Multivariate Analysis Reveals That Unsubstituted β-Ring and C8-Keto Structures Are Important Factors for Anti-Inflammatory Activity of Carotenoids

Preventive effect of siphonaxanthin, a carotenoid from green algae, against diabetic nephropathy and lipid metabolism insufficiency in skeletal muscle

Diabetic nephropathy is a complication of diabetes mellitus characterized by the gradual progression of renal insufficiency, resulting in renal failure. Approximately 15 % or more of patients with type 2 diabetes mellitus have diabetic nephropathy. Siphonaxanthin is a green algal carotenoid noted for its strong biological activities, including anti-obesity effects. In this study, we aimed to evaluate the preventive effects of siphonaxanthin on diabetic nephropathy using db/db mice as a type 2 diabetes mellitus and diabetic nephropathy model. Ingestion of AIN-93G containing 0.004 % w/w siphonaxanthin did not improve plasma creatinine and urine albumin levels but significantly mitigated renal morphological changes in diabetic mice. Moreover, siphonaxanthin restored the decreased mRNA expression of fatty acid β-oxidation-related proteins in the skeletal muscle. These results indicate that siphonaxanthin can potentially ameliorate type 2 diabetes mellitus-induced kidney damage and lipid metabolism insufficiency in skeletal muscle. This study provides a possible daily nutraceutical solution for treating diabetic nephropathy and lipid metabolic abnormalities.

Recent progress in carotenoid encapsulation: Effects on storage stability, bioaccessibility and bioavailability for advanced innovative food applications

The incorporation of bioactive ingredients in food products has attracted considerable interest in recent years because of the numerous health benefits these compounds can offer to the human body. Carotenoids are a group of functional components with notable antioxidant and anti-inflammatory properties. Their addition to food products not only provides coloration but can also deliver certain bioactive effects, leading to both increased shelf life and beneficial health benefits. However, carotenoids are prone to oxidation, as they can be easily degraded from light or heat treatments. To address this, encapsulation has emerged as an effective method to protect carotenoids during their incorporation into foods as well as during storage. This review provides a comprehensive overview of the current state of the art regarding encapsulation methods utilized for carotenoids entrapment. The effect of various techniques- such as microemulsification, freeze- drying, spray- drying, and novel nanoencapsulation methods like electrospinning and formation of solid-liquid nanoparticles- are discussed with respect to their positive and negative impacts on carotenoid antioxidant activity, bioaccessibility, bioavailability and the shelf life of the final product. Depending on the type of carotenoid or its intended application, different methods could be employed, which could significantly enhance the overall biological activities of the final food product. This review critically presents the advantages and limitations of each method and highlights the potential health implications that nanoencapsulation techniques might pose before introducing new encapsulated products to the food market.

Dehydrometabolites of siphonaxanthin, a carotenoid from green algae, suppress toll-like receptor 1/2-induced inflammatory response more strongly than siphonaxanthin

Siphonaxanthin (3,19,3'-trihydroxy-7,8-dihydro-β,ε-caroten-8-one) is a carotenoid found in green algae that exhibits potent anti-inflammatory activities. We previously reported that ingested siphonaxanthin accumulates in various organs of mice; however, its metabolic conversion remains largely unknown. In this study, we isolated three siphonaxanthin dehydrometabolites and determined their chemical structures. Two of these metabolites were obtained using the postmitochondrial supernatant prepared from mouse liver, whereas the third was obtained using the postmitochondrial supernatant prepared from rat liver. The human liver S9 fraction also generated two metabolites: one was identical to one of the rat metabolites, and the other was identical to one of the mouse metabolites. 1H-NMR revealed that all three metabolites had one or two additional α,β-unsaturated carbonyl groups (compared with siphonaxanthin). We also evaluated their anti-inflammatory activities and found that these three metabolites suppressed toll-like receptor 1/2-mediated interferon regulatory factor (IRF) activation more potently than siphonaxanthin. Pharmacological inhibition studies revealed that activation of nuclear factor erythroid 2-related factor 2 (Nrf2) is crucial for the inhibition of IRF activation by these metabolites. The Nrf2-mediated decrease in the mRNA expression of the stimulator of interferon genes was determined to be one of the molecular mechanisms underlying this suppression. Thus, the hepatic metabolic conversion of siphonaxanthin generates an α,β-unsaturated carbonyl group, which boosts its IRF-inhibitory effect by activating Nrf2.

Advance on the effects of algal carotenoids on inflammatory signaling pathways

The development of inflammation has an indispensable importance in the self-protection of the human body. However, over-inflammation may damage human health, and inflammatory pathways and inflammasomes have a significant impact on the onset of inflammation. Therefore, how to constrain the development of inflammation through inflammatory pathways or inflammasomes becomes a hot research issue. Carotenoids are a natural pigment and an active substance in algae, with anti-inflammatory and antioxidant effects. Many studies have shown that carotenoids have inhibitory effects on the inflammatory pathways and inflammasomes. In this review, we discussed the mechanism of carotenoids targeting those important inflammatory pathways and their effects on common inflammasome NLRP3 and inflammation-related diseases from the perspective of several inflammatory pathways, including p38 MAPK, IL-6/JAK/STAT3, and PI3K, with a focus on the targets and targeting effects of carotenoids on different inflammatory signaling pathways, and at last proposed possible anti-inflammatory targets.

Carotenoid-derived norsesquiterpenoids and sesquiterpenoids from Tagetes erecta L

Tagetes erecta L. (marigold), a common landscaping flower widely cultivated in America, Africa, Asia and Europe, is the fundamental source of carotenoids (especially lutein) in food and pharmaceutical industry. Carotenoids are well-known to possess various healthy and beneficial biological activities such as eye protection, anti-aging, and anti-inflammatory. In our exploitation of carotenoid-derived products from T. erecta, nine previously undescribed compounds including seven megastigmane-type norsesquiterpenoids (1-7), one carotenoid-derived sesquiterpenoid (8), and one natural 3-hydroxyl-α-ionylideneacetic acid derivative (9), along with twelve known compounds (10-21), were afforded from the 95% ethanol extract of the petals of T. erecta. Their planar chemical structures and the absolute configurations were established by analysis of the extensive spectroscopic data including HRESI-MS, 1D/2D NMR and the simulation of ECD. Further, a plausible biosynthesis pathway for compounds 1-20 is proposed.

Intestinal Absorption and Anti-Inflammatory Effects of Siphonein, a Siphonaxanthin Fatty Acid Ester from Green Algae

Siphonein is a C19 acylated siphonaxanthin found in some edible green algae (e.g., Codium fragile and Caulerpa lentillifera). Although the content of siphonein in these green algae is similar to or higher than that of siphonaxanthin, studies of health-related biological activity of siphonein are much less than those of siphonaxanthin. Given the difference in the position of the acyl chain, one cannot infer intestinal absorption of siphonein from other general carotenoid fatty acid esters. In this study, we first investigated the intestinal absorption of siphonein using mouse and cell culture models. A small amount of siphonein was detected in the plasma of treated mice, and its concentration was higher than that of siphonaxanthin (i.e., the hydrolyzed product of ingested siphonein) from 1 to 6 h after administration. Pharmacological inhibition tests with differentiated Caco-2 cells showed that Nieman-Pick C1-like 1-mediated facilitated diffusion was involved in the cellular uptake of siphonein. These results indicate that, unlike general carotenoid fatty acid esters, siphonein can be absorbed without hydrolysis. We also evaluated the anti-inflammatory effect of siphonein in differentiated Caco-2 cells. Siphonein pretreatment modulated lipopolysaccharide-induced cellular lipidome alterations and suppressed mRNA expression of proinflammatory chemokines, CXCL8 protein release, and activation of NF-κB. This study provides new insights into the absorption processes of carotenoids and shows the anti-inflammatory effect of siphonein for the first time.

Dietary Protective Potential of Fucoxanthin as an Active Food Component on Neurological Disorders

The prevalence of neurodegenerative, cerebrovascular, and psychiatric diseases and other neurological disorders has increased dramatically worldwide. Fucoxanthin is an algal pigment with many biological functions, and there is rising evidence that fucoxanthin plays a preventive and therapeutic role in neurological disorders. This review focuses on the metabolism, bioavailability, and blood-brain barrier penetration of fucoxanthin. Furthermore, the neuroprotective potential of fucoxanthin in neurodegenerative diseases, cerebrovascular diseases, and psychiatric diseases as well as other neurological disorders such as epilepsy, neuropathic pain, and brain tumors by acting on multiple targets will be summarized. The multiple targets include regulating apoptosis, reducing oxidative stress, activating the autophagy pathway, inhibiting Aβ aggregation, improving dopamine secretion, reducing α-synuclein aggregation, attenuating neuroinflammation, modulating gut microbiota, and activating brain-derived neurotrophic factor, etc. Additionally, we look forward to brain-targeted oral transport systems due to the low bioavailability and blood-brain barrier permeability of fucoxanthin. We also propose exploring the systemic mechanisms of fucoxanthin metabolism and transport through the gut-brain process and envision new therapeutic targets for fucoxanthin to act on the central nervous system. Finally, we propose dietary fucoxanthin delivery interventions to achieve preventive effects on neurological disorders. This review provides a reference for the application of fucoxanthin in the neural field.

Anti-Inflammatory Effects of Marine Bioactive Compounds and Their Potential as Functional Food Ingredients in the Prevention and Treatment of Neuroinflammatory Disorders

Functional foods include enhanced, enriched, fortified, or whole foods that impart health benefits beyond their nutritional value, particularly when consumed as part of a varied diet on a regular basis at effective levels. Marine sources can serve as the sources of various healthy foods and numerous functional food ingredients with biological effects can be derived from these sources. Microalgae, macroalgae, crustaceans, fungi, bacteria fish, and fish by-products are the most common marine sources that can provide many potential functional food ingredients including phenolic compounds, proteins and peptides, and polysaccharides. Neuroinflammation is closely linked with the initiation and progression of various neurodegenerative diseases, including Alzheimer's disease, Huntington's disease, and Parkinson's disease. Activation of astrocytes and microglia is a defense mechanism of the brain to counter damaged tissues and detrimental pathogens, wherein their chronic activation triggers neuroinflammation that can further exacerbate or induce neurodegeneration. Currently, available therapeutic agents only provide symptomatic relief from these disorders and no therapies are available to stop or slow down the advancement of neurodegeneration. Thereffore, natural compounds that can exert a protective effect against these disorders have therapeutic potential. Numerous chemical compounds, including bioactive peptides, fatty acids, pigments, alkaloids, and polysaccharides, have already been isolated from marine sources that show anti-inflammatory properties, which can be effective in the treatment and prevention of neuroinflammatory disorders. The anti-inflammatory potential of marine-derived compounds as functional food ingredients in the prevention and treatment of neurological disorders is covered in this review.

Carotenoids from Marine Sources as a New Approach in Neuroplasticity Enhancement

An increasing number of people experience disorders related to the central nervous system (CNS). Thus, new forms of therapy, which may be helpful in repairing processes' enhancement and restoring declined brain functions, are constantly being sought. One of the most relevant physiological processes occurring in the brain for its entire life is neuroplasticity. It has tremendous significance concerning CNS disorders since neurological recovery mainly depends on restoring its structural and functional organization. The main factors contributing to nerve tissue damage are oxidative stress and inflammation. Hence, marine carotenoids, abundantly occurring in the aquatic environment, being potent antioxidant compounds, may play a pivotal role in nerve cell protection. Furthermore, recent results revealed another valuable characteristic of these compounds in CNS therapy. By inhibiting oxidative stress and neuroinflammation, carotenoids promote synaptogenesis and neurogenesis, consequently presenting neuroprotective activity. Therefore, this paper focuses on the carotenoids obtained from marine sources and their impact on neuroplasticity enhancement.