Torularhodin Ameliorates Oxidative Activity in Vitro and d-Galactose-Induced Liver Injury via the Nrf2/HO-1 Signaling Pathway in Vivo

Antioxidant and anti-apoptotic properties of heme oxygenase-1 in red swamp crayfish Procambarus clarkii

Heme oxygenase-1 (HO-1), which is significantly induced in response to oxidative stress, plays a crucial role in mitigating oxidative damage. However, the function of HO-1 in crayfish remains unknown. In this study, HO-1 in Procambarus clarkii (PcHO-1) was identified, and its functional domain was conserved across different species based on sequence alignment and structural prediction. Through RT-qPCR analysis, PcHO-1 showed the highest expression level in the hepatopancreas. Under the stimulation of Aeromonas hydrophila or glufosinate ammonium (GLA), the crayfish showed oxidative stress damage, whereas the expression levels of PcHO-1 were increased. Knocking down of PcHO-1 with RNA interference significantly reduced the antioxidant capacity of crayfish compared to the control group under A. hydrophila or GLA stimulation. Furthermore, the expression level of PcHO-1 increased after induction with CoPPIX, which increased the antioxidant level of crayfish and reduced the apoptosis. These findings indicated that PcHO-1 manifests the antioxidant and anti-apoptotic capacity, thereby aiding in the repairing of damage caused by A. hydrophila or GLA in P. clarkii.

Isolation, characterization and palliative effect of D-gal-induced liver injury of Stropharia rugosoannulata exopolysaccharide

In this study, a homogeneous polysaccharide component, namely SREP-1, was purified from Stropharia rugosoannulata fermentation broth. SREP-1 was identified as a novel water-soluble neutral polysaccharide, with a molecular weight of 9.6 kDa. Monosaccharide composition analysis showed that SREP-1 was composed of glucose, galactose and mannose in a molar ratio of 78.6: 13.6: 7.8. The primary structure was elucidated through FT-IR, methylation analysis and NMR spectroscopy, revealing a backbone of →4)-α-D-Glcp-(1 → and →4,6)-α-D-Glcp-(1 → residues, and →6)-α-D-Galp-(1→, β-D-Manp-(1 → and α-D-Glcp-(→1 residues for the branched chains. Results indicated that SREP-1 possessed an amorphous globular-like structure, good thermally stability and triple-helix conformation in water. In vivo results showed that SREP-1 reversed D-galactose (D-gal)-induced body weight and organ indexes decrease, and alleviated liver damage according to improved histopathology and declined indicators in serum. Amelioration of oxidative stress and abnormal inflammation of aging liver might be due to the elevated nuclear factor-erythroid 2-related factor 2 (Nrf2) expression and decreased that of nuclear factor-κB p65 (NF-κB p65). Interestingly, the beneficial effects of SREP-1 were abolished after pretreatment with antibiotics. Our findings demonstrated that the role of SREP-1 in attenuating aging-related liver injury might involve the regulation of Nrf2-NF-κB signaling pathway and its prebiotic effect.

The carotenoid torularhodin alleviates NAFLD by promoting Akkermanisa muniniphila-mediated adenosylcobalamin metabolism

Torularhodin, a unique carotenoid, confers beneficial effects on nonalcoholic fatty liver disease (NAFLD). However, the precise mechanism underlying its therapeutic effects remains unknown. Here, we report that torularhodin alleviates NAFLD in male mice by modulating the gut microbiota. Additionally, transplanting fecal microbiota from torularhodin-treated mice to germ-free mice also improves NAFLD. Mechanistically, torularhodin specifically enriches the abundance of Akkermansia muciniphila, which alleviates NAFLD by promoting the synthesis of adenosylcobalamin. Utilizing a human gastrointestinal system and a colonic organoid model, we further demonstrate that adenosylcobalamin confers protective effects against NAFLD through reducing ceramides, a well-known liver damaging compound, and this effect is mediated by inhibition of the hypoxia-inducible factor 2α pathway. Notably, we construct electrospun microsphere-encapsulated torularhodin, which facilitates the slow release of torularhodin in the colon. Together, our findings indicate the therapeutic potential of microbial utilization of carotenoids, such as torularhodin, for treating NAFLD.

Improvement of torularhodin production by Rhodotorula glutinis through the stimulation of physicochemical stress and application of the bioproduct as an additive in the food industry

Carotenoids are pigments responsible for the red-orange colorations in valuable food products, and they can be produced via biotechnological means through microorganisms. Beyond their role as natural colorants, some carotenoids offer significant health benefits due to their antioxidant properties, making them valuable nutritional additives in the food industry. However, obtaining these compounds from natural sources with high quantity and purity poses challenges which reduces its market share when produced through a biotechnological route. This study proposes utilizing nutritional and physical stress to enhance carotenoid production, specifically torularhodin, using the yeast Rhodotorula glutinis CCT-2186. A Design of Experiments approach identified malt extract as the most suitable nitrogen source for maximizing carotenoid production. Furthermore, introducing a surfactant (Tween 80) in the culture medium, and extending the cultivation time to 96 h, led to an increase in torularhodin production, reaching a notable 2.097 mg/mL (377,68% more when compared to the initial condition) under the best condition [(%w/v): dextrose (1), KH2PO4 (0.052), MgSO4.7H2O (0.052) and NH4NO3 (0.4), malt extract with a pH of 5.0/ 96 h/30 °C]. Lastly, to demonstrate the viability of utilizing the carotenoid extract as a food colorant, it was applied in edible gelatin. These findings highlight the critical role of nutritional, physical, and mechanical stresses in optimizing torularhodin production, particularly the conversion of γ-carotene to torularhodin by R. glutinis.

Investigating the modulatory effects of Pu-erh tea on the gut microbiota in ameliorating hyperuricemia induced by circadian rhythm disruption

Circadian rhythm disruption (CRD) can induce a variety of metabolic disorders. Our previous laboratory studies have shown that Pu-erh tea could alleviate CRD-induced syndromes, including obesity, intestinal dysfunction, and tryptophan metabolism disorders. However, its potential protective mechanism against CRD-induced hyperuricaemia remains unclear. In this work, we found that polyphenols of Pu-erh tea were significantly released in the stage of intestinal digestion, which might promote their interaction with gut microbes. Through animal experiments, C57BL6/J mice were given water or different doses of Pu-erh tea for 60 days, followed by a 90-day CRD, the lifestyle of modern individuals who frequently stay up late. Our results indicated that CRD mice exhibited high serum uric acid levels and gut microbiota disorders. Pu-erh tea intake significantly reshaped the gut microbiome, especially increasing the abundance of Bifidobacterium, Akkermansia and Faecalibaculum, and increased the production of short-chain fatty acids (SCFAs), especially acetic acid, which restored the function of the intestinal barrier. This improvement further regulated oxidative stress pathways (NRF2/HO-1), reduced systemic inflammatory response (IL-6, IL-1β, and TNF-α), restored hepatic function (SOD, MOD, CAT, and GSH) and modulated the activity of enzymes related to UA metabolism in the liver (XOD and ADA). Finally, Pu-erh tea intake promoted the excretion of UA and reduced the levels of UA and xanthine in the serum. Moreover, the results of antibiotic experiments showed that the UA improvement effect of Pu-erh tea depended on the existence of the gut microbiota. Collectively, Pu-erh tea intake has the potential to prevent CRD-induced hyperuricaemia by reshaping the gut microbiota.

Aruncus Dioicus Var. Kamtschaticus Extract Prevents Ocular Endoplasmic Reticulum Stress, Inflammation, and Oxidative Stress In Vitro

The aim of this study was to determine the anti-inflammatory and anti-endoplasmic reticulum (ER) stress effects of Aruncus dioicus var. kamtschaticus (ADK) extract on ARPE-19 cells. Pretreatment with ADK effectively mitigated thapsigargin (Tg)-induced increases in vascular endothelial growth factor protein secretion and intracellular calcium levels. Furthermore, pretreatment with ADK suppressed ocular ER stress-related protein expression in a dose-dependent manner, inhibited the loss of tight junctions, and suppressed interleukin-6 gene expression. Moreover, ADK pretreatment significantly prevented lipopolysaccharide-inducible proinflammatory cytokine gene expression at the transcription level and the phosphorylation of proteins involved in the mitogen-activated protein kinase-nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) axis at the posttranslational level. Additionally, ADK extract enhanced antioxidant activity, as evidenced by increased heme oxygenase-1 protein expression and increased 2,2-diphenyl-1-picrylhydrazyl radical scavenging and ferric-reducing antioxidant power. In conclusion, ADK extract effectively protected ARPE-19 cells from ocular ER stress, inflammation, and oxidative stress, demonstrating its potential as a nutraceutical intervention for ocular diseases.

Transcriptomic and metabolomic analyses reveal the positive effect of moderate concentration of sodium chloride treatment on the production of β-carotene, torulene, and torularhodin in oleaginous red yeast Rhodosporidiobolus odoratus XQR

Carotenoids, a family of lipid-soluble pigments, have garnered growing interest for their health-promoting benefits and are widely utilized in the food, feed, pharmaceutical, and cosmetic industries. Rhodosporidiobolus odoratus, a representative oleaginous red yeast, is considered a promising alternative for producing high-value carotenoids including β-carotene, torulene, and torularhodin. Here, the impact of varying concentrations of NaCl treatments on carotenoid contents in R. odoratus XQR after 120 h of incubation was examined. The results indicated that, as compared to the control (59.37 μg/gdw), the synthesis of total carotenoids was significantly increased and entirely suppressed under low-to-moderate (0.25 mol/L: 68.06 μg/gdw, 0.5 mol/L: 67.62 μg/gdw, and 0.75 mol/L: 146.47 μg/gdw) and high (1.0, 1.25, and 1.5 mol/L: 0 μg/gdw) concentrations of NaCl treatments, respectively. Moreover, the maximum production of β-carotene (117.62 μg/gdw), torulene (21.81 μg/gdw), and torularhodin (7.04 μg/gdw) was achieved with a moderate concentration (0.75 mol/L) of NaCl treatment. Transcriptomic and metabolomic analyses suggested that the increase in β-carotene, torulene, and torularhodin production might be primarily attributed to the up-regulation of some key protein-coding genes involved in the terpenoid backbone biosynthesis (atoB, HMGCS, and mvaD), carotenoid biosynthesis (crtYB and crtI), and TCA cycle (pckA, DLAT, pyc, MDH1, gltA, acnA, IDH1/2, IDH3, sucA, sucB, sucD, LSC1, SDHA, and fumA/fumB). The present study not only demonstrates a viable method to concurrently increase the production of β-carotene, torulene, torularhodin, and total carotenoids in R. odoratus XQR, but it also establishes a molecular foundation for further enhancing their production through genetic engineering.

A New Method for Selective Extraction of Torularhodin from Red Yeast Using CO2-SFE Technique

Torularhodin is a dark pink colored carotenoid belonging to the xanthophylls group that can be biologically synthesized by red yeasts, especially by Rhodotorula and Sporobolomyces genera. The growing interest in this molecule is due to its biological activities such as antioxidant, anticholesterolemic, anti-inflammatory, antimicrobial, and anticancer. To satisfy potential commercial markets, numerous methods have been proposed to develop a cost-effective and environmentally friendly downstream process for the purification of torularhodin. However, obtaining high purity products without resorting to the use of toxic solvents, which can leave residues in the final preparations, remains a major challenge. In this context, the present study aimed to develop a new efficient method for the isolation of torularhodin from the red yeast Rhodotorula strain ELP2022 by applying the extraction technique with supercritical CO2 (CO2-SFE) in two sequential steps. In particular, in the first step, the dried lysed biomass of yeast was subjected to the action of CO2 in supercritical conditions (CO2SC) as sole solvent for extraction of apolar carotenoids. In the second step, the residual biomass was subjected to the action of CO2SC using ethanol as a polar co-solvent for the extraction of torularhodin. Both steps were carried out at different operating parameters of temperature (40 and 60 °C) and pressure (from 300 to 500 bar) with a constant CO2 flow of 6 L min-1. Regardless of the operating conditions used, this method allowed to obtain an orange-colored oily extract and a red-colored extract after the first and second step, respectively. In all trials, torularhodin represented no less than 95.2% ± 0.70 of the total carotenoids in the red extracts obtained from the second step. In particular, the best results were obtained by performing both steps at 40 °C and 300 bar, and the maximum percentage of torularhodin achieved was 97.9% ± 0.88. Since there are no data on the selective recovery of torularhodin from red yeast using the SFE technique, this study may be a good starting point to optimize and support the development of industrial production of torularhodin by microbial synthesis. This new method can significantly reduce the environmental impact of torularhodin recovery and can be considered an innovation for which an Italian patent application has been filed. In a circular bioeconomy approach, this method will be validated up to a pilot scale, culturing the strain Rhodotorula spp. ELP2022 on low-cost media derived from agri-food wastes.

A polysaccharide from Alhagi honey protects the intestinal barrier and regulates the Nrf2/HO-1-TLR4/MAPK signaling pathway to treat alcoholic liver disease in mice

ETHNOPHARMACOLOGICAL RELEVANCE

According to the theory of traditional Chinese medicine, the main factors related to alcoholic liver disease (ALD) are qi stagnation and blood stasis of the five viscera. Previously, we showed that the bioactive components of Alhagi honey have various pharmacological effects in treating liver diseases, but the influence of Alhagi honey on ALD (and its mechanism of action) is not known.

AIM OF THE STUDY

To determine the efficacy of the main active component of Alhagi honey, the polysaccharide AHPN80, in ALD and to explore the potential mechanism of action.

MATERIALS AND METHODS

AHPN80 was isolated from dried Alhagi honey and identified by transmission electron microscopy, Fourier-transform infrared spectroscopy, and gas chromatography. Venous blood, liver tissue, and colon tissue were collected in a mouse model of alcohol-induced acute liver injury. Histology, staining (Oil Red O, Alcian Blue-Periodic Acid Schiff) and measurement of reactive oxygen species (ROS) levels were used to detect histopathologic and lipid-accumulation changes in the liver and colon. Lipopolysaccharide (LPS) levels and the content of proinflammatory cytokines in serum were measured by enzyme-linked immunosorbent assays. Commercial kits were employed to detect biochemistry parameters in serum and the liver. A terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining kit was used to identify hepatocyte apoptosis. Expression of tight junction-associated proteins in colon tissues and nuclear factor erythroid 2-related factor 2/heme oxygenase-1/toll-like receptor-4/mitogen-activated protein kinase (Nrf2/HO-1/TLR4/MAPK) pathway-related proteins in liver tissues and HepG2 cells were analyzed by immunofluorescence or western blotting.

RESULTS

In a mouse model of alcohol-induced acute liver injury, AHPN80 therapy: significantly improved liver parameters (cytochrome P450 2E1, alcohol dehydrogenase, aldehyde dehydrogenase, superoxide dismutase, malondialdehyde, glutathione peroxidase, catalase, total cholesterol, triglycerides, alanine transaminase, aspartate transaminase); reduced serum levels of LPS, interleukin (IL)-1β, IL-6, and tumor necrosis faction-α; increased levels of IL-10 and interferon-gamma. AHPN80 reduced ALD-induced lipid accumulation and ROS production, improved alcohol-induced inflammatory damage to hepatocytes, and inhibited hepatocyte apoptosis. Immunofluorescence staining and western blotting suggested that AHPN80 might eliminate hepatic oxidative stress by activating the Nrf2/HO-1 signaling pathway, repair the intestinal barrier, inhibit the LPS/TLR4/MAPK signaling pathway, and reduce liver inflammation.

CONCLUSIONS

AHPN80 may activate the Nrf2/HO-1 pathway to eliminate oxidative stress, protect the intestinal barrier, and regulate the TLR4/MAPK pathway to treat ALD in mice. AHPN80 could be a functional food and natural medicine to prevent ALD and its complications.

Structural properties of Kudzu protein enzymatic hydrolysate and its repair effect on HepG2 cells damaged by H2O2 oxidation

We investigated the structural properties, foaming capacity and foaming stability, antioxidant activity, and amino acid composition of Kudzu protein (KP) and Kudzu protein hydrolysate (KPH). The peptide sequence of KPH was analyzed using ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS), and the binding ability of the peptide sequence to Keap1 was predicted through molecular docking simulations. The electrophoresis and molecular weight distribution analysis results showed that the molecular weight of KPH was significantly lower than that of KP, with a mean molecular weight of approximately 2000-5000 Da. The structures and properties were characterized using Fourier transform infrared spectroscopy, relative fluorescence, and circular dichroism. The results showed that KP exposed a large number of hydrophobic groups after enzymatic hydrolysis, and its structure changed from α-helical to random coils. KPH has a higher foaming capacity (200%) and foaming stability (97.5%) than KP, which may be related to the change in structure. These results indicate that moderate hydrolysis can improve the functional properties of KP, providing a new opportunity for its application as a food ingredient. The antioxidant assay results showed that KP and KPH had a good hydroxyl radical, superoxide anion, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging capacity and a high reducing capacity. KPH exerted better antioxidant effects than KP. The scavenging rates for DPPH, ABTS, hydroxyl radicals, and superoxide anions were 89.31%, 93.14%, 85.74%, and 58.29%, respectively, and its reducing capacity was 2.191, which may be related to the increase in amino acids with antioxidant activity after enzymolysis. In vitro, KP and KPH could significantly repair H2O2-induced oxidative damage in HepG2 cells, reduce the apoptosis rate, activate the Nrf2-Keap1 signaling pathway, reduce the accumulation of reactive oxygen species and malondialdehyde after oxidative damage, increase the activities of superoxide dismutase and glutathione (GSH) peroxidase, and increase the content of GSH and the total antioxidant capacity. Twenty-one peptide components were identified in KPH using UPLC-MS/MS, and the binding ability of 21 peptide components to Keap1 was analyzed through molecular docking technology. The results showed that all 21 peptides in KPH had good antioxidant activity, and real-time quantitative PCR (qRT-PCR) analysis was conducted to further explain the high antioxidant activity of KPH at the genetic level. These results show that KP and KPH are suitable for preparing antioxidant foods and related health foods to prevent oxidation-related diseases. KPH has more beneficial effects than KP.

Coffee prevents IQ-induced liver damage by regulating oxidative stress, inflammation, endoplasmic reticulum stress, autophagy, apoptosis, and the MAPK/NF-κB signaling pathway in zebrafish

2-Amino-3-methylimidazole[4,5-f]quinoline (IQ), one of heterocyclic amines (HCAs) produced in proteinaceous foods upon heating, is recognized as a carcinogen. Previous studies have confirmed that IQ intake can cause liver damage in zebrafish. In the current study, we revealed the protective effects of coffee against IQ-induced liver damage. We exposed one-month-old wild-type zebrafish to IQ (80 ng/mL) and coffee at 50 mg/L, 100 mg/L, and 300 mg/L for 35 days. Markers of oxidative stress, inflammation, endoplasmic reticulum stress (ERS), autophagy, and apoptosis in the liver were assessed to explore the potential mechanisms of the protective effects. The results showed that coffee effectively improved IQ-induced liver damage by reducing ALT, AST, TC, TG, and LDL-C levels, increasing HDL-C level, and restoring hepatic morphology. Moreover, coffee showed an antioxidative effect by increasing GSH, GSH-Px, GST, CAT, and SOD levels and attenuating ROS and MDA contents. Additionally, coffee reduced the NO, iNOS, TNF-α, IL-6, IL-1β, and IL-12 expression levels, presenting an anti-inflammatory effect. Furthermore, coffee protected against ERS, autophagy dysfunction, and apoptosis by decreasing the GRP78, CHOP, and p62 while increasing the Atg5-Atg12, Beclin1, LC3-II, and Bcl-2 expression levels. TUNEL results showed that coffee rescued IQ-induced hepatocyte apoptosis. In addition, coffee interrupted the MAPK/NF-κB signaling pathway by suppressing the phosphorylation expressions of JNK, ERK, p38, p65, and IκB. These findings indicated that coffee prevents IQ-induced liver damage with antioxidative, anti-inflammatory, anti-ERS, anti-apoptotic, and pro-autophagic effects, thus to serve as a functional beverage with potential health benefits.

Study on the Cellular Anti-Inflammatory Effect of Torularhodin Produced by Sporidiobolus pararoseus ZQHL Isolated from Vinegar Fungus

The red stretcher bacterium Sporidiobolus pararoseus is a high producer of carotenoids such as torularhodin, but its presence in vinegar has not been detected. Moreover, torularhodin has several biological activities, but its effect on the LPS-induced RAW 264.7 inflammatory cell model has also yet to be elucidated. In this study, S. pararoseus was identified in different vinegar samples from China by ITS sequencing. Meanwhile, one of the strains was deeply resolved by whole genome sequencing and functional annotation and named S. pararoseus ZQHL. Subsequently, the antioxidant effect of the fungal carotenoid torularhodin was investigated using in vitro DPPH, ABTS, and cellular models. Finally, LPS-induced RAW 264.7 cells were used as an inflammation model to assess torularhodin's protective effect on inflammatory cells and to determine whether the TLR4 pathway is associated with this process. The results indicate that torularhodin has good free radical scavenging ability in vitro and can contribute to cell viability. More importantly, torularhodin alleviated LPS-induced cellular inflammatory damage and reduced the expression of inflammatory factors such as TLR4, MyD88, and TNF-a. The mechanism may attenuate the cellular inflammatory response by inhibiting the TLR4 inflammatory pathway. In conclusion, torularhodin produced by S. pararoseus fungi in vinegar samples significantly scavenged free radicals in vitro and alleviated RAW 264.7 cellular inflammation by modulating the TLR4 pathway.

Torularhodin-Loaded Bilosomes Ameliorate Lipid Accumulation and Amino Acid Metabolism in Hypercholesterolemic Mice

SCOPE

Hypercholesterolemia is a cause of cardiovascular disease. Torularhodin is a carotenoid, and its entrapment in bilosomes helps to improve its bioavailability.

METHODS AND RESULTS

The effects of torularhodin-loaded bilosomes on lipid accumulation, inflammatory response, and serum metabolic profiles in hypercholesterolemic ApoE-/- C57BL/6J mice were investigated by feeding a high-fat, high-cholesterol diet (HFHCD) for 20 weeks. At the same time, mice were gavaged with torularhodin-loaded bilosomes for 10 weeks. The results showed that torularhodin successfully alleviated weight gain and insulin resistance in mice and could also lower blood lipids. Meanwhile, torularhodin improved liver lipid accumulation in mice and modulated inflammatory factors in the "blood-liver-ileum." Nontargeted metabolomics revealed that torularhodin significantly increased the concentrations of l-tryptophan, glyceraldehyde, hypotaurine, pyrophosphate, and niacinamide in serum (p < 0.01). In addition, targeted amino acid metabolomics verification found that torularhodin promoted the metabolism of serum amino acids in mice, particularly for branched-chain amino acids, thereby helping to improve hypercholesterolemia in mice. Finally, interaction network bioinformatics was used to demonstrate that amino acid metabolism represented an important mechanism by which torularhodin improves lipid accumulation and inflammatory response in mice.

CONCLUSIONS

Torularhodin can improve hypercholesterolemia in HFHCD-fed mice, thereby supporting the feasibility of its usage in food applications for cardiovascular disease prevention.

Osthole Alleviates D-Galactose-Induced Liver Injury In Vivo via the TLR4/MAPK/NF-κB Pathways

Osthole, a coumarin derivative, is found in several medicinal herbs. However, the protective effects of osthole against D-galactose (D-Gal)-induced liver injury still remain unclear. In this study, osthole treatment effectively reversed D-Gal-induced liver injury, according to the results of liver HE staining, and improved ALT and AST activities. Feeding with D-Gal significantly increased MDA content, and reduced the level or activity of SOD, CAT and GSH-Px, which were all alleviated by osthole intervention. Meanwhile, osthole treatment significantly inhibited the D-Gal-induced secretion of pro-inflammatory cytokines, such as TNF-α, IL-1β and IL-6, in both serum and liver tissue. Investigations revealed that osthole ameliorated the D-Gal-induced activation of TLR4, MYD88 and its downstream signaling pathways of MAPK (p38 and JNK) and NF-κB (nucleus p65). Therefore, osthole mediates a protective effect against D-Gal-induced liver injury via the TLR4/MAPK/NF-κB pathways, and this coumarin derivative could be developed as a candidate bioactive component for functional food.

Torularhodin Alleviates Hepatic Dyslipidemia and Inflammations in High-Fat Diet-Induced Obese Mice via PPARα Signaling Pathway

Torularhodin is a β-carotene-like compound from Sporidiobolus pararoseus, and its protective effect against high-fat diet (HFD)-induced hepatic dyslipidemia and inflammation was investigated. Compared to mice of C57BL/6J fed on HFD, the addition of Torularhodin into the HFD (HFD-T) significantly reduced body weight, serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), and the inflammatory mediators of TNF-α, IL-6, IL-1β, and lipopolysaccharide (LPS). A significant increase of high-density lipoprotein cholesterol (HDL-c), which is beneficial to cholesterol clearance, was also observed in HFD-T group. Proteomic analysis showed HDL-C-c is highly correlated with proteins (e.g., CPT1A and CYP7A1) involved in lipid β-oxidation and bile acid synthesis, whereas the other phenotypic parameters (TC, TG, LDL, and inflammatory cytokines) are highly associated with proteins (e.g., SLC27A4) involved in lipid-uptake. The up-regulated anti-inflammation proteins FAS, BAX, ICAM1, OCLN, GSTP1, FAF1, LRP1, APEX1, ROCK1, MANF, STAT3, and INSR and down-regulated pro-inflammatory proteins OPTN, PTK2B, FADD, MIF, CASP3, YAP1, DNM1L, and NAMPT not only demonstrate the occurrence of HFD-induced hepatic inflammation, but also prove the anti-inflammatory property of Torularhodin. KEGG signaling pathway analysis revealed that the PPARα signaling pathway is likely fundamental to the health function of Torularhodin through up-regulating genes related to fatty acid β-oxidation, cholesterol excretion, HDL-Cc formation, and anti-inflammation. Torularhodin, as a new food resource, may act as a therapeutic agent to prevent hepatic dyslipidemia and related inflammation for improved health.

Isinglass Polysaccharides Regulate Intestinal-Barrier Function and Alleviate Obesity in High-Fat Diet Mice through the HO-1/Nrf2 Pathway and Intestinal Microbiome Environment

Plant polysaccharide intervention has shown significant potential to combat obesity. However, studies on animal polysaccharides are indeed rare. The aim of this study was to investigate the potential functions of CIP (IL) on obesity, intestinal microflora dysbiosis, and the possible protection of intestinal barrier in mice fed with high-fat diet (HFD). Our results revealed that after 13 weeks, the HFD+L (high-fat diet + 25 mg/kg CIP) group showed significantly more weight loss and fat accumulation relative to the HFD+H (high-fat diet + 50 mg/kg CIP) group. Furthermore, CIP intervention modulated lipid metabolism and mRNA levels of inflammatory mediators in liver. Overall, CIP clearly improved the intestinal barrier in HFD-fed mice. Additionally, we observed that CIP intervention improved intestinal microbiota community richness and diversity in HFD-fed mice. The CIP intervention mice group showed a relatively low Firmicutes to Bacteroidetes ratio compared to the HFD group. This study concluded that CIP could be used as a functional food to prevent adipocyte accumulation, reduce systemic inflammation, and protect the intestinal barrier.

Microbial torularhodin – a comprehensive review

The demand for food, feed, cosmeceutical, and nutraceutical supplements/additives from natural sources has been rapidly increasing, with expectations for a faster expansion than the growth of the global markets in the coming years. In this framework, a particular interest is given to carotenoids due to their outstanding antioxidant activities, particularly the xanthophylls class. Torularhodin is one of these carotenoids that stands out for its multifunctional role as: antioxidant, anticancer and antimicrobial, yet its commercial potential is still unexplored. Although most xanthophylls can be naturally found in: microbial, plant and animal sources, torularhodin is only produced by microbial species, especially red oleaginous yeast. The microbial production of xanthophylls has many advantages as compared to other natural sources, such as: the need for low production area, easier extraction, high yields (at optimum operating conditions), and low (or no) seasonal, climatic, and geographic variation dependency. Due to the importance of natural products and their relevance to the market, this review provides a comprehensive overview of the: properties, characteristics and potential health benefits of torularhodin. Moreover, the most promising developments in both upstream and downstream processing to obtain this colorant from microbial sources are considered. For this purpose, the main microorganisms used for torularhodin production are firstly reviewed, including biosynthesis pathway and torularhodin properties. Following, an overall analysis of the processing aspects related with its: extraction, separation and purification is provided. Lastly, current status and future trends of torularhodin-based processes and products such as therapeutic agents or biomaterials are discussed, indicating promising directions toward biorefinery and circular economy.

The impact of the physical form of torularhodin on its metabolic fate in the gastrointestinal tract

Torularhodin is a fungal carotenoid with multiple health benefits. However, the relationship between its physical form and metabolic fate in the gastrointestinal tract (GIT), which is essential to its bioavailability and health efficacy, has rarely been studied. Thus, physical forms of torularhodin including nanoemulsion powder (T-EP), capsules of the T-EP by alginate (T-EPA), and solution in MCT oil (T-oil) were used in the study. T-EP was produced through OSA-starch-mediated torularhodin emulsification and spray drying whereas the T-EPA was alginate-based capsules of the T-EP particles that were entrapped in the network structure of the alginate matrix as observed by scanning electron microscopy (SEM). The oil digestibility in the simulated small intestine was decreased from T-EP (100%), T-oil (60%) to T-EPA (40%), and the bioaccessibilities were 27%, 15% and 12%, respectively. The in vivo study using mice revealed that the content of torularhodin gradually decreased along with the digestion time in both the stomach and small intestine while a significantly higher colonic accumulation was observed in T-EPA compared to T-oil and T-EP. In vitro fecal fermentation showed that propionate (32 mM) was the predominant metabolite produced by torularhodin in the physical form of T-EPA. Thus, the physical form of torularhodin is a significant contributing factor to its GIT metabolic fate, and a health outcome-oriented design of the physical form of torularhodin or other nutraceuticals is beneficial for the development of functional foods with enhanced health benefits.

Transcriptomic and Metabolomic Analyses Provide Insights into the Enhancement of Torulene and Torularhodin Production in Rhodotorula glutinis ZHK under Moderate Salt Conditions

Carotenoids are a group of tetraterpene pigments widely used in the food, pharmaceutical, and cosmetic industries. Torulene, torularhodin, and β-carotene, three principal carotenoids synthesized by Rhodotorula glutinis ZHK, possess strong health-promoting properties such as antioxidant, provitamin A, and antitumor. Here, the effect of different salt conditions on carotenoids production of R. glutinisZHK was investigated. The results showed that the total carotenoids were significantly enhanced in 0.5 M (3.91 mg/L) and 0.75 M (5.41 mg/L) NaCl treatments than that in 1.0 M (0.35 mg/L) and control (1.42 mg/L) after 120 h of cultivation. Of which, the increase in torulene and torularhodin production acts as the main contributor to the enhancement of total carotenoids. Transcriptome profiling revealed that salt stress efficiently promotes the gene expression of crtI, which could explain the molecular mechanisms of the enhanced torulene and torularhodin production under salt stress. Further experiments indicated that torulene and torularhodin play an important role in quenching excrescent reactive oxygen species induced by salt stress. Together, the present study reports an effective strategy for simultaneously improving torulene and torularhodin production in R. glutinis ZHK.

Astaxanthin attenuates oxidative stress and immune impairment in D-galactose-induced aging in rats by activating the Nrf2/Keap1 pathway and suppressing the NF-κB pathway

As a potential antioxidant, astaxanthin (AST) exhibits anti-aging effects. However, its relationships to oxidative stress and immunity have yet to be sufficiently investigated. In this research, integrated analysis of oxidative stress and immunosenescence was performed to elucidate the efficacy and potential mechanisms of AST in d-galactose-induced aging in rats. The results showed that AST significantly decreased malonaldehyde (MDA) levels and increased antioxidase activity, in addition to demonstrating the ability to repair histopathological injuries to the liver, thereby attenuating oxidative stress. Nuclear factor erythroid 2-related factor 2 (Nrf2) expression was up-regulated by 117.95%, whereas Kelch-like ECH-associated protein-1 (Keap1) expression was simultaneously down-regulated by 51.22%. Moreover, AST significantly reduced interleukin-1β (IL-1β) and interleukin-6 (IL-6) levels, as well as expression of nuclear factor-kappa B (NF-κB) (p65) and i-kappa-B-alpha (IκBα) proteins. Findings of repair of immune organs, as well as elevated levels of interleukin-2 (IL-2), immunoglobulin M (IgM) and immunoglobulin G (IgG), suggest a novel mechanism by which AST could regulate cellular immunity and humoral immunity to attenuate immunosenescence. The anti-aging effects of AST were shown to be due in part to the Nrf2/Keap1 and NF-κB pathways, and AST treatment ameliorated oxidative stress and immune impairment overall.

Echinacea purpurea polysaccharide prepared by fractional precipitation prevents alcoholic liver injury in mice by protecting the intestinal barrier and regulating liver-related pathways

Oxidative damage and intestinal dysbiosis are regarded as crucial culprits in alcoholic liver disease (ALD). This study aimed to examine the protective effects of Echinacea purpurea polysaccharides (EPPs) against ALD and explore the underlying mechanisms based on hepatic oxidative stress, inflammation, and intestinal barrier function. Three polysaccharide fractions, namely, EPP40, EPP60, and EPP80, were obtained by stepwise ethanol precipitation, and their antioxidant activity in vitro was investigated. The results showed that EPP80 with Mw 11.82 kDa had the strongest radical-scavenging capacity against DPPH, ABTS, and •OH radicals. Besides, EPP80 comprised arabinose, galactose, glucose, mannose, galacturonic acid, and glucuronic acid in molar ratios of 13.42:25.12:10.92:8.59:2.07:0.82. The in vivo results showed that EPP80 increased the activities of antioxidant enzymes and reduced the levels of inflammatory cytokines both in mouse serum and liver. Moreover, EPP80 upregulated the expression of Occludin and ZO-1, revealing its protective effect against intestinal barrier dysfunction. Furthermore, EPP80 inhibited alcohol-induced oxidative damage by promoting the expression of Nrf2, HO-1, and NQO1 in the liver. In summary, EPP80 markedly scavenged free radicals in vitro and ameliorated alcohol-induced liver injury via Nrf2/HO-1 pathways in vivo. These findings suggested that EPP80 could provide effective supplementary support in preventing and treating ALD.

Aloe polysaccharides ameliorate acute colitis in mice via Nrf2/HO-1 signaling pathway and short-chain fatty acids metabolism

Aloe polysaccharides (APs) are acetyl polysaccharides. It has been reported APs could protect mice from ulcerative colitis (UC), but the complex interactions between APs and the intestinal barrier were unclear. Here, we investigated the relationship between APs and UC, and determined the synergistic effects of Nrf2/HO-1 signaling pathway and short-chain fatty acids (SCFAs) metabolism on protecting intestinal barrier in acute UC mice. Results showed APs could scavenge free radicals in vitro. In vivo, APs had the antioxidant and anti-inflammatory effect both in serum and colon. Besides, the pathological results showed APs could alleviate colonic lesions. Furthermore, our study indicated treatment with APs effectively increased SCFAs production. The inhibition of acute UC in mice was correlated with the APs-mediated effects on improving the expression of ZO-1, occludin, Nrf2, HO-I, and NQO1. Thus, APs effectively promoted the intestinal barrier via Nrf2/HO-1 signaling pathway and SCFAs metabolism, effectively ameliorating acute colitis in mice.

Magnesium-L-threonate alleviate colonic inflammation and memory impairment in chronic-plus-binge alcohol feeding mice

Magnesium-l-threonate (MgT) is considered a food supplement. Alcohol-mediated diseases (AMD) are accompanied by inflammation and memory impairment. The purpose of this study is to investigate the function of MgT in AMD. Hence, chronic-plus-binge alcohol feeding mice model and multiply bioinformatics analysis were performed. Consequently, the expression of inflammatory cytokines downregulated, while the activities of antioxidases decreased in serum, colon, and brain. Interestingly, MgT relieved gut barrier dysfunction and reshaped microbiota. The relative abundance of Akkermansia, Odoribacter, and Blautia were increased, while that of Alloprevotella and Clostridium were decreased. Metabolic analysis elucidated amino acids and glutamate metabolism were enhanced in MgT-treated mice. Furthermore, morris water maze test confirmed memory ability was enhanced. Inflammation cytokines were negatively correlated with Blautia, and Akkermansia. Collectively, MgT relieved inflammation in gut-brain axis of mice, reshaped gut microbiota, and enhanced the amino acids and glutamate metabolism. MgT may be used as a food supplement to prevent inflammation and memory impairment induced by alcohol abuse.

D-galactose-induced liver aging model: Its underlying mechanisms and potential therapeutic interventions

Aging is associated with a variety of morphological and functional changes in the liver. Oxidative stress and inflammation are now widely accepted as the main mechanisms involved in the aging process that may subsequently cause severe injury to mitochondrial DNA which leads to apoptosis. As aging may increase the risks for various liver diseases and plays as an adverse prognostic factor increasing the mortality rate, knowledge regarding the mechanisms of age-related liver susceptibility and the possible therapeutic interventions is imperative. Due to cost and time constraints, a mimetic aging model is generally preferred to naturally aged animals to study the underlying mechanisms of aging liver. The use of D-galactose in aging research is dated back to 1962 and has since been used widely. This review aims to comprehensively summarize the effects of D-galactose-induced aging on the liver and the underlying mechanisms involved. Its potential therapeutic interventions are also discussed. It is hoped that this invaluable information may facilitate researchers in choosing the appropriate aging model and provide a valuable platform for testing potential therapeutic strategies for the prevention and treatment of age-related liver diseases.

Nuclear factor erythroid-2 related factor 2 inhibits human disc nucleus pulpous cells apoptosis induced by excessive hydrogen peroxide

OBJECTIVE Nuclear factor erythroid-2 related factor 2 (Nrf2)/ antioxidant response element (ARE) is a novel defensive pathway involved in the oxidative and chemical stress of cells. The aim of the study was to explore the role of Nrf2 on the apoptosis of human disc nucleus pulpous cells induced by hydrogen peroxide (H2O2). METHODS The degeneration model of human intervertebral disc nucleus pulpous cells was established. The expression of Nrf2 was interfered with using sulforaphane (SFN); for that end, three groups were established: a blank group (H2O2-/SFN-), control group (H2O2+/SFN-), and an experimental group (H2O2+/SFN+). CCK8, Hoechst 33258 living cell staining was used to detect reactive oxygen species (ROS) content. RESULTS The apoptotic rates of the three groups were [(0.40±0.46)%], [(25.98±11.28)%], and [(3.83±2.06)%, respectively. The difference was statistically significant (p<0.05). The relative content of ROS in the three groups was [(100±7)%], [(1538±91)%], and [(818±63)%]; the difference was statistically significant (p<0.05). In Western blotting, Nrf2 content in the experimental group was higher than that in the control group. CONCLUSION Nrf2 exists in the nucleus pulpous cells of human intervertebral discs, which is related to the degeneration of the intervertebral disc. It has negative feedback regulation and can prevent the degeneration of the intervertebral disc by inhibiting the apoptosis of nucleus pulpous cells of human intervertebral discs caused by excessive ROS, which provides a new intervention strategy for the prevention and treatment of the degeneration of intervertebral discs.

Torularhodin from Sporidiobolus pararoseus Attenuates d-galactose/AlCl3-Induced Cognitive Impairment, Oxidative Stress, and Neuroinflammation via the Nrf2/NF-κB Pathway

Oxidative stress and neuroinflammation are considered as crucial culprits in Alzheimer's disease (AD). Torularhodin, a carotenoid pigment, possesses powerful antioxidant activity. This study aimed to elucidate the protective effects of torularhodin in the AD-like mouse model and investigated the underlying mechanisms. Behavioral and histopathological results suggested that torularhodin relieved cognitive impairments, attenuated Aβ accumulation, and inhibited glial overactivation in d-gal/AlCl₃-induced ICR mice. Simultaneously, torularhodin also markedly increased antioxidant enzyme capacities, lowered the contents of RAGE, and reduced levels of inflammatory cytokines. Western blot results showed that torularhodin ameliorated neuronal oxidative damage via activation of Nrf2 translocation, upregulation of HO-1, and inactivation of NF-κB in vivo and in vitro. Thus, torularhodin effectively ameliorated cognitive impairment, oxidative stress, and neuroinflammation, possibly through the Nrf2/NF-κB signaling pathways, suggesting torularhodin might offer a promising prevention strategy for neurodegenerative diseases.

New Acylated Phenolic Glycosides with ROS-Scavenging Activity from Psidium guajava Leaves

Reactive oxygen species and subsequent oxidative stress are reported to play important roles in chronic metabolic diseases. Plant-derived polyphenols, especially food-derived phenolics, have attracted a lot of attention due to their potential usage against oxidative stress-related diseases. The leaf of Psidium guajava (known as guava) is regarded as a good resource of polyphenols and its products are commercially available in Japan as functional foods against multiple chronic metabolism disorders. In the course of finding novel polyphenols with antioxidative activities from guava leaf, 11 acylated phenolic glycosides (1-11), including 5 new oleuropeic acid-conjugated phenolic glycosides, named guajanosides A-E (1, 2, and 5-7), along with 17 known meroterpenoides (12-28), were isolated and identified. Their structures were determined by spectroscopic data analysis, chemical degradation, and acid hydrolysis. Compounds 1, 2, and 5-11 displayed potent reactive oxygen species-scavenging activity in lipopolysaccharide-stimulated RAW 264.7 macrophage cells. Western blot revealed that compound 6 markedly increased the expression levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), NAD(P)H quinone dehydrogenase 1 (NQO1), and the glutamate-cysteine ligase catalytic subunit. The current study revealed the presence of oleuropeic acid-derived phenolic glycosides in guava leaf and highlighted the potential usage of this type of phenolics against oxidative stress-related metabolic diseases via activation of the Nrf2 signaling pathway.