Hydrophilic Astaxanthin: PEGylated Astaxanthin Fights Diabetes by Enhancing the Solubility and Oral Absorbability

Enhancing the Stability, Solubility, and Antioxidant Activity of Cinchonine through Pharmaceutical Cocrystallization

PURPOSE

Cinchoninze hydrochloride solves the problem of the low solubility of cinchonine, but it is unstable and susceptible to deliquescence. In this study, we designed and prepared cinchonine cocrystal salts or cinchonine salts with better stability, solubility and antioxidant activity than cinchonine.

METHOD

We successfully synthesized and characterized three cinchonine salts, namely, cinchonine-fumaric acid, cinchonine-isoferulic acid, and cinchonine-malic acid. The high humidity (92.5% RH) and high temperature (60°C) tests were conducted to determine the physical stability and hygroscopicity of cinchonine hydrochloride, cinchonine and three cinchonine salts. And the ultraviolet spectrophotometry was conducted to determine the equilibrium solubility and intrinsic dissolution rate of cinchonine and salts. Moreover, the DPPH, ABTS, and FRAP assays determined the antioxidant activity of cinchonine and salts.

RESULT

Compared with cinchonine hydrochloride and cinchonine, all three cinchonine salts exhibited good physical stability over 15 days under high humidity (92.5% RH) and high temperature (60°C) conditions. While cinchonine and cinchonine hydrochloride are categorized as hygroscopic and deliquescent, respectively, three cinchonine salts are classified as slightly hygroscopic, meaning that they have a lower hygroscopicity than cinchonine and cinchonine hydrochloride. And three cinchonine salts had higher equilibrium solubility, faster intrinsic dissolution rates, and higher antioxidant activity in comparison to cinchonine. Moreover, they showed a "spring and parachute" pattern in the phosphate buffer (pH = 6.8).

CONCLUSION

Cocrystallization technology is a viable option for improving cinchonine's poor physicochemical qualities.

Prevention of Hypercholesterolemia with "Liposomes in Microspheres" Composite Carriers: A Promising Approach for Intestinal-Targeted Oral Delivery of Astaxanthin

Cardiovascular diseases are caused by hypercholesterolemia. Astaxanthin (AST) has been reported to exhibit antioxidant and anti-inflammatory properties. However, its bioavailability is poor because of low solubility and instability. In order to improve the bioavailability of AST, we developed an intestinal-responsive composite carrier termed as "liposomes in micropheres" incorporating N-succinyl-chitosan (NSC)-poly(ethylene glycol) (PEG) liposomes that functionalized by neonatal Fc receptors (FcRn) into hydrogels of sodium alginate (SA) and carboxymethyl chitosan (CMCS). In the AST NSC/HSA-PEG liposomes@SA/CMCS microspheres, the AST's encapsulation efficiency (EE) was 96.26% (w/w) and its loading capacity (LC) was 6.47% (w/w). AST NSC/HSA-PEG liposomes had stability in the gastric conditions and achieved long-term release of AST in intestinal conditions. Then, AST NSC/HSA-PEG liposomes@SA/CMCS bind to intestinal epithelial cell targets by the neonatal Fc receptor. In vitro permeation studies show that there was a 4-fold increase of AST NSC/HSA-PEG liposomes@SA/CMCS in AST permeation across the intestinal epithelium. Subsequent in vivo experiments demonstrated that the composite carrier exhibited a remarkable mucoadhesive capacity, allowing for extended intestinal retention of up to 12 h, and it displayed deep penetration through the mucus layer, efficiently entering the intestinal villi epithelial cells, and enhancing the absorption of AST and its bioavailability in vivo. And oral administration of AST NSC/HSA-PEG liposomes@SA/CMCS could effectively prevent hypercholesterolemia caused by a high-fat, high-cholesterol diet (HFHCD). These advancements highlight the potential of NSC/HSA-PEG liposomes@SA/CMCS composite carriers for targeted and oral uptake of hydrophobic bioactives.

The Effect of PEGylation on Drugs' Pharmacokinetic Parameters; from Absorption to Excretion

Until the drugs enter humans life, they may face problems in transportation, drug delivery, and metabolism. These problems can cause reducing drug's therapeutic effect and even increase its side effects. Together, these cases can reduce the patient's compliance with the treatment and complicate the treatment process. Much work has been done to solve or at least reduce these problems. For example, using different forms of a single drug molecule (like Citalopram and Escitalopram); slight changes in the drug's molecule like Meperidine and α-Prodine, and using carriers (like Tigerase®). PEGylation is a recently presented method that can use for many targets. Poly Ethylene Glycol or PEG is a polymer that can attach to drugs by using different methods and resulting sustained release, controlled metabolism, targeted delivery, and other cases. Although they will not necessarily lead to an increase in the effect of the drug, they will lead to the improvement of the treatment process in certain ways. In this article, the team of authors has tried to collect and carefully review the best cases based on the PEGylation of drugs that can help the readers of this article.

PEGylation of Chrysin Improves Its Water Solubility while Preserving the In Vitro Biological Activity

Chrysin is a natural flavonoid that despite having numerous biological properties, its therapeutic value is limited due to its very low solubility in aqueous media. In this work, chrysin was conjugated with methoxypolyethylene glycols (mPEGs) of different molecular weights (350, 500, 750, and 2000 g/mol), affording PEGylated chrysins with high yields and excellent purities. In all cases, an increase in the water solubility of the conjugates was observed, which was highest when 500 g/mol of mPEG was used in the PEGylation reaction. Furthermore, in aqueous solution, PEGylated chrysins formed aggregates of ellipsoid shape. Electrochemical studies showed that the redox properties were conserved after PEGylation. While in vitro antibacterial and antifungal studies probed that the intrinsic activity was conserved, in vitro antitumor activities against HepG2 (liver carcinoma cells) and PC3 (prostate cancer cell) showed that PEGylated chrysins retained the cytotoxic activity and the ability of induction of apoptosis for the evaluated human cancer cells.

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.

Lyoprotectant Formulation and Optimization of the J-Aggregates Astaxanthin/BSA/Chitosan Nanosuspension

Astaxanthin is a carotenoid with excellent antioxidant activity. However, this small lipid-soluble molecule is insoluble in water and has low stability. Although this situation can be improved when astaxanthin is prepared as a nanosuspension, the aqueous form is still not as convenient and safe as the dry powder form for storage, transport, and use. The lyophilization process provides better protection for thermosensitive materials, but this leads to collapse and agglomeration between nanoparticles. To improve this situation, appropriate lyophilization protectants are needed to offer support between the nanoparticles, such as sugars, amino acids, and hydroxy alcohols. The purpose of this work is to screen lyophilization protectants by single-factor experiments and response surface optimization experiments and then explore the optimal ratio of compound lyophilization protectants, and finally, make excellent astaxanthin/BSA/chitosan nanosuspension (ABC-NPs) lyophilized powder. The work shows that the optimal ratio of the compounding lyophilization protectant is 0.46% oligomeric mannose, 0.44% maltose, and 0.05% sorbitol (w/v). The ABC-NPs lyophilized powder prepared under the above conditions had a re-soluble particle size of 472 nm, with a ratio of 1.32 to the particle size of the sample before lyophilization. The lyophilized powder was all in the form of a pink layer. The sample was fluffy and dissolved entirely within 10 s by shaking with water. Consequently, it is expected to solve the problem of inconvenient storage and transportation of aqueous drugs and to expand the application of nanomedicine powders and tablets.

Salecan confers anti-inflammatory effects in liver injury via regulating gut microbiota and its metabolites

Salecan, a natural β-glucan and one of the novel food ingredients approved in China, has been shown a variety of positive health effects, yet the mechanism of liver injury remains poorly understood. In addition, β-glucan could induce the shifts in gut microbiota, however, whether modulation of gut microbiota by β-glucan is associated with their positive health effects remain elusive. Here, the anti-inflammatory effects and the underlying mechanism of Salecan supplementation in CCl4-induced liver injury were investigated. After 8 weeks of treatment, we observed that Salecan alleviated liver injury by regulating inflammatory response and M2 macrophage polarization. In addition, Salecan treatment modulated the composition of gut microbiota and antibiotic cocktail treatment indicated that the hepatoprotective effect of Salecan was dependent on the gut microbiota. Fecal microbiota transplantation was used to further verify the mechanism, and we confirmed that microbial colonization partially alleviated liver injury. Besides, microbiota-derived metabolites of Salecan also contributed to the hepatoprotective and anti-inflammatory effect of Salecan against liver injury. These findings supported that Salecan intervention attenuated liver injury by regulating gut microbiota and its metabolites.

Improving the biological activities of astaxanthin using targeted delivery systems

The antioxidant and anti-inflammatory properties of astaxanthin (AST) enable it to protect against oxidative stress-related and inflammatory diseases with a range of biological effects. These activities provide the potential to develop healthier food products. Therefore, it would be beneficial to design delivery systems for AST to overcome its low stability, control its release, and/or improve its bioavailability. This review discusses the basis for AST's various biological activities and the factors limiting these activities, including stability, solubility, and bioavailability. It also discusses the different systems available for the targeted delivery of AST and their applications in enhancing the biological activity of AST. These include systems that are candidates for preventive and therapeutic effects, which include nerves, liver, and skin, particularly for possible cancer reduction. Targeted delivery of AST to specific regions of the gastrointestinal tract, or more selectively to target tissues and cells, can be achieved using targeted delivery systems to increase the biological activities of AST.

Effects of microencapsulation in dairy matrix on the quality characteristics and bioavailability of docosahexaenoic acid astaxanthin

BACKGROUND

Compared with free astaxanthin (Asta), docosahexaenoic acid astaxanthin monoester (Asta-C22:6) has higher stability and bioavailability. However, Asta-E is still unable to be used in the water system. Hence it is necessary to build a water-soluble delivery system. In this study, Asta-C22:6 microemulsion and microcapsule using whey protein isolate (WPI) and hydroxypropyl-β-cyclodextrin (HPβ-CD) as composite wall material were prepared. They were added to three dairy products (milk powder, yogurt and flavored dairy product). A dairy product rich in Asta-C22:6 with high bioavailability was designed by measuring quality characteristics, sensory evaluation and in vivo experiments.

RESULTS

Compared with spray drying, the freeze-drying microcapsule had a higher encapsulation efficiency (72.5%), water content (4%) and better solubility, and Asta-C22:6 microcapsule (1 g L^-1 ) yogurt had the best quality. The bioavailability of Asta-C22:6 microcapsule yogurt was further evaluated. After a single oral dose in mice, the bioavailability of Asta-C22:6 microcapsule in yogurt was significantly increased (C_max  = 0.31 μg mL^-1 , AUC_0-T  = 3.20 h μg mL^-1 ).

CONCLUSION

We successfully prepared Asta-C22:6 microcapsule yogurt, which improved the stability and bioavailability of Asta. The present research is meaningful for delivering unstable bioactive small molecules based on WPI and HPβ-CD. It provides an experimental basis for the application of Asta-C22:6 and the development of functional dairy products. © 2022 Society of Chemical Industry.

Synthesis, Pharmacokinetic Characterization and Antioxidant Capacity of Carotenoid Succinates and Their Melatonin Conjugates

Carotenoid succinates were synthesized from hydroxy carotenoids and were coupled to a commercially available derivative of melatonin via amide bond for producing more powerful anti-oxidants and yet new hybrid lipophilic bifunctional molecules with additional therapeutic effects. The coupling reactions produced conjugates in acceptable to good yields. Succinylation increased the water solubility of the carotenoids, while the conjugation with melatonin resulted in more lipophilic derivatives. The conjugates showed self-assembly in aqueous medium and yielded relatively stable colloidal solutions in phosphate-buffered saline. Antioxidant behavior was measured with ABTS and the FRAP methods for the carotenoids, the carotenoid succinates, and the conjugates with melatonin. A strong dependence on the quality of the solvent was observed. TEAC values of the new derivatives in phosphate-buffered saline were found to be comparable to or higher than those of parent carotenoids, however, synergism was observed only in FRAP assays.

The Putative Role of Astaxanthin in Neuroinflammation Modulation: Mechanisms and Therapeutic Potential

Neuroinflammation is a protective mechanism against insults from exogenous pathogens and endogenous cellular debris and is essential for reestablishing homeostasis in the brain. However, excessive prolonged neuroinflammation inevitably leads to lesions and disease. The use of natural compounds targeting pathways involved in neuroinflammation remains a promising strategy for treating different neurological and neurodegenerative diseases. Astaxanthin, a natural xanthophyll carotenoid, is a well known antioxidant. Mounting evidence has revealed that astaxanthin is neuroprotective and has therapeutic potential by inhibiting neuroinflammation, however, its functional roles and underlying mechanisms in modulating neuroinflammation have not been systematically summarized. Hence, this review summarizes recent progress in this field and provides an update on the medical value of astaxanthin. Astaxanthin modulates neuroinflammation by alleviating oxidative stress, reducing the production of neuroinflammatory factors, inhibiting peripheral inflammation and maintaining the integrity of the blood-brain barrier. Mechanistically, astaxanthin scavenges radicals, triggers the Nrf2-induced activation of the antioxidant system, and suppresses the activation of the NF-κB and mitogen-activated protein kinase pathways. With its good biosafety and high bioavailability, astaxanthin has strong potential for modulating neuroinflammation, although some outstanding issues still require further investigation.

Colon and gut microbiota greatly affect the absorption and utilization of astaxanthin derived from Haematococcus pluvialis

Astaxanthin has been widely favored as a health food supplement by individuals but its absorption in the body seems not to be satisfactory. In addition, the peak time of astaxanthin derived from Haematococcus pluvialis in the plasma was much longer than other carotenoids found in our previous research. Thus, it is necessary to explore the process that affects the absorption of astaxanthin in order to potentially find a novel approach to improve the absorption in the future. In this study, we confirmed that the colon has an ability to absorb astaxanthin and conducted acute feeding experiments with the treatment of antibiotics in C57BL/6J mice and chronic feeding experiments in germ-free (GF) mice to detect the relationship between the gut microbiota and the absorption of astaxanthin. Our study showed that the decrease of gut microbiota led to a less oral absorbability, which might be related to the decreased expression of SR-BI in the small intestine and the reduction of free form and Z-astaxanthin converted by the gut microbiota found in the vitro culture. The experiments of anaerobic culture also implied that Lactobacillus might play an important role in the absorption of astaxanthin.

Astaxanthin: A super antioxidant from microalgae and its therapeutic potential

Astaxanthin is a ketocarotenoid, super antioxidant molecule. It has higher antioxidant activity than a range of carotenoids, thus has applications in cosmetics, aquaculture, nutraceuticals, therapeutics, and pharmaceuticals. Naturally, it is derived from Haematococcus pluvialis via a one-stage process or two-stage process. Natural astaxanthin significantly reduces oxidative and free-radical stress as compared to synthetic astaxanthin. The present review summarizes all the aspects of astaxanthin, including its structure, chemistry, bioavailability, and current production technology. Also, this paper gives a detailed mechanism for the potential role of astaxanthin as nutraceuticals for cardiovascular disease prevention, skin protection, antidiabetic and anticancer, cosmetic ingredient, natural food colorant, and feed supplement in poultry and aquaculture. Astaxanthin is one of the high-valued microalgae products of the future. However, due to some risks involved or not having adequate research in terms of long-term consumption, it is still yet to be explored by food industries. Although the cost of naturally derived astaxanthin is high, it accounts for only a 1% share in total astaxanthin available in the global market. Therefore, scientists are looking for ways to cut down the cost of natural astaxanthin to be made available to consumers.

Improvement of stability and in vivo antioxidant effect of human glutathione peroxidase mutant by PEGylation

Human glutathione peroxidase (GPx), as an important kind of antioxidant enzyme, is often used for the removal of reactive oxygen species. Unfortunately, the application has been hindered by its limited source and poor stability. To solve these problems, human glutathione peroxidase mutant (GPxM) with high activity and yield was obtained using Escherichia coli BL21(DE3) cys auxotrophic strain and the single-protein production system in our previous work. However, the antioxidant effect of this novel recombinant protein drug in animals has not been demonstrated, and its immunogenicity and short biological half-life as a biological macromolecule may have seriously hindered its clinical application. Therefore, it is important to find an effective strategy to address the above issues. In this work, PEGylated GPxM was prepared by conjugating the corresponding mutant with monomethoxy polyethylene glycol succinimidyl succinate (SS-mPEG). We researched the structure, stability, pharmacokinetic properties, antioxidant effect in vivo and protective mechanism against adriamycin (ADR)-mediated cardiotoxicity of modified products, and compared with the above properties of GPxM. The results revealed that GPxM had an excellent antioxidant effect in vivo, and PEGylation can enhance the stability, half-life and antioxidant effect of GPxM while reducing immunogenicity. In addition, the above improvement of PEGylated GPx1M was stronger than that of monoPEGylated GPx4M. Hence, PEGylation might be an effective method to broaden the applications of GPxM as the important antioxidant drug, especially the PEGylated GPx1M with high antioxidant effect.

Dietary astaxanthin: an excellent carotenoid with multiple health benefits

Astaxanthin is a carotenoid widely found in marine organisms and microorganisms. With extensive use in nutraceuticals, cosmetics, and animal feed, astaxanthin will have the largest share in the global market for carotenoids in the near future. Owing to its unique molecular features, astaxanthin has excellent antioxidant activity and holds promise for use in biochemical studies. This review focuses on the observed health benefits of dietary astaxanthin, as well as its underlying bioactivity mechanisms. Recent studies have increased our understanding of the role of isomerization and esterification in the structure-function relationship of dietary astaxanthin. Gut microbiota may involve the fate of astaxanthin during digestion and absorption; thus, further knowledge is needed to establish accurate recommendations for dietary intake of both healthy and special populations. Associated with the regulation of redox balance and multiple biological mechanisms, astaxanthin is proposed to affect oxidative stress, inflammation, cell death, and lipid metabolism in humans, thus exerting benefits for skin condition, eye health, cardiovascular system, neurological function, exercise performance, and immune response. Additionally, preclinical trials predict its potential effects such as intestinal flora regulation and anti-diabetic activity. Therefore, astaxanthin is worthy of further investigation for boosting human health, and wide applications in the food industry.

Anti-Inflammatory and Anticancer Effects of Microalgal Carotenoids

Acute inflammation is a key component of the immune system’s response to pathogens, toxic agents, or tissue injury, involving the stimulation of defense mechanisms aimed to removing pathogenic factors and restoring tissue homeostasis. However, uncontrolled acute inflammatory response may lead to chronic inflammation, which is involved in the development of many diseases, including cancer. Nowadays, the need to find new potential therapeutic compounds has raised the worldwide scientific interest to study the marine environment. Specifically, microalgae are considered rich sources of bioactive molecules, such as carotenoids, which are natural isoprenoid pigments with important beneficial effects for health due to their biological activities. Carotenoids are essential nutrients for mammals, but they are unable to synthesize them; instead, a dietary intake of these compounds is required. Carotenoids are classified as carotenes (hydrocarbon carotenoids), such as α- and β-carotene, and xanthophylls (oxygenate derivatives) including zeaxanthin, astaxanthin, fucoxanthin, lutein, α- and β-cryptoxanthin, and canthaxanthin. This review summarizes the present up-to-date knowledge of the anti-inflammatory and anticancer activities of microalgal carotenoids both in vitro and in vivo, as well as the latest status of human studies for their potential use in prevention and treatment of inflammatory diseases and cancer.

Astaxanthin Inhibits Autophagic Cell Death Induced by Bisphenol A in Human Dermal Fibroblasts

Astaxanthin, a natural antioxidant carotenoid, is a nutrient with diverse health benefits, given that it decreases the risk of oxidative stress-related diseases. In the present study, we investigate the functional role of astaxanthin during autophagic cell death induced by the estrogenic endocrine-disrupting chemical bisphenol A (BPA) in normal human dermal fibroblasts (NHDF). BPA significantly induced apoptotic cell death and autophagy in NHDF. Autophagic cell death evoked by BPA was significantly restored upon a treatment with astaxanthin (10 μM) via the inhibition of intracellular reactive oxygen species (ROS) production. Astaxanthin inhibited the phosphorylation of extracellular signal-regulated kinases (ERK) stimulated by ROS production, but it did not influence the activation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) in BPA-treated NHDF. Astaxanthin abrogated the ERK-mediated activation of nuclear factor-kappa B (NF-κB), which is responsible for the mRNA expression of LC3-II, Beclin-1, Atg12, and Atg14 during apoptotic cell death induced by BPA. These results indicate that astaxanthin is a pharmacological and nutritional agent that blocks the skin fibroblastic autophagic cell death induced by BPA in human dermal fibroblasts.

Heterologous expression and metabolic engineering tools for improving terpenoids production

Terpenoids, also referred to as isoprenoids, are the largest group of natural compounds which have contributed significantly to the pharmaceutical industry. The challenges in producing bioactive terpenoids from their original host or by organic synthesis methods spurred the endeavors of producing terpenoids in heterologous host. Modern advances utilizing synthetic biology and biological engineering tools have provided a variety of pharmaceutical terpenoids in large-scale and with diversified structures. In this review, we will summarize the progress in production of typical terpenoids skeletons using heterologous expression method assisted by metabolic engineering techniques, with the purpose of enlightening further efforts in developing advanced cell factories for producing terpenoid based pharmaceuticals.

Natural antioxidants in diabetes treatment and management: prospects of astaxanthin

Diabetes remains a major health emergency in our entire world, affecting hundreds of millions of people worldwide. In conjunction with its much-dreaded complications (e.g., nephropathy, neuropathy, retinopathy, cardiovascular diseases, etc.) it substantially reduces the quality of life, increases mortality as well as economic burden among patients. Over the years, oxidative stress and inflammation have been highlighted as key players in the development and progression of diabetes and its associated complications. Much research has been devoted, as such, to the role of antioxidants in diabetes. Astaxanthin is a powerful antioxidant found mostly in marine organisms. Over the past years, several studies have demonstrated that astaxanthin could be useful in the treatment and management of diabetes. It has been shown to protect β-cells, neurons as well as several organs including the eyes, kidney, liver, etc. against oxidative injuries experienced during diabetes. Furthermore, it improves glucose and lipid metabolism along with cardiovascular health. Its beneficial effects are exerted through multiple actions on cellular functions. Considering these and the fact that foods and natural products with biological and pharmacological activities are of much interest in the 21st-century food and drug industry, astaxanthin has a bright prospect in the management of diabetes and its complications.

Astaxanthin n-Octanoic Acid Diester Ameliorates Insulin Resistance and Modulates Gut Microbiota in High-Fat and High-Sucrose Diet-Fed Mice

Astaxanthin n-octanoic acid diester (AOD) is a type of astaxanthin connecting medium-chain fatty acids with a more stable structure. In this study, we examined the role of AOD in ameliorating insulin resistance (IR) induced by a high-fat and high-sucrose diet (HFD) as well as its effect on modulating gut microbiota in mice, with free astaxanthin (AST) as a comparison. Four groups of male C57BL/6J mice (6 weeks old; n = 10 per group) were fed with a normal control diet (NC), HFD orally administered with AOD, AST (50 mg/kg body weight), or vehicle for 8 weeks. AOD improved glucose tolerance, IR, systematic and intestinal inflammation, and intestinal integrity better than AST. Further, both AOD and AST modulated gut microbiota. A significantly higher abundance of Bacteroides and Coprococcus was found in AOD than in AST, and the predicted pathway of carbohydrate metabolism was significantly impacted by AOD. Overall, AOD may play a role in alleviating IR and inflammation with the modulating effect on microbiota in HFD-fed mice. Our findings could facilitate the development of AOD as a bioactive nutraceutical and more stable alternative to AST.