Natural products as a source of Coronavirus entry inhibitors

The COVID-19 pandemic has had a significant and lasting impact on the world. Four years on, despite the existence of effective vaccines, the continuous emergence of new SARS-CoV-2 variants remains a challenge for long-term immunity. Additionally, there remain few purpose-built antivirals to protect individuals at risk of severe disease in the event of future coronavirus outbreaks. A promising mechanism of action for novel coronavirus antivirals is the inhibition of viral entry. To facilitate entry, the coronavirus spike glycoprotein interacts with angiotensin converting enzyme 2 (ACE2) on respiratory epithelial cells. Blocking this interaction and consequently viral replication may be an effective strategy for treating infection, however further research is needed to better characterize candidate molecules with antiviral activity before progressing to animal studies and clinical trials. In general, antiviral drugs are developed from purely synthetic compounds or synthetic derivatives of natural products such as plant secondary metabolites. While the former is often favored due to the higher specificity afforded by rational drug design, natural products offer several unique advantages that make them worthy of further study including diverse bioactivity and the ability to work synergistically with other drugs. Accordingly, there has recently been a renewed interest in natural product-derived antivirals in the wake of the COVID-19 pandemic. This review provides a summary of recent research into coronavirus entry inhibitors, with a focus on natural compounds derived from plants, honey, and marine sponges.

Structurally Orientated Rheological and Gut Microbiota Fermentation Property of Mannans Polysaccharides and Oligosaccharides

Three mannan polysaccharides and their oligosaccharides were investigated in terms of physicochemical characteristics and effects on gut microbiota. Oligosaccharides from guar gum had the fastest fermentation kinetics for SCFAs generation at the initial stage, while the locust bean of both polymers and oligosaccharides demonstrated the lowest SCFAs through the whole fermentation process. In contrast, konjac gum steadily increased SCFAs and reached its maximum level at 24 h fermentation, indicating its fermentation character may be associated with its rheological properties. Compared to their corresponding polysaccharides, all the oligosaccharides demonstrated a faster fermentation kinetics, followed by an enriched abundance of propionate-producing bacterial Prevotella and a decreased abundance of Megamonas and Collinsella. Meanwhile, oligosaccharides reduced the Firmicutes/Bacteroidota ratio as well as the abundance of Bacteroidetes and Escherichia-Shigella. The fermentation of konjac substrate significantly promoted the abundance of butyrate-producing bacterial Faecalibacterium. In contrast, although the fermentation of locust bean and guar gum substrates benefited Bifidobacterium abundance due to their similar structure and monosaccharides composition, the fermentation of locust bean gum led to greater Bifidobacterium than the others, which may be associated with its higher mannose composition in the molecules. Interestingly, the partial hydrolysis of the three polysaccharides slightly reduced their prebiotic function.

Mapping the metabolic characteristics of probiotic-fermented Ganoderma lucidum and its protective mechanism against Cd-induced nephrotoxicity

An animal model of Cd-induced kidney damage was designed to investigate the nephroprotective potential of the probiotic-fermented Ganoderma lucidum (FGL) via metabonomic analysis. The results showed that FGL enhanced sugar and amino acid metabolism. The interaction of Ganoderma lucidum (GL) and probiotics efficiently elevated short-chain fatty acid production following gut microbiota fermentation. The current data revealed that the FGL intervention alleviated Cd-induced nephrotoxicity via elevating the activity of antioxidant enzymes and decreasing the levels of pro-inflammatory and apoptotic factors. Based on transcriptome analysis, FGL intervention mediated renal dysfunction via decreasing the expressions of Nos2, Tnfsf14, S100a9, Map3k6 and Hk3, which were involved in oxidative stress, inflammatory response and the apoptosis process. The current study highlights a new approach for achieving positive nephroprotection via natural product intervention.

Impact of de-branched starch molecules and fatty acids complexes on the attenuation of ageing-induced cognitive impairment

BACKGROUND

Ageing and associated cognitive impairments are becoming serious issues around the world. In this study, the physiological property of three kinds of complexes of fatty acid (capric, stearic and oleic acid, respectively) and de-branched starch molecules was investigated via a D-galactose-induced ageing model. This study revealed the difference in the regulation of cognitive impairment and brain damage following different complexes intervention, which might highlight a potent approach for the prevention of this chronic disease.

RESULTS

Data indicated that three complexes improved response time and cognitive function and the bio-parameter markers associated with oxidative stress in ageing rats. Among them, the complexes prepared from de-branched starch-oleic acid showed a greater improvement compared to others. In addition, de-branched starch-capric acid complex showed a higher improvement in the morphology of colon cells and hippocampal neuronal cells. The consumption of de-branched starch-capric acid and -oleic acid complexes generated more short-chain fatty acids in the gut. More importantly, the complexation of de-branched starch with either caprate or stearate enhanced gut Akkermansia. Therefore, it was proposed that the richness in Akkermansia and gut metabolites might be associated with reduced the damage of the hippocampal neuronal cells induced by ageing progress. Moreover, AMPK pathway was activated in liver in de-branched starch-capric acid complex diet. In summary, de-branched starch-capric acid complex exhibited a greater effect on the attenuation of ageing-induced cognitive impairment.

CONCLUSION

This study might highlight a new approach for intervening the cognitive impairment during the ageing progress via a food supply. This article is protected by copyright. All rights reserved.

Characterization of Pickering emulsion by SCFAs-modified debranched starch and a potent for delivering encapsulated bioactive compound

The Pickering emulsion was prepared by short-chain fatty acids (SCFAs) esterified debranched starch. The microstructure, particle size distribution, rheological properties and stability of the emulsions showed that the introduction of acyl groups improved the ability of starch to stabilize the emulsions, in which the butyrylated starch with longer acyl side chains exhibited higher emulsifying ability compared to acetylated and propionylated starches. Pickering emulsions stabilized with butyrylated starch as stabilizer have better stability after 30 days of storage. The particle size distribution of SCFAs-esterified starch emulsions with enzymatic debranching pretreatment was more concentrated and the droplet size was further reduced, which improved the instability factors such as flocculation, agglomeration or Ostwald ripening of emulsions induced by conventional SCFAs-esterified emulsions and further improved the stability of SCFAs-esterified emulsions. More importantly, butyrylated starch (with or without debranched pretreatment) emulsions exhibited smaller and more uniform droplet shapes and higher curcumin encapsulation efficiency (EE%) in SCFAs-esterified starch emulsions, and the EE% of curcumin in debranched butyrylated starch emulsion increasing from 10.04 % in native starch emulsions to 50.70 %.

Association of gut microbiota characteristics and metabolites reveals the regulation mechanisms under cadmium consumption circumstance

BACKGROUND

Cadmium is a non-biodegradable heavy metal with a long biological half-life. Although its negative impact on human health has been previously reported, the association of cadmium consumption overdose with changes in the gut microbiota and its corresponding metabolites has not been fully elucidated so far.

RESULTS

Cadmium consumption overdose led to a reduced body weight gain accompanied by an enhanced level of the proinflammatory cytokine tumor necrosis factor-α, interleukin-6, and histamine in the serum of the rats in comparison with normal rats. Furthermore, hepatotoxicity was also observed to be induced by cadmium, which was consistent with abnormal hepatic activities of alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase and oxidative stress. In contrast, Lactobacillus rhamnosus-fermented Ganoderma lucidum (FGL) slice supplementation improved the aforementioned physiological properties. More importantly, microbiome and metabolites analysis indicated cadmium exposure significantly reduced the generation of short-chain fatty acids in the gut, particularly butyrate. However, rats in the FGL group had the highest level of butyrate in the feces, characterized with significantly enriched probiotics (Lactobacillus, Bifidobacterium) and butyrate-producing bacteria (Roseburia).

CONCLUSION

The targeted regulation of the gut microbial community and its metabolites might be the essential association for attenuating body dysfunction induced by cadmium. The supplementation of FGL, as evidenced in this study, might highlight a novel approach to this field. © 2022 Society of Chemical Industry.

Starch propionylation acts as novel encapsulant for probiotic bacteria: A structural and functional analysis

Propionylated potato starch (PPS) with different degrees of substitution (DS) was prepared from native potato starch (NPS) and their potential to encapsulate Lactobacillus rhamnosus GG (LGG) was analyzed. Fourier transform infrared spectroscopy (FTIR) showed a characteristic peak of propionyl groups, which appeared at 1746 cm^-1, demonstrating that propionylation occurred. X-ray diffraction (XRD) results revealed that the characteristic diffraction peak intensity of PPS gradually disappeared with the increasing of the DS, which was related to the loss of the ordered crystalline structure of starch granules. Propionylation resulted in the starch to be more thermally stable than its native starch. Furthermore, the propionylated starch had a higher resistance to digestion and hydrophobicity. More importantly, the micro-capsulated LGG derived from propionylated starch could achieve a maximum embedding efficiency of 87.77% at starch DS = 1.54, and also demonstrated a higher resistance to a strong acidic condition and a greater storage stability at 4 °C. This study may highlight a novel approach for probiotic encapsulation using propionylated potato starch as an encapsulant.

Physicochemical and volatile characteristics present in different grain layers of various rice cultivars

Five rice cultivars were applied for investigating effect of milling degree on rice physicochemical properties. The first layer had the lowest peak viscosity, followed by the second and third layers, indicating the effect of non-starchy components on starch gelatinization behaviors. Consistently, more content of non-starch components in the first layer led to an enhanced gelatinization temperature. Rheological study demonstrated the G' and G" were successively increased as the layer moved inward, indicating a stronger gel network due to the increased amylose content and crystallinity in the corresponding layer. This is the first study to reveal the second layer has the highest digestibility, suggesting both non-starch components and starch structure control starch digestion. Furthermore, analysis of volatile compounds found alcohols and ketones concentrated in the first layer, whilst compounds including (E,E)-2,4-decadienal, 3-octanone and 3-nonen-2-one only existed in the second layer, serving as an indicator for managing the rice quality during milling.

Gut microbiota derived structural changes of phenolic compounds from colored rice and its corresponding fermentation property

The influence of phenolic compounds extracts from three colored rice cultivars on gut microbiota was investigated. The results revealed that protocatechuic acid, chlorogenic acid, caffeic acid and p-coumaric acid were...

Microbiota fermentation characteristics of acylated starches and the regulation mechanism of short-chain fatty acids on hepatic steatosis

Starches acylated with specific short-chain fatty acids (SCFAs) have the potential to provide specificity in SCFA delivery. It is well documented that SCFAs are involved in lipid metabolism, but the underlying mechanism is still unclear. For characterizing the fermentation properties of acylated starches with various SCFAs in terms of SCFA production, three different acylated starches were prepared following the esterification of high amylose maize starch (HAMS) using acetic anhydride, propionic anhydride and butyric anhydride, respectively. Compared with HAMS, the gut microbiota fermentation of acetylated, propionylated and butylated starches specifically increased the production of acetic acid, propionic acid, and butyric acid, respectively, indicating that the introduced acyl group can be effectively released during the fermentation process. Furthermore, the utilization of these starches generated more total SCFAs, suggesting that they can be effectively fermented by the microbiota as a carbohydrate substrate. Study on an in vitro model of cultured rat hepatocytes indicated that either mixed SCFAs or butyrate play an important role in regulating lipid metabolism via activating AMPK and PPAR signaling pathways, implying the importance of butyrate in the improvement of lipid metabolism and accumulation. This study may provide further understanding of the individual function of the corresponding SCFA.

Manipulation of the internal structure of starch by propionyl treatment and its diverse influence on digestion and in vitro fermentation characteristics

High amylose maize starch (HAMS) and waxy maize starch (WMS) were modified by propionylation and their corresponding physicochemical characteristics, digestion and fermentation properties were studied. The results indicated that two new peaks related to methylene (2.20 ppm) and methyl (0.97 ppm) in the NMR spectrum were formed, indicating the occurrence of propionylation, and this was further confirmed by the formation of a characteristic absorption at 1747 cm^-1 in the FTIR spectrum. The propionylation led the modified starch having a lower electron density contrast between the crystalline and amorphous flakes, resulting in the formation of a more compact structure following the increased degrees of substitution (DS). The propionylated starch also had a higher thermal stability and hydrophobicity. These structural changes increased the content of resistant starch (RS) and reduced the predicted glycemic index. More importantly, the gut microbiota fermentation properties indicated that the propionylation of the starch can not only increase the yield of propionate, but also increase the concentration of total short-chain fatty acids (SCFAs). This study highlights a new approach to significantly enhance the RS content in starch, together with an increased SCFA generation capacity.

Manipulations of glucose/lipid metabolism and gut microbiota of resistant starch encapsulated Ganoderma lucidum spores in T2DM rats

Our team previously demonstrated that Ganoderma lucidum spores (GLS) and resistant starch (RS) had hypoglycemic effects separately on type 2 diabetic mellitus (T2DM) rats. This work was to explore the effects of administering encapsulated GLS within RS (referred to as EGLS) in the T2DM rats, which were induced by streptozotocin (STZ). The EGLS was orally administered to rats for 28 days. The parameters of glycometabolism and lipometabolism were evaluated, and fecal microbiota composition was investigated. The results showed that EGLS significantly enhanced glycometabolism and lipometabolism parameters in T2DM rats, which might be associate with the enhancement of the glucose and lipid metabolism, insulin secretion, and glycogen synthesis and reduced lipogenesis. Furthermore, the intervention of EGLS also reduced the Proteobacteria community and improved dysfunctional gut microbiota. This study indicated EGLS may be a potential candidate for dietary intervention to modulate diabetes.

Hitting the sweet spot: A systematic review of the bioactivity and health benefits of phenolic glycosides from medicinally used plants

Phenolic acid and flavonoid glycosides form a varied class of naturally occurring compounds, characterised by high polarity-resulting from the glycone moiety-and the presence of multiple phenol functionalities, which often leads to strong antioxidant activity. Phenolic glycosides, and in particular flavonoid glycosides, may possess strong bioactive properties with broad spectrum activity. This systematic literature review provides a detailed overview of 28 studies examining the biological activity of phenolic and flavonoid glycosides from plant sources, highlighting the potential of these compounds as therapeutic agents. The activity of glycosides depends upon the biological activity type, identity of the aglycone and the identity and specific location of the glycone moiety. From studies reporting the activity of both glycosides and their respective aglycones, phenolic glycosides appear to generally be a storage/reserve pool of precursors of more bioactive compounds. The glycosylated compounds are likely to be more bioavailable compared to their aglycone forms, due to the presence of the sugar moieties. Hydrolysis of the glycoside in the in vivo environment would release the free aglycone, potentiating their biological activity. However, further high-quality studies are needed to firmly establish the clinical efficacy of glycosides from many of the plant species studied.

Preparation, structural characteristics and physiological property of resistant starch

Starch is of the most important carbohydrates in human diets for maintaining normal body's energy metabolisms. However, due to the increased number of chronic diseases worldwide, the further study of the starch property in the dietary formula becomes essential for revealing its association with preventing or intervening the occurrence of such diseases as diabetes, obesity, intestinal diseases and even cardiovascular diseases. Considering that different starches demonstrate different digestion property based on their individual structural characteristics, in particular, the existence of resistant starch (RS) attracts much more interests recently because of its being a major producer of short-chain fatty acids followed by gut microbial fermentation. Furthermore, the understanding of the interaction between RS and microbiota in the gut and its substantial influence on the regulation of diabetes, kidney, disease hypertension and others is still being under investigated. Therefore, this chapter summarized the fine structure of starch, resistant starch structural characteristics, formation and preparation of resistant starches and their corresponding physiological property.

Association of enriched metabolites profile with the corresponding volatile characteristics induced by rice yellowing process

Change in metabolites and volatiles during yellowing process in six rice cultivars was analyzed. Based on the yellowness, the study indicated Japonica was more prone to yellowing than Indica rice. Metabonomics analysis showed most differential metabolites were up-regulated, in which pathways of flavone and flavonol biosynthesis were significantly enriched following the yellowing process. Meanwhile, 54 differential metabolites were overlapped in six comparative groups, which is characterized by commonly-shared metabolic regulation pathway in each rice. Phenylalanine content was increased, followed by the enhanced phenylpropanoids formation, showing transformation between primary and secondary metabolites during yellowing process. Furthermore, 43 volatile compounds were identified, and the yellowed rice had more volatiles, including ketones, alcohols, esters and hydrocarbons, suggesting a positive correlation with the yellowing. Compounds 6-methyl-5-hepten-2-one and 6,10,14-trimethyl-2-pentadecanone were increased steadily during yellowing process, which may be applied for monitoring rice yellowing progress. This investigation provides further insight for revealing rice yellowing mechanism.

Regulation of hyperglycemia in diabetic mice by autolysates from β-mannanase-treated brewer's yeast

BACKGROUND

Diabetes mellitus is a serious chronic disease, characterized by hyperglycemia. This study administered either β-mannanase-treated yeast cell autolysis supernatant (YCS) or yeast cell-wall residues after autolysis (YCR) to investigate their influence on the alleviation of diabetes in a diabetic mouse model.

RESULTS

Application of either YCS or YCR led to body weight gain, blood glucose reduction, and an improvement in lipid composition in the diabetic mice. Administration of YCS was more effective in inhibiting oxidative stress than YCR. The expression of PPARα and CPT1α was enhanced, improving lipid biosynthesis, and Trx1 and HIF-1-α genes were downregulated due to the activation of thioredoxin following the interventions, indicating that the processes of lipid metabolism and oxidative stress were heavily involved in the reduction of diabetic characteristics following the interventions. The current study revealed that consumption of YCR also led to a reduction in hyperglycemia, this being associated with its richness in mineral elements, such as chromium and selenium.

CONCLUSION

This study may highlight the potential of both YCS and YCR as functional ingredients in dietary formula for improving diabetic syndromes. © 2019 Society of Chemical Industry.

Abundance of Probiotics and Butyrate-Production Microbiome Manages Constipation via Short-Chain Fatty Acids Production and Hormones Secretion

SCOPE

The characteristics of gut microbiota and host metabolism are hypothesized to be associated with constipation status, but the regulation mechanism is not fully understood. Thus, the current study investigates the effect of constipation symptoms on gut functionality following the modulation of gut microbiota and metabolites via dietary fiber intervention.

METHODS AND RESULTS

Constipation causes a significantly reduced short-chain fatty acids (SCFAs) production and a higher level of iso-butyrate. The feces of constipated people are characterized with inhibited Faecalibacterium, Ruminococcaceae and Roseburia abundance. Desulfovibrionaceae is identified to be an important endotoxin producer in constipated patients, and a butyrate-enriched SCFAs profile achieved by dietary fiber supplement accelerates gastrointestinal transit and increases the thickness of the mucosal layer, possibly through triggering the secretion of colonic hormones and enhancing the expression of tight junction proteins for maintaining intestinal barrier integrity. More importantly, an interacting regulatory mechanism among SCFAs, in particular butyrate and propionate, may be involved in signaling between the microbiome and host cells in the colon.

CONCLUSION

Gut microbiota, characterized with enriched butyrate-producing and depressed Desulfovibrionaceae bacteria, attenuates constipation symptoms through promoting intestinal hormones secretion and maintaining gut barrier integrity.

Generation of a nitric oxide signaling pathway in mesenchymal stem cells promotes endothelial lineage commitment

Enhancing differentiation of mesenchymal stem cells (MSCs) to endothelial cells may improve their ability to vascularize tissue and promote wound healing. This study describes a novel role for nitric oxide (NO) in reprogramming MSCs towards an endothelial lineage and highlights the role of Wnt signaling and epigenetic modification by NO. Rat MSCs were transduced with lentiviral vectors expressing endothelial nitric oxide synthase (pLV-eNOS) and a mutated caveolin gene (pLV-CAV-1^F92A ) to enhance NO generation resulting in increased in vitro capillary tubule formation and endothelial marker gene expression. An exogenous source of NO could also stimulate CD31 expression in MSCs. NO was associated with an arterial-specific endothelial gene expression profile of Notch1, Dll4, and Hey2 and significantly reduced expression of venous markers. Wnt signaling associated with NO was evident through increased gene expression of Wnt3a and β-catenin protein, and expression of the endothelial marker Pecam-1 could be significantly reduced by treatment with the Wnt signaling inhibitor Dkk-1. The role of NO as an epigenetic modifier was evident with reduced gene expression of the methyltransferase, DNMT1, and bisulfite sequencing of the endothelial Flt1 promoter region in NO-producing MSCs showed significant demethylation compared to control cells. Finally, subcutaneous implantation of NO-producing MSCs seeded in a biomaterial scaffold (NovoSorb®) resulted in survival of transplanted cells and the formation of blood vessels. In summary, this study describes, NO as a potent endothelial programming factor which acts as an epigenetic modifier in MSCs and may provide a novel platform for vascular regenerative therapy.

γ-Aminobutyric Acid Attenuates High-Fat Diet-Induced Cerebral Oxidative Impairment via Enhanced Synthesis of Hippocampal Sulfatides

Long-term high-fat diet (HFD) in rats triggered cerebral oxidative stress, reflected by reactive oxygen species accumulation and antioxidant decline in peripheral and cerebral tissues, together with hippocampal lipid disturbance, particularly for triglyceride accumulation and sulfatide deficiency. Hippocampal formation and cerebral cortex also exhibited pathological changes, characterized by neurofibrillary tangle and reduced Nissl bodies. Sulfatides were noted to protect hippocampal neurons from oxidative damage through the clearance of β-amyloid protein, with apolipoprotein E transporting and low-density lipoprotein receptor binding. Delightedly, we found γ-aminobutyric acid (GABA) supplement delivered by rice bran to rats significantly promoted hippocampal sulfatide synthesis and reversed the HFD-induced sulfatide deficiency and oxidative-triggered cerebral impairment. Elevated GABA concentration in hippocampus and the activation of GABA B-type receptors might be the primary contributors. This study demonstrated the potential of GABA-enriched rice bran as a novel dietary supplement to enhance a sulfatide-based therapeutic approach for neurodegenerative diseases in the early stages.

Attenuation of metabolic syndrome in the ob/ob mouse model by resistant starch intervention is dose dependent

The effect of different RS concentrations on the morphology of colon (A), liver (B) and adipose tissue (C).

Peptides derived from lupin proteins confer potent protection against oxidative stress

BACKGROUND

Lupin seeds are rich in proteins, which are utilized in the food industry. There is an increased interest in lupin research due to its association with health-related benefits, such as reduction of hypertension and hyperglycemia. However, studies on the peptides derived from lupin proteins are rare.

RESULTS

Lupin protein hydrolysates (LPHs) were prepared by proteolysis using alcalase, trypsin and pepsin, respectively. All the hydrolysates demonstrated higher antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activities compared to lupin proteins. The hydrolysates were fractionated into three fractions based on molecular weight (MW), and the peptides with MW < 3 kDa (LPH3) had the highest antioxidant and ACE inhibitory activities compared to other fractions. Cell model study revealed that LPH3 fraction had the highest protection against the generation of reactive oxygen species in HepG2 cells, which was associated with increased activities of superoxide dismutase and glutathione peroxidase through upregulation of SOD1, GPX1, GCLM, SLC7A11 and SRXN1 expression.

CONCLUSIONS

The analysis of amino acid composition indicated that the peptides were characterized with high content of hydrophobic amino acids, which may be responsible for the greatest antioxidant activity. This study highlights the promising potential of lupin peptides as a functional ingredient in healthy foods. © 2018 Society of Chemical Industry.

Characterization of endogenous antioxidant attributes and its influence on thermal stability of canola oil

Difference in thermal stability of two commercially available canola oils prepared by either expeller-extraction (EE) or solvent-extraction (SE) method was investigated. After 5 days consecutive deep-fry, content of oxidized-triacylglycerols (oxTAGs) in SE oil increased by 250.0% compared to its original status. However, 62.5% increase of oxTAGs in EE oil occurred, indicating that EE oil exhibits superior thermal stability to SE oil. Antioxidant capacity of EE oil was highly retained and loss rate of tocopherols in EE oil was much slower than in SE oil during deep-fry. Lipidomics showed that although there was no significant difference in molecular profile of either triacylglycerols or diacylglycerols between two oils, EE oil was characterized with 19 times higher phosphatidylcholine contents than SE oil. Considering no difference in antioxidant capacity between the two oils in their original status, it is proposed that synergetic mechanism is simultaneously initiated by antioxidant compounds and phosphatidylcholines, which plays key roles for maintaining better thermo-stability of vegetable oil during deep-fry.

Wheat bran with enriched gamma-aminobutyric acid attenuates glucose intolerance and hyperinsulinemia induced by a high-fat diet

In this study, the level of gamma-aminobutyric acid (GABA) in wheat bran was increased to be six times higher through the action of endogenous glutamate decarboxylase compared with untreated bran. The process of GABA formation in wheat bran also led to an increased level of phenolic compounds with enhanced antioxidant capacity 2 times higher than the untreated status. The interventional effect of a diet containing GABA-enriched bran on hyperinsulinemia induced by a high-fat diet (HFD) was investigated in a rat model. The results showed that, when compared with animals fed with HFD-containing untreated bran (NB group), the consumption of HFD-containing GABA-enriched bran (GB group) demonstrated a greater improvement of insulin resistance/sensitivity as revealed by the changes in the homeostatic model assessment for insulin resistance index (HOMA-IR) and the quantitative insulin sensitivity check index (QUICKI). The expression of hepatic genes, cytochrome P450 family 7 subfamily A member 1 (Cyp7a1) and ubiquitin C (Ubc), which are involved in the adipogenesis-associated PPAR signalling pathway, was found to be significantly down-regulated in the GB group compared with the HFD group (P = 0.0055). Meanwhile, changes in the expression of a number of genes associated with lipid metabolism and gluconeogenesis were also noted in the GB group versus the HFD group, but not in the NB group, indicating different regulatory patterns between the two brans in a high-fat diet. More importantly, the analysis of key genes related to glucose metabolism further revealed that the expression of insulin-induced gene 1/2 (Insig-1/2) was increased following GB intervention with a corresponding reduction in phosphoenolpyruvate carboxykinase 1 (Pepck) and glucose-6-phosphatase, catalytic subunit (G6pc) expression, suggesting that glucose homeostasis is greatly improved through the intervention of GABA-enriched bran in the context of a high-fat diet.

Lentiviral vector expression of Klf4 enhances chondrogenesis and reduces hypertrophy in equine chondrocytes

Monolayer expansion of chondrocytes in culture results in the dedifferentiation of chondrocytes with inferior cartilage specific extracellular matrix synthesis and proliferation when compared with its native counterpart. We aimed to enhance chondrocyte proliferation and articular cartilage specific gene expression through ectopic expression of the major pluripotency transcription factors (Oct4, Sox2, Klf4 and c-Myc). We also aimed to provide insights to the modulation of TGFβ receptor mRNA with Klf4 overexpression. Equine chondrocytes pooled from three donors were transduced with lentiviral vectors expressing the induced pluripotency factors, Oct4, Sox2. Klf4 and c-Myc (OSKM), singly, or in combination or together with green fluorescent protein (GFP) as a control. Klf4 and c-Myc overexpressing chondrocytes showed a significant increase in mitosis when compared to the control (P < 0.01 and P < 0.0001 respectively). Furthermore, overexpression of Klf4 or OSKM in three dimensional (3D) culture of equine chondrocytes resulted in a significant increase in Col2a1 mRNA levels relative to the controls (P < 0.05 and P < 0.01 respectively) while all transcription factors significantly lowered the mRNA of the fibrocartilage marker Col1a1. We also employed a Col2a1 promoter driven GFP reporter for real time monitoring of Col2a1 gene activation in 3D micromass culture, which showed significantly higher promoter activity when cultures were treated with the growth factor TGFβ3 (P < 0.05). The chondrogenic properties of Klf4 transduced chondrocytes at a lower passage (P4) showed significant increases in Sox9 (P < 0.001), Col2a1 (P < 0.05) and TGFβ receptor I (P < 0.05) and II (P < 0.001) expression relative to the DS-Red expressing control. The chondrocyte dedifferentiation marker Col1a1 and hypertrophic marker Col10a1 were significantly downregulated with the inclusion of Klf4 (P < 0.01 and P < 0.05 respectively). In Conclusion, chondrogenic re-differentiation and proliferation of equine chondrocytes is promoted through ectopic expression of Klf4 while suppressing chondrocyte dedifferentiation.

Impact on the nutritional attributes of rice bran following various stabilization procedures

Rice bran, a valuable byproduct of the rice milling process, has limitations in food industrial applications due to its instability during storage. This review summaries the methodology for stabilization and its impact on the nutritional properties of rice bran. A variety of treatments have been used and these include heat treatment, low-temperature storage, biological and chemical approaches and these will be discussed in terms of their ability to destroy/inhibit enzyme activity and improve storage performance of rice bran. More importantly, changes in the nutritional value of rice bran in terms of vitamins, polyphenols, tocopherols, flavonoids, free fatty acids caused by stabilization of rice bran will also be discussed. This review highlights the importance of appropriate design of processes for stabilization and controlling storage conditions to ensure quality of the rice bran and enhancing levels of phytochemicals in the bran for novel applications in functional foods.

Gamma-aminobutyric Acid Enriched Rice Bran Diet Attenuates Insulin Resistance and Balances Energy Expenditure via Modification of Gut Microbiota and Short-Chain Fatty Acids

In this study, gamma-aminobutyric acid (GABA) enriched rice bran (ERB) was supplemented to obese rats to investigate the attenuation of metabolic syndromes induced by high-fat diet. ERB-containing diet stimulated butyrate and propionate production by promoting Anaerostipes, Anaerostipes sp., and associated synthesizing enzymes. This altered short-chain fatty acid (SCFA) distribution further enhanced circulatory levels of leptin and glucagon-like peptide-1, controlling food intake by downregulating orexigenic factors. Together with the enhanced fatty acid β-oxidation highlighted by Prkaa2, Ppara, and Scd1 expression via AMPK signaling pathway and nonalcoholic fatty liver disease pathway, energy expenditure was positively modulated. Serum lipid compositions showed ERB supplement exhibited a more efficient effect on lowering serum sphingolipids, which was closely associated with the status of insulin resistance. Consistently, genes of Ppp2r3b and Prkcg, involved in the function of ceramides in blocking insulin action, were also downregulated following ERB intervention. Enriched GABA and phenolic acids were supposed to be responsible for the health-beneficial effects.

Gut Microbiome-Induced Shift of Acetate to Butyrate Positively Manages Dysbiosis in High Fat Diet

SCOPE

A recent study revealed that the accumulation of gut microbiota-produced acetate (GMPA) led to insulin over-secretion and obesity symptom. To further develop this scientific point, the effect of resistant starch (RS) or exogenous acetate carried by RS (RSA) in the gut on metabolic syndrome is investigated using diet-induced obese rats.

METHODS AND RESULTS

The metabonomics analysis shows that the gut of rats in the RSA group generate more butyrate in both serum and feces rather than acetate compared to the rats in RS group, indicating the conversion among metabolites, in particular from acetate to butyrate via gut microbiota. Consistently, the gut microbiome uses acetate as a substrate to produce butyrate, such as Coprococcus, Faecalibacterium, Roseburia, and Eubacterium and was highly promoted in RSA group, which further supports the metabolic conversion. This is the first report to reveal the accumulation of gut microbiota-produced butyrate (GMPB) but not GMPA significantly enriched AMPK signaling pathway with reduced expression of lipogenesis-associated genes for suppressing sphingosines and ceramides biosynthesis to trigger insulin sensitivity.

CONCLUSION

Gut microbiome profile and lipogenesis pathway are regulated by GMPB, which substantially influences energy harvesting in the gut from patterns opposed to GMPA.

A comparison of RS4-type resistant starch to RS2-type resistant starch in suppressing oxidative stress in high-fat-diet-induced obese rats

The anti-obesity effects of two types of resistant starch (RS) in high-fat-diet-induced obese rats were investigated.

Resistant starch attenuates impaired lipid biosynthesis induced by dietary oxidized oil via activation of insulin signaling pathways

The current study found that deep-frying process led to an increased content of oxidized triacylglycerols in canola oil, 3.5 times higher than that of fresh canola oil (not used for frying).

Characterization of fecal fat composition and gut derived fecal microbiota in high-fat diet fed rats following intervention with chito-oligosaccharide and resistant starch complexes

The current study analyzed the different effects of intervention in high-fat diet fed rats using chito-oligosaccharides (CO group), resistant starch (RS group) and their complexes (CO–RS group), respectively.