Astaxanthin: A mechanistic review on its biological activities and health benefits

Astaxanthin reduces TBPH-induced neurobehavioral deficits in mice by the ROS-ERK1/2-FOS pathway

The persistence of the novel brominated flame retardant, bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH), in the environment and its potential for bioaccumulation in living organisms, including humans, further exacerbate its health risks. Therefore, ongoing research is crucial for fully understanding the extent of TBPH's neurotoxicity and for developing effective mitigation strategies. This study aims to investigate the potential neurotoxicity of TBPH on mouse neurobehavior and to evaluate the protective effects of the natural antioxidant astaxanthin (AST) against TBPH-induced neurotoxicity. The results indicate that exposure to TBPH can lead to a decline in learning and memory abilities and abnormal behaviors in mice, which may be associated with oxidative stress responses and apoptosis in the hippocampus. TBPH may disrupt the normal function of hippocampal neurons by activating the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway. Mice exposed to TBPH treated with AST showed improved learning and memory abilities in the Morris water maze (MWM) and Step-down test (SDT). AST, through its antioxidant action, was able to significantly reduce the increase in reactive oxygen species (ROS) levels induced by TBPH, the increased expression of apoptosis markers, and the activation of the ERK1/2-FOS signaling pathway, alleviating TBPH-induced apoptosis in hippocampal neurons and improving neurobehavioral outcomes. These findings suggest that AST may alleviate the neurotoxicity of TBPH by modulating molecular events related to apoptosis and the ERK1/2-FOS signaling pathway. Thus, this study provides evidence for AST as a potential interventional strategy for the prevention or treatment of cognitive decline associated with environmental neurotoxicant exposure.

Defining the mechanisms behind the hepatoprotective properties of curcumin

As a critical cause of human dysfunctionality, hepatic failure leads to approximately two million deaths per year and is on the rise. Considering multiple inflammatory, oxidative, and apoptotic mechanisms behind hepatotoxicity, it urges the need for finding novel multi-targeting agents. Curcumin is a phenolic compound with anti-inflammatory, antioxidant, and anti-apoptotic roles. Curcumin possesses auspicious health benefits and protects against several diseases with exceptional safety and tolerability. This review focused on the hepatoprotective mechanisms of curcumin. The need to develop novel delivery systems of curcumin (e.g., nanoparticles, self-micro emulsifying, lipid-based colloids, solid lipid nanoparticles, cyclodextrin inclusion, phospholipid complexes, and nanoemulsions) is also considered.

Effects of dietary astaxanthin on immune status and lipid metabolism in gilthead seabream (Sparus aurata)

Astaxanthin (AX) is a carotenoid known to have one of the highest documented antioxidant capacities and has attracted considerable scientific and commercial interest. The incorporation of AX into aquaculture practices has been associated with improved pigmentation, modulation of the immune and endocrine systems, stress reduction, reproductive efficiency and general fish health. This study describes the effects of dietary AX (0, control, 20, 100 and 500 mg kg-1 AX per kg of diet) for 15 and 30 days on growth performance, immune and antioxidant status, histology and gene expression in gilthead seabream (Sparus aurata). Fish fed diets enriched with 500 mg kg-1 of AX for 15 days decreased in skin mucus peroxidase activity while at 30 days of trial, fish fed a diet supplemented with 20 mg kg-1 AX increased the peroxidase activity in serum. In addition, bactericidal activity against Vibrio harveyi increased in the skin mucus of fish fed any of the AX supplemented diets. Regarding antioxidant activities in the liver, catalase and glutathione reductase were decreased and increased, respectively, in fish fed a diet supplemented with 500 mg kg-1 of AX. Finally, although the expression of up to 21 inflammatory and lipid metabolism-related genes was analysed in visceral adipose tissue, only the expression of the interleukin 6 (il6) gene was up-regulated in fish fed a diet supplemented with 20 mg kg-1 of AX. The present results provide a detailed insight into the potent antioxidant properties of AX and its possible modulatory effects on the immune status and lipid metabolism of seabream, which may be of interest to the aquaculture sector.

Plant-derived bioactive compounds and their novel role in central nervous system disorder treatment via ATF4 targeting: A systematic literature review

Central nervous system (CNS) disorders exhibit exceedingly intricate pathogenic mechanisms. Pragmatic and effective solutions remain elusive, significantly compromising human life and health. Activating transcription factor 4 (ATF4) participates in the regulation of multiple pathophysiological processes, including CNS disorders. Considering the widespread involvement of ATF4 in the pathological process of CNS disorders, the targeted regulation of ATF4 by plant-derived bioactive compounds (PDBCs) may become a viable strategy for the treatment of CNS disorders. However, the regulatory relationship between PDBCs and ATF4 remains incompletely understood. Here, we aimed to comprehensively review the studies on PDBCs targeting ATF4 to ameliorate CNS disorders, thereby offering novel directions and insights for the treatment of CNS disorders. A computerized search was conducted on PubMed, Embase, Web of Science, and Google Scholar databases to identify preclinical experiments related to PDBCs targeting ATF4 for the treatment of CNS disorders. The search timeframe was from the inception of the databases to December 2023. Two assessors conducted searches using the keywords "ATF4," "Central Nervous System," "Neurological," "Alzheimer's disease," "Parkinson's Disease," "Stroke," "Spinal Cord Injury," "Glioblastoma," "Traumatic Brain Injury," and "Spinal Cord Injury." Overall, 31 studies were included, encompassing assessments of 27 PDBCs. Combining results from in vivo and in vitro studies, we observed that these PDBCs, via ATF4 modulation, prevent the deposition of amyloid-like fibers such as Aβ, tau, and α-synuclein. They regulate ERS, reduce the release of inflammatory factors, restore mitochondrial membrane integrity to prevent oxidative stress, regulate synaptic plasticity, modulate autophagy, and engage anti-apoptotic mechanisms. Consequently, they exert neuroprotective effects in CNS disorders. Numerous PDBCs targeting ATF4 have shown potential in facilitating the restoration of CNS functionality, thereby presenting expansive prospects for the treatment of such disorders. However, future endeavors necessitate high-quality, large-scale, and comprehensive preclinical and clinical studies to further validate this therapeutic potential.

Randomized clinical trial of astaxanthin supplement on serum inflammatory markers and ER stress-apoptosis gene expression in PBMCs of women with PCOS

Polycystic ovarian syndrome (PCOS) is related to pro-apoptotic and pro-inflammatory conditions generated by Endoplasmic reticulum (ER) stress. This study aimed to determine the effect of Astaxanthin (ASX), as carotenoid with potent antioxidant and anti-inflammatory properties, on serum inflammatory markers, apoptotic factors and ER stress-apoptotic genes in peripheral blood mononuclear cells (PBMCs) of women with PCOS. This randomized, double-blind clinical trial included 56 PCOS patients aged 18-40. For 8 weeks, subjects were randomly assigned to one of two groups: either 12 mg ASX (n = 28) or placebo (n = 28). Real-time PCR was used to quantify gene expression associated with ER stress-apoptosis in PCOS women's PBMCs. The levels of TNF-α, IL18, IL6 and CRP were determined by obtaining blood samples from all patients before and after the intervention using Enzyme-linked immunosorbent assay (ELISA). Also, the levels of active caspase-3 and caspase-8 were detected in the PBMC by ELISA kit. Furthermore, we evaluated the efficacy of ASX on disease symptoms. Following the 8-week intervention, ASX supplementation was able to reduce the expression of GRP78 (p = 0.051), CHOP (p = 0.008), XBP1 (p = 0.002), ATF4 (0.038), ATF6 (0.157) and DR5 (0.016) when compared to the placebo. However, this decrease was not statistically significant for ATF6 (p = 0.067) and marginally significant for GRP78 (p = 0.051). The levels of TNF-α (p = 0.009), IL-18 (p = 0.003), IL-6 (p = 0.013) and active caspase-3 (p = 0.012) were also statistically significant lower in the therapy group. However, there was no significant difference in CRP (p = 0.177) and caspase-8 (p = 0.491) levels between the treatment and control groups. In our study, ASX had no significant positive effect on BMI, hirsutism, hair loss and regularity of the menstrual cycle. It appears that ASX may benefit PCOS by changing the ER stress-apoptotic pathway and reducing serum inflammatory markers; however, additional research is required to determine this compound's potential relevance.

Advances in microbial astaxanthin production

This work explores astaxanthin (AXT), a valuable xanthophyll ketocarotenoid pigment with significant health benefits and diverse applications across various industries. It discusses the prevalence of synthetic AXT, and the development of natural-based alternatives derived from microorganisms such as microalgae, bacteria, and yeast. The chapter examines the potential of microbial AXT production, highlighting the advantages and challenges associated with natural AXT. Key microorganisms like Haematococcus pluvialis, Paracoccus carotinifaciens, and Phaffia rhodozyma are emphasized for their role in commercially producing this valuable ketocarotenoid. The narrative covers the complexities and opportunities in microbial AXT production, from cell structure implications to downstream processing strategies. Additionally, the chapter addresses current applications, commercialization trends, and market dynamics of natural microbial AXT, emphasizing the importance of cost-effective production, regulatory compliance, and technological advancements to reduce the market cost of the final product. As demand for natural microbial-based AXT rises, this chapter envisions a future where research, innovation, and collaboration drive sustainable and competitive microbial AXT production, fostering growth in this dynamic market.

Protective effect of astaxanthin on indomethacin-induced gastric ulcerations in mice

Gastric ulcer disease remains one of the common medical burdens affecting millions worldwide due to its prevalent risk factors with the chronic usage of non-steroidal anti-inflammatory drugs at the top, reportedly through the stimulation of oxidative stress and triggering of inflammatory and apoptotic cascades in the gastric mucosa. Astaxanthin, a dietary keto-carotenoid derived from marine organisms is gaining a wide interest as a nutraceutical for its pronounced antioxidant properties. Here, we aim to examine the potential modulatory role of astaxanthin on indomethacin-induced gastric ulceration in experimental mice. Twenty-four Swiss albino mice were randomly distributed into four groups: a control group, an indomethacin group, and two groups pre-treated with either omeprazole or astaxanthin. The gastric tissues were assessed using gross morphology, ulcer scoring, gastric juice acidity, as well as reduced glutathione (GSH) and malondialdehyde (MDA) levels. Histopathological examination and immunostaining for nuclear factor-kappa B (NF-κB) and caspase-3 levels were also employed. Indomethacin group tended to show a higher number of mucosal ulcerations relative to control and pre-treated groups. The indomethacin group also showed significantly lower GSH levels and higher MDA levels relative to control. Immunostaining of gastric tissue sections showed a higher reactivity to NF-κB and caspase-3 in indomethacin group. Astaxanthin pre-treatment significantly elevated gastric juice pH, normalized GSH levels, and lowered the indomethacin-induced elevations in MDA, NF-κB, and caspase-3 levels. These results indicate that astaxanthin exhibits a comparable protective effect to omeprazole, against indomethacin-induced gastric ulceration. This anti-ulcerogenic effect could be mediated through its antioxidant, anti-inflammatory, and anti-apoptotic modulatory activities.

Krill Oil for Knee Osteoarthritis: A Randomized Clinical Trial

Importance

Knee osteoarthritis is disabling, with few effective treatments. Preliminary evidence suggested that krill oil supplementation improved knee pain, but effects on knee osteoarthritis remain unclear.

Objective

To evaluate efficacy of krill oil supplementation, compared with placebo, on knee pain in people with knee osteoarthritis who have significant knee pain and effusion-synovitis.

Design, Setting, and Participants

Multicenter, randomized, double-blind, placebo-controlled clinical trial in 5 Australian cities. Participants with clinical knee osteoarthritis, significant knee pain, and effusion-synovitis on magnetic resonance imaging were enrolled from December 2016 to June 2019; final follow-up occurred on February 7, 2020.

Interventions

Participants were randomized to 2 g/d of krill oil (n = 130) or matching placebo (n = 132) for 24 weeks.

Main Outcomes and Measures

The primary outcome was change in knee pain as assessed by visual analog scale (range, 0-100; 0 indicating least pain; minimum clinically important improvement = 15) over 24 weeks.

Results

Of 262 participants randomized (mean age, 61.6 [SD, 9.6] years; 53% women), 222 (85%) completed the trial. Krill oil did not improve knee pain compared with placebo (mean change in VAS score, -19.9 [krill oil] vs -20.2 [placebo]; between-group mean difference, -0.3; 95% CI, -6.9 to 6.4) over 24 weeks. One or more adverse events was reported by 51% in the krill oil group (67/130) and by 54% in the placebo group (71/132). The most common adverse events were musculoskeletal and connective tissue disorders, which occurred 32 times in the krill oil group and 42 times in the placebo group, including knee pain (n = 10 with krill oil; n = 9 with placebo), lower extremity pain (n = 1 with krill oil; n = 5 with placebo), and hip pain (n = 3 with krill oil; n = 2 with placebo).

Conclusions and Relevance

Among people with knee osteoarthritis who have significant knee pain and effusion-synovitis on magnetic resonance imaging, 2 g/d of daily krill oil supplementation did not improve knee pain over 24 weeks compared with placebo. These findings do not support krill oil for treating knee pain in this population.

Trial Registration

Australian New Zealand Clinical Trials Registry Identifier: ACTRN12616000726459; Universal Trial Number: U1111-1181-7087.

The Role of Oral Supplementation for the Management of Age-Related Macular Degeneration: A Narrative Review

The majority of neurodegenerative eye disorders occur with aging and significantly impair quality of life. Age-related macular degeneration (AMD) is the third most common cause of visual impairment and blindness worldwide. One of the most important elements in the pathophysiology of neurodegenerative eye disease is certainly oxidative stress, with neuroinflammation and ocular ischemia which may also be significant factors. Antioxidants, either by food or oral supplementation, may be able to mitigate the deleterious effects of reactive oxygen species that build as a result of oxidative stress, ischemia, and inflammation. Over the past few decades, a number of research works examining the potential adjuvant impact of antioxidants in AMD have been published. In fact, there is not only more and more interest in already known molecules but also in new molecules that can help clinicians in the management of this complex multifactorial disease, such as astaxanthin and melatonin. However, while some studies showed encouraging outcomes, others were conflicting. In addition, more and more attention is also being paid to nutrition, considered a pivotal key point, especially to prevent AMD. For this reason, the purpose of this review is to analyze the main antioxidant molecules currently used as oral supplements for AMD treatment, as well as the role of diet and food intake in this ocular disease, to better understand how all these factors can improve the clinical management of AMD patients.

Astaxanthin Supplementation as a Potential Strategy for Enhancing Mitochondrial Adaptations in the Endurance Athlete: An Invited Review

Astaxanthin, a potent antioxidant found in marine organisms such as microalgae and krill, may offer ergogenic benefits to endurance athletes. Originally used in fish feed, astaxanthin has shown a greater ability to mitigate various reactive oxygen species and maintain the structural integrity of mitochondria compared to other exogenous antioxidants. More recent work has shown that astaxanthin may improve: (1) cycling time trial performance, (2) cardiorespiratory measures such as submaximal heart rate during running or cycling, (3) recovery from delayed-onset muscle soreness, and (4) endogenous antioxidant capacity such as whole blood glutathione within trained populations. In this review, the history of astaxanthin and its chemical structure are first outlined before briefly describing the various adaptations (e.g., mitochondrial biogenesis, enhanced endogenous antioxidant capacity, etc.) which take place specifically at the mitochondrial level as a result of chronic endurance training. The review then concludes with the potential additive effects that astaxanthin may offer in conjunction with endurance training for the endurance athlete and offers some suggested practical recommendations for athletes and coaches interested in supplementing with astaxanthin.

Astaxanthin reduces inflammation and promotes a chondrogenic phenotype by upregulating SIRT1 in osteoarthritis

OBJECTIVE

To investigate the effects of astaxanthin (AST) on mouse osteoarthritis (OA) and lipopolysaccharide (LPS)-induced ATDC5 cell damage and to explore whether SIRT1 protein plays a role.

METHODS

In this study, some mouse OA models were constructed by anterior cruciate ligament transection (ACLT). Imaging, molecular biology and histopathology methods were used to study the effect of AST administration on traumatic OA in mice. In addition, LPS was used to stimulate ATDC5 cells to mimic the inflammatory response of OA. The effects of AST on the cell activity, inflammatory cytokines, matrix metalloproteinases and collagen type II levels were studied by CCK8 activity assay, reverse transcription polymerase chain reaction and protein imprinting. The role of SIRT1 protein was also detected.

RESULTS

In the mouse OA model, the articular surface collapsed, the articular cartilage thickness and cartilage matrix protein abundance were significantly decreased, while the expression of inflammatory cytokines and matrix metalloproteinases was increased; but AST treatment reversed these effects. Meanwhile, AST pretreatment could partially reverse LPS-induced ATDC5 cell damage and upregulate SIRT1 expression, but this protective effect of AST was attenuated by concurrent administration of the SIRT1 inhibitor Ex527.

CONCLUSION

AST can protect against the early stages of OA by affecting SIRT1 signalling, suggesting that AST might be a potential therapeutic agent for OA treatment.

Naringenin: its chemistry and roles in neuroprotection

According to epidemiological research, as the population ages, neurological illnesses are becoming a bigger issue. Despite improvements in the treatment of these diseases, there are still widespread worries about how to find a long-lasting remedy. Several neurological diseases can be successfully treated with natural substances. As a result, current research has been concentrated on finding effective neuroprotective drugs with improved efficacy and fewer side effects. Naringenin is one potential treatment for neurodegenerative diseases. Many citrus fruits, tomatoes, bergamots, and other fruits are rich in naringenin, a flavonoid. This phytochemical is linked to a variety of biological functions. Naringenin has attracted a lot of interest for its ability to exhibit neuroprotection through several mechanisms. In the current article, we present evidence from the literature that naringenin reduces neurotoxicity and oxidative stress in brain tissues. Also, the literatures that are currently accessible shows that naringenin reduces neuroinflammation and other neurological anomalies. Additionally, we found several studies that touted naringenin as a promising anti-amyloidogenic, antidepressant, and neurotrophic treatment option. This review's major goal is to reflect on advancements in knowledge of the molecular processes that underlie naringenin's possible neuroprotective effects. Furthermore, this article also provides highlights of Naringenin with respect to its chemistry and pharmacokinetics.

Michael Acceptors as Anti-Cancer Compounds: Coincidence or Causality?

Michael acceptors represent a class of compounds with potential anti-cancer properties. They act by binding to nucleophilic sites in biological molecules, thereby disrupting cancer cell function and inducing cell death. This mode of action, as well as their ability to be modified and targeted, makes them a promising avenue for advancing cancer therapy. We are investigating the molecular mechanisms underlying Michael acceptors and their interactions with cancer cells, in particular their ability to interfere with cellular processes and induce apoptosis. The anti-cancer properties of Michael acceptors are not accidental but are due to their chemical structure and reactivity. The electrophilic nature of these compounds allows them to selectively target nucleophilic residues on disease-associated proteins, resulting in significant therapeutic benefits and minimal toxicity in various diseases. This opens up new perspectives for the development of more effective and precise cancer drugs. Nevertheless, further studies are essential to fully understand the impact of our discoveries and translate them into clinical practice.

Comparative transcriptome analysis reveals the redirection of metabolic flux from cell growth to astaxanthin biosynthesis in Yarrowia lipolytica

Engineering Yarrowia lipolytica to produce astaxanthin provides a promising route. Here, Y. lipolytica M2 producing a titer of 181 mg/L astaxanthin was isolated by iterative atmospheric and room-temperature plasma mutagenesis and diphenylamine-mediated screening. Interestingly, a negative correlation was observed between cell biomass and astaxanthin production. To reveal the underlying mechanism, RNA-seq analysis of transcriptional changes was performed in high producer M2 and reference strain M1, and a total of 1379 differentially expressed genes were obtained. Data analysis revealed that carbon flux was elevated through lipid metabolism, acetyl-CoA and mevalonate supply, but restrained through central carbon metabolism in strain M2. Moreover, upregulation of other pathways such as ATP-binding cassette transporter and thiamine pyrophosphate possibly provided more cofactors for carotenoid hydroxylase and relieved cell membrane stress caused by astaxanthin insertion. These results suggest that balancing cell growth and astaxanthin production may be important to promote efficient biosynthesis of astaxanthin in Y. lipolytica.

Advances in encapsulation systems of Antarctic krill oil: From extraction to encapsulation, and future direction

Antarctic krill oil (AKO) is highly sought after by consumers and the food industry due to its richness in a variety of nutrients and physiological activities. However, current extraction methods are not sufficient to better extract AKO and its nutrients, and AKO is susceptible to lipid oxidation during processing and storage, leading to nutrient loss and the formation of off-flavors and toxic compounds. The development of various extraction methods and encapsulation systems for AKO to improve oil yield, nutritional value, antioxidant capacity, and bioavailability has become a research hotspot. This review summarizes the research progress of AKO from extraction to encapsulation system construction. The AKO extraction mechanism, technical parameters, oil yield and composition of solvent extraction, aqueous enzymatic extraction, supercritical/subcritical extraction, and three-liquid-phase salting-out extraction system are described in detail. The principles, choice of emulsifier/wall materials, preparation methods, advantages and disadvantages of four common encapsulation systems for AKO, namely micro/nanoemulsions, microcapsules, liposomes and nanostructured lipid carriers, are summarized. These four encapsulation systems are characterized by high encapsulation efficiency, low production cost, high bioavailability and high antioxidant capacity. Depending on the unique advantages and conditions of different encapsulation methods, as well as consumer demand for health and nutrition, different products can be developed. However, existing AKO encapsulation systems lack relevant studies on digestive absorption and targeted release, and the single product category of commercially available products limits consumer choice. In conjunction with clinical studies of AKO encapsulation systems, the development of encapsulation systems for special populations should be a future research direction.

Preparation and characterization of astaxanthin-loaded microcapsules stabilized by lecithin-chitosan-alginate interfaces with layer-by-layer assembly method

Astaxanthin is a kind of keto-carotenes with various health benefits. However, its solubility and chemical stability are poor, which leads to low bio-availability. Microcapsules have been reported to improve the solubility, chemical stability, and bio-availability of lipophilic bioactives. Freeze-dried astaxanthin-loaded microcapsules were prepared by layer-by-layer assembly of tertiary emulsions with maltodextrin as the filling matrix. Tertiary emulsions were fabricated by performing chitosan and sodium alginate electrostatic deposition onto soybean lecithin stabilized emulsions. 0.9 wt% of chitosan solution, 0.3 wt% of sodium alginate solution and 20 wt% of maltodextrin were optimized as the suitable concentrations. The prepared microcapsules were powders with irregular blocky structures. The astaxanthin loading was 0.56 ± 0.05 % and the encapsulation efficiency was >90 %. A slow release of astaxanthin could be observed in microcapsules promoted by the modulating of chitosan, alginate and maltodextrin. In vitro simulated digestion displayed that the microcapsules increased the bio-accessibility of astaxanthin to 69 ± 1 %. Chitosan, alginate and maltodextrin can control the digestion of microcapsules. The coating of chitosan and sodium alginate, and the filling of maltodextrin in microcapsules improved the chemical stability of astaxanthin. The constructed microcapsules were valuable to enrich scientific knowledge about improving the application of functional ingredients.

Pretreatment with Liposome-Encapsulated Shrimp Shell Extract Attenuated Neuronal Damage and Death in Aβ1-42-Induced Memory Deficits in Rats

The accumulation of amyloid-beta (Aβ) peptides is a crucial factor in the neuronal degeneration of Alzheimer's disease (AD). The current study investigated the underlying neuroprotective mechanisms of shrimp shell extract (SSE) and liposome-encapsulated SSE (SSE/L) against Aβ1-42-induced neuronal damage and death in rats. Intracerebroventricular infusion of Aβ1-42 effectively induced memory decline, as observed in a reduction of the rat's discriminating ability in the novel object recognition and novel object location tasks. Oral pretreatment with 100 mg/kg of SSE demonstrated no preventive effect on the memory decline induced by Aβ1-42 infusion. However, treatment with SSE/L 100 mg/kg BW effectively attenuated memory deficits in both behavioral assessments following two and four weeks after Aβ1-42 infusion. Moreover, SSE/L exerted neuroprotective effects by reducing lipid peroxidation and increasing Nrf2/HO-1 expression. There was a significant decrease in Iba1 and GFAP (biomarkers of microglia and astrocyte activity, respectively), as well as a decrease in the levels of NF-κB expression and the inflammatory cytokines TNF-α and IL-6 in the cortical and hippocampal tissues. Treatment with SSE/L also reduced the pro-apoptotic proteins Bax and cleaved caspase-3 while raising the anti-apoptotic protein Bcl2. In addition, the beneficial effects of SSE/L were along with the effects of a positive control commercial astaxanthin (AST). The findings of this study indicated that SSE/L provided neuroprotective effects on Aβ1-42-induced AD rats by ameliorating oxidative stress, neuroinflammation and apoptotic cell death. Therefore, SSE/L might be employed to prevent and mitigate Aβ accumulation-induced neurotoxicity in AD.

Digestive characteristics of astaxanthin oil in water emulsion stabilized by a casein-caffeic acid-glucose ternary conjugate

To overcome the barrier of poor oral bioavailability of astaxanthin, a stable oil-in-water emulsion was constructed using casein-caffeic acid-glucose ternary conjugates (CSC) to deliver astaxanthin, and its gastrointestinal behavior was evaluated in vitro with sodium caseinate (CSN) as a control. Results showed that, CSC-stabilized emulsion shower better resistance to the adverse conditions of the gastric environment than CSN-stabilized emulsion, and exhibited lower average particle size and aggregation (4972.33 nm, -5.93 mv) after simulated gastric digestion. Besides, after simulated intestinal digestion, the reducing capacity and astaxanthin transfer efficiency of CSC emulsion into the micellar phase were 686.74 μmol Trolox/100 mL and 26.2 %, which were 2.6 and 4.05-fold higher than that of CSN emulsion. The above results suggest that CSC can be used for better delivery of astaxanthin, which could be useful in designing foods such as functional beverages, pharmaceuticals and nutritional supplements for delivery of lipophilic bioactives.

Nrf2 Plays a Key Role in Erythropoiesis during Aging

Aging is characterized by increased oxidation and reduced efficiency of cytoprotective mechanisms. Nuclear factor erythroid-2-related factor (Nrf2) is a key transcription factor, controlling the expression of multiple antioxidant proteins. Here, we show that Nrf2-/- mice displayed an age-dependent anemia, due to the combined contributions of reduced red cell lifespan and ineffective erythropoiesis, suggesting a role of Nrf2 in erythroid biology during aging. Mechanistically, we found that the expression of antioxidants during aging is mediated by activation of Nrf2 function by peroxiredoxin-2. The absence of Nrf2 resulted in persistent oxidation and overactivation of adaptive systems such as the unfolded protein response (UPR) system and autophagy in Nrf2-/- mouse erythroblasts. As Nrf2 is involved in the expression of autophagy-related proteins such as autophagy-related protein (Atg) 4-5 and p62, we found impairment of late phase of autophagy in Nrf2-/- mouse erythroblasts. The overactivation of the UPR system and impaired autophagy drove apoptosis of Nrf2-/- mouse erythroblasts via caspase-3 activation. As a proof of concept for the role of oxidation, we treated Nrf2-/- mice with astaxanthin, an antioxidant, in the form of poly (lactic-co-glycolic acid) (PLGA)-loaded nanoparticles (ATS-NPs) to improve its bioavailability. ATS-NPs ameliorated the age-dependent anemia and decreased ineffective erythropoiesis in Nrf2-/- mice. In summary, we propose that Nrf2 plays a key role in limiting age-related oxidation, ensuring erythroid maturation and growth during aging.

Astaxanthin Inhibits STING Carbonylation and Enhances Antiviral Responses

STING-mediated DNA sensing pathway plays a crucial role in the innate antiviral immune responses. Clarifying its regulatory mechanism and searching STING agonists has potential clinical implications. Although multiple STING agonists have been developed to target cancer, there are few for the treatment of infectious diseases. Astaxanthin, a natural and powerful antioxidant, serves many biological functions and as a potential candidate drug for many diseases. However, how astaxanthin combats viruses and whether astaxanthin regulates the cyclic GMP-AMP synthase-STING pathway remains unclear. In this study, we showed that astaxanthin markedly inhibited HSV-1-induced lipid peroxidation and inflammatory responses and enhanced the induction of type I IFN in C57BL/6J mice and mouse primary peritoneal macrophages. Mechanistically, astaxanthin inhibited HSV-1 infection and oxidative stress-induced STING carbonylation and consequently promoted STING translocation to the Golgi apparatus and oligomerization, which activated STING-dependent host defenses. Thus, our study reveals that astaxanthin displays a strong antiviral activity by targeting STING, suggesting that astaxanthin might be a promising STING agonist and a therapeutic target for viral infectious diseases.

Recent advances in the potential effects of natural products from traditional Chinese medicine against respiratory diseases targeting ferroptosis

Respiratory diseases, marked by structural changes in the airways and lung tissues, can lead to reduced respiratory function and, in severe cases, respiratory failure. The side effects of current treatments, such as hormone therapy, drugs, and radiotherapy, highlight the need for new therapeutic strategies. Traditional Chinese Medicine (TCM) offers a promising alternative, leveraging its ability to target multiple pathways and mechanisms. Active compounds from Chinese herbs and other natural sources exhibit anti-inflammatory, antioxidant, antitumor, and immunomodulatory effects, making them valuable in preventing and treating respiratory conditions. Ferroptosis, a unique form of programmed cell death (PCD) distinct from apoptosis, necrosis, and others, has emerged as a key area of interest. However, comprehensive reviews on how natural products influence ferroptosis in respiratory diseases are lacking. This review will explore the therapeutic potential and mechanisms of natural products from TCM in modulating ferroptosis for respiratory diseases like acute lung injury (ALI), asthma, pulmonary fibrosis (PF), chronic obstructive pulmonary disease (COPD), lung ischemia-reperfusion injury (LIRI), pulmonary hypertension (PH), and lung cancer, aiming to provide new insights for research and clinical application in TCM for respiratory health.

Orally administered dual-targeted astaxanthin nanoparticles as novel dietary supplements for alleviating hepatocyte oxidative stress

The enhancement of bioavailability of food bioactive compounds as dietary supplements can be achieved through the development of targeted delivery systems. This study aimed to develop a novel dual-targeted delivery system for hepatocytes and mitochondria using phacoemulsification self-assembly. The delivery systems were engineered by modifying whey protein isolate (WPI) with galactose oligosaccharide (GOS) and triphenylphosphonium (TPP) to improve AXT transport to the liver and promote hepatic well-being. The dual-targeted nanoparticles (AXT@TPP-WPI-GOS) significantly reduced reactive oxygen species in in vitro experiments, thereby slowing down apoptosis. The AXT@TPP-WPI-GOS exhibited a prominent mitochondrial targeting capacity with a Pearson correlation coefficient of 0.76 at 4 h. In vivo pharmacokinetic experiments revealed that AXT@TPP-WPI-GOS could enhance AXT utilization by 28.18 ± 11.69%. Fluorescence imaging in mice demonstrated significantly higher levels of AXT@TPP-WPI-GOS accumulation in the liver compared to that of free AXT. Therefore, these nanoparticles hold promising applications in nutrient fortification, improving the bioavailability of AXT and supporting hepatic well-being.

Astaxanthin and meclizine extend lifespan in UM-HET3 male mice; fisetin, SG1002 (hydrogen sulfide donor), dimethyl fumarate, mycophenolic acid, and 4-phenylbutyrate do not significantly affect lifespan in either sex at the doses and schedules used

In genetically heterogeneous (UM-HET3) mice produced by the CByB6F1 × C3D2F1 cross, the Nrf2 activator astaxanthin (Asta) extended the median male lifespan by 12% (p = 0.003, log-rank test), while meclizine (Mec), an mTORC1 inhibitor, extended the male lifespan by 8% (p = 0.03). Asta was fed at 1840 ± 520 (9) ppm and Mec at 544 ± 48 (9) ppm, stated as mean ± SE (n) of independent diet preparations. Both were started at 12 months of age. The 90th percentile lifespan for both treatments was extended in absolute value by 6% in males, but neither was significant by the Wang-Allison test. Five other new agents were also tested as follows: fisetin, SG1002 (hydrogen sulfide donor), dimethyl fumarate, mycophenolic acid, and 4-phenylbutyrate. None of these increased lifespan significantly at the dose and method of administration tested in either sex. Amounts of dimethyl fumarate in the diet averaged 35% of the target dose, which may explain the absence of lifespan effects. Body weight was not significantly affected in males by any of the test agents. Late life weights were lower in females fed Asta and Mec, but lifespan was not significantly affected in these females. The male-specific lifespan benefits from Asta and Mec may provide insights into sex-specific aspects of aging.

Effects of dietary astaxanthin on growth performance, muscle composition, non-specific immunity, gene expression, and ammonia resistance of juvenile ivory shell (Babylonia areolate)

Astaxanthin is one of the important immunopotentators in aquaculture. However, little is known about the physiological changes and stress resistance effects of astaxanthin in marine gastropods. In this study, the effects of different astaxanthin concentrations (0, 25, 50, 75, and 100 mg/kg) on the growth, muscle composition, immune function, and resistance to ammonia stress in Babylonia areolata were investigated after three months of rearing. With the increase in astaxanthin content, the weight gain rate (WGR), specific growth rate (SGR), and survival rate (SR) of B. areolata showed an increasing trend. The 75-100 mg/kg group was significantly higher than the control group (0 mg/kg). There was no significant difference in the flesh shell ratio (FSR), viscerosomatic index (VSI), and soft tissue index (STI) of the experimental groups. Astaxanthin (75 mg/kg) significantly increased muscle crude protein content and increased hepatopancreas alkaline phosphatase (AKP), superoxide dismutase (SOD), and catalase (CAT) activity. Astaxanthin (75-100 mg/kg) significantly increased the total antioxidant capacity (T-AOC) and acid phosphatase (ACP) of the hepatopancreas and decreased the malondialdehyde (MDA) content of B. areolata. Astaxanthin significantly induced the expression levels of functional genes, such as SOD, Cu/ZnSOD, ferritin, ACP, and CYC in hepatopancreas and increased the survival rate of B. areolata under ammonia stress. The addition of 75-100 mg/kg astaxanthin to the feed improved the growth performance, muscle composition, immune function, and resistance to ammonia stress of B. areolata.

Possibility of nanostructured lipid carriers encapsulating astaxanthin from Haematococcus pluvialis to alleviate skin injury in radiotherapy

PURPOSE

The study aimed to protect patients' skin against ionizing irradiation during radiotherapy by using astaxanthin-encapsulated nanostructured lipid carriers (NLC-ATX).

MATERIALS AND METHODS

NLC-ATX was prepared by a combined method of hot homogenization and sonication. Cytotoxicity of NLC-ATX was evaluated by MTT colorimetric assay. The in vitro radioprotection of NLC-ATX for human fibroblast (HF) cells was investigated based on the level of ROS (reactive oxygen species), DNA damage, and cell death caused by X-irradiation. In addition, the in vivo radioprotection was evaluated based on the appearance and histological structure of the irradiated skin.

RESULTS

NLC-ATX was successfully prepared, with a mean particle size, zeta potential, and encapsulation efficiency of 114.4 nm, -34.1 mV, and 85.67%, respectively. Compared to the control, NLC-ATX, at an optimum ATX concentration under in vitro condition, reduced the amount of generated ROS and DNA damage of 81.6% and 41.6%, respectively, after X-radiation, resulting in a significant decrease in cell death by 62.69%. Under in vivo condition, after the 9th day of X-irradiation (equivalent to an accumulated dose of 14 Gy), the dorsal skin of five out of six NLC-ATX-untreated mice exhibited grade-1 skin damage, according to CTCAE v5.0, while treatment with NLC-ATX protected 6/6 mice from acute skin damage. Moreover, on the 28th day after the first X-irradiation, the histological images illustrated that NLC-ATX at an ATX concentration of 0.25 µg/mL exhibited good recovery of the skin, with barely any difference noted in the collagen fibers and sebaceous glands compared to normal skin.

CONCLUSIONS

NLC-ATX shows potential for application in skin protection against adverse effects of ionizing rays during radiotherapy.

Astaxanthin suppresses LPS-induced myocardial apoptosis by regulating PTP1B/JNK pathway in vitro

PURPOSE

Myocardial injury induced by sepsis can increase the patient's mortality, which is an important complication of sepsis. Myocardial apoptosis plays a key role in septic myocardial injury. Here we explored the potential mechanism of astaxanthin (ATX) inhibiting myocardial apoptosis induced by lipopolysaccharide (LPS) in vitro.

METHODS

The H9C2 cell experiment was conducted in three parts. In the first part, we set up three groups: control group, LPS group (10 µg/ml), a model of septic myocardial injury, and LPS + ATX (5, 10, 30 µM); In the second part, we set up four groups: control group, LPS group, LPS + PTP1B-IN-1, a protein tyrosine phosphatase 1B (PTP1B) inhibitor, and LPS + PTP1B-IN-1 + ATX; In the third part, we set up four groups: control group, LPS group, LPS + Anisomycin, a c-Jun N-terminal kinase (JNK) activator, and LPS + Anisomycin + ATX. We assessed H9C2 cell viability using the Cell Counting Kit-8 (CCK-8) assay. We observed cell apoptosis using flow cytometry analysis. We tested the mitochondrial membrane potential (ΔΨm) using JC-1 staining. To identify the molecular targets of ATX, Astaxanthin targets were predicted through the SwissTargetPrediction database. We verified the binding affinity of ATX and its targets using microscale thermophoresis (MST). We investigated the p-JNK expression using immunofluorescence staining. Finally, Western blot was used to evaluate PTP1B, JNK, p-JNK and the mitochondrial apoptosis-associated protein expression.

RESULTS

LPS inhibited H9C2 cell viability in a time-dependent manner and ATX treatment enhances H9C2 cell viability in a concentration dependent manner after LPS administration. ATX inhibited the LPS-induced apoptosis and loss of mitochondrial membrane potential in H9C2 cells. As predicted by the SwissTargetPrediction database, PTP1B was a potential target of ATX, and the interaction between ATX and PTP1B was further verified by MST. ATX attenuated the LPS-induced protein expression of PTP1B and p-JNK, regardless of PTP1B inhibition. Both immunofluorescence staining and Western blotting showed that ATX suppressed the LPS-induced p-JNK expression in H9C2 cells, regardless of Anisomycin administration. In addition, by adding Anisomycin to overexpress JNK, ATX inhibited the LPS-induced apoptosis, loss of mitochondrial membrane potential and upregulation of mitochondrial apoptosis-associated proteins in H9C2 cells via JNK signaling.

CONCLUSION

ATX inhibited LPS-induced mitochondrial apoptosis of H9C2 cells by PTP1B/JNK pathway and PTP1B was the target of ATX.

Skin Protection by Carotenoid Pigments

Sunlight, despite its benefits, can pose a threat to the skin, which is a natural protective barrier. Phototoxicity caused by overexposure, especially to ultraviolet radiation (UVR), results in burns, accelerates photoaging, and causes skin cancer formation. Natural substances of plant origin, i.e., polyphenols, flavonoids, and photosynthetic pigments, can protect the skin against the effects of radiation, acting not only as photoprotectors like natural filters but as antioxidant and anti-inflammatory remedies, alleviating the effects of photodamage to the skin. Plant-based formulations are gaining popularity as an attractive alternative to synthetic filters. Over the past 20 years, a large number of studies have been published to assess the photoprotective effects of natural plant products, primarily through their antioxidant, antimutagenic, and anti-immunosuppressive activities. This review selects the most important data on skin photodamage and photoprotective efficacy of selected plant carotenoid representatives from in vivo studies on animal models and humans, as well as in vitro experiments performed on fibroblast and keratinocyte cell lines. Recent research on carotenoids associated with lipid nanoparticles, nanoemulsions, liposomes, and micelles is reviewed. The focus was on collecting those nanomaterials that serve to improve the bioavailability and stability of carotenoids as natural antioxidants with photoprotective activity.

Bi-functional astaxanthin macromolecular nanocarriers to alleviate dextran sodium sulfate-induced inflammatory bowel disease

Dextran sulfate sodium is one of the important members in the field of polysaccharide biotechnology, which can induce inflammatory bowel disease (IBD) in the gastrointestinal tract. Nevertheless, the application of astaxanthin (AST) and epigallocatechin-3-gallate (EGCG), known for their pronounced antioxidant and anti-inflammatory properties, is encumbered by limited stability and bioavailability. To surmount this challenge, dual nutritional macromolecular nanoparticles were provided for alleviating IBD. The forementioned strategy entailed the utilization of EGCG as a wall material via the Mannich reaction, resulting in the creation of specialized nanocarriers capable of mitochondrial targeting and glutathione-responsive AST delivery. In vitro investigations, these nanocarriers demonstrated an enhanced propensity for mitochondrial accumulation, leading to proficient elimination of reactive oxygen species and preservation of optimal mitochondrial membrane potential about 1.5 times stronger than free AST and EGCG. Crucially, in vivo experiments showed that the colon length of IBD mice treated with these nanocarriers increased by 51.29 % and facilitated the polarization of M2 macrophages. Moreover, the assimilation of these nanocarriers exerted a favorable impact on the composition of gut microbiota. These findings underscore the immense potential of dual nutrition nanocarriers in contemporaneously delivering hydrophobic biological activators through oral absorption, thereby presenting a highly promising avenue for combating IBD.

Enhanced Z-Isomerization of Astaxanthin in Paracoccus carotinifaciens via Microwave Drying

The effects of microwave drying conditions of a Paracoccus carotinifaciens culture solution on astaxanthin Z-isomerization and degradation were investigated. The microwave drying significantly increase the ratio of astaxanthin Z-isomers, and the higher the microwave power and the longer the drying time, the higher the total Z-isomer ratio of astaxanthin, but such conditions also accelerated astaxanthin degradation. We found that the addition of powdered oils enhanced the Z-isomerization reaction. For example, when the P. carotinifaciens culture solution was dried at 1000 W power for 5 min without and with powdered rapeseed oil, total Z-isomer ratios of astaxanthin in resulting dried powder were 14.9 and 47.4%, respectively. Furthermore, the storage test of the dried P. carotinifaciens powder showed that astaxanthin Z- isomers were stable at 4℃ in a low-oxygen atmosphere. As astaxanthin Z-isomers have greater bioavailability and potentially exhibit superior biological activities than the all-E-isomer, the dried P. carotinifaciens powder obtained by the method of this study is expected to be used as a value-added astaxanthin source.

Astaxanthin from microalgae: A review on structure, biosynthesis, production strategies and application

Astaxanthin is a red-colored secondary metabolite with excellent antioxidant properties, typically finds application as foods, feed, cosmetics, nutraceuticals, and medications. Astaxanthin is usually produced synthetically using chemicals and costs less as compared to the natural astaxanthin obtained from fish, shrimps, and microorganisms. Over the decades, astaxanthin has been naturally synthesized from Haematococcus pluvialis in commercial scales and remains exceptional, attributed to its higher bioactive properties as compared to synthetic astaxanthin. However, the production cost of algal astaxanthin is still high due to several bottlenecks prevailing in the upstream and downstream processes. To that end, the present study intends to review the recent trends and advancements in astaxanthin production from microalgae. The structure of astaxanthin, sources, production strategies of microalgal astaxanthin, and factors influencing the synthesis of microalgal astaxanthin were discussed while detailing the pathway involved in astaxanthin biosynthesis. The study also discusses the relevant downstream process used in commercial scales and details the applications of astaxanthin in various health related issues.

Dietary Astaxanthin: A Promising Antioxidant and Anti-Inflammatory Agent for Brain Aging and Adult Neurogenesis

Decreased adult neurogenesis, or the gradual depletion of neural stem cells in adult neurogenic niches, is considered a hallmark of brain aging. This review provides a comprehensive overview of the intricate relationship between aging, adult neurogenesis, and the potential neuroregenerative properties of astaxanthin, a carotenoid principally extracted from the microalga Haematococcus pluvialis. The unique chemical structure of astaxanthin enables it to cross the blood-brain barrier and easily reach the brain, where it may positively influence adult neurogenesis. Astaxanthin can affect molecular pathways involved in the homeostasis, through the activation of FOXO3-related genetic pathways, growth, and regeneration of adult brain neurons, enhancing cell proliferation and the potency of stem cells in neural progenitor cells. Furthermore, astaxanthin appears to modulate neuroinflammation by suppressing the NF-κB pathway, reducing the production of pro-inflammatory cytokines, and limiting neuroinflammation associated with aging and chronic microglial activation. By modulating these pathways, along with its potent antioxidant properties, astaxanthin may contribute to the restoration of a healthy neurogenic microenvironment, thereby preserving the activity of neurogenic niches during both normal and pathological aging.

Characteristics of LED light-induced geometrical isomerization and degradation of astaxanthin and improvement of the color value and crystallinity of astaxanthin utilizing the photoisomerization

The effects of light-emitting diode (LED) irradiation characterized by different emission wavelengths on the E/Z-isomerization and degradation of astaxanthin were investigated. LED irradiation slightly promoted Z-isomerization of astaxanthin, whereas the all-E-isomerization was highly efficiently promoted at specific wavelengths, especially at 365 nm. Astaxanthin isomers did not degrade significantly when dissolved in ethanol and subjected to LED irradiation conditions for 300 min. However, significant degradation was achieved when ethyl acetate was used for dissolution, and the samples were irradiated at the wavelength of 405 nm. The addition of α-tocopherol suppressed the photodegradation of astaxanthin. LED irradiation significantly affected the physical properties of astaxanthin Z-isomers. Irradiation with 365, 405, and 470 nm LEDs enhanced the color value (redness) and crystallinity of the Z-isomers via an all-E-isomerization reaction. These findings can contribute to the development of technologies that can arbitrarily control the E/Z-isomer ratio and physical properties of astaxanthin.

Astaxanthin Supplementation Augments the Benefits of CrossFit Workouts on Semaphorin 3C and Other Adipokines in Males with Obesity

Regular physical activity and the use of nutritional supplements, including antioxidants, are recognized as efficacious approaches for the prevention and mitigation of obesity-related complications. This study investigated the effects of 12 weeks of CrossFit training combined with astaxanthin (ASX) supplementation on some plasma adipokines in males with obesity. Sixty-eight males with obesity (BMI: 33.6 ± 1.4 kg·m-2) were randomly assigned into four groups: the control group (CG; n = 11), ASX supplementation group (SG; n = 11), CrossFit group (TG; n = 11), and training plus supplement group (TSG; n = 11). Participants underwent 12 weeks of supplementation with ASX or placebo (20 mg/day capsule daily), CrossFit training, or a combination of both interventions. Plasma levels of semaphorin 3C (SEMA3C), apelin, chemerin, omentin1, visfatin, resistin, adiponectin, leptin, vaspin, and RBP4 were measured 72 h before the first training session and after the last training session. The plasma levels of all measured adipokines were significantly altered in SG, TG, and TSG groups (p < 0.05). The reduction of resistin was significantly higher in TSG than in SG (p < 0.05). The plasma levels of omentin1 were significantly higher in both training groups of TG and TSG than SG (p < 0.05), although such a meaningful difference was not observed between both training groups (p > 0.05). Significant differences were found in the reductions of plasma levels of vaspin, visfatin, apelin, RBP4, chemerin, and SEMA3C between the SG and TSG groups (p < 0.05). The study found that a 12-week intervention using ASX supplementation and CrossFit exercises resulted in significant improvements in several adipokines among male individuals with obesity. Notably, the combined approach of supplementation and training had the most pronounced results. The findings presented in this study indicate that the supplementation of ASX and participation in CrossFit exercise have the potential to be effective therapies in mitigating complications associated with obesity and enhancing metabolic health.

Comprehensive Update on Carotenoid Colorants from Plants and Microalgae: Challenges and Advances from Research Laboratories to Industry

The substitution of synthetic food dyes with natural colorants continues to be assiduously pursued. The current list of natural carotenoid colorants consists of plant-derived annatto (bixin and norbixin), paprika (capsanthin and capsorubin), saffron (crocin), tomato and gac fruit lycopene, marigold lutein, and red palm oil (α- and β-carotene), along with microalgal Dunaliella β-carotene and Haematococcus astaxanthin and fungal Blakeslea trispora β-carotene and lycopene. Potential microalgal sources are being sought, especially in relation to lutein, for which commercial plant sources are lacking. Research efforts, manifested in numerous reviews and research papers published in the last decade, have been directed to green extraction, microencapsulation/nanoencapsulation, and valorization of processing by-products. Extraction is shifting from conventional extraction with organic solvents to supercritical CO2 extraction and different types of assisted extraction. Initially intended for the stabilization of the highly degradable carotenoids, additional benefits of encapsulation have been demonstrated, especially the improvement of carotenoid solubility and bioavailability. Instead of searching for new higher plant sources, enormous effort has been directed to the utilization of by-products of the fruit and vegetable processing industry, with the application of biorefinery and circular economy concepts. Amidst enormous research activities, however, the gap between research and industrial implementation remains wide.

Treatment of Dry Eye Disease (DED) in Asia: Strategies for Short Tear Film Breakup Time-Type DED

Dry eye disease (DED) is a multifactorial disorder in which tear fluid homeostasis is lost, resulting in increased tear film osmolarity and ocular surface irritation. In Asia, the short tear film breakup time-type DED, which has become a global problem in recent years, is common. While the mainstay of DED treatment in the West is the suppression of inflammation, the first goal of treatment is the stabilization of the tear film in Asia. To date, artificial tears and steroid eye drops have been the main treatment for DED. However, artificial tears require frequent administration of eye drops and thus pose adherence problems, while steroids have problems with side-effects (cataracts, increased intraocular pressure). This review evaluates the new generation therapies in Asia based on what is known about them and demonstrates that they are more effective for DED than traditional therapies such as artificial tears and steroids. Based on considerations, it is proposed that the optimal treatment for the short tear film breakup time-type DED is the initial application of mucin-secretion-enhancing eye drops (long-acting diquafosol) and oral supplements; and if additional treatment is needed, cyclosporine eye drops and the adjunctive therapies presented in this review are added.

Biological interactions and attenuation of MPTP-induced toxicity in Drosophila melanogaster by Trans-astaxanthin

Trans-astaxanthin (TA) is a carotenoid with amphipathic chemical structure found in yeast, and aquatic organisms. It is known to possess both antioxidative and anti-inflammatory properties. This study was carried out to investigate the ameliorative action of TA on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced toxicity in Drosophila melanogaster (Fruit fly). The flies were orally treated with TA (2.5 mg/10 g diet) and/or MPTP (500 µM) for 5 days. Thereafter, we evaluated selected biomarkers of locomotor deficits (acetylcholinesterase (AChE) and negative geotaxis), oxidative stress (hydrogen peroxide (H2O2), protein carbonyls (PC)), antioxidants (total thiols (T-SH), non-protein thiols, glutathione-S-transferase (GST) and catalase), and inflammation (nitric oxide (nitrite/nitrate) in the flies. Furthermore, we investigated molecular docking analysis of TA against Kelch-like ECH-associated protein 1 (Keap1)) of Homo sapiens and D. melanogaster. The results indicated that TA increased MPTP-induced decreased activities of AChE, GST, and catalase, as well as levels of non-protein thiols and T-SH compared with MPTP-treated flies (p < 0.05). Furthermore, TA attenuated inflammation, and improved locomotor deficit in the flies. The molecular docking data showed that TA had docking scores for binding both the Human and Drosophila Keap1, nearly closer to or higher than the standard inhibitor. The attenuating effects of TA against MPTP-induced toxicity could arise from its antioxidative and anti-inflammatory properties as well as its chemical structure.

Astaxanthin ameliorates spinal cord edema and astrocyte activation via suppression of HMGB1/TLR4/NF-κB signaling pathway in a rat model of spinal cord injury

Spinal cord edema is a quick-onset phenomenon with long-term effects. This complication is associated with inflammatory responses, as well as poor motor function. No effective treatment has been developed against spinal edema, which urges the need to provide novel therapies. Astaxanthin (AST) is a fat-soluble carotenoid with anti-inflammatory effects and a promising candidate for treating neurological disorders. This study aimed to investigate the underlying mechanism of AST on the inhibition of spinal cord edema, astrocyte activation, and reduction of inflammatory responsesin a rat compression spinal cord injury (SCI) model. Male rats underwent laminectomy at thoracic 8-9, and the SCI model was induced using an aneurysm clip. After SCI, rats received dimethyl sulfoxide or AST via intrathecal injection. The effects of AST were examined on the motor function, spinal cord edema, integrity of blood-spinal cord barrier (BSCB), and expression of high mobility group box 1 (HMGB1), toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), glial fibrillary acidic protein (GFAP), and aquaporin-4 (AQP4), and matrix metallopeptidase- 9 (MMP-9) post-SCI. We showed that AST potentially improved the recovery of motor function and inhibited the spinal cord edema via maintaining the integrity of BSCB, reducing the expression of HMGB1, TLR4, and NF-κB, MMP-9 as well as downregulation of astrocyte activation (GFAP) and AQP4 expression. AST improves motor function and reduces edema and inflammatory responses in the spinal tissue. These effects are mediated by suppression of the HMGB1/TLR4/NF-κB signaling pathway, suppressing post-SCI astrocyte activation, and decreasing AQP4 and MMP-9 expression.

Stabilized Astaxanthin Nanoparticles Developed Using Flash Nanoprecipitation to Improve Oral Bioavailability and Hepatoprotective Effects

In this study, we developed stabilized astaxanthin (AX) nanoparticles (sNP/AX) to improve the physicochemical properties, oral bioavailability, and hepatoprotection of AX. A flash nanoprecipitation technique was used with a multi-inlet vortex mixer to prepare the sNP/AX. Vitamins E (VE) and C (VC) were used as co-stabilizers with poloxamer 407 as a stabilizer to inhibit the oxidative degradation of AX during sNP/AX formation and storage. VC stabilized AX in the aqueous phase during the preparation, whereas VE markedly improved the storage stability of sNP/AX, as evidenced by the AX contents remaining at 94 and 81% after 12 weeks of storage at 4 °C and 25 °C, respectively. The mean sNP/AX diameter was 215 nm, which resulted in higher AX release properties than those of crystalline AX. Rats, orally administered sNP/AX (33.2 mg AX/kg), exhibited higher systemic exposure to AX, whereas oral absorption in the crystalline AX group was negligible. In the rat hepatic injury model, oral pretreatment with sNP/AX (33.2 mg AX/kg) markedly attenuated hepatic damage, as shown by the histopathological analysis and reduced levels of plasma biomarkers for hepatic injury. These findings suggest that strategically including antioxidative additives in the sNP/AX has the potential to improve the physicochemical and nutraceutical properties of AX.

Astaxanthin nanoparticles ameliorate dextran sulfate sodium-induced colitis by alleviating oxidative stress, regulating intestinal flora, and protecting the intestinal barrier

This study aimed to develop a novel astaxanthin nanoparticle using gum arabic (GA) and whey protein powder enriched with milk fat globule membranes (MFGM-WPI) as carriers and to investigate its effect and alleviation mechanism on colitis in mice. We demonstrated that MFGM-GA-astaxanthin could improve the bioaccessibility of astaxanthin and cope with oxidative stress more effectively in a Caco-2 cell model. In vivo studies demonstrated that MFGM-GA-astaxanthin alleviated colitis symptoms and repaired intestinal barrier function by increasing the expression of mucin 2, occludin, and zonula occludens-1. This was attributed to the alleviating effect of MFGM-GA-astaxanthin on oxidative stress. Moreover, MFGM-GA-astaxanthin restored the abnormalities of flora caused by dextran sulfate sodium, including Lactobacillus, Bacteroides, Ruminococcus, and Shigella. This study provides a basis for the therapeutic effect of astaxanthin nanoparticles on colon diseases.

Astaxanthin attenuated the stress-induced intestinal motility disorder via altering the gut microbiota

Gut microbiota and short-chain fatty acids (SCFAs) are recognized as key factors in the pathophysiology of irritable bowel syndrome. Astaxanthin is a carotenoid with strong antioxidant and anti-inflammatory activities. In this study, we examined the effects of astaxanthin on gut microbiota-, SCFAs-, and corticotropin-releasing factor (CRH)-induced intestinal hypermotility. Male Wistar rats (n=12 per group) were fed a diet with or without 0. 02% (w/w) astaxanthin for four weeks and CRH or saline was administered intravenously. The number of fecal pellets was counted 2 h after injection. Then the rats were sacrificed, and the cecal content were collected 3 h after injection. The number of feces was significantly increased by CRH injection in the control group (2.0 vs. 6.5; p=0.028), but not in the astaxanthin group (1.0 vs. 2.2; p=0.229) (n=6 per group). The cecal microbiota in the astaxanthin group was significantly altered compared with that in the control group. The concentrations of acetic acid (81.1 μmol/g vs. 103.9 μmol/g; p=0.015) and butyric acid (13.4 μmol/g vs. 39.2 μmol/g; p<0.001) in the astaxanthin group were significantly lower than that in the control group (n=12 per group). Astaxanthin attenuates CRH-induced intestinal hypermotility and alters the composition of gut microbiota and SCFAs.

The potential modulation of gut microbiota and oxidative stress by dietary carotenoid pigments

Gut microbiota plays a crucial role in regulating the response to immune checkpoint therapy, therefore modulation of the microbiome with bioactive molecules like carotenoids might be a very effective strategy to reduce the risk of chronic diseases. This review highlights the bio-functional effect of carotenoids on Gut Microbiota modulation based on a bibliographic search of the different databases. The methodology given in the preferred reporting items for systematic reviews and meta-analyses (PRISMA) has been employed for developing this review using papers published over two decades considering keywords related to carotenoids and gut microbiota. Moreover, studies related to the health-promoting properties of carotenoids and their utilization in the modulation of gut microbiota have been presented. Results showed that there can be quantitative changes in intestinal bacteria as a function of the type of carotenoid. Due to the dependency on several factors, gut microbiota continues to be a broad and complex study subject. Carotenoids are promising in the modulation of Gut Microbiota, which favored the appearance of beneficial bacteria, resulting in the protection of villi and intestinal permeability. In conclusion, it can be stated that carotenoids may help to protect the integrity of the intestinal epithelium from pathogens and activate immune cells.

Ultrasonic-Assisted Extraction of Astaxanthin from Shrimp By-Products Using Vegetable Oils

BACKGROUND

The use of conventional astaxanthin extraction methods, typically involving organic solvents, leads to a heightened environmental impact. The aim of this study was to explore the potential use of environmentally friendly extraction solvents, such as vegetable oils, for recovering the shrimp by-product astaxanthin.

METHODS

Ultrasound-assisted extraction (UAE) in vegetable oils, including olive oil (OO), sunflower oil (SO), and flaxseed oil (FO), was employed to extract astaxanthin. The astaxanthin antioxidant activity was evaluated using an ABTS assay, and a mixture of gum Arabic and soy lecithin was used to form coacervates to produce astaxanthin encapsulation.

RESULTS

A by-product-vegetable oil ratio of 1:60, extraction time of 210 min, 60% amplitude of the extraction process, and the use of OO as the extracting medium resulted in an astaxanthin yield of 235 ± 4.07 μg astaxanthin/g by-products. The astaxanthin encapsulation efficiency on day 0 and astaxanthin recovery on day 1 were recorded at 66.6 ± 2.7% and 94.4 ± 4.6%, respectively.

CONCLUSIONS

The utilization of OO as an extraction solvent for astaxanthin from shrimp by-products in UAE represents a novel and promising approach to reducing the environmental impact of shrimp by-products. The effective astaxanthin encapsulation efficiency highlights its potential application in food industries.

Combined Donepezil with Astaxanthin via Nanostructured Lipid Carriers Effective Delivery to Brain for Alzheimer's Disease in Rat Model

Introduction

Donepezil (DPL), a specific acetylcholinesterase inhibitor, is used as a first-line treatment to improve cognitive deficits in Alzheimer's disease (AD) and it might have a disease modifying effect. Astaxanthin (AST) is a natural potent antioxidant with neuroprotective, anti-amyloidogenic, anti-apoptotic, and anti-inflammatory effects. This study aimed to prepare nanostructured lipid carriers (NLCs) co-loaded with donepezil and astaxanthin (DPL/AST-NLCs) and evaluate their in vivo efficacy in an AD-like rat model 30 days after daily intranasal administration.

Methods

DPL/AST-NLCs were prepared using a hot high-shear homogenization technique, in vitro examined for their physicochemical parameters and in vivo evaluated. AD induction in rats was performed by aluminum chloride. The cortex and hippocampus were isolated from the brain of rats for biochemical testing and histopathological examination.

Results

DPL/AST-NLCs showed z-average diameter 149.9 ± 3.21 nm, polydispersity index 0.224 ± 0.017, zeta potential -33.7 ± 4.71 mV, entrapment efficiency 81.25 ±1.98% (donepezil) and 93.85 ±1.75% (astaxanthin), in vitro sustained release of both donepezil and astaxanthin for 24 h, spherical morphology by transmission electron microscopy, and they were stable at 4-8 ± 2°C for six months. Differential scanning calorimetry revealed that donepezil and astaxanthin were molecularly dispersed in the NLC matrix in an amorphous state. The DPL/AST-NLC-treated rats showed significantly lower levels of nuclear factor-kappa B, malondialdehyde, β-site amyloid precursor protein cleaving enzyme-1, caspase-3, amyloid beta (Aβ1‑42), and acetylcholinesterase, and significantly higher levels of glutathione and acetylcholine in the cortex and hippocampus than the AD-like untreated rats and that treated with donepezil-NLCs. DPL/AST-NLCs showed significantly higher anti-amyloidogenic, antioxidant, anti-acetylcholinesterase, anti-inflammatory, and anti-apoptotic effects, resulting in significant improvement in the cortical and hippocampal histopathology.

Conclusion

Nose-to-brain delivery of DPL/AST-NLCs is a promising strategy for the management of AD.

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.

Nanotechnology-Based Topical Delivery of Natural Products for the Management of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic eczematous inflammatory disease that may arise from environmental, genetic, and immunological factors. Despite the efficacy of current treatment options such as corticosteroids, such approaches are mainly focused on symptom relief and may present certain undesirable side effects. In recent years, isolated natural compounds, oils, mixtures, and/or extracts have gained scientific attention because of their high efficiency and moderate to low toxicity. Despite their promising therapeutic effects, the applicability of such natural healthcare solutions is somewhat limited by their instability, poor solubility, and low bioavailability. Therefore, novel nanoformulation-based systems have been designed to overcome these limitations, thus enhancing the therapeutic potential, by promoting the capacity of these natural drugs to properly exert their action in AD-like skin lesions. To the best of our knowledge, this is the first literature review that has focused on summarizing recent nanoformulation-based solutions loaded with natural ingredients, specifically for the management of AD. We suggest that future studies should focus on robust clinical trials that may confirm the safety and effectiveness of such natural-based nanosystems, thus paving the way for more reliable AD treatments.

Astaxanthin improves fatty acid dysregulation in diabetes by controlling the AMPK-SIRT1 pathway

Due to the rising prevalence of metabolic disorders, including type 2 diabetes (T2DM), new prevention and treatment strategies are needed. The aim was to examine the effect of astaxanthin (AST) on the major regulatory metabolism pathway SIRT-MAPK and fatty acid (FA) profile of plasma in patients with T2DM. This clinical trial included 68 T2DM patients randomly assigned to receive 10 mg/day of oral AST (n = 34) or placebo (n = 33) for 12 weeks. The expression level of SIRT1, AMPK activity, and the level of fatty acids in the serum were examined. The results showed that AST could modify the serum levels of saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA), particularly that of Arachidonic acid, from 11.31±0.35 to 8.52±0.72 %. Also, AST increased the expression and activity levels of SIRT1 and AMPK, respectively. Pearson analysis also revealed a significant association between AMPK activity and Linoleic acid serum (LA) levels (~ -0.604, p~0.013). AST can modify the FA profile of plasma by inducing metabolizing cells to uptake them. Also, it can activate the SIRT-AMPK pathway related to metabolism regulation. See also Figure 1(Fig. 1).

Oral Microalgae-Nano Integrated System against Radiation-Induced Injury

The increasing applications of ionizing radiation in society raise the risk of radiation-induced intestinal and whole-body injury. Astaxanthin is a powerful antioxidant to reduce the reactive oxygen generated from radiation and the subsequent damage. However, the oral administration of astaxanthin remains challenging owing to its low solubility and poor bioavailability. Herein, we facilely construct an orally used microalgae-nano integrated system (SP@ASXnano) against radiation-induced intestinal and whole-body injury, combining natural microalgae Spirulina platensis (SP) with astaxanthin nanoparticles (ASXnano). SP and ASXnano show complementation in drug delivery to improve distribution in the intestine and blood. SP displays limited gastric drug loss, prolonged intestinal retention, constant ASXnano release, and progressive degradation. ASXnano improves drug solubility, gastric stability, cell uptake, and intestinal absorption. SP and ASXnano have synergy in many aspects such as anti-inflammation, microbiota protection, and fecal short-chain fatty acid up-regulation. In addition, the system is ensured with biosafety for long-term administration. The system organically combines the properties of microalgae and nanoparticles, which was expected to expand the medical application of SP as a versatile drug delivery platform.

In Vitro Evaluation of Skin-Related Physicochemical Properties and Biological Activities of Astaxanthin Isomers

Dietary astaxanthin exists predominantly as the all-E-isomer; however, certain amounts of the Z-isomers are universally present in the skin, whose roles remain largely unknown. The aim of this study was to investigate the effects of the astaxanthin E/Z-isomer ratio on skin-related physicochemical properties and biological activities using human dermal fibroblasts and B16 mouse melanoma cells. We revealed that astaxanthin enriched in Z-isomers (total Z-isomer ratio = 86.6%) exhibited greater UV-light-shielding ability and skin antiaging and skin-whitening activities, such as anti-elastase and anti-melanin formation activities, than the all-E-isomer-rich astaxanthin (total Z-isomer ratio = 3.3%). On the other hand, the all-E-isomer was superior to the Z-isomers in singlet oxygen scavenging/quenching activity, and the Z-isomers inhibited type I collagen release into the culture medium in a dose-dependent manner. Our findings help clarify the roles of astaxanthin Z-isomers in the skin and would help in the development of novel skin health-promoting food ingredients.

Astaxanthin protected against the adverse effects induced by diesel exhaust particulate matter via improving membrane stability and anti-oxidative property

Diesel exhaust particulate matter (DPM), which has been clarified as a Group I carcinogenic agent, is still challenging in its detoxification due to the complex composition and toxic mechanisms. Astaxanthin (AST) is a pleiotropic small biological molecule widely used in medical and healthcare with surprising effects and applications. The present study aimed to investigate the protective effects of AST on DPM-induced injury and the underlying mechanism. Our results indicated that AST significantly suppressed the generation of phosphorylated histone H2AX (γ-H2AX, marker of DNA damage) and inflammation caused by DPM both in vitro and in vivo. Mechanistically, AST prevented the endocytosis and intracellular accumulation of DPM via regulating the stability and fluidity of plasma membranes. Moreover, the oxidative stress elicited by DPM in cells could also be effectively inhibited by AST, together with protecting the structure and function of mitochondria. These investigations provided clear evidence that AST notably reduced DPM invasion and intracellular accumulation by modulating the membrane-endocytotic pathway, which eventually reduced intracellular oxidative stress caused by DPM. Our data might provide a novel clue for curing and treating the harmful effects of particulate matter.

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.