The anti-obesity and gut microbiota modulating effects of taxifolin in C57BL/6J mice fed with a high-fat diet

BACKGROUND

Taxifolin is a natural dihydroflavonol found in many plants and health products. In the present study, its anti-obesity and gut microbiota modulating effects were studied. C57BL/6J mice were fed with a high-fat diet (HFD) supplemented with taxifolin (0, 0.5 and 1 mg mL^-1 , respectively) in drinking water for 15 weeks.

RESULTS

Taxifolin supplementation showed no influence on food and water intake. However, it decreased body weight gain, inhibited fat accumulation, and decreased total cholesterol and triacylglycerol level in mice liver. Taxifolin enhanced superoxide dismutase (SOD) activity in mice liver, which in turn protected the liver from lipid peroxidation damage. It also improved insulin resistance in obese mice. Metagenomic analysis of bacterial 16S rRNA demonstrated that HFD decreased gut microbiota diversity and caused dysbiosis. However, taxifolin improved the gut microbiota diversity and decreased the Firmicutes/Bacteroidetes ratio. In particular, it inhibited Proteobacteria from blooming, this being a signature of dysbiosis in gut microbiota.

CONCLUSION

Taxifolin ameliorated the symptoms of obesity, hepatic steatosis, lipid peroxidation, insulin resistance, and gut microbiota dysbiosis in HFD fed C57BL/6J mice. © 2021 Society of Chemical Industry.

Dihydromyricetin Improves Cognitive Impairments in d-Galactose-Induced Aging Mice through Regulating Oxidative Stress and Inhibition of Acetylcholinesterase

SCOPE

Alzheimer's disease (AD) is a neurodegenerative disease with phenomena of cognitive impairments. Oxidative stress and cholinergic system dysfunction are two widely studied pathogenesis of AD. Dihydromyricetin (DMY) is a natural dihydroflavonol with many bioactivities. In this study, it is aimed to investigate the effects of DMY on cognitive impairment in d-galactose (d-gal) induced aging mice.

METHODS AND RESULTS

Mice are intraperitoneally injected with d-gal for 16 weeks, and DMY is supplemented in drinking water. The results show that DMY significantly improves d-gal-induced cognitive impairments in novel object recognition and Y-maze studies. H&E and TUNEL staining show that DMY could improve histopathological changes and cell apoptosis in mice brain. DMY effectively induces the activities of catalase, superoxide dismutase and glutathione peroxidase, and reduces malondialdehyde level in mice brain and liver. Furthermore, DMY reduces cholinergic injury by inhibiting the activity of Acetylcholinesterase (AChE) in mice brain. In vitro studies show that DMY is a non-competitive inhibitor of AChE with IC50 value of 161.2 µg mL^-1 .

CONCLUSION

DMY alleviates the cognitive impairments in d-gal-induced aging mice partly through regulating oxidative stress and inhibition of acetylcholinesterase.

p53 regulates lipid metabolism in cancer

Reprogrammed cell metabolism is a well-accepted hallmark of cancer. Metabolism changes provide energy and precursors for macromolecule biosynthesis to satisfy the survival needs of cancer cells. The specific changes in different aspects of lipid metabolism in cancer cells have been focused in recent years. These changes can affect cell growth, proliferation, differentiation and motility through affecting membranes synthesis, energy homeostasis and cell signaling. The tumor suppressor p53 plays vital roles in the control of cell proliferation, senescence, DNA repair, and cell death in cancer through various transcriptional and non-transcriptional activities. Accumulating evidences indicate that p53 also regulates cellular metabolism, which appears to contribute to its tumor suppressive functions. Particularly the role of p53 in regulating lipid metabolism has gained more and more attention in recent decades. In this review, we summarize recent advances in the function of p53 on lipid metabolism in cancer. Further understanding and research on the role of p53 in lipid metabolism regulation will provide a potential therapeutic window for cancer treatment.

In vivo and in vitro comparison of three astilbin encapsulated zein nanoparticles with different outer shells

Three shell materials, lecithin (ZNP-L), chitosan (ZNP-CH) and sodium caseinate (ZNP-SC), were used to prepare core-shell zein nanoparticles. Astilbin was encapsulated as a model flavonoid to compare the influence of the shell materials on zein nanoparticles both in vitro and in vivo. The particle size was moderately increased by lecithin and sodium caseinate, but notably increased by chitosan. All the shell materials provided good redispersibility for the nanoparticles and significantly improved the colloidal stability. Chitosan and sodium caseinate significantly delayed and decreased the feces excretion of astilbin in rats, while lecithin exhibited a very weak effect. The results may be attributed to the difference in mucoadhesive properties between the shell materials. As a consequence, the bioavailability values of astilbin in rats were 18.2, 9.3 and 1.89 times increased through ZNP-CH, ZNP-SC and ZNP-L compared with that of free astilbin, respectively.

Digestive properties and effects of Chimonanthus nitens Oliv polysaccharides on antioxidant effects in vitro and in immunocompromised mice

The study was aimed to investigate the simulated digestion behavior of the bioactive polysaccharides from Chimonanthus nitens Oliv (COP1), antioxidant activity in vitro, and prevention against cyclophosphamide (CP) induced oxidative damage in mice. The results showed that COP1 were 18.843 kDa, and consisted of arabinose (56.6 mol%), galactose (24.9 mol%), xylose (11.1 mol%), and glucose (7.4 mol%). Gastrointestinal digestion significantly improved the radical (DPPH, OH, and ABTS⁺) scavenging activities of COP1. Meanwhile, administration of COP1 (150, 300, and 600 mg/kg, continuous 16 days) prevented hepatotoxicity in CP-induced mice (reducing liver index and transaminase levels, alleviating liver damage). COP1 also attenuated oxidative stress as evident from as shown by reduced levels of MDA and enhanced activity of antioxidant enzymes (CAT, SOD, and GSH-Px). In addition, COP1 regulated the Nrf2/Keap1 signaling pathway in CP-treated mice, decreasing the upstream factor Keap1 and increasing the upstream factor Nrf2, which in turn enhanced the expression of downstream factors (NQO1, HO-1, GSH-Px, SOD1, and CAT). COP1 also protected the body from CP-induced oxidative damage by down-regulating Bax and caspase3 in the apoptosis pathway and up-regulating Bcl-2 mRNA levels. Overall, COP1 might be harnessed as an effective natural antioxidant for medical and food industries.

Genome-wide DNA methylation profiling of high-fat emulsion-induced hyperlipidemia mice intervened by a polysaccharide from Cyclocarya paliurus (Batal) Iljinskaja

Genome-wide DNA methylation was used to study the lipid-lowering effect of Cyclocarya paliurus (Batal) Iljinskaja polysaccharide (CPP). The objective of this study was to investigate the hypolipidemic effects and the potential underlying mechanisms of action of CPP-2 in high-fat emulsion (HFE)-induced mice. The results showed that CPP-2 reduced the level of genome-wide DNA methylation in the liver of HFE-induced mice, which had a lipid-lowering effect by regulating the AMP-activated protein kinase (AMPK) signaling-, fatty acid metabolism-, fatty acid biosynthesis- and adipocytokine signaling pathways. A series of lipid metabolism genes were screened out by conjoint analysis of the Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Hereafter, fatty acid synthase (FAS) and peroxisome proliferators-activated receptor α (PPARα) as target genes were selected to validate the accuracy of the results. The findings demonstrated that CPP-2 might be effective in lowering the lipid content, thereby protecting against HFE-induced hyperlipidemia.

Decolorization of molasses alcohol wastewater by thermophilic hydrolase with practical application value

The aim of this work was to explore the ability of cutinase in the decolorization of molasses wastewater. Thermophilic cutinase from Thermobifida alba eliminated 76.1-78.2% of colorants and exhibited the highest decolorization efficiency amongst all of the cutinases tested. Cutinase from Thermobifida alba was immobilized on an affordable and efficient modified chitosan carrier and achieved a decolorization yield of 79.3-81.2%. This cutinase removed 66.3-71.1% of pigments and lasted continuously for 5 days. Importantly, it was also shown to continuously and effectively remove COD and BOD₅. Compared to other enzymes, the immobilized cutinase from Thermobifida alba had the advantage of being low-cost and had a high expression level and activity. The results confirmed the decolorization occurred by destroying the conjugated system of melanoidins via an addition reaction by cutinase from Thermobifida alba. Thus, this study contributes a more practical and efficient approach to enzymatic decolorization of molasses wastewater.

Structural characterization and antioxidant activity of an acetylated Cyclocarya paliurus polysaccharide (Ac-CPP0.1)

The aim of this study was to investigate the primary structure of an acetylated Cyclocarya paliurus polysaccharide (Ac-CPP_0.1) and its protective effect on H₂O₂-treated dendritic cells. The backbone of Ac-CPP_0.1 was →3)-β-D-Galp-(1→, with some branches α-L-Araf-(1→ residues at O-6 and O-5, β-D-Galp-(1→ and 3,5,6)-β-D-Galf-(1 residues at O-4 and acetyl groups were substituted at the O-2 and O-6 positions of 3)-β-D-Galp-(1 residues. The CPP_0.1 and Ac-CPP_0.1 significantly increased the levels of superoxide dismutase, glutathione peroxidase and catalase on H₂O₂-treated dendritic cells. Meanwhile, both CPP_0.1 and Ac-CPP_0.1 up-regulated the expression of Nrf2 (NF-E2-related factor 2) and down-regulated the Keap1 (Kelch-like ECH-associated protein-1), but Ac-CPP_0.1 had a better effect on antioxidant capacity. These results indicated that potential application of Ac-CPP_0.1 as an antioxidant agent.

Protective effect of the new prepared Atractylodes macrocephala Koidz polysaccharide on fatty liver hemorrhagic syndrome in laying hens

Fatty liver hemorrhage syndrome (FLHS) is the most common noninfectious cause of death in backyard chickens worldwide, which can cause a sudden drop in egg production in the affected flocks and cause huge losses to the laying hens breeding industry. In this study, we prepared polysaccharide from Atractylodes macrocephala Koidz (PAMK) by one-step alcohol precipitation. The structural analysis found that PAMK with a molecular weight of 2.816 × 10³ Da was composed of glucose and mannose, in a molar ratio of 0.582 to 0.418. Furthermore, we investigated the hepatoprotective effects of PAMK on high-energy and low-protein (HELP) diet-induced FLHS in laying hens. The results showed that the hens' livers of the HELP diet showed yellowish-brown, greasy, and soft, whereas the supplement of PAMK (200 mg/kg or 400 mg/kg) could alleviate such pathological changes. The liver index, the abdominal fat percentage, and liver injury induced by the HELP diet were reduced in PAMK (200 mg/kg or 400 mg/kg). Supplementing 200 mg/kg or 400 mg/kg PAMK showed improvements of the antioxidant capacity in laying hens. Furthermore, we found that the HELP diet increased the expression of hepatic lipogenesis genes and decreased the expression of fatty acid β-oxidation genes, which could be reversed by 200 mg/kg or 400 mg/kg PAMK supplementation. Nevertheless, there is no difference between the addition of 40 mg/kg PAMK and the HELP group. Collectively, these results showed that PAMK supplements could ameliorate HELP diet-induced liver injury through regulating activities of antioxidant enzymes and hepatic lipid metabolism. Therefore, PAMK could be a potential feedstuff additive to alleviate FLHS in laying hens.

Food Safety Knowledge, Attitudes, and Self-Reported Practices Among Medical Staff in China Before, During and After the COVID-19 Pandemic

PURPOSE

To compare food safety knowledge, attitudes, and self-reported practices among medical staff in China before, during, and after the COVID-19 pandemic.

PATIENTS AND METHODS

The questionnaire was anonymous. All respondents were Chinese medical personnel. A Chi-square contingency table was used to compare the knowledge and attitudes of Chinese medical staff before, during and after COVID-19. R statistical software (v4.0.0) was used for analysis.

RESULTS

A total of 1431 valid responses (57.3% from female respondents) were included in our analysis. Medical professionals were geographically distributed as follows: eastern China, 55.5%; central China, 19.7%; western China, 24.1%; Hong Kong, Macau, or Taiwan, 0.05%. Medical professionals reported that they paid greater attention to food safety after the COVID-19 pandemic compared with before the epidemic. Self-reported knowledge of and attitudes toward food safety among medical staff were significantly different before, during, and after the COVID-19 pandemic (both P<0.001).

CONCLUSION

After the COVID-19 pandemic, medical professionals paid increasing attention to food safety, which is a clinically important change. Because medical professionals can influence public understanding of food safety, their increased attention to this subject may enable them to promote food safety knowledge more actively in their work. This may in turn promote a better understanding of food safety and protect the health of the general public.

Fabrication and characterization of dihydromyricetin encapsulated zein-caseinate nanoparticles and its bioavailability in rat

Dihydromyricetin (DMY) encapsulated zein-caseinate nanoparticles (DZP) were fabricated by antisolvent method. The encapsulation and loading efficiency of DMY in DZP were 90.2% and 22.6% as determined by HPLC. DZP is spherical with particle size and ζ potential of 206.4 nm and -29.6 mV, respectively. Physicochemical characterization showed that DMY existed in amorphous form in DZP and its interaction with proteins was found. The fabrication of DZP significantly improved the stability of DMY. Besides, the diffusion rate of DMY in DZP was faster than its suspensions in both simulated gastric and intestinal fluid. The adhesion of DMY in mice gastrointestinal tract was also improved. Besides DMY itself, its methylated metabolites with further sulfation and glucuronide were identified in rat plasma by UPLC-QTOF-MS. UPLC-QqQ-MS/MS quantitative analysis showed that the oral bioavailability of DMY was 1.95 times enhanced. Besides, the concentration of DMY metabolites in plasma were all increased.

Sulfated modification, characterization, immunomodulatory activities and mechanism of the polysaccharides from Cyclocarya paliurus on dendritic cells

In this study, a crude and purified polysaccharide from Cyclocarya paliurus (CPP, CPP_0.05) were performed with chlorosulfonic acid-pyridine (CSA-Pyr) method to obtain sulfated derivatives (S-CPP, S-CPP_0.05). After comparatively investigating, characterization results showed that the modifications were successful. Polysaccharides were used to culture mouse bone marrow-derived dendritic cells (BM-DCs) to evaluate their immunomodulatory activity and explore mechanism. The functional activity of CPP was significantly stronger than that of the purified polysaccharide CPP_0.05. Meanwhile, S-CPP showed stronger immunomodulatory activity than CPP through determination of cytokine expression levels. We found that p-JNK, p-p38MAPK and NF-κB p65 proteins were significantly increased by stimulus of CPP and S-CPP, blocking TLR2/4 could significantly decreased proteins above which proved that immune regulation effect of CPP and S-CPP on DCs was performed via MAPK and NF-κB signaling pathways by triggering TLR2/4. S-CPP could serve as potential immunomodulatory agents used as complementary medicine or functional foods.

Structure analysis of polysaccharides purified from Cyclocarya paliurus with DEAE-Cellulose and its antioxidant activity in RAW264.7 cells

CPP was isolated from Cyclocarya paliurus (C. paliurus) and CPP-D was purified from CPP with a further step by DEAE-Cellulose. In this study, the structure and antioxidant activities of these two polysaccharides were investigated. The molecular weight of CPP was determined as 1.15 × 10⁵ Da and the monosaccharides of it were Rha, Ara, Xyl, Man, Glc, Gal in a molar ratio of 0.021:0.237:0.020:0.036:0.454:0.231, while the molecular weight of CPP-D was 9.1 × 10³ Da and the monosaccharides of it were Man, Glc, Gal in a molar ratio of 0.235:0.677:0.088. CPP-D consisted of three structural residues →4)-β-D-Glc-(1→, →2,6)-β-D-Man-(1→ and →4)-β-D-Gal. These structures were characterized by SEM, FT-IR, GC-MS, HPGPC, and NMR. The antioxidant assay in RAW264.7 cell showed that both CPP and CPP-D promoted cell viability and antioxidant activity, which decreased the content of MDA and increased the activity of SOD, T-AOC, CAT (P < .05). As a result, CPP-D isolated by DEAE-Cellulose didn't reduce the antioxidant activity of C. paliurus polysaccharide and could enhance the cell viability.

The structural characteristics, antioxidant and hepatoprotection activities of polysaccharides from Chimonanthus nitens Oliv. leaves

This work aimed to investigate the structural characteristics, antioxidant activities and hepatoprotection effect of Chimonanthus nitens Oliv. leaves polysaccharides (COP) on alcohol-induced oxidative damage in mice. Physical and chemical analysis showed that COP contained four monosaccharides including arabinose (Ara), mannose (Man), glucose (Glu) and galactose (Gal), with mass percentages of 26.6%, 5.1%, 32.2% and 36.0%, respectively, which was a heteropolysaccharide with both α- and β- configurations. In vivo experiments indicated that oral administration COP significantly reduced the levels of ALT, AST and MDA in serum, and significantly increased the activity of SOD and GSH-Px. Mice pretreated with COP had a higher superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity in liver and lower content of TNF-α, IL-6 and IL-1β in the liver and serum when compared with alcohol exposure. In addition, the liver histopathological changes induced by alcohol returned to normal in the COP pretreatment group. These results suggest that COP has a protective effect on acute liver injury induced by alcohol.

Effects of polysaccharides from Yingshan Yunwu tea on meat quality, immune status and intestinal microflora in chickens

The present study was aimed to investigate the effects of the addition of Yingshan Yunwu green tea polysaccharide conjugates (GTPC) on meat quality, immune response and gut microflora in chickens. A total of 200 chickens with average initial body weight were randomly allotted to 4 groups. Intestinal samples were collected at the end of experiment for bacterial culture and microbial community analysis by 16S rDNA gene sequencing using Illumina MiSeq. Chicken breast muscle and serum were also sampled for analysis of meat quality and immune function. The results showed that dietary GTPC addition increased (P < 0.05) chicken breast muscle pH and redness-greenness (a*) value and decreased (P < 0.05) the values of lightness (L*), yellowness-blueness (b*), hardness, toughness and adhesiveness. In addition, dietary supplementation of GTPC increased (P < 0.05) the weight of thymus and bursa and serum concentrations of IgA and IgG. Furthermore, of the 10 bacterial phyla, the predominant taxa across all sampling time-points were Bacteroidetes, Firmicutes, Proteobacteria, and Deferribacteres, representing >97% of all sequences. GTPC increased the abundance of Bacteroidetes and Lactobacillus, and decreased the abundance of Proteobacteria. These findings provided some references of the application of GTPC in the poultry industry.

Nanobody-based electrochemical competitive immunosensor for the detection of AFB1 through AFB1-HCR as signal amplifier

A novel nanobody (Nb)-based voltammetric immunosensor coupled with horseradish peroxidase concatemer-modified hybridization chain reaction (HRP-HCR) signal amplifying system is described to realize the rapid and ultrasensitive detection of AFB₁. To design such an immunoassay, anti-AFB₁ Nbs with smaller molecular size were coated densely onto the surface of Au nanoparticle-tungsten disulfide-multi-walled carbon nanotubes (AuNPs/WS₂/MWCNTs) functional nanocomposites as an effective molecular recognition element, whereas AFB₁-streptavidin (AFB₁-SA) conjugates were ingeniously bound with biotinylated HCR dsDNA nanostructures as the competitor, amplifier, and signal report element. In the presence of AFB₁ targets, a competitive immunoreaction was performed between the analyte and AFB₁-SA-labeled HCR (AFB₁-HCR) platform. Upon the addition of SA-modified polyHRP (SA-polyHRP), AFB₁-HCR nanostructures containing abundant biotins were allowed to cross-link to a quantity of HRP by streptavidin-biotin chemistry for signal amplification and signal conversion. Under optimal conditions, the immunosensor displayed a good linear correlation toward AFB₁ ranging from 0.5 to 10 ng mL^-1 with a sensitivity of 2.7 μA • (mL ng^-1) and an ultralow limit of detection (LOD) of 68 fg mL^-1. The specificity test showed that the AFB₁ immunosensor had no obvious cross-reaction with OTA, DON, ZEN, and FB₁. The signal of this sensor decreased by 10.18% in 4 weeks indicating satisfactory stability, and its intra- and inter-laboratory reproducibility was 3.42~10.35% and 4.03%~12.11%, respectively. This biosensing system will open up new opportunities for the detection of AFB₁ in food safety and environmental analysis and extend a wide range of applications in the analysis of other small molecules. Graphical abstract.