Protective effects of syringic acid in nonalcoholic fatty liver in rats through regulation of Nrf2/HO-1 signaling pathway.

Nonalcoholic fatty liver disease (NAFLD) is an alarming ailment that leads to severe liver damage and increases the risk of serious health conditions. The prevalence of NAFLD due to oxidative stress could be mitigated by plant-derived antioxidants. This study aims to investigate the effects of syringic acid (SA) on NAFLD in a high-fat diet (HFD) rat model. Twenty-four rats were randomly divided into four groups (n = 6): normal control, HFD, SA-administered HFD, and positive control SA on a normal diet. Rats in the normal control and positive control groups received a normal diet, and the remaining groups received an HFD for 8 weeks. SA (20 mg/kg b.w.) was orally (gavage) administered for 8 weeks. Lipid profiles were controlled by SA against HFD-fed rats (p < 0.05). SA reduced the serum aspartate aminotransferase and alanine aminotransferase levels by 70%-190%. SA also suppressed pro-inflammatory cytokines and attenuated histopathological and immunohistochemical changes against HFD-fed rats. SA reversed oxidative stress by suppressing the malondialdehyde formation by 82% and replenished the nonenzymatic and enzymatic antioxidant activities (p < 0.05). Gene expressions of nuclear factor-erythroid 2-related factor/heme oxygenase 1 (Nrf2/HO-1) were elevated in SA-treated rats. Ameliorative effects of SA on NAFLD induced by an HFD in rats were prominent through the reversal of oxidative stress and inflammation, regulated by an intrinsic mechanism of defense against oxidative stress, the Nrf2/HO-1 pathway.

Nutritional composition, phenolic compounds and biological activities of selected unconventional food plants.

This review highlights the nutritional content, phytochemical compounds, and biological properties of three unconventional food plants consumed in the Amazon: ora-pro-nóbis (Pereskia aculeata Mill.), taioba (Xanthosoma sagittifolium), and vitória-régia (Victoria amazonica). These plants show significant nutritional, functional, and economic potential, which can enhance the intake of daily nutrients, energy, and bioactive compounds. Ora-pro-nóbis is a rich source of caftaric acid, quercetin, and isorhamnetin; taioba contains syringic acid, caffeic acid, and quercetin; and vitória-régia shows cinnamic acid, caffeic acid, and sinapic acid in its composition. These compounds confer antioxidant, anticancer, antimicrobial, anti-inflammatory, analgesic, and antiproliferative properties on these plants. These unconventional plants can be exploited by the food industry as food and supplements and therapeutic plants to develop valuable products for food, cosmetics, pharmaceutical, and medical applications.

Leonurine Exerts Anti-Inflammatory Effects in Lipopolysaccharide (LPS)-Induced Endometritis by Modulating Mouse JAK-STAT/PI3K-Akt/PPAR Signaling Pathways.

Endometritis is a common disease in postpartum cows, characterized by delayed uterine recovery due to endometrial inflammation. Although antibiotics and hormones are commonly used, they have certain limitations. One potential alternative is using motherwort extract, specifically leonurine, which exhibits anti-inflammatory properties. However, leonurine's exact molecular mechanism of action remains unclear. In this study, 40 mice were randomly divided into four groups: a control group, endometritis model group, LPS + leonurine group (30 mg/kg), and LPS + dexamethasone group (5 mg/kg). Transcriptomic analysis revealed that leonurine modulates multiple signaling pathways, including JAK-STAT/PI3K-Akt, and influences the expression of key genes, such as Prlr, Socs2, Col1a1, and Akt1. Furthermore, leonurine effectively reduces levels of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and IL-1ß (p < 0.01), which play a crucial role in regulating acute endometritis. Additionally, leonurine helps maintain cholesterol homeostasis and attenuates inflammation through the peroxisome proliferator-activated receptor (PPAR) signaling pathway by modulating genes such as Cyp27a1, Hmgcs1, and Scd2. These findings suggest that leonurine has a protective effect against LPS-induced endometritis and that its anti-inflammatory properties involve multiple pathways and targets, which are potentially mediated by regulating signaling pathways such as JAK-STAT/PI3K-Akt and PPAR.

Syringic acid suppresses Cutibacterium acnes-induced inflammation in human keratinocytes via regulating the NLRP3/caspase-1/IL-1ß signaling axis by activating PPARγ/Nrf2-antioxidant pathway.

BACKGROUND: Our previous studies have demonstrated a strong relationship betweenCutibacterium acnes(C. acnes), oxidative stress, and acne inflammation. Syringic acid (SA) is a plant widely used for its antimicrobial, anti-inflammatory, and antioxidant activities, but lacking data on acne. This study aims to investigate the effect and mechanism of SA on acne inflammation induced by C. acnes in vitro and in vivo. METHODS: After using the SA to expose HaCaT keratinocytes, we reevaluated the effect of the SA on cell viability, cell apoptosis, ROS, CAT, SOD, and other inflammatory variables in the heat-killed C. acnes-treated HaCaT cells. Next, to induce mice with acne inflammation, ICR mice were given an intradermal injection of live C. acnes into their right ears. The effect of SA on this inflammation was then examined. Moreover, we explored the mechanism of SA on PPARγ/Nrf2 and NLRP3/caspase-1/IL-1ß pathways by ELISA, immunofluorescence microscopy, and western blot assay. RESULTS: Heat-killed C. acnes triggered remarkable cell apoptosis, ROS production, interleukin (IL)-1ß, IL-18, IL-6, and TNF-α release, reduced SOD and CAT activity, and upregulated the expression of proteins in HaCaT cells, including up-regulating IL-1ß, PPARγ, Nrf2, HO-1, NQO1, NLRP3, and caspase-1, whereas SA inhibited these effects by partially impairing PPARγ activation. In addition, PPARγ silencing decreased C. acnes-induced IL-1ß secretion and the production of intracellular ROS, down-regulating the expression of Nrf2. Nrf2 activator (SFN) enhanced anti-inflammatory activity through antioxidant mechanisms, boosting intracellular ROS production, reducing SOD and CAT activity, and promoting the increase in ROS, HO-1, NQO1, and IL-1ß levels, while PPARγ inhibitor (GW662) effectively inhibited this effect in heat-killed C. acnes-treated cells. Finally, SA also exhibited notable improvements in ear redness, swelling, and the expression of PPARγ, NLRP3, and IL-1ß in vivo. CONCLUSIONS: SA inhibited C. acnes-induced inflammation via regulating the NLRP3/caspase-1/IL-1ß signaling axis by activating the PPARγ/Nrf2-antioxidant pathway, suggesting a new treatment possibility for acne vulgaris.

Methyl Syringate: A Primary Driving Factor in Manuka Honeys Ability to Ameliorate Neutrophil Intracellular ROS Activity and NETosis.

BACKGROUND: Neutrophils use both the production of reactive oxygen species (ROS) and a specialized process called NETosis to defend the body from material deemed foreign. While these neutrophil behaviors are critical in preventing infection, a dysregulated response can lead to tissue damage and fibrosis at host-biomaterial interfaces. It was hypothesized that applying the flavonoids found in Manuka honey: chrysin, pinocembrin, and pinobanksin, and the phenolic compound methyl syringate to neutrophils exhibiting pro-inflammatory behavior will reduce ROS activity and prevent NETosis in primary human neutrophils. METHODS: Using primary human neutrophils isolated from donor (n = 5) peripheral blood, concentrations between 1 nM and 10 µM of each flavonoid, 10 µM and 2 mM of methyl syringate, 0.1% v/v and 10% v/v Manuka honey, and combinations of both 1 nM-10 µM of each flavonoid and 10 µM-2 mM of methyl syringate were assayed for reductions in NETosis using Sytox orange extracellular DNA staining and reduction in intracellular ROS activity via standard dichloro-dihydro-fluorescein diacetate (DCFH-DA) oxidation assay. RESULTS: Compared to positive control levels, individual flavonoids showed moderate effect sizes. Higher concentrations of flavonoids, especially in combination, stimulated ROS activity by up to 105%. Whole Manuka honey reduced neutrophil extracellular trap (NET) levels by up to 91% but only reduced ROS activity by 36%. However, methyl syringate reduced NET levels by up to 68% and ROS activity by 66%. CONCLUSIONS: Methyl syringate and whole Manuka honey are potent inhibitors of neutrophil intracellular ROS activity and NET formation. Methyl syringate potentially drives the anti-inflammatory capabilities of Manuka honey demonstrated by previous studies.

Leonurine Ameliorates Diabetic Nephropathy through GPX4-Mediated Ferroptosis of Endothelial Cells.

BACKGROUND: Diabetic nephropathy (DN) is a common microvascular complication of diabetes mellitus (DM). Ferroptosis is an atypical form of iron-dependent, modulated cell death that has been shown to occur in human umbilical vein endothelial cells (HUVECs). Leonurine (LEO) is a single active ingredient extracted from Leonurus japonicus Houtt. It has various biological activities, including anti-inflammatory and anti-cancer effects. However, whether LEO affects ferroptosis in DN has yet to be investigated. METHODS: An animal model of DN was established by subjecting C57/BL6 mice to a high-fat diet (HFD) while being induced with Streptozotocin (STZ). A cellular model of DN was established by exposing HUVECs to a high glucose (HG) concentration of 30 mM. RESULTS: LEO was found to improve DN and to attenuate the degree of glomerulosclerosis and tubular atrophy in the mouse model. Additionally, it markedly decreased the levels of ferroptosis markers. Molecular analyses revealed that LEO inhibited HG-induced oxidative stress in HUVECs, thereby decreasing endothelial cell (EC) dysfunction. Furthermore, LEO was found to reduce ferroptosis and reverse EC dysfunction by increasing the expression of glutathione peroxidase 4 (GPX4) and nuclear factor erythroid 2-related factor 2 (Nrf2). The suppression of Nrf2 in HG-induced HUVECs inhibited LEO-GPX4 axis-mediated ferroptosis and increased EC dysfunction. CONCLUSIONS: LEO exerts anti-DN effects both in vivo and in vitro by suppressing GPX4-mediated EC ferroptosis. Mechanistically, LEO appears to induce Nrf2-mediated GPX4 expression to inhibit ferroptosis, thereby reducing EC dysfunction. This study provides a new perspective on the treatment of diseases using natural medicines. It involves a novel form of cell death that could potentially lead to better treatment of DN.

Engineering cascade biocatalysis in whole cells for syringic acid bioproduction.

BACKGROUND: Syringic acid (SA) is a high-value natural compound with diverse biological activities and wide applications, commonly found in fruits, vegetables, and herbs. SA is primarily produced through chemical synthesis, nonetheless, these chemical methods have many drawbacks, such as considerable equipment requirements, harsh reaction conditions, expensive catalysts, and numerous by-products. Therefore, in this study, a novel biotransformation route for SA production was designed and developed by using engineered whole cells. RESULTS: An O-methyltransferase from Desulfuromonas acetoxidans (DesAOMT), which preferentially catalyzes a methyl transfer reaction on the meta-hydroxyl group of catechol analogues, was identified. The whole cells expressing DesAOMT can transform gallic acid (GA) into SA when S-adenosyl methionine (SAM) is used as a methyl donor. We constructed a multi-enzyme cascade reaction in Escherichia coli, containing an endogenous shikimate kinase (AroL) and a chorismate lyase (UbiC), along with a p-hydroxybenzoate hydroxylase mutant (PobA**) from Pseudomonas fluorescens, and DesAOMT; SA was biosynthesized from shikimic acid (SHA) by using whole cells catalysis. The metabolic system of chassis cells also affected the efficiency of SA biosynthesis, blocking the chorismate metabolism pathway improved SA production. When the supply of the cofactor NADPH was optimized, the titer of SA reached 133 µM (26.2 mg/L). CONCLUSION: Overall, we designed a multi-enzyme cascade in E. coli for SA biosynthesis by using resting or growing whole cells. This work identified an O-methyltransferase (DesAOMT), which can catalyze the methylation of GA to produce SA. The multi-enzyme cascade containing four enzymes expressed in an engineered E. coli for synthesizing of SA from SHA. The metabolic system of the strain and biotransformation conditions influenced catalytic efficiency. This study provides a new green route for SA biosynthesis.

Gallic acid pretreatment mitigates parathyroid ischemia-reperfusion injury through signaling pathway modulation.

Thyroid surgery often results in ischemia-reperfusion injury (IRI) to the parathyroid glands, yet the mechanisms underlying this and how to ameliorate IRI remain incompletely explored. Our study identifies a polyphenolic herbal extract-gallic acid (GA)-with antioxidative properties against IRI. Through flow cytometry and CCK8 assays, we investigate the protective effects of GA pretreatment on a parathyroid IRI model and decode its potential mechanisms via RNA-seq and bioinformatics analysis. Results reveal increased apoptosis, pronounced G1 phase arrest, and significantly reduced cell proliferation in the hypoxia/reoxygenation group compared to the hypoxia group, which GA pretreatment mitigates. RNA-seq and bioinformatics analysis indicate GA's modulation of various signaling pathways, including IL-17, AMPK, MAPK, transient receptor potential channels, cAMP, and Rap1. In summary, GA pretreatment demonstrates potential in protecting parathyroid cells from IRI by influencing various genes and signaling pathways. These findings offer a promising therapeutic strategy for hypoparathyroidism treatment.

Intermolecular copigmentation of anthocyanins with phenolic compounds improves color stability in the model and real blueberry fermented beverage.

To improve the color stability of anthocyanins (ACNs) in blueberry fermented beverage, the intermolecular copigmentation between ACNs and 3 different phenolic compounds, including (-)-epigallocatechin gallate (EGCG), ferulic acid (FA), and gallic acid (GA) as copigments, was compared in the model and the real blueberry fermented beverage, respectively. The copigmented ACNs by EGCG presented a high absorbance (0.34 a.u.) and redness (27.09 ± 0.17) in the model blueberry fermented beverage. The copigmentation by the participation of the 3 different phenolic compounds showed all a spontaneous exothermic reaction, and the Gibbs free energy (ΔG°) of the system was lowest (-5.90 kJ/mol) using EGCG as copigment. Furthermore, the molecular docking model verified that binary complexes formed between ACNs and copigments by hydrogen bonds and π-π stacking. There was a high absorbance (1.02 a.u.), percentage polymeric color (PC%, 68.3 %), and good color saturation (C*ab, 43.28) in the real blueberry fermented beverage aged for 90 days, and more malvidin-3-O-glucoside had been preserved in the wine using EGCG as copigment. This finding may guide future industrial production of blueberry fermented beverage with improved color.

Biodegradable ultrafiltration membrane enhanced with anti-biofouling agent from Anacardium occidentale extract.

Our research focuses on developing environmentally friendly biodegradable ultrafiltration (UF) membranes for small-scale water purification in areas lacking infrastructure or during emergencies. To address biofouling challenges without resorting to harmful chemicals, we incorporate bio-based extracts, such as methyl gallate from A. occidentale leaves, a Malaysian ulam herb, known for its quorum sensing inhibition (QSI) properties. The methyl gallate enriched extract was purified by solvent partitioning and integrated into cellulose-based UF membranes (0 to 7.5% w w-1) through phase inversion technique. The resulting membranes exhibited enhanced anti-organic fouling and anti-biofouling properties, with flux recovery ratio (FRR) of 87.84 ± 2.00% against bovine serum albumin and FRRs of 76.67 ± 1.89% and 69.57 ± 1.77% against E. coli and S. aureus, respectively. The CA/MG-5 membrane showed a 224% improvement in pure water flux (PWF) compared to the neat CA membrane. Our innovative approach significantly improves PWF, presenting an environmentally friendly method for biofouling prevention in UF membrane applications.

Inhibition mechanism of theaflavins on matrix metalloproteinase-2: inhibition kinetics, multispectral analysis, molecular docking and molecular dynamics simulation.

Dental caries is a chronic and destructive disease and matrix metalloproteinase-2 (MMP-2) plays a major role in caries. The inhibitory mechanisms of theaflavins [theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3'-gallate (TF2B), and theaflavin-3,3'-digallate (TF3)] on MMP-2 were investigated using techniques such as enzyme inhibition kinetics, multi-spectral methods, molecular docking, and molecular dynamics simulations. The results showed that TF1, TF2A, TF2B, and TF3 all competitively and reversibly inhibited MMP-2 activity. Fluorescence spectra and molecular docking indicated that four theaflavins spontaneously bind to MMP-2 through noncovalent interactions, driven by hydrogen bonds and hydrophobic interactions, constituting a static quenching mechanism and resulting in an altered tryptophan residue environment around MMP-2. Molecular dynamic simulations demonstrated that four theaflavins can form stable, compact complexes with MMP-2. In addition, the order of theaflavins' ability to inhibit MMP-2 was found to be TF1 > TF2B > TF2A > TF3. Interestingly, the order of binding capacity between MMP-2 and TF1, TF2A, TF2B, and TF3 was consistent with the order of inhibitory capacity, and was opposite to the order of steric hindrance of theaflavins. This may be due to the narrow space of the active pocket of MMP-2, and the smaller the steric hindrance of theaflavins, the easier it is to enter the active pocket and bind to MMP-2. This study provided novel insights into theaflavins as functional components in the exploration of natural MMP-2 inhibitors.

Effects of preheat treatment and syringic acid modification on the structure, functional properties, and stability of black soybean protein isolate.

This study investigated preheated (25-100°C) black soybean protein isolate (BSPI) conjugated with syringic acid (SA) (25 and 50 µmol/g protein) under alkaline conditions, focusing on the structure, functional properties, and storage stability. The results revealed that the SA binding equivalent and binding rate on BSPI increased continuously as the preheat temperature increased. Additionally, preheating positively impacted the surface hydrophobicity (H0) of BSPI, with further enhancement observed upon SA binding. Preheating and SA binding altered the secondary and tertiary structure of BSPI, resulting in protein unfolding and increased molecular flexibility. The improvement in BSPI functional properties was closely associated with both preheating temperature and SA binding. Specifically, preheating decreased the solubility of BSPI but enhanced the emulsifying activity index (EAI) and foaming capacity (FC) of BSPI. Conversely, SA binding increased the solubility of BSPI with an accompanying increase in EAI, FC, foaming stability, and antioxidant activity. Notably, the BSPI100-SA50 exhibited the most significant improvement in functional properties, particularly in solubility, emulsifying, and foaming attributes. Moreover, the BSPI-SA conjugates demonstrated good stability of SA during storage, which positively correlated with the preheating temperature. This study proposes a novel BSPI-SA conjugate with enhanced essential functional properties, underscoring the potential of preheated BSPI-SA conjugates to improve SA storage stability. PRACTICAL APPLICATION: Preheated BSPI-SA conjugates can be used as functional ingredients in food or health products. In addition, preheated BSPI shows potential as a candidate for encapsulating and delivering hydrophobic bioactive compounds.

Piperine Enhances Antimalarial Activity of Methyl Gallate and Palmatine Combination.

PURPOSE: Artemisinin combination therapies, the first-line antimalarials in Nigeria, have reportedly suffered multiple failures in malaria treatment, hence the search for novel combination of other compounds. Methyl gallate and palmatine have been reported to exhibit antiplasmodial activities but the antimalarial activity of their combination has not been evaluated. Therefore, the evaluation of the combination of methyl gallate and palmatine for antimalarial activity in vitro and in vivo in the presence of piperine was carried out. MATERIALS AND METHODS: The inhibitory potential of methyl gallate and palmatine combination on ß-hematin (hemozoin) formation was studied in vitro. Also, the antimalarial activity of methyl gallate and palmatine combination with/without a bioenhancer (piperine) was evaluated in Plasmodium berghei NK65-infected mice. RESULTS: Methyl gallate and palmatine in the ratio 3:2 acted synergistically in vitro and had the highest inhibitory effect (IC50 = 0.73 µg/mL) on ß-hematin (hemozoin) formation. The 3:2 combination of methyl gallate and palmatine exhibited no antimalarial activity in vivo in the absence of piperine but caused reduction in parasitemia that exceeded 40% in the presence of piperine at the dose of 25 mg/kg body weight on days 6 and 8 post-inoculation in mice. CONCLUSION: The 3:2 combination of methyl gallate and palmatine in the presence of piperine exhibited antimalarial activity in vivo, possibly by synergistic inhibition of hemozoin formation which may cause accumulation of haem within the food vacuole of Plasmodium spp. and its death.

A facile fluorescence-coupling approach to visualizing leonurine uptake and distribution in living cells and Caenorhabditis elegans.

BACKGROUND: Caenorhabditis elegans (C. elegans) has been recognized for being a useful model organism in small-molecule drug screens and drug efficacy investigation. However, there remain bottlenecks in evaluating such processes as drug uptake and distribution due to a lack of appropriate chemical tools. PURPOSE: This study aims to prepare fluorescence-labeled leonurine as an example to monitor drug uptake and distribution of small molecule in C. elegans and living cells. METHODS: FITC-conjugated leonurine (leonurine-P) was synthesized and characterized by LC/MS, NMR, UV absorption and fluorescence intensity. Leonurine-P was used to stain C. elegans and various mammalian cell lines. Different concentrations of leonurine were tested in conjunction with a competing parent molecule to determine whether leonurine-P and leonurine shared the same biological targets. Drug distribution was analyzed by imaging. Fluorometry in microplates and flow cytometry were performed for quantitative measurements of drug uptake. RESULTS: The UV absorption peak of leonurine-P was 490∼495 nm and emission peak was 520 nm. Leonurine-P specifically bound to endogenous protein targets in C. elegans and mammalian cells, which was competitively blocked by leonurine. The highest enrichment levels of leonurine-P were observed around 72 h following exposure in C. elegans. Leonurine-P can be used in a variety of cells to observe drug distribution dynamics. Flow cytometry of stained cells can be facilely carried out to quantitatively detect probe signals. CONCLUSIONS: The strategy of fluorescein-labeled drugs reported herein allows quantification of drug enrichment and visualization of drug distribution, thus illustrates a convenient approach to study phytodrugs in pharmacological contexts.

Syringic acid attenuates acute lung injury by modulating macrophage polarization in LPS-induced mice.

BACKGROUND: Acute lung injury (ALI) is a continuum of lung changes caused by multiple lung injuries, characterized by a syndrome of uncontrolled systemic inflammation that often leads to significant morbidity and death. Anti-inflammatory is one of its treatment methods, but there is no safe and available drug therapy. Syringic acid (SA) is a natural organic compound commonly found in a variety of plants, especially in certain woody plants and fruits. In modern pharmacological studies, SA has anti-inflammatory effects and therefore may be a potentially safe and available compound for the treatment of acute lung injury. PURPOSE: This study attempts to reveal the protective mechanism of SA against ALI by affecting the polarization of macrophages and the activation of NF-κB signaling pathway. Trying to find a safer and more effective drug therapy for clinical use. METHODS: We constructed the ALI model using C57BL/6 mice by intratracheal instillation of LPS (10 mg/kg). Histological analysis was performed with hematoxylin and eosin (H&E). The wet-dry ratio of the whole lung was measured to evaluate pulmonary edema. The effect of SA on macrophage M1-type was detected by flow cytometry. BCA protein quantification method was used to determine the total protein concentration in bronchoalveolar lavage fluid (BALF). The levels of Interleukin (IL)-6, IL-1ß, and tumor necrosis factor (TNF)-α in BALF were determined by the ELISA kits, and RT-qPCR was used to detect the expression levels of IL-6, IL-1ß and TNF-α mRNA of lung tissue. Western blot was used to detect the expression levels of iNOS and COX-2 and the phosphorylation of p65 and IκBα in the NF-κB pathway in lung tissue. In vitro experiments were conducted with RAW267.4 cell inflammation model induced by 100 ng/ml LPS and A549 cell inflammation model induced by 10 µg/ml LPS. The effects of SA on M1-type and M2-type macrophages of RAW267.4 macrophages induced by LPS were detected by flow cytometry. The toxicity of compound SA to A549 cells was detected by MTT method which to determine the safe dose of SA. The expressions of COX-2 and the phosphorylation of p65 and IκBα protein in NF-κB pathway were detected by Western blot. RESULTS: We found that the pre-treatment of SA significantly reduced the degree of lung injury, and the infiltration of neutrophils in the lung interstitium and alveolar space of the lung. The formation of transparent membrane in lung tissue and thickening of alveolar septum were significantly reduced compared with the model group, and the wet-dry ratio of the lung was also reduced. ELISA and RT-qPCR results showed that SA could significantly inhibit the production of IL-6, IL-1ß, TNF-α. At the same time, SA could significantly inhibit the expression of iNOS and COX-2 proteins, and could inhibit the phosphorylation of p65 and IκBα proteins. in a dose-dependent manner. In vitro experiments, we found that flow cytometry showed that SA could significantly inhibit the polarization of macrophages from M0 type macrophages to M1-type macrophages, while SA could promote the polarization of M1-type macrophages to M2-type macrophages. The results of MTT assay showed that SA had no obvious cytotoxicity to A549 cells when the concentration was not higher than 80 µM, while LPS could promote the proliferation of A549 cells. In the study of anti-inflammatory effect, SA can significantly inhibit the expression of COX-2 and the phosphorylation of p65 and IκBα proteins in LPS-induced A549 cells. CONCLUSION: SA has possessed a crucial anti-ALI role in LPS-induced mice. The mechanism was elucidated, suggesting that the inhibition of macrophage polarization to M1-type and the promotion of macrophage polarization to M2-type, as well as the inhibition of NF-κB pathway by SA may be the reasons for its anti-ALI. This finding provides important molecular evidence for the further application of SA in the clinical treatment of ALI.

The enzymatic synthesis of theaflavin-3-gallate oxidation product and its determination.

In this work, the oxidation of theaflavin-3-gallate (TF-3-G) was investigated using (-)-epicatechin (EC) and (-)-epigallocatechin gallate (EGCG) as substrates in a one-pot reaction. The resulting TF-3-G oxidation product was acquired by employing acetonitrile/water and ethanol/water as eluents, respectively, which was identified as theanaphthoquinone-3'-gallate (TNQ-3'-G). Surprisingly, we discovered that TNQ-3'-G could react with certain protic solvents to form new and unstable complexes through intermolecular hydrogen bond. This reactivity was also confirmed by the presence of irregular peaks in reverse-phase high-performance liquid chromatography (RP-HPLC) besides spectroscopic data. Therefore, we inferred that the number of carboxyl groups may increase through the successive oxidative polymerization of the TFs oxidation products. The high-molecular polymer could also interact with biomacromolecules in a similar manner to their interaction with protic solvents. This interaction might be one of the main factors contributing to the broad hump of thearubigins (TRs) on the RP-HPLC baseline. Additionally, these findings lay a solid foundation for interpreting the structures of TRs and understanding their generation mechanism.

Advancing Photodynamic Antimicrobial Strategy: Sustainable Fabrication of Novel Lauryl Gallate-Chitosan Hydrophobic Films with Rapid Bacterial Capture and Biofilms Elimination Capabilities for Promoting Wound Healing.

Bioinspired photoactive composites, in terms of photodynamic inactivation, cost-effectiveness, and biosafety, are promising alternatives to antibiotics for combating bacterial infections while avoiding antibacterial resistance. However, the weak bacterial membrane affinity of the photoactive substrate and the lack of synergistic antibacterial effect remain crucial shortcomings for their antibacterial applications. Herein, we developed a hydrophobic film from food antioxidant lauryl gallate covalently functionalized chitosan (LG-g-CS conjugates) through a green radical-induced grafting reaction that utilizes synergistic bacteria capture, contact-killing, and photodynamic inactivation activities to achieve enhanced bactericidal and biofilm elimination capabilities. Besides, the grafting reaction mechanism between LG and CS in the ascorbic acid (AA)/H2O2 redox system was further proposed. The LG-g-CS films feature hydrophobic side chains and photoactive phenolic hydroxyl groups, facilitating dual bactericidal activities through bacteria capture and contact-killing via strong hydrophobic and electrostatic interactions with bacterial membranes as well as blue light (BL)-driven photodynamic bacterial eradication through the enhanced generation of reactive oxygen species. As a result, the LG-g-CS films efficiently capture and immobilize bacteria and exhibit excellent photodynamic antibacterial activity against model bacteria (Escherichia coli and Staphylococcus aureus) and their biofilms under BL irradiation. Moreover, LG-g-CS films could significantly promote the healing process of S. aureus-infected wounds. This research demonstrates a new strategy for designing and fabricating sustainable bactericidal and biofilm-removing materials with a high bacterial membrane affinity and photodynamic activity.

Novel insights into the protective effects of leonurine against acute kidney injury: Inhibition of ER stress-associated ferroptosis via regulating ATF4/CHOP/ACSL4 pathway.

Acute kidney injury (AKI) is a common and serious global health problem with high risks of mortality and the development of chronic kidney diseases. Leonurine is a unique bioactive component from Leonurus japonicus Houtt. and exerts antioxidant, antiapoptotic or anti-inflammatory properties. This study aimed to explore the benefits of leonurine on AKI and the possible mechanisms involved, with a particular foc on the regulation of ferroptosis and endoplasmic reticulum (ER) stress. Our results showed that leonurine exhibited prominent protective effects against AKI, as evidenced by the amelioration of histopathological alterations and reduction of renal dysfunction. In addition, leonurine significantly suppressed ferroptosis in AKI both in vivo and in vitro by effectively restoring ultrastructural abnormalities in mitochondria, decreasing ASCL4 and 4-HNE levels, scavenging reactive oxygen species (ROS), as well as increasing GPX4 and GSH levels. In parallel, leonurine also markedly mitigated ER stress via down-regulating PERK, eIF-2α, ATF4, CHOP and CHAC1. Further studies suggested that ER stress was closely involved in erastin-induced ferroptosis, and leonurine protected tubular epithelial cells in vitro by inhibiting ER stress-associated ferroptosis via regulating ATF4/CHOP/ASCL4 signalling pathway. Mechanistically, ATF4 silencing in vitro regulated CHOP and ACSL4 expressions, ultimately weakening both ER stress and ferroptosis. Notably, analyses of single-cell RNA sequencing data revealed that ATF4, CHOP and ASCL4 in renal tubular cells were all abnormally upregulated in patients with AKI compared to healthy controls, suggesting their contributions to the pathogenesis of AKI. Altogether, these findings suggest that leonurine alleviates AKI by inhibiting ER stress-associated ferroptosis via regulating ATF4/CHOP/ASCL4 signalling pathway, thus providing novel mechanisms for AKI treatment.

Syringic acid guards against indomethacin-induced gastric ulcer by alleviating inflammation, oxidative stress and apoptosis.

The purpose of this study was to evaluate the effects of syringic acid, an anti-oxidant, on indomethacin induced gastric ulcers in rats. Experimental groups were control, ulcer, ulcer treated with 20 mg/kg esomeprazole (a proton pump inhibitor that reduces acid secretion), and ulcer treated with 100 mg/kg syringic acid. Rats were pretreated with esomeprazole or syringic acid two weeks before ulcer induction. Our histopathological observations showed that either syringic acid or esomeprazole attenuated the severity of gastric mucosal damage. Moreover, syringic acid and esomeprazole pretreatments alleviated indomethacin-induced damage by regulating oxidative stress, inflammatory response, the level of transforming growth factor-ß (TGF-ß), expressions of COX and prostaglandin E2, cell proliferation, apoptosis and regulation of the NF-κB signaling pathway. We conclude that either esomeprazole or syringic acid administration protected the gastric mucosa from harmful effects of indomethacin. Syringic acid might, therefore be a potential therapeutic agent for preventing and treating indomethacin-induced gastric damage.

Ascorbic acid potentiates photodynamic inactivation mediated by octyl gallate and blue light for rapid eradication of planktonic bacteria and biofilms.

This study reported for the first time that Ascorbic acid (AA) could appreciably boost the efficiency of Octyl gallate (OG)-mediated photodynamic inactivation (PDI) on Escherichia coli and Staphylococcus aureus in planktonic and biofilm states. The combination of OG (0.075 mM) and AA (200 mM) with 420 nm blue light (212 mW/cm2) led to a >6 Log killing within only 5 min for E. coli and S. aureus and rapid eradication of biofilms. The mechanism of action appears to be the generation of highly toxic hydroxyl radicals (•OH) via photochemical pathways. OG was exposed to BL irradiation to generate various reactive oxygen radicals (ROS) and the addition of AA could transform singlet oxygen (1O2) into hydrogen peroxide (H2O2), which could further react with AA to generate enormous •OH. These ROS jeopardized bacteria and biofilms by nonspecifically attacking various biomacromolecules. Overall, this PDI strategy provides a powerful microbiological decontamination modality to guarantee safe food products.