Acetylation Process Research Articles

Acetylation Process and Antioxidant Activity of a Polysaccharide from Loquat (Eriobotrya japonica) Leaves

Chemical modifications of polysaccharides can provide an opportunity to obtain new agents with possible therapeutic uses. In this study, a water-soluble polysaccharide extracted from Loquat Leaves (coded LLPs) was purified by the column chromatography, which was used to investigate its acetylation process by the acetic anhydride method. The Degree of Substitution (DS) was used as the index, the effect of acetylated reagent amounts, reaction temperature and reaction time on DS was investigated. Acetylation process of LLPs was optimized by Response Surface Methodology (RSM) coupled with Box-Behnken design based on the results of single factor experiments. Characterization and antioxidant activities of Acetylated LLPs (Ac-LLPs) were investigated. Results showed that the optimal acetylation process of LLPs was obtained as following: Acetylated reagent amounts 2.60 mL, reaction time 2.10 h, reaction temperature 31℃. Under the optimal acetylation process, the maximum DS was 0.3570. Moreover, the analysis of Fourier-Transform Infrared spectroscopy (FT-IR) confirmed that the structural modification of Ac-LLPs was successful. In addition, the antioxidant activities assay in vitro suggested that Ac-LLPs possessed better DPPH radical scavenging capacity and stronger hydroxyl radical scavenging capacity compared with LLPs, whereas the scavenging capacity of LLPs on superoxide anion radical was slightly higher than Ac-LLPs. The results indicated that Ac-LLPs had enormous potential to become a new food additive or antioxidant supplement in food and pharmaceutical industries.

Impact of birch xylan composition and structure on film formation and properties

AbstractCommercial birch xylan (CX) and alkali-soluble birch xylan (ASX) were subjected to controlled acetylation and used for film formation in the presence (20% and 40%) or absence of plasticizers (i.e. glycerol, sorbitol and xylitol). Although the content of Klason lignin was similar (1.2–1.4%), the acetylation process was favored by the high-purity CX (97% xylan) over the ASX (89% xylan). On the other hand, the presence of residual pectin heteropolysaccharides rather than xylan in the ASX sample was beneficial for film formation. These heteropolysaccharides seemed to act as natural plasticizers during film formation, allowing the formation of coherent films from ASX, even in the absence of an external plasticizer. The use of plasticizers favored the mechanical properties of films, especially in a dosage of 40%, when plastic behavior was created. Acetylation favored the film formation and slightly improved the mechanical properties of the films, and this improvement was in the same range as that achieved when using 20% plasticizer in non-acetylated ASX.

Dysregulation of histone acetylation pathways in hippocampus and frontal cortex of Alzheimer's disease patients

Memory impairment is the main feature of Alzheimer's disease (AD). Initial impairments originate in the temporal lobe area and propagate throughout the brain in a sequential manner. Epigenetic mechanisms, especially histone acetylation, regulate plasticity and memory processes. These may be dismantled during the disease. The aim of this work was to establish changes in the acetylation-associated pathway in two key brain regions affected in AD: the hippocampus and the F2 area of frontal cortex in end-stage AD patients and age-matched controls. We found that the F2 area was more affected than the hippocampus. Indeed, CREB-Binding Protein (CBP), P300/CBP-associated protein (PCAF), Histone Deacetylase 1 (HDAC1) and HDAC2 (but not HDAC3) levels were strongly decreased in F2 area of AD compared to controls patients, whereas only HDAC1 was decreased and CBP showed a downward trend in the hippocampus. At the histone level, we detected a substantial increase in total (H3 and H2B) histone levels in the frontal cortex, but these were decreased in nuclear extracts, pointing to a dysregulation in histone trafficking/catabolism in this brain region. Histone H3 acetylation levels were increased in cell nuclei mainly in the frontal cortex. These findings provide evidence for acetylation dysfunctions at the level of associated enzymes and of histones in AD brains, which may underlie transcriptional dysregulations and AD-related cognitive impairments. They further point to stronger dysregulations in the F2 area of the frontal cortex than in the hippocampus at an end-stage of the disease, suggesting a differential vulnerability and/or compensatory mechanisms efficiency towards epigenetic alterations.

The effect of concentration and acid types on the acidification process for improving the glycerol concentration and its application as a bio additive

The rise of biodiesel production resulted in an increase in the formation of glycerol as a by-product. It takes some effort to purified the crude glycerol and convert it into more valuable product. One of these is by converting glycerol into triacetin which can be used as a bio additive in fuel through the acetylation process. This study aims to determine the effect of concentration and type of acid used in the glycerol purification. The purification were done by acidification, adsorption, filtration, distillation and evaporation. The acidification processes used H3PO4, H2SO4, HCl with percentage of 0.5%, 1%, 2.5%, 5%, 7.5%, 10%. The purified glycerol was analyzed to determine glycerol content, water content, density and viscosity and converted through acetylation reaction using Ni/Zeolite as a catalyst. The reaction products were analyzed by NaOH titration to determine the unreacted acetic acid which is converted into conversion of reaction. It can be concluded that the highest glycerol concentration was achieved in the addition 5% of H3PO4 with glycerol content of 79.59% and glycerol conversion in acetylation reaction of 82.39%. And its application as a bio additive can increase the Octane Number of commercial gasoline by 6.5%.

A transesterification–acetalization catalytic tandem process for the functionalization of glycerol: the pivotal role of isopropenyl acetate

A catalytic tandem sequence was implemented by which a pool of innocuous reactants (isopropenyl acetate, acetic acid and acetone) allowed upgrading of glycerol through selective acetylation and acetalization processes.

Preparation and Characterization of Bioplastic from Sorghum Husk

The increase in global population and advances in technology have made plastic materials to have wide applications in every aspect of life. However, the non-biodegradability of these petrochemical-based materials, and their increasing accumulation in the environment has been a threat to the planet and has been a source of environmental concerns and hence, the driving force in the search for ‘green’ alternatives for which agricultural waste remains the front liner. Sorghum husk, an agricultural waste with potentials as raw material in production of bioplastic was used in this research to prepared bioplastic using sulphuric acid catalyzed acetylation process. The prepared bioplastic were characterized by X-ray diffraction and FT-IR. The FTIR spectra of the product displayed the presence of OH, C-H, C=O and C-O absorption peaks which confirmed the formation of bioplastic. The new bioplastic obtained was biodegradable and was affected by acid, salt and alkali to a lesser extent, and this indicated that the produced bioplastic were much closed or has the same chemical resistance test with traditional plastic hence the prepared bioplastic can replaced the traditional plastic. Therefore, this revealed the new bioplastics with better environmental and sustainable properties can be produced from agricultural waste which may have application in many industries.

Synthesis of Cellulose Acetate-Polystyrene Membrane Composites from Pineapple Peel Wastes for Methylene Blue Removal

The cellulose acetate-polystyrene or CA-PS composite membrane from pineapple peel waste for methylene blue removal has been conducted. The steps were nata de pina preparation, cellulose acetylation process, preparation, and characterization of CA-PS composite membrane. The CA-PS composite membrane was characterized using Fourier Transform Infrared (FT-IR), Scanning Electron Microscopy (SEM), tensile and strain examination, respectively. The as-synthesized CA-PS composite membrane has the characteristic of rejection ability was about 29.96% with the pore size, membrane modulus, stress and strain were 1.9 μm, 12.48 MPa, 31.91 MPa, and 2.55, respectively. In this research, CA-PS composite membrane from pineapple peel waste was successfully removed the methylene blue dye even needs improvement to enhance its capability in rejection efficiency as same as membrane characteristics.

Conversion of Crude Glycerol from by-Product Biodiesel into Bio-additive of Fuel through Acetylation Reaction based on Modified Zeolite Catalyst

<p class="BodyAbstract">Biodiesel is one of the alternative fuels produced from the transesterification reaction between triglycerides and alcohols with glycerol by-products. So far, the resulting crude glycerol has not been maximally utilized because of its low purity. So, it is necessary to purify glycerol before turning it into a more useful compound. The purified glycerol can be reacted with acetic acid within esterification reaction (acetylation process) using an acid catalyst to produce glycerol triacetate (triacetin). One of the uses of triacetin as an additive in gasoline and biodiesel. The purpose of this study is to utilize glycerol from by-products from biodiesel production to bio-additive materials that can improve fuel quality and are environmentally friendly. The method used in this study begins with the purification of crude glycerol, modification of zeolite catalyst with impregnated of nickel metal followed by an acetylation reaction which held on temperature of 100°C for 60 min. The experimental results are analyzed using base titration to determine the remaining unreacted acids and are applied as bio-additives by adding them to commercial fuels and measured the increasing octane numbers. The result shows that the reaction conversion increases with increasing mole ratio of reactants and catalysts with the best results in the mole ratio of acetic acid and glycerol is 9:1 and catalyst 5% by weight of acetic acid with a conversion of 66.02%. As bio-additives the reaction product could increase the octane number of commercial fuel by 6.5 up to 8.5%.</p><p> </p>Keywords: glycerol, acetylation reaction, mofified zeolite, bio-additive

Effect of processing parameters on the electrospinning of cellulose acetate studied by response surface methodology

Cellulose acetate (CA) is the acetate ester of cellulose produced from cellulose via the process of acetylation. Currently, electrospinning has become a widely used technique to produce CA nanofibers for potential applications such as filtration, medical dressings, and food packaging. Being biodegradable and biocompatible, CA nanofibers bring additional advantages for these applications, e.g., high surface area, high porosity, and light weight. The quality of the CA nanofibers, which can be characterized by the prevalence of fiber defects, pore size, and fiber diameter, directly affects their performance. Fiber quality is, in turn, directly determined by the electrospinning process parameters. Therefore, in this project, we aimed to investigate the effect of electrospinning parameters, including CA concentration, voltage, and spinning distance, on the electrospinnability of CA nanofibers and fiber diameter, using process optimization principles and response surface methodology. Certain process parameters, including solvent (acetone), needle diameter (gauge 22, inner diameter 0.413 mm), temperature (20 °C), and feed rate (2 mL/h), were kept constant throughout the experiment. Preliminary experiments were conducted to determine the extreme conditions of each parameter and to define a working boundary. Then, trials of electrospinning CA nanofibers were conducted following a 3-factor, 3-level Box-Behnken design within the predetermined range. CA nanofibers morphology was characterized by scanning electron microscope (SEM) and ImageJ software to obtain their mean diameter. The mean electrospun fiber diameters fell into the range from 404 to 1346 nm and increased with increasing CA concentration. The fiber diameter was impacted less significantly by the other two parameters, i.e., voltage and spinning distance.

The Effect of Hydroxamic Siderophores Structure on Acetylation of Histone H3 and Alpha Tubulin in Pinus sylvestris Root Cells.

Protein acetylation affects gene expression, as well as other processes in cells, and it might be dependent on the availability of the metals. However, whether iron chelating compounds (siderophores) can have an effect on the acetylation process in plant roots is largely unknown. In the present study, western blotting and confocal microscopy was used to examine the degree of acetylation of histone H3 and alpha tubulin in Pinus sylvestris root cells in the presence of structurally different siderophores. The effect of metabolites that were produced by pathogenic and mycorrhizal fungi was also assessed. No effect was observed on histone acetylation. By contrast, the metabolites of the pathogenic fungus were able to decrease the level of microtubule acetylation, whereas treatment with iron-free ferrioxamine (DFO) was able to increase it. This latter was not observed when ferrioxamine-iron complexes were used. The pathogen metabolites induced important modifications of cytoskeleton organization. Siderophores also induced changes in the tubulin skeleton and these changes were iron-dependent. The effect of siderophores on the microtubule network was dependent on the presence of iron. More root cells with a depolymerized cytoskeleton were observed when the roots were exposed to iron-free siderophores and the metabolites of pathogenic fungi; whereas, the metabolites from mycorrhizal fungi and iron-enriched forms of siderophores slightly altered the cytoskeleton network of root cells. Collectively, these data indicated that the metabolites of pathogenic fungi mirror siderophore action, and iron limitation can lead to enhanced alternations in cell structure and physiology.

Microwaved cement boards with alkali-treated pineapple and water hyacinth fibers

Pineapple fibers (PFs) and water hyacinth fibers (WHFs) were treated with sodium carbonate (Na2CO3) and sodium hydroxide (NaOH) solutions for soaking times of 0·5, 1·0, 1·5 and 2·0 h. Analyses showed that the best treatment parameters for PFs were 2·0 M sodium carbonate for 1·5 h and 2·0 M sodium hydroxide for 0·5 h; those for WHFs were 1·5 M sodium carbonate for 0·5 h and 1·0 M sodium hydroxide for 1 h. The untreated and treated PFs showed similar Fourier transform infrared spectra ranging from 2924 to 2926 cm−1, which signify the presence of acidic oxygen (O)–hydrogen (H) stretching vibrations on a carbonyl group. The sodium hydroxide-treated WHFs had the 2926 cm−1 transmittance peak absent compared with the untreated WHFs. The acetylation process on both fibers resulted in increased roughness of fibers, which were analyzed under scanning electron microscopy of 10 μm magnification. The fibers treated under the determined best parameters were then used in the fabrication of cement boards. The specimens underwent microwave curing with regimes under 119 and 280 W. The cement board with aligned sodium carbonate-treated combined PFs and WHFs performed 16–41% better than the cement board with non-woven oriented fibers in terms of flexural strength.

Polyamine acetylation and substrate-induced oligomeric states in histone acetyltransferase of multiple drug resistant Acinetobacter baumannii

Histone acetyltransferase (Hpa2) is an unusual acetyltransferase, with a wide range of substrates; including histones, polyamines and aminoglycosides antibiotic. Hpa2 belongs to GNAT superfamily and GNATs are well known for the formation of homo-oligomers. However, the reason behind their oligomerization remained unexplored. Here, oligomeric states of Hpa2 were explored, to understand the functional significance of oligomerization. Biochemical analysis suggests that Hpa2 exists as dimer in solution and self-assembles into tetramer in the spermine, spermidine and kanamycin bound form. Stability analysis with denaturants concludes that homo-oligomerization of Hpa2 relies on bound substrate and not on experimental conditions. Homo-oligomerization in Hpa2 depicts direct correlation with its polyamine acetylating capacity. This correlation and in silico model structures suggest that oligomerization of Hpa2 is associated with the hastening of acetylation process. Interestingly, polyamine acetylation down regulates biofilms formation in E. coli BL21/Hpa2-transformants cells. Therefore, we propose that Hpa2 manipulates survival strategies of the bacterium via polyamines and antibiotics acetylation.

Acetylated cellulose nanocrystals with high-crystallinity obtained by one-step reaction from the traditional acetylation of cellulose

One-step reaction instead of two-step or multi-step reaction is simple and feasible to prepare the acetylated cellulose nanocrystals (ACNCs). Herein, a common and moderate one-step reaction for obtaining the acetylated cellulose nanocrystals (ACNCs) with high-crystallinity via traditional acetylation of cellulose is first proposed. Morphology property analysis indicates that ACNCs with a rod-like structure have a length of 21-140 nm and a width of 12-20 nm. The ACNCs show an allomorph of cellulose II with a high-crystallinity of ∼70%. 13C NMR and FT-IR analysis indicate that the obtained ACNCs have been acetylated, and the DS of ACNC-1.5 and ACNC-2.0 are 0.18 and 0.42, respectively. By studying the reaction mechanism, it can be found that ACNCs were obtained in the synergetic process of hydrolysis and acetylation. They can be redispersed in both water and organic solvent systems. This study provides a simple new method to prepare the acetylated CNCs with high crystallinity.

Preparation and characterization of cellulose acetate from cotton

The preparation and characterization of cellulose acetate from cotton was conducted in this study. Cotton was hydrolyzed using various concentrations of sulfuric acid (10, 20, 30 and 40%). The bleaching process was performed by using H2O2 solution. The acetylation process was conducted using acetic acid solution. The obtained cellulose acetate was then characterized using Fourier Transform Infrared Spectroscopy (FTIR) in order to observe the functional groups, Scanning Electron Microscopy (SEM) to examine the surface morphology and X-Ray Diffraction (XRD) to observe the crystallinity of cellulose acetate. The results of FTIR analysis confirmed the formation of cellulose acetate. SEM images showed the irregular sizes of cellulose acetate. XRD patterns exhibited that the acetylation process increased the crystallinity of cellulose.

Epstein-Barr Virus BART Long Non-coding RNAs Function as Epigenetic Modulators in Nasopharyngeal Carcinoma.

Epstein-Barr virus (EBV) establishes lifelong latent infection in humans and is associated with several lymphoid and epithelial cancers. In nasopharyngeal carcinoma (NPC), EBV expresses few viral proteins but elevated levels of Bam-HI A rightward transcripts (BARTs) RNA, which includes viral microRNAs and long non-coding RNAs (lncRNAs). BART lncRNAs localize within the nucleus of EBV-infected cells and knockdown of BART lncRNAs significantly affects the expression of genes associated with cell adhesion, oxidoreductase activity, inflammation, and immunity. Notably, downregulation of IKAROS family zinc finger 3 (IKZF3/Aiolos), which plays a role in lymphocyte development and cell attachment, occurred in NPC C666-1 cells following BART lncRNA-knockdown. Since Aiolos expression is normally restricted to lymphoid cells and rarely observed in epithelial cells, induction of Aiolos by BART lncRNA was confirmed by expressing the major BART lncRNA isoform, RPMS1, in EBV-positive and -negative cells. BART lncRNA associated with the CBP/p300 complex and RNA polymerase II (Pol II) in the nucleus, suggesting that BART lncRNAs may mediate epigenetic regulation of gene expression through interaction with the chromatin remodeling machinery. This contention is further supported by evidence that BART lncRNA appears to stall Pol II at the promoter region and may regulate IFNB1 and CXCL8 expression by inhibiting transcription by Pol II in NPC. We hypothesize that EBV BART lncRNA expression modulates host gene expression and maintains EBV latency by interfering with histone methylation and acetylation processes. Aberrant expression of affected host genes mediated by BART lncRNA may lead to immune evasion, progression, and metastasis of NPC.

Changes in Histone H3 Acetylation in the Rat Hippocampus Due to Severe Hypoxia and the Role of Hypoxic Postconditioning

Objective. To study the effects of severe hypobaric hypoxia followed by sessions of moderate hypobaric hypoxia using a postconditioning regime (PostC) with neuroprotective properties on the level of acetylation of histone H3 in rat hippocampal neurons. Materials and methods. A quantitative immunocytochemical method was used to study total histone acetylation and histone H3 acetylation at lysine 9 (acH3K9), which influences the conformational properties of chromatin and gene expression in the pyramidal neuron layer in hippocampal field CA1 (n = 84) in response to different hypoxia regimes. Results. Severe harmful hypoxia for four days did not lead to significant changes in the level of acetylation of acH3K9. Moderate hypobaric hypoxia in the PostC regime induced a significant increase in the acH3K9 level one day after the first session, supporting the initiation of adaptive processes induced by PostC. Conclusions. The process of histone acetylation, and particularly acetylation of histone H3, plays an important role in supporting the neuroprotective effect of hypoxic PostC.

Solvent-Free Acetylation of Cellulose by 1-Ethyl-3-methylimidazolium Acetate-Catalyzed Transesterification

Cellulose acetate is one of the oldest synthetic thermoplastic polymers and has various applications including usage as films, fibers, and membrane products. Traditionally, cellulose acetate is prepared by reacting cellulose with acetic anhydride in acetic acid using sulfuric acid as a catalyst. This process suffers from extensive depolymerization of the cellulose molecules and corrosion of the equipment from the use of the acidic solvent and catalyst. Herein we present an acid-free cellulose acetylation process using vinyl acetate as both the reactant and reaction medium and 1-ethyl-3-methylimidazolium acetate as the catalyst. The obtained cellulose acetate was confirmed by FTIR, NMR, and XRD studies. Additionally, the reaction kinetics, mechanism of the process, and properties of the obtained cellulose acetate were studied. Cellulose triacetate was obtained by our process within 2 h at 90 °C. The reaction kinetics was described with the classical pseudo-first-order rate expression of heterogeneous cellulose acetylation. The reaction mechanism was shown to be a peel-off mechanism similar to that of cellulose acetylation by the traditional acetic acid process. The molecular weight of the cellulose acetate produced by this new process was significantly higher than that from the traditional acetic acid process because of the absence of strong acids, which can depolymerize cellulose. In summary, we describe a new acid-free process to produce cellulose acetate that limits cellulose depolymerization and avoids the use of corrosive chemicals.

Embryonic Ontogeny of 5-Hydroxyindoles and 5-Methoxyindoles Synthesis Pathways in the Goose Pineal Organ.

The aim of this study was to characterize the embryonic ontogeny of 5-hydroxyindoles and 5-methoxyindoles synthesis pathways in the goose pineal organ. The study was performed on embryos aged 14–28 days, which have been incubated under a 12L:12D cycle. The pineal organs were collected for measurements of indole content by HPLC every 6 h on embryonic day (ED) 14, ED 16, ED 18 and ED 22 or every 2 h on ED 24, ED 26 and ED 28. The level of tryptophan showed no significant changes during development and no day-night variations. The content of 5-hydroxytryptophan increased between ED 14 and ED 26. It was significantly higher during scotophase than during photophase starting from ED 14. The serotonin content was low during the early stages of development (ED 14–ED 18) and prominently increased from ED 20. The serotonin levels also showed day-night differences; however, they were less conspicuous than those of 5-hydroxytryptophan. The changes in the level of 5-hydroxyindole acetic acid were similar to those of serotonin. 5-Hydroxytryptophol was measurable from ED 18. Levels of N-acetylserotonin, which were detectable for the first time on ED 16, prominently increased between ED 22 and ED 28 and showed significant day–night differences from ED 20. Melatonin was detectable from ED 18. Like N-acetylserotonin, its content increased rapidly between ED 22 and ED 28, and from ED 20 showed diurnal variations. 5-Methoxyindole acetic acid and 5-methoxytryptophol occurred at measurable levels from ED 18 and ED 26, respectively. The obtained results showed that embryonic development of indole metabolism in the goose pineal organ starts with the beginning of serotonin synthesis. The processes of serotonin acetylation and 5-hydroxyindoles methylation were turned on later. Diurnal rhythmicity develops very early in the embryonic pineal organ of the goose when the eggs are incubated under a 12 h light: 12 h dark schedule. Two processes are responsible for generation of the diurnal rhythms of 5-hydroxyindoles and 5-methoxyindoles: (i) hydroxylation of tryptophan and (ii) acetylation of serotonin.

Comparison of Various Chemical Treatments Efficiency in Relation to the Properties of Flax, Hemp Fibers and Cotton trichomes

ABSTRACT The main aim of this study was to chemically modify the plant fiber surface. Hemp, flax fibers and cotton trichomes were subject of surface treatments using silanization, acetylation, benzoylation, and mercerization processes. The fiber properties were evaluated with the use of fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), wide-angle X-ray analysis (WAXS) and thermogravimetric analysis (TGA). Additionally, humidity and color of the modified fibers were evaluated. Chemical treatment of the plant fibers reduced their hydrophilic nature, increased the moisture resistance, and improved their thermal stability. In all the cases the silanization process proved to be the most effective method of improving fiber thermal stability and moisture resistance, yet mercerization and benzoylation methods offered satisfying results as well.

SIRT1-regulated HMGB1 release is partially involved in TLR4 signal transduction: A possible anti-neuroinflammatory mechanism of resveratrol in neonatal hypoxic-ischemic brain injury

Neonatal hypoxic-ischemic brain injury (HIBI) is a knotty disease that lacks appropriate treatment. Inflammation is an important contributor to brain damage, and microglia are responsible for eliciting early and pronounced inflammatory reactions in the immature brain after hypoxic-ischemic (HI) insult. Acetylated HMGB1 can be released from immune cells into the extracellular space, where it acts as a danger-associated molecular pattern molecule to activate TLR4 signalling-mediated inflammatory responses. Resveratrol has neuroprotective and anti-inflammatory effects against HIBI, but whether these effects involve the regulation of the TLR4 signalling pathway and whether HMGB1 participates in this process is still unclear. We investigated the anti-inflammatory effects of resveratrol in HIBI and the molecular mechanisms potentially involved in the effect. The in vivo and in vitro results indicated that the level of cytoplasmic HMGB1 in microglia increased after insult and that treating experimental animals or mouse BV2 microglial cells with resveratrol attenuated HI insult-induced neuroinflammation, which was characterized by improved behavioural defects, reduced microglial activation and TLR4/MyD88/NF-κB signalling, and attenuated primary neuronal damage; this was accompanied by the inhibition of HMGB1 nucleoplasmic transfer and extracellular release. EX527 pretreatment reversed these effects. In addition, co-immunoprecipitation confirmed that SIRT1 was directly involved in the HMGB1 acetylation process in BV2 cells after oxygen glucose deprivation. These data demonstrate that resveratrol plays a neuroprotective role in neonatal HIBI by activating SIRT1 to inhibit HMGB1/TLR4/MyD88/NF-κB signalling and subsequent neuroinflammatory responses.