Tuning the selectivity of natural oils and fatty acids/esters deoxygenation to biofuels and fatty alcohols:A review

The chemical transformation of natural oils provides alternatives to limited fossil fuels and produces compounds with added value for the chemical industries.The selective deoxygenation of natural oils to diesel-ranged hydrocarbons,bio-jet fuels,or fatty alcohols with controllable selectivity is especially attractive in natural oil feedstock biorefineries.This review presents recent progress in catalytic deoxygenation of natural oils or related model compounds(e.g.,fatty acids)to renewable liquid fuels(green diesel and bio-jet fuels)and valuable fatty alcohols(unsaturated and saturated fatty alcohols).Besides,it discusses and compares the existing and potential strategies to control the product selectivity over heterogeneous catalysts.Most research conducted and reviewed has only addressed the production of one category;therefore,a new integrative vision exploring how to direct the process toward fuel and/or chemicals is urgently needed.Thus,work conducted to date addressing the development of new catalysts and studying the influence of the reaction parameters(e.g.,temperature,time and hydrogen pressure)is summarized and critically discussed from a green and sustainable perspective using efficiency indicators(e.g.,yields,selectivity,turnover frequencies and catalysts lifetime).Special attention has been given to the chemical transformations occurring to identify key descriptors to tune the selectivity toward target products by manipulating the reaction conditions and the structures of the catalysts.Finally,the challenges and future research goals to develop novel and holistic natural oil biorefineries are proposed.As a result,this critical review provides the readership with appropriate information to selectively control the transformation of natural oils into either biofuels and/or value-added chemicals.This new flexible vision can help pave the wave to suit the present and future market needs.

SYNIHESIS AND SURFACE ACTIVE PROPERTIES OF OXYETHYLENATED FATTY ALCOHOL 2-HYDROXYPROPYL SULFONATES

Synthesis and surface active properties of the oxyethylenated fatty alcohol 2-hydroxypropyl sulfonates were investigated.Of all surface active compounds studied,those with a 2-hydroxypropyl (HP) moiety in the molecule are more surface-active than the corresponding compounds without it.

The effect of lengths of branched-chain fatty alcohols on the efficacy and safety of docetaxel-prodrug nanoassemblies

The self-assembly prodrugs are usually consisted of drug modules,activation modules,and assembly modules.Keeping the balance between efficacy and safety by selecting suitable modules remains a challenge for developing prodrug nanoassemblies.This study designed four docetaxel(DTX)prodrugs using disulfide bonds as activation modules and different lengths of branched-chain fatty alcohols as assembly modules(C_(16),C_(18),C_(20),and C_(24)).The lengths of the assembly modules determined the self-assembly ability of prodrugs and affected the activation modules’sensitivity.The extension of the carbon chains improved the prodrugs’self-assembly ability and pharmacokinetic behavior while reducing the cytotoxicity and increased cumulative toxicity.The use of C_(20) can balance efficacy and safety.These results provide a great reference for the rational design of prodrug nanoassemblies.

Comparison between metabolic-associated fatty liver disease and nonalcoholic fatty liver disease:From nomenclature to clinical outcomes

As a result of the obesity epidemic,Nonalcoholic fatty liver disease(NAFLD)and its complications have increased among millions of people.Consequently,a group of experts recommended changing the term NAFLD to an inclusive terminology more reflective of the underlying pathogenesis;metabolic-associated fatty liver disease(MAFLD).This new term of MAFLD has its own disease epidemiology and clinical outcomes prompting efforts in studying its differences from NAFLD.This article discusses the rationale behind the nomenclature change,the main differences,and its clinical implications.

Comparison of Hair Fatty Alcohols by N-Alkylpyridinium Isotope Quaternization and Matrix-assisted Laser Desorptionl ionization Mass Spectrometry for Drug Abuse Monitoring

Based on our previous report on N-alkylpyridinium isotope quaternization （NAPIQ） for the analysis of alcoholic and α,β-unsaturated ketone compounds, we have further applied NAPIQ method in the screening of hair lipids in drug abusers. Relative isotopic quantification was used for comparison of fatty alcohols between normal and drug abuse group, The NAPIQ strategy was proven to be a high-throughput method in the metabolic comparison studies of different group samples. The attached N-cationic pyridinium significantly improved the detection sensitivity for these fatty alcohols in matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric （MALDI-FTMS） analysis. The experimental results showed that the levels of fatty alcohols in the hair of heroin abuse group decreased significantly compared with the normal groups, which may be the results of the inducing of peroxidation enzyme. NAPIQ was proven to be an effective and alternative method in the research of fatty alcoholic metabolism for drug abuse monitoring.

Significance of gut microbiota in alcoholic and non-alcoholic fatty liver diseases

Liver-gut communication is vital in fatty liver diseases,and gut microbes are the key regulators in maintaining liver homeostasis.Chronic alcohol abuse and persistent overnutrition create dysbiosis in gut ecology,which can contribute to fatty liver disease.In this review,we discuss the gut microbial compositional changes that occur in alcoholic and nonalcoholic fatty liver diseases and how this gut microbial dysbiosis and its metabolic products are involved in fatty liver disease pathophysiology.We also summarize the new approaches related to gut microbes that might help in the diagnosis and treatment of fatty liver disease.

Desmethylbellidifolin protects against chronic alcoholic fatty liver disease by regulating Akt-mTORC1 pathway mediated autophagy

OBJECTIVE To investigate the protective effect and potential mechanism of desmethylbellidifolin(DMB)in chronic alcoholic fatty liver disease.METHODS C57BL/6 mice were randomly divided into five groups.Control,metadoxine and DMB group(high dose and low dose)mice were fed with Lieber-DeCarli liquid diet containing 5%alcohol for six weeks.Pair-fed group mice were fed with a liquid diet containing the same calories.After treatment,serum GOT,GPT,TG and hepatic T-CHO,TG,GSH,GSH-Px,SOD and CAT levels were measured.Ectopic liver lipid deposition was determined by oil red O and hematoxylin-eosin(HE)staining.Lipid metabolism and autophagy related genes expression were determined by real-time PCR and Western blotting.Electron microscope and laser scanning confocal microscope were used to detect autophagosome and autophagy flux.RESULTS DMB treatment markedly reduced serum TG,GOT and GPT levels in alcohol-induced mice,as well as hepatic levels of T-CHO,TG and MDA,while increased the GSH,GSH-Px,SOD and CAT levels in the liver.Oil red O and HE staining showed that the alcohol-induced lipid accumulation and hepatocyte morphology changes were significantly improved by DMB treatment.Mechanistically,the expression of stearoyl-CoA desaturase 1 and fatty acid synthase were significantly decreased,while lipolysis related hormone-sensitive lipase was elevated in mouse liver by DMB treatment.In addition,DMB could inhibit the phosphorylation of Akt and mTORC1,and activate autophagy process by inducing autophagy related genes expression,such as LC3,ATG5 and ATG7.Moreover,treatment with DMB notably increased the number of autolysosome and promote the autophagy flux,which may therefore induce the lipolysis and oxidation of lipids and prevent the alcohol-induced excessive lipid accumulation in the liver.CONCLUSION DMB exerts a protective role in alcoholic fatty liver disease by regulating the Akt-mTORC1 pathway mediated autophagy activation.

Research on the Mechanism of the treatment of non‑alcoholic fatty liver by Jianwei Gexia Zhuyu Decoction based on network pharmacology and molecular docking

Objective:To analyse the key compounds,targets and pathways of the treatment of non‑alcoholic fatty liver disease(NAFLD)by Jianwei Gexia Zhuyu Decoction based on network pharmacology,in order to explore the molecular mechanism of its therapeutic effects.Methods:The differential genes between sick and normal conditions were screened by GEO‑Datasets,and the heat map and volcano map were drawn.The active compounds in Jianwei Gexia Zhuyu Decoction were searched by TCMSP platform and Drugbank database.OB≥30%and DL≥0.18 were set as thresholds to screen potential active compounds and action targets.The molecular target maps of Jianwei Gexia Zhuyu Decoction and NAFLD differential genes were constructed,and the PPI network and network topology parameters were obtained by STRING database.The PPI network and network topology parameters were visually analyzed by Cytoscape,and the core regulatory genes were screened.At the same time,the SwissDock platform was used to dock the main active components with the target.The main pathways were determined by GO biological function enrichment analysis and KEGG metabolic pathway enrichment analysis by DAVID.Results:After screening,377 differential genes(127 up‑regulated genes and 250 down‑regulated genes),225 active compounds of Jianwei Gexia Zhuyu Decoction,308 corresponding targets were obtained;14 key targets were screened,corresponding to 168 compounds,and the key targets involved MYC,FOSL2,FOS,etc.The results of GO functional enrichment analysis showed that Jianwei Gexia Zhuyu Decoction mainly regulated the activity expression of DNA binding transcriptional activator and the specific transcription of RNA polymeraseⅡ;The results of molecular docking showed that the main active components quercetin and baicalein had good binding activity with VCAM1,HSPB1,MYC,JUN and so on;The results of KEGG enrichment analysis showed that it was mainly involved in IL‑17 signal pathway,Wnt receptor signal pathway,NF‑κB signal pathway,TNF signal pathway and AGE‑RAGE signal pathway in diabetic complications.Conclusion:Through the interaction of multi‑components and multi‑targets,Jianwei Gexia Zhuyu Decoction has achieved the goal of overall treatment of NAFLD from many ways.The application of network pharmacology provides a new research approach and scientific basis for further study on the mechanism of Jianwei Gexia Zhuyu Decoction in the treatment of NAFLD.

Dietary supplementation in patients with alcoholic liver disease: a review on current evidence

BACKGROUND：Alcoholic liver disease（ALD）is one of the main causes of liver disease worldwide.Although the pathogenesis of ALD has not yet been well elucidated,the oxidative metabolites of ethanol such as acetaldehyde and reactive oxygen species play a pivotal role in the clinical and pathological spectrum of the disease.This review summarizes the existing evidences on dietary supplements considered to have antioxidant,and/or anti-inflammatory properties,and their role in the management of ALD and the proposed mechanisms.DATA SOURCES：The present study reviewed all studies published in Pub Med,Science Direct and Scopus,from 1959 to2015,indicating the role of different dietary supplementation in attenuation of many pathophysiological processes involved in development and progression of ALD.Full-texts of citations were used except for those that were published in languages other than English.RESULTS：Significant progress has been made to understand the key events and molecular players for the onset and progression of ALD from both experimental and clinical studies;however,there is no successful treatment currently available.The present review discussed the role of a variety of dietary supplements（e.g.vitamin A,carotenoids,vitamins B3,C and E,in addition to antioxidants and anti-inflammatory agents）in treating ALD.It has been shown that supplementation with some carotenoids,vitamin B3,vitamin C,silymarin,curcumin,probiotics,zinc,S-adenosylmethionine and garlic may havepotential beneficial effects in animal models of ALD;however,the number of clinical studies is very limited.In addition,supplementation should be accompanied with alcohol cessation.CONCLUSIONS：Since oxidative stress and inflammation are involved in the pathogenesis of ALD,dietary supplements that can modulate these pathologies could be useful in the treatment of ALD.In addition to alcohol cessation,these supplements have shown beneficial effects on animal models of ALD.Clinical trials are needed to validate the beneficiary role of these supplements in patients with ALD.

Obese children with fatty liver: Between reality and disease mongering

Following the current epidemic of obesity, the worldwide prevalence of nonalcoholic fatty liver disease(NAFLD)has increased with potential serious health implications. While it is established that in adults NAFLD can progress to end-stage liver disease in many cases, the risk of progression during childhood is less well defined. Since most obese children are not adherent to lifestyle modifications and hypocaloric diets, there is a growing number of studies on pharmacological interventions with the risk of disease mongering, the practice of widening the boundaries of illness in order to expand the markets for treatment. Here, we propose a critical appraisal of the best available evidence about long-term course of pediatric NAFLD and efficacy of treatments other than hypocaloric diet and physical exercise. As a result, the number of NAFLD children with a poor outcome is small in spite of the alarming tones used in some papers; large-scale longitudinal studies with longterm follow-up of pediatric NAFLD patients are lacking; the studies on ancillary pharmacological interventions have been performed in few patients with inconclusive and conflicting results.

Intestinal virome:An important research direction for alcoholic and nonalcoholic liver diseases

In recent years,the interaction between the gut microflora and liver diseases has attracted much attention.The intestinal microflora is composed of bacteria,archaea,fungi and viruses.There are few studies on the intestinal virome,and whether it has a causal relationship with bacterial changes in the gut is still unclear.However,it is undeniable that the intestinal virome is also a very important portion of the blueprint for the development of liver diseases and the diagnosis and therapeutic modalities in the future.

Analysis of docosanol using GC/MS:Method development,validation,and application to ex vivo human skin permeation studies

Docosanol is the only US Food and Drug Administration(FDA)approved over-the-counter topical product for treating recurrent oral-facial herpes simplex labialis.Validated analytical methods for docosanol are required to demonstrate the bioequivalence of docosanol topical products.A gas chromatography/selected ion monitoring mode mass spectrometry(GC/SIM-MS)method was developed and validated for docosanol determination in biological samples.Docosanol and isopropyl palmitate(internal standard)were separated on a high-polarity GC capillary column with(88%cyanopropy)aryl-polysiloxane employed as the stationary phase.The ions of m/z 83 and 256 were selected to monitor docosanol and isopropyl palmitate,respectively;the total run time was 20 min.The GC/SIM-MS method was validated in accordance with US FDA guidelines,and the results met the US FDA acceptance criteria.The docosanol calibration standards were linear in the 100-10000 ng/mL concentration range(R^(2)>0.994).The recoveries for docosanol from the receptor fluid and skin homogenates were>93.2%and>95.8%,respectively.The validated method was successfully applied to analyze ex vivo human cadaver skin permeation samples.On applying Abreva®cream tube and Abreva®cream pump,the amount of docosanol that penetrated human cadaver skin at 48 h was 21.5±7.01 and 24.0±6.95 ng/mg,respectively.Accordingly,we concluded that the validated GC/SIM-MS was sensitive,specific,and suitable for quantifying docosanol as a quality control tool.This method can be used for routine analysis as a costeffective alternative to other techniques.

Chronic exposure to ethanol causes steatosis and inflammation in zebrafish liver

AIM To evaluate the effects of chronic exposure to ethanol in the liver and the expression of inflammatory genesin zebrafish.METHODS Zebrafish(n = 104),wild type,adult,male and female,were divided into two groups:Control and ethanol(0.05 v/v).The ethanol was directly added into water;tanks water were changed every two days and the ethanol replaced.The animals were fed twice a day with fish food until satiety.After two and four weeks of trial,livers were dissected,histological analysis(hematoxilineosin and Oil Red staining) and gene expression assessment of adiponectin,adiponectin receptor 2(adipor2),sirtuin-1(sirt-1),tumor necrosis factor-alpha(tnf-a),interleukin-1b(il-1b) and interleukin-10(il-10) were performed.Ultrastructural evaluations were conducted at fourth week.RESULTS Exposing zebrafish to 0.5% ethanol developed intense liver steatosis after four weeks,as demonstrated by oil red staining.In ethanol-treated animals,the main ultrastructural changes were related to cytoplasmic lipid particles and droplets,increased number of rough endoplasmic reticulum cisterns and glycogen particles.Between two and four weeks,hepatic mR NA expression of il-1b,sirt-1 and adipor2 were upregulated,indicating that ethanol triggered signaling molecules which are key elements in both hepatic inflammatory and protective responses.Adiponectin was not detected in the liver of animals exposed and not exposed to ethanol,and il-10 did not show significant difference.CONCLUSION Data suggest that inflammatory signaling and ultrastructural alterations play a significant role during hepatic steatosis in zebrafish chronically exposed to ethanol.

COVID-19 and liver diseases,what we know so far

Coronavirus disease 2019(COVID-19)pneumonia outbreak started in December 2019.On March 12,2020,the World Health Organization(WHO)declared that the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)constitutes a pandemic,and as of May 2021,SARS-CoV-2 has infected over 167.3 million patients,including 3.4 million deaths,reported to WHO.In this review,we will focus on the relationship between SARS-CoV-2 infection and the liver.We will discuss how chronic liver diseases affect the COVID-19 disease course and outcomes.We will also discuss the SARS-CoV-2 effects on the liver,mechanisms of acute liver injury,and potential management plans.

Regulatory T cells and their associated factors in hepatocellular carcinoma development and therapy

Liver cancer is the third leading cause of cancer-related death worldwide with primary type hepatocellular carcinoma(HCC).Factors,including carcinogens,infection of hepatitis viruses,alcohol abuse,and non-alcoholic fatty liver disease(NAFLD),can induce HCC initiation and promote HCC progression.The prevalence of NAFLD accompanying the increased incidence of obesity and type 2 diabetes becomes the most increasing factor causing HCC worldwide.However,the benefit of current therapeutic options is still limited.Intrahepatic immunity plays critically important roles in HCC initiation,development,and progression.Regulatory T cells(Tregs)and their associated factors such as metabolites and secreting cytokines mediate the immune tolerance of the tumor microenvironment in HCC.Therefore,targeting Tregs and blocking their mediated factors may prevent HCC progression.This review summarizes the functions of Tregs in HCC-inducing factors including alcoholic and NAFLD,liver fibrosis,cirrhosis,and viral infections.Overall,a better understanding of the role of Tregs in the development and progression of HCC provides treatment strategies for liver cancer treatment.

Deletion of Gab2 in mice protects against hepatic steatosis and steatohepatitis:a novel therapeutic target for fatty liver disease

Fatty liver disease is a serious health problem worldwide and is the most common cause for chronic liver disease and metabolic disorders.The major challenge in the prevention and intervention of this disease is the incomplete understanding of the underlying mechanism and thus lack of potent therapeutic targets due to multifaceted and interdependent disease factors.In this study,we investigated the role of a signaling adaptor protein,GRB2-associated-binding protein 2(Gab2),in fatty liver using an animal disease model.Gab2 expression in hepatocytes responded to various disease factor stimulations,and Gab2 knockout mice exhibited resistance to fat-induced obesity,fat-or alcohol-stimulated hepatic steatosis,as well as methionine and choline deficiency-induced steatohepatitis.Concordantly,the forced expression or knockdown of Gab2 enhanced or diminished oleic acid(OA)-or ethanol-induced lipid production in hepatocytes in vitro,respectively.During lipid accumulation in hepatocytes,both fat and alcohol induced the recruitment of PI3K or Socs3 by Gab2 and the activation of their downstream signaling proteins AKT,ERK,and Stat3.Therefore,Gab2 may be a disease-associated protein that is induced by pathogenic factors to amplify and coordinate multifactor-induced signals to govern disease development in the liver.Our research provides a novel potential target for the prevention and intervention of fatty liver disease.

Effects of intestine-specific deletion of fibroblast growth factor 15 on alcoholic liver disease development in mice

Background and aims:Alcoholic liver disease(ALD)is an important and growing cause for the development of chronic liver diseases in the world.Bile acid(BA)levels are increased in patients with ALD anddysregulation of BA homeostasis worsens ALD.BA synthesis is critically regulated by fibroblast growthfactor(FGF)15 in mice and FGF19 in humans.FGF15/19 are mainly produced in the ileum and their mainfunction is to suppress BA synthesis in the liver through the activation of fibroblast growth factor receptor 4(FGFR4)on hepatocytes.The effects of intestine-specific Fgf15 deficiency on the development ofALD were determined in the current study.Methods:Enterocyte-specific Fgf15 knockout mice(Fgf15intint^(-/-))and the established mouse model bychronic and binge ethanol feeding(NIAAA model)were adapted in this study.Results:The Fgf15intint^(-/-)mice had increased BA pool size,consistent with negative effects of FGF15-FGFR4signaling on BA synthesis.There were not obviously physical and hepatic histological abnormalitiespresented in Fgf15intint^(-/-)mice compared to wild-type mice.Following alcohol treatment,the Fgf15intint^(-/-)mice exhibited a higher degree of liver injury,increased hepatic expression of Cd14,a receptor forlipopolysaccharide expressed in the liver,and increased hepatic lipid levels.We did not observe alterations in the levels of fibrosis in the liver or expression of genes involved in hepatic fibrosis,regardless ofgenotypes or following the alcohol treatment.Conclusions:FGF15 may prevent hepatic steatosis in the development of ALD in mice,and maintainingFGF19/FGFR4 signaling may be critical in the prevention and/or treatment of ALD in humans in thefuture.

Screening neutral sites for metabolic engineering of methylotrophic yeast Ogataea polymorpha

Methylotrophic yeast Ogataea polymorpha is capable to utilize multiple carbon feedstocks especially methanol as sole carbon source and energy,making it an ideal host for bio-manufacturing.However,the lack of gene integration sites limits its systems metabolic engineering,in particular construction of genome-integrated pathway.We here screened the genomic neutral sites for gene integration without affecting cellular fitness,by genomic integration of an enhanced green fluorescent protein(eGFP)gene via CRISPR-Cas9 technique.After profiling the growth and fluorescent intensity in various media,17 genome positions were finally identified as potential neutral sites.Finally,integration of fatty alcohol synthetic pathway genes into neutral sites NS2 and NS3,enabled the production of 4.5 mg/L fatty alcohols,indicating that these neutral sites can be used for streamline metabolic engineering in O.polymorpha.We can anticipate that the neutral sites screening method described here can be easily adopted to other eukaryotes.

Characterizing and engineering promoters for metabolic engineering of Ogataea polymorpha

Bio-manufacturing via microbial cell factory requires large promoter library for fine-tuned metabolic engi-neering.Ogataea polymorpha,one of the methylotrophic yeasts,possesses advantages in broad substrate spec-trum,thermal-tolerance,and capacity to achieve high-density fermentation.However,a limited number of available promoters hinders the engineering of O.polymorpha for bio-productions.Here,we systematically characterized native promoters in O.polymorpha by both GFP fluorescence and fatty alcohol biosynthesis.Ten constitutive promoters(P_(PDH),P_(PYK),P_(FBA),P_(PGM),P_(GLK),P_(TRI),P(GPI),P_(ADH1),P_(TEF1) and P_(GCW14))were obtained with the activity range of 13%–130% of the common promoter P_(GAP)(the promoter of glyceraldehyde-3-phosphate de-hydrogenase),among which P_(PDH) and P_(GCW14) were further verified by biosynthesis of fatty alcohol.Furthermore,the inducible promoters,including ethanol-induced P_(ICL1),rhamnose-induced P_(LRA3) and P_( LRA4),and a bidirectional promoter(P_(Mal)-P_(Per))that is strongly induced by sucrose,further expanded the promoter toolbox in O.polymorpha.Finally,a series of hybrid promoters were constructed via engineering upstream activation sequence(UAS),which increased the activity of native promoter P LRA3 by 4.7–10.4 times without obvious leakage expression.Therefore,this study provided a group of constitutive,inducible,and hybrid promoters for metabolic engineering of O.polymorpha,and also a feasible strategy for rationally regulating the promoter strength.