing power methods. The results revealed that the fresh and processed shrimp flesh had significant nutritional value and the fresh and treated shrimp powders have high antioxidant activity, but the cooking processes have significant effects on the nutritional value and antioxidant activity of shrimp flesh. These effects were greater significantly in grilled shrimp followed by boiled shrimp and then fried shrimp. It is concluded that the high nutritional value and antioxidant activity of shrimp flesh make it an important food for nutritional health promotion for the community.

DFT and Raman study of all-trans astaxanthin optical isomers

Astaxanthin (AST) is a xanthophyll carotenoid widely distributed in aquatic animals, which has many physiological functions such as antioxidant, anti-inflammatory, anti-hypertensive and anti-diabetic activities. AST has three optical isomers, including a pair of enantiomers (3S,3'S and 3R,3'R) and a meso form (3R,3'S). Different optical isomers have differences in a variety of physiological functions. Traditionally, High Performance Liquid Chromatography (HPLC) has been used to distinguish these isomers. In this work, it was found that Raman spectroscopy can be employed to distinguish the three optical isomers. The intensities of two Raman bands at 1190 and 1215 cm^-1 of three isomers are different. Density Functional Theory (DFT) calculations are performed to analyze the spectral differences. The mainly occupied conformers of these three optical isomers are speculated and identified.

Anti-inflammatory action of astaxanthin and its use in the treatment of various diseases

Astaxanthin (AST) is a red pigmented carotenoid with significant antioxidant, anti-inflammatory, anti-proliferative, and anti-apoptotic properties. In this study, we summarize the available literature on the anti-inflammatory efficacy of AST in various chronic and acute disorders, such as neurodegenerative, renal-, hepato-, skin- and eye-related diseases, as well as gastrointestinal disorders. In addition, we elaborated on therapeutic efficacy of AST and the role of several pathways, including PI3K/AKT, Nrf2, NF-κB, ERK1/2, JNK, p38 MAPK, and JAK-2/STAT-3 in mediating its effects. However, additional experimental and clinical studies should be performed to corroborate the anti-inflammatory effects and protective effects of AST against inflammatory diseases in humans. Nevertheless, this review suggests that AST with its demonstrated anti-inflammatory property may be a suitable candidate for drug design with novel technology.

Therapeutic potential of astaxanthin and superoxide dismutase in Alzheimer's disease

Oxidative stress, the imbalance of the antioxidant system, results in an accumulation of neurotoxic proteins in Alzheimer's disease (AD). The antioxidant system is composed of exogenous and endogenous antioxidants to maintain homeostasis. Superoxide dismutase (SOD) is an endogenous enzymatic antioxidant that converts superoxide ions to hydrogen peroxide in cells. SOD supplementation in mice prevented cognitive decline in stress-induced cells by reducing lipid peroxidation and maintaining neurogenesis in the hippocampus. Furthermore, SOD decreased expression of BACE1 while reducing plaque burden in the brain. Additionally, Astaxanthin (AST), a potent exogenous carotenoid, scavenges superoxide anion radicals. Mice treated with AST showed slower memory decline and decreased depositions of amyloid-beta (Aβ) and tau protein. Currently, the neuroprotective potential of these supplements has only been examined separately in studies. However, a single antioxidant cannot sufficiently resist oxidative damage to the brain, therefore, a combinatory approach is proposed as a relevant therapy for ameliorating pathological changes in AD.

Bioactive Compounds of Nutraceutical Value from Fishery and Aquaculture Discards

Seafood by-products, produced by a range of different organisms, such as fishes, shellfishes, squids, and bivalves, are usually discarded as wastes, despite their possible use for innovative formulations of functional foods. Considering that “wastes” of industrial processing represent up to 75% of the whole organisms, the loss of profit may be coupled with the loss of ecological sustainability, due to the scarce recycling of natural resources. Fish head, viscera, skin, bones, scales, as well as exoskeletons, pens, ink, and clam shells can be considered as useful wastes, in various weight percentages, according to the considered species and taxa. Besides several protein sources, still underexploited, the most interesting applications of fisheries and aquaculture by-products are foreseen in the biotechnological field. In fact, by-products obtained from marine sources may supply bioactive molecules, such as collagen, peptides, polyunsaturated fatty acids, antioxidant compounds, and chitin, as well as catalysts in biodiesel synthesis. In addition, those sources can be processed via chemical procedures, enzymatic and fermentation technologies, and chemical modifications, to obtain compounds with antioxidant, anti-microbial, anti-cancer, anti-hypertensive, anti-diabetic, and anti-coagulant effects. Here, we review the main discards from fishery and aquaculture practices and analyse several bioactive compounds isolated from seafood by-products. In particular, we focus on the possible valorisation of seafood and their by-products, which represent a source of biomolecules, useful for the sustainable production of high-value nutraceutical compounds in our circular economy era.

Unlocking the Health Potential of Microalgae as Sustainable Sources of Bioactive Compounds

Microalgae are known to produce a plethora of compounds derived from the primary and secondary metabolism. Different studies have shown that these compounds may have allelopathic, antimicrobial, and antipredator activities. In addition, in vitro and in vivo screenings have shown that several compounds have interesting bioactivities (such as antioxidant, anti-inflammatory, anticancer, and antimicrobial) for the possible prevention and treatment of human pathologies. Additionally, the enzymatic pathways responsible for the synthesis of these compounds, and the targets and mechanisms of their action have also been investigated for a few species. However, further research is necessary for their full exploitation and possible pharmaceutical and other industrial applications. Here, we review the current knowledge on the chemical characteristics, biological activities, mechanism of action, and the enzymes involved in the synthesis of microalgal metabolites with potential benefits for human health.

Astaxanthin and its Effects in Inflammatory Responses and Inflammation-Associated Diseases: Recent Advances and Future Directions

Astaxanthin is a natural lipid-soluble and red-orange carotenoid. Due to its strong antioxidant property, anti-inflammatory, anti-apoptotic, and immune modulation, astaxanthin has gained growing interest as a multi-target pharmacological agent against various diseases. In the current review, the anti-inflammation mechanisms of astaxanthin involved in targeting for inflammatory biomarkers and multiple signaling pathways, including PI3K/AKT, Nrf2, NF-κB, ERK1/2, JNK, p38 MAPK, and JAK-2/STAT-3, have been described. Furthermore, the applications of anti-inflammatory effects of astaxanthin in neurological diseases, diabetes, gastrointestinal diseases, hepatic and renal diseases, eye and skin disorders, are highlighted. In addition to the protective effects of astaxanthin in various chronic and acute diseases, we also summarize recent advances for the inconsistent roles of astaxanthin in infectious diseases, and give our view that the exact function of astaxanthin in response to different pathogen infection and the potential protective effects of astaxanthin in viral infectious diseases should be important research directions in the future.

Safety assessment of astaxanthin from Haematococcus pluvialis: Acute toxicity, genotoxicity, distribution and repeat-dose toxicity studies in gestation mice

Natural astaxanthin is the strongest antioxidant ever discovered, with many biological functions, and it is widely used in the fields of health food and biomedical research. In the present study, we aimed to investigate the plasma concentration, distribution and safety of astaxanthin from Haematococcus pluvialis in pregnant mice. In the acute studies, the oral LD₅₀ of astaxanthin was greater than 20 g/kg·bw. In mouse bone marrow micronucleus test, 10 g/kg·bw astaxanthin did not cause damage to chromosomes and mitotic apparatus of pregnant mice. After treatment with a single dose of 500 mg/kg·bw astaxanthin, the concentration of astaxanthin in plasma reached the maximum at 8 h (55.7 μg/L), which was completely metabolized after 48 h. In the repeat-dose toxicity test, 100, 250 and 500 mg/kg·bw astaxanthin showed no abnormalities in terms of body and organ weight as well as hematological and biochemical parameters in clinical observation throughout the pregnancy. During pregnancy, the liver accumulated the highest content of astaxanthin, while the eye exhibited the least. The results indicated that administration of astaxanthin from H. pluvialis throughout pregnancy had no adverse effect on mice.

Astaxanthin anticancer effects are mediated through multiple molecular mechanisms: A systematic review

During the latest decades, the interest on the effectiveness of natural compounds and their impact on human health constantly increased, especially on those demonstrating to be effective on cancer. Molecules coming from nature are currently used in chemotherapy like Taxol, Vincristine or Vinblastine, and several other natural substances have been showed to be active in reducing cancer cell progression and migration. Among them, astaxanthin, a xanthophyll red colored carotenoid, displayed different biological activities including, antinflammatory, antioxidant, proapoptotic, and anticancer effects. It can induce apoptosis through downregulation of antiapoptotic protein (Bcl-2, p-Bad, and survivin) expression and upregulation of proapoptotic ones (Bax/Bad and PARP). Thanks to these mechanisms, it can exert anticancer effects towards colorectal cancer, melanoma, or gastric carcinoma cell lines. Moreover, it possesses antiproliferative activity in many experimental models and enhances the effectiveness of conventional chemotherapic drugs on tumor cells underling its potential future use. This review provides an overview of the current knowledge on the anticancer potential of astaxanthin by modulating several molecular targets. While it has been clearly demonstrated its multitarget activity in the prevention and regression of malignant cells in in vitro or in preclinical investigations, further clinical studies are needed to assess its real potential as anticancer in humans.

A combined effect of Cavacurcumin, Eicosapentaenoic acid (Omega-3s), Astaxanthin and Gamma -linoleic acid (Omega-6) (CEAG) in healthy volunteers- a randomized, double-blind, placebo-controlled study

BACKGROUND

Inflammation plays a key role and is one of the early steps in the pathogenesis of endothelial function, thereby increasing the risk of hypertension (HTN), coronary artery disease (CAD), stroke and several other risk factors of cardiovascular disease (CVD). We assessed the efficacy for improving cardiovascular health (blood pressure, inflammation and endothelial reactivity) over a 4-week intervention period in healthy individuals.

METHODS

We performed a randomized, double-blinded, placebo-controlled, randomized clinical trial to investigate Curcumin, Eicosapentaenoic acid (EPA), Astaxanthin and Gamma -linoleic acid (GLA) (CEAG) supplements with 80 individuals (30 men and 50 women). The mean age of participants was 48.8 ± 16.0 years. Participants were enrolled and randomized to active or placebo and followed for 4 weeks. Paired and Independent T-tests were used to analyze the mean differences between and within groups.

RESULTS

The primary endpoints of the study were the effect on inflammatory markers (IL-6, CRP), endothelial function and blood pressure at 4 weeks. There was a significant reduction in mean SBP at 4 weeks in the CEAG group compared to placebo [mean ± SD 4.7 ± 6.8 (p = 0.002)]. Relative to placebo, active group showed a significant decrease in High sensitivity C Reactive Protein (hsCRP) (-0.49 ± 1.9 vs + 0.51 ± 2.5, p = 0.059) and blunted increase in IL-6 (+0.2 vs + 0.4 in placebo, p = 0.60).

CONCLUSION

Inflammatory markers were reduced or blunted by CEAG, with a robust increase in both EPA levels and the fatty acid index. Furthermore, systolic BP was reduced over 4 weeks with concurrent improvement in endothelial function. CLINICALTRIALS.

GOV ID

NCT03906825.

Thermal stability and oral absorbability of astaxanthin esters from Haematococcus pluvialis in Balb/c mice

BACKGROUND

Astaxanthin is used as a functional nutraceutical and pigment in many food products. It is mostly exists in the form of a fatty acid ester in nature. However, no detailed descriptions are available concerning the stability and oral absorbability of astaxanthin esters. In the present study, the thermal stability and absorbability of astaxanthin esters from Haematococcus pluvialis were evaluated in comparison with free-form astaxanthin.

RESULTS

The thermal stability of astaxanthin esters was found to be higher than that of free-form astaxantin. After gavage with astaxanthin esters, only free-form astaxanthin was detected in the digestive tract wall, blood plasma and liver, indicating that astaxanthin esters must be hydrolyzed to free-form astaxanthin in the gut before absorption. Furthermore, there was a considerable selective accumulation of different astaxanthin isomers in Balb/c mice, which selectivity decreased in the order: 13-cis > all-trans > 9-cis. Accumulated astaxanthin was mainly distributed in the heart, liver, spleen, muscle and adipose tissue, although significant differences between tissues were observed.

CONCLUSION

From the present study, it can be concluded that astaxanthin esters had a higher thermal stability and higher bioavailability than free-form astaxanthin. These results provide important evidence with respect to using astaxanthin esters as bioactive components to replace free-form astaxanthin in functional food products. © 2019 Society of Chemical Industry.

Maternal allocation of carotenoids increases tolerance to bacterial infection in brown trout

Life-history theory predicts that iteroparous females allocate their resources differently among different breeding seasons depending on their residual reproductive value. In iteroparous salmonids there is typically much variation in egg size, egg number, and in the compounds that females allocate to their clutch. These compounds include various carotenoids whose functions are not sufficiently understood yet. We sampled 37 female and 35 male brown trout from natural streams, collected their gametes for in vitro fertilizations, experimentally produced 185 families in 7 full-factorial breeding blocks, raised the developing embryos singly (n = 2960), and either sham-treated or infected them with Pseudomonas fluorescens. We used female redness (as a measure of carotenoids stored in the skin) and their allocation of carotenoids to clutches to infer maternal strategies. Astaxanthin contents largely determined egg colour. Neither egg weight nor female size was correlated with the content of this carotenoid. However, astaxanthin content was positively correlated with larval growth and with tolerance against P. fluorescens. There was a negative correlation between female skin redness and the carotenoid content of their eggs. Although higher astaxanthin contents in the eggs were associated with an improvement of early fitness-related traits, some females appeared not to maximally support their current offspring as revealed by the negative correlation between female red skin colouration and egg carotenoid content. This correlation was not explained by female size and supports the prediction of a maternal trade-off between current and future reproduction.

New horizons in the extraction of bioactive compounds using deep eutectic solvents: A review

With the rapid development of ionic liquid analogues, termed 'deep eutectic solvents' (DESs), and their application in a wide range of chemical and biochemical processes in the past decade, the extraction of bioactive compounds has attracted significant interest. Recently, numerous studies have explored the extraction of bioactive compounds using DESs from diverse groups of natural sources, including animal and plant sources. This review summarizes the-state-of-the-art effort dedicated to the application of DESs in the extraction of bioactive compounds. The aim of this review also was to introduce conventional and recently-developed extraction techniques, with emphasis on the use of DESs as potential extractants for various bioactive compounds, such as phenolic acid, flavonoids, tanshinone, keratin, tocols, terpenoids, carrageenans, xanthones, isoflavones, α-mangostin, genistin, apigenin, and others. In the near future, DESs are expected to be used extensively for the extraction of bioactive compounds from various sources.

Neuroprotective mechanisms of astaxanthin: a potential therapeutic role in preserving cognitive function in age and neurodegeneration

Astaxanthin (AXT) is a carotenoid with multiple health benefits. It is currently marketed as a health supplement and is well known for its antioxidant capacity. Recent evidence has emerged to suggest a broad range of biological activities. The interest in this compound has increased dramatically over the last few years and many studies are now applying this molecule across many disease models. Results from the current research are beginning to come together to suggest neuroprotective properties including anti-inflammatory, anti-apoptotic, and antioxidant effects, as well as the potential to promote or maintain neural plasticity. These emergent mechanisms of actions implicate AXT as a promising therapeutic agent for neurodegenerative disease. This review will examine and extrapolate from the recent literature to build support for the use of AXT in mitigating neuropathy in normal aging and neurodegenerative disease.

Stereoisomers of Astaxanthin Inhibit Human Colon Cancer Cell Growth by Inducing G2/M Cell Cycle Arrest and Apoptosis

Astaxanthin (AST) is a xanthophyll carotenoid with potential protective effects against carcinogenesis. Different stereoisomers of AST (ASTs) exist in a variety of food sources. Due to limited information on the bioactivities of ASTs, the present study investigated the inhibitory effects of ASTs on HCT116 and HT29 human colon cancer cells. ASTs investigated herein included 3S,3'S (S) from Haematococcus pluvialis, 3R,3'R (R) from Phaffia rhodozyma, and a statistical mixture (S: meso: R = 1:2:1) (M) from synthetic AST. Cell viability assay showed that ASTs all inhibited colon cancer cell growth in a time-dependent (24-72 h) and dose-dependent (4-16 μM) manner, and there was no significant difference among the IC₅₀ values of ASTs (p > 0.05). Flow cytometry analysis indicated that ASTs induced G2/M cell cycle arrest and cellular apoptosis in cancer cells. The cell cycle arrest caused by ASTs was associated with increases in the expression levels of p21^Cip1/Waf1, p27, and p53, as well as decreases in the levels of CDK4 and CDK6. Meanwhile, the apoptosis induced by ASTs was confirmed by activation of caspase-3 and PARP in the cancer cells. The results indicated that hydroxyl (OH) at C3 and C3' of terminal ring structure might not be the major factor that affects the anticancer activity of AST. This study revealed important information on the inhibitory effects of ASTs on human colon cancer cells, which provided a basis for using ASTs as chemopreventive agents for colon cancer.

Effect of dietary formic acid and astaxanthin on the survival and growth of Pacific white shrimp (Litopenaeus vannamei) and their resistance to Vibrio parahaemolyticus

A 90-day feeding trial was conducted to evaluate the effects of formic acid (FA) and astaxanthin (AX) on growth, survival, immune parameters, and tolerance to Vibrio infection in Pacific white shrimp. The study was divided into two experiments. In experiment 1, postlarvae-12 were randomly distributed into six groups and then fed four times daily with six experimental diets contained 0.3 % FA, 0.6 % FA, 50 ppm AX, 0.3 % FA + 50 ppm AX, 0.6 % FA + 50 ppm AX, or none of these supplements (control diet). After 60 days of the feeding trials, the body weight of all treatment groups was not significantly different from the control group, although shrimp fed formic acid had significantly lower body weight than shrimp fed 50 ppm AX. However, the 0.6 % FA + 50 ppm AX group had a significantly higher survival rate (82.33 ± 8.32 %) than the control group (64.33 ± 10.12 %). In experiment 2, Vibrio parahaemolyticus was added to each tank to obtain a final concentration of 10(4) colony-forming units/mL. Each treatment group received the aforementioned diets for another 30 days. At the end of this experiment, there was no difference in the weight gain among all experimental groups. However, the survival rate of shrimps whose diet included FA, AX, and their combination (in the range of 45.83-67.50 %) was significantly higher than the control group (20.00 ± 17.32 %). FA-fed shrimps also had significantly lower total intestinal bacteria and Vibrio spp. counts, while immune parameters [total hemocyte count (THC), phagocytosis activity, phenoloxidase (PO) activity, and superoxide dismutase (SOD) activity] of AX-fed groups were significantly improved compared with the other groups. In conclusion, FA, AX, and their combination are useful in shrimp aquaculture.

Characterization of Shrimp Oil from Pandalus borealis by High Performance Liquid Chromatography and High Resolution Mass Spectrometry

Northern shrimp (Pandalus borealis) oil, which is rich in omega-3 fatty acids, was recovered from the cooking water of shrimp processing facilities. The oil contains significant amounts of omega-3 fatty acids in triglyceride form, along with substantial long-chain monounsaturated fatty acids (MUFAs). It also features natural isomeric forms of astaxanthin, a nutritional carotenoid, which gives the oil a brilliant red color. As part of our efforts in developing value added products from waste streams of the seafood processing industry, we present in this paper a comprehensive characterization of the triacylglycerols (TAGs) and astaxanthin esters that predominate in the shrimp oil by using HPLC-HRMS and MS/MS, as well as ¹³C-NMR. This approach, in combination with FAME analysis, offers direct characterization of fatty acid molecules in their intact forms, including the distribution of regioisomers in TAGs. The information is important for the standardization and quality control, as well as for differentiation of composition features of shrimp oil, which could be sold as an ingredient in health supplements and functional foods.

Four different methods comparison for extraction of astaxanthin from green alga Haematococcus pluvialis

Haematococcus pluvialis is one of the potent organisms for production of astaxanthin. Up to now, no efficient method has been achieved due to its thick cell wall hindering solvent extraction of astaxanthin. In this study, four different methods, hydrochloric acid pretreatment followed by acetone extraction (HCl-ACE), hexane/isopropanol (6 : 4, v/v) mixture solvents extraction (HEX-IPA), methanol extraction followed by acetone extraction (MET-ACE, 2-step extraction), and soy-oil extraction, were intensively evaluated for extraction of astaxanthin from H. pluvialis. Results showed that HCl-ACE method could obtain the highest oil yield (33.3 ± 1.1%) and astaxanthin content (19.8 ± 1.1%). Quantitative NMR analysis provided the fatty acid chain profiles of total lipid extracts. In all cases, oleyl chains were predominant, and high amounts of polyunsaturated fatty acid chains were observed and the major fatty acid components were oleic acid (13–35%), linoleic acid (37–43%), linolenic acid (20–31%), and total saturated acid (17–28%). DPPH radical scavenging activity of extract obtained by HCl-ACE was 73.2 ± 1.0%, which is the highest amongst the four methods. The reducing power of extract obtained by four extraction methods was also examined. It was concluded that the proposed extraction method of HCl-ACE in this work allowed efficient astaxanthin extractability with high antioxidant properties.