Search Results (800)

Steroid hormones exert diverse and tissue-specific biological effects despite sharing a conserved tetracyclic scaffold. Among these, anabolic–androgenic steroids (AAS) present a longstanding paradox: structurally related compounds can elicit markedly different anabolic, androgenic, and cardiovascular outcomes. This narrative review integrates advances in steroid structural chemistry, androgen receptor (AR) biology, and intracellular signaling to elucidate the molecular mechanisms underlying anabolic–androgenic dissociation. We summarize classical genomic and emerging non-genomic modes of steroid action, emphasizing how receptor conformation, ligand-binding domain architecture, co-regulator recruitment, and signaling bias shape downstream biological responses. Particular focus is placed on the structure–activity relationships of endogenous and synthetic androgens, with C17-substitution chemistry highlighted as a central determinant of receptor affinity, metabolic stability, pharmacokinetics, and tissue selectivity. By linking molecular structure to receptor-level mechanisms, we contextualize the physiological and pathophysiological effects of major AAS classes used clinically and non-medically, including testosterone esters, 19-nor derivatives, 17α-alkylated steroids, heterocyclic compounds, and halogenated compounds. While much of the mechanistic evidence derives from preclinical models, the integrated framework presented here provides a coherent basis for interpreting divergent anabolic, androgenic, and cardiovascular effects observed in humans. Collectively, this review bridges fundamental steroid biology with applied physiology and sports medicine, offering mechanistic insight relevant to therapeutic development, anti-doping science, and risk assessment of supraphysiological androgen exposure. Full article

Introduction: Fourier-transform infrared spectroscopy (FTIR) is a key technique in the characterization of biomaterials, allowing the identification of functional groups and the verification of bioactive compound incorporation in nanostructured systems. In this study, the spectral signature of raw materials used in the formulation of a nanoemulsion with curcumin, sunflower oil, annatto oil, and Cremophor applied in the production of a dressing consisting of a natural latex biomembrane (Hevea brasiliensis) was evaluated. Methodology: FTIR spectra were obtained from isolated raw materials (curcumin, vegetable oils, and Cremophor) and from the curcumin-containing nanoemulsion formulation, aiming to compare their spectral profiles and identify possible chemical interactions. Results: Curcumin showed characteristic bands around 3328–3508 cm⁻¹ (–OH), 1637 cm⁻¹ (C=O and conjugated C=C), and 1505 cm⁻¹ (aromatic ring), confirming its polyphenolic structure. Sunflower oil exhibited an intense peak at 1744 cm⁻¹ (ester carbonyl), associated with its triglyceride composition, while annatto oil showed a band at 1633 cm⁻¹ (conjugated C=O), indicative of bixine and carotenoids. Cremophor presented peaks at 3460 cm⁻¹ (–OH) and 1726 cm⁻¹ (C=O), typical of ethoxylated surfactants. In the curcumin-containing nanoemulsion, the Cremophor spectral profile predominated, but new bands between 1511 and 1637 cm⁻¹, associated with curcumin, confirmed its incorporation into the matrix. Conclusion: The FTIR results confirmed the preservation of the spectral signatures of the raw materials and the successful integration of curcumin into the nanoemulsion, reinforcing its potential for application in biomaterial-based dressings Full article

The addition of Bifidobacterium animalis subsp. lactis and prebiotics to fermented milk can enhance its flavor and sensory properties; however, research on the effects of their combined supplementation on flavor profiles remains limited. This study investigated the impact of simultaneously adding B. lactis IU100 and resistant starch type III (RS3) to fermented milk on flavor and texture. The results showed that co-supplementation shortened the fermentation time by 1 h. It also increased hardness by 28.8%, springiness by 1.14 mm, and water holding capacity by 12.45%, accompanied by the formation of a more continuous and dense gel network. Headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS) combined with odor activity value analysis indicated the enrichment of 115 key aromatic compounds, among which ethyl caprylate, ethyl n-butyrate, 1-octanol, and 2,3-heptanedione were identified as representative flavor compounds associated with fruity and creamy notes. KEGG pathway analysis revealed that 24 differential metabolites were predominantly enriched in purine metabolism and amino acid-related pathways. Within these pathways, coordinated enzymatic reactions convert α-keto acids and fatty acid metabolites into key flavor esters and catalyze the formation of volatile alcohols from amino acids and aromatic fatty acid precursors. Overall, this combined strategy effectively optimized fermentation efficiency, texture, and flavor through the targeted reprogramming of microbial metabolic flux. Full article

Biodiesel’s application in compression–ignition engines is mostly limited by the type of methyl esters it contains rather than the total amount of feedstocks. In order to modify the fatty acid methyl ester (FAME) profile for better combustion and emissions, cottonseed (CSOME), neem (NOME), and orange peel oil methyl esters (OPOMEs) were carefully mixed. Fuel chemistry was examined using Gas Chromatography–Mass Spectrometry (GC-MS) and Fourier Transform Infrared (FTIR), which confirmed variations in oxygenated functional groups, saturation levels, and volatility. In a single-cylinder CI engine, diesel, single, binary, and ternary biodiesel mixes were tested over 25–100% load at compression ratios of 17 and 18, both with and without 10% EGR. The ester-optimized ternary blend HBO70 delivered the best overall performance at CR 18 with EGR, exhibiting only a 0.61% reduction in BTE while achieving significant reductions in smoke (44%), PM (51%), NO_x (30%), HC (11%), CO (10%), and specific fuel consumption (SFC) (6.8%). Regression analysis confirmed a temperature- and oxygen-controlled NO_x–PM trade-off, demonstrating that ester-profile optimization is an excellent way to achieve cleaner and more efficient CI engine operation. Full article

Translocator protein (TSPO) regulates mitochondrial function, inflammation, and oxidative stress; however, its role in acute myocardial injury (MI) remains incompletely understood. While previous studies have examined TSPO ligands in cardiac injury, the interplay between TSPO modulation and nitric oxide (NO) signaling in AMI has not been systematically investigated. The aim of this study was to investigate the effects of TSPO modulation by PK11195, alone or in combination with nitric oxide synthase (NOS) inhibition by Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME), on cardiometabolic, inflammatory, oxidative stress, and histopathological parameters in an experimental model of isoprenaline-induced MI in rats. Male Wistar albino rats were divided into four groups: control (C); isoprenaline + saline-treated (ISO); isoprenaline + PK11195-treated (IP); and isoprenaline + PK11195 + L-NAME-treated (IPLN) groups. Isoprenaline administration induced MI, evidenced by elevated cardiac biomarkers, electrocardiographic (ECG) alterations, and histopathological damage. PK11195 treatment significantly attenuated MI and reduced pro-inflammatory cytokine levels while increasing anti-inflammatory cytokine levels, indicating protective effects. Nevertheless, TSPO modulation was associated with adverse metabolic effects, notably elevated fibrinogen and plasma homocysteine levels. Co-administration of L-NAME mechanistically demonstrated that NO availability is essential for PK11195 cardioprotective effects, as NOS inhibition partially abolished cardioprotection and modified oxidative stress parameters. Overall, TSPO modulation exerts complex actions in acute MI through regulating mitochondrial function, inflammatory signaling, and NO pathways, suggesting that TSPO is a potential, multifaceted therapeutic target. Full article

This study investigates the synthesis and physicochemical characterization of biolubricant base oils derived from sunflower oil methyl esters (SUNOMEs) via transesterification with trimethylolpropane (TMP) using guanidine carbonate (GNDC) as a green and efficient catalyst. The transesterification process was optimized to achieve high conversion and desirable physicochemical properties suitable for lubrication applications. The synthesized esters were characterized by viscosity, density, pour point, and oxidation stability, confirming their suitability as environmentally friendly lubricants. Reaction parameters, such as catalyst concentration (3.0–5.0 wt%), were optimized under both solvent-free and vacuum-assisted conditions. The use of guanidine carbonate achieved enhanced physicochemical properties with significantly reduced reaction times (≈6 h) and eliminated soap formation. The resulting TMP triesters exhibited kinematic viscosities in ranges of 41.27–52.73 cSt (40 °C) and 8.668–10.02 cSt (100 °C), a viscosity index in the range of 180–196, and excellent oxidation stability (RSSOT: up to 54.27 min). Fourier transform infrared (FTIR) analysis confirmed the formation of complete triester structures with characteristic carbonyl and C–O stretching bands at 1735 cm⁻¹ and 1050 cm⁻¹, respectively. Spectra showed also distinct stretching vibrations near 1640–1670 cm⁻¹ and 3300–3400 cm⁻¹, which correspond to amide carbonyl and N–H characteristic groups. The tribological performance was evaluated using Four-Ball Standard Test Method, demonstrating significant improvements compared to commercial mineral oils. The results indicate that guanidine carbonate is an effective catalyst for producing sunflower-oil-derived esters with favorable lubricating properties, highlighting their potential as sustainable biolubricants for industrial applications. Full article

Near-critical and supercritical carbon dioxide (SC-CO₂) is extensively utilized in high-pressure separation, extraction, polymer processing, and carbon capture and utilization (CCU) technologies owing to its tunable density, low viscosity, high diffusivity, and environmentally benign nature. Reliable phase equilibrium data are indispensable for process design and optimization, especially in the near-critical region characterized by pronounced non-idealities, high compressibility, and density fluctuations. This review synthesizes experimental phase behaviour studies for binary mixtures of CO₂ with diverse components, including hydrocarbons, alcohols, ethers, esters, ketones, water, monomers/polymers, ionic liquids (ILs), and deep eutectic solvents (DESs), compiling extensive vapour–liquid equilibrium (VLE), liquid–liquid equilibrium (LLE), and critical data across industrially relevant pressure (up to 40 MPa) and temperature (up to 400 K) ranges. It critically evaluates analytical (sampling and non-sampling) and synthetic methodologies, addressing challenges in CO₂-rich phase handling, depressurization artefacts, and near-critical phenomena, while assessing data consistency against established reliability criteria. Key trends emerge, such as enhanced solubility with increasing pressure and CO₂ density, chain-length dependencies in hydrocarbons and alcohols, and Lewis acid–base interactions driving solvation in polar systems. The review highlights gaps in multicomponent data and proposes integrating high-quality experiments with advanced thermodynamic modelling to enhance predictive accuracy. Future directions emphasize high-precision in situ techniques, expanded datasets for complex mixtures, and novel CO₂-philic solvents to advance sustainable SC-CO₂ applications. Full article

This study evaluated the suitability of a new glutinous rice cultivar of Gureumchal as a raw material for Makgeolli, a traditional Korean rice wine, by comparing Makgeolli produced from Gureumchal with those made from a non-glutinous rice and another glutinous rice cultivar. Makgeolli was prepared using single and blended rice combinations, and their physicochemical characteristics, amino acids, volatile aromatic compounds, and E-tongue were analyzed. The Gureumchal produced generally higher levels of total amino acids and ester compounds, particularly fruity esters, when compared with the other rice formulations. A volatile aromatic compound analysis indicated that non-glutinous rice favored the formation of acetate esters typically associated with the acetyl-CoA pathway, whereas Gureumchal produced higher levels of fruity acyl-CoA-derived esters, such as ethyl hexanoate and ethyl octanoate. An E-tongue analysis further demonstrated that rice type strongly shaped the Makgeolli’s taste profile: glutinous rice samples, including Gureumchal, exhibited higher sweetness but low umami, whereas non-glutinous rice produced higher acidity and umami. Blended samples confirmed that manipulating the proportion of glutinous and non-glutinous rice allows the systematic adjustment of taste balance. Overall, Gureumchal formed a distinct flavor profile characterized by fruity esters and pronounced sweetness, indicating its potential to diversify Makgeolli quality and support targeted flavor design. Full article

Recently, co-fermentation of functional medicinal plants with fungi has emerged as a promising strategy to enhance the overall quality of fermented foods. Monascus fermentation products have long been confronted with bottlenecks in both functionality and palatability, such as low monacolin K (MK) yield and poor flavor. Therefore, this study investigated the effects of co-fermenting Monascus purpureus with honeysuckle (Lonicera japonica Thunb.) on the bioactive metabolites and volatile flavor compounds of the fermented product. Through single-factor optimization, the addition of 0.8 g/L honeysuckle powder was identified as optimal, resulting in a 1.54-fold increase in MK yield compared to the control. Additionally, nine key genes were upregulated in the MK biosynthetic cluster (mokA–mokI). Co-fermentation also significantly increased the total flavonoid and polyphenol contents by 3.93-and 2.01-fold, respectively, and enhanced in vitro antioxidant activity. Gas chromatography-mass spectrometry analysis revealed that ketones, esters, and alcohols were the dominant volatile compounds. Orthogonal partial least squares-discriminant analysis identified 11 differential volatile compounds (variable importance in projection > 1), indicating a substantial shift in the flavor profile toward more desirable notes, with a reduction in undesirable aldehydes. These findings demonstrate that honeysuckle co-fermentation enhances the biofunctional properties of M. purpureus fermentation products and improves their sensory appeal, providing a viable bioprocessing strategy for developing high-value Monascus-based functional foods or ingredients. Full article

Innovative developments of GC-MS over the last two decades made this methodology a powerful tool for profiling a broad range of volatile metabolites and non-volatile ones of non-polar, semi-polar and even polar nature after appropriate derivatization. Indeed, the high potential of GC-MS in the analysis of low molecular weight metabolites involved in essential cellular functions (energy production, metabolic adjustment, signaling) made it the method of choice for the life and plant scientists. However, despite these advances, due to their intrinsic thermal lability, multiple classes of hydrophilic low-molecule weight metabolites (like nucleotides, sugar phosphates, cofactors, CoA esters) are unsuitable under the high-temperature conditions of the split–splitless (SSL) injection and GC separation, which makes the analysis of such compounds by GC-MS challenging. Therefore, to ensure comprehensive coverage of the plant metabolome, the GC-MS-based metabolomics platform needs to be efficiently combined with other metabolomics techniques and instrumental strategies. Moreover, to get a deeper insight into dynamics of plant cell metabolism in response to endogenic and exogenic clues, integration of the metabolomics data with the output obtained from other post-genomics techniques is desired. Therefore, here, we overview different strategies for the integration of the GC-MS-based metabolite profiling output with the data, acquired by other metabolomics techniques in terms of the multi-platform metabolomics approach. Further, we comprehensively discuss the implementation of the GC-MS-based metabolomics in multi-omics strategies and the data integration strategies behind this. This approach is the promising strategy, as it gives deep and multi-level insight into physiological processes in plants in the systems biology context, with consideration of all levels of gene expression. However, multiple challenges may arise in the way of integrating data from different omics technologies, which are comprehensively discussed in this review. Full article

Daqu is the core saccharifying and fermenting starter for strong-flavor Baijiu, and its quality is strongly shaped by the workshop microenvironment. Here, mature Daqu from a newly built workshop and a long-established workshop within the same distillery were compared under identical raw materials and process conditions. Physicochemical properties, volatile flavor compounds (HS-SPME-GC–MS), bacterial and fungal communities (16S/ITS sequencing), and Tax4Fun-predicted functions were jointly analyzed. The quality indicators of the Daqu in the new workshop are qualified, but the acidity (and moisture) is higher, and the fermentation, saccharification and liquefaction abilities are lower. The Daqu in the old workshop is rich in esters, the aroma is more mature, and the total ester content is about twice that of the new workshop. Both Daqu types shared similar core taxa, but the new workshop was dominated by a simpler Weissella–Thermomyces consortium, while the old workshop was enriched in Bacillus, lactic acid bacteria, Rhizomucor, Saccharomycopsis, and Wickerhamomyces. Correlation and network analyses linked these old-workshop core genera to key ethyl esters, higher alcohols and pyrazines, and Tax4Fun indicated a stronger bias toward amino acid/carbohydrate metabolism and membrane transport in the old workshop. These results show that workshop age reshapes Daqu quality by co-modulating physicochemical traits, microbial consortia and functional potential, and suggest microbial and functional targets for accelerating the “maturation” of new workshops. Full article

Acetate esters, synthesized by alcohol acyltransferase (AATases) encoded primarily by the ATF1 gene, are pivotal for the desirable fruity aroma in fermented foods. However, the role and regulatory impact of ATF1 in solid-state fermented meat remain largely unexplored. This study engineered Saccharomyces cerevisiae by knocking out and overexpressing ATF1 to investigate its influence on flavor formation in a sour meat model system. Compared to the wild-type strain, ATF1 overexpression (SCpA group) increased ethyl acetate content by 70.15% and uniquely produced significant levels of isoamyl acetate. Conversely, ATF1 deletion (SCdA group) led to a 61.23% reduction in ethyl acetate. Transcriptomic analysis revealed that ATF1 overexpression triggered a systemic metabolic shift, not only activating the final esterification step but also upregulating key genes in central carbon metabolism (SUC2, ICL1), amino acid biosynthesis, and precursor supply pathways (ACS2, ADH1). This synergistic regulation redirected metabolic flux towards the accumulation of both alcohol and acyl-CoA precursors, thereby amplifying acetate ester synthesis. Our findings demonstrate that ATF1 is a critical engineering target for flavor enhancement in fermented meats and uncover a broader metabolic network it influences, providing a robust strategy for the targeted modulation of food flavor profiles. Full article

Fabricating polyimide (PI) membranes with outstanding anti-plasticization ability and gas separation performance remains a challenge. In this study, two novel diamine monomers, DAMBO (methyl 3,5-diamino-4-methylbenzoate) and DAPGBO (3-hydroxypropyl 3,5-diamino-4-methylbenzoate), were synthesized through esterification reactions. Then, we copolymerized each of these two new monomers with 4,4′-diaminodiphenylmethane (DAM) and 4,4′-(Hexafluoroisopropylidene) diphthalic anhydride (6FDA) separately to yield two monoesterified PIs. Following this, we further prepared the ester-crosslinked PIs by inducing a transesterification crosslinking reaction within the PI-PGBO membrane via thermal treatment. As expected, we found that the formation of cross-linked structures can effectively regulate the microporous structure, enhance its sieving performance, and thus improve the membrane’s gas selectivity. Furthermore, the resulting network structure endowed the thermally treated PI membrane with excellent anti-plasticization ability. Physical characterization results show that after heat treatment, both the d-spacing and BET surface area of the PI membrane decreased, but the solvent resistance of the thermally treated PIs was significantly improved. Gas separation experiments revealed that the representative membrane (PI-PGBO-300) exhibited the optimal CO₂/CH₄ separation performance, with a CO₂ permeability of 371.05 Barrer, a CO₂/CH₄ selectivity of 28.11, and a CO₂ plasticization pressure exceeding 30 bar. This study provides valuable insights into the design of cross-linked polyimides (PIs) via transesterification reactions, which are capable of enhancing the performance of membrane-based gas separation processes. Full article

Vascular endothelial injury is a key pathological characteristic of multiple diseases, such as atherosclerosis, stroke, and mastitis. Aspirin eugenol ester (AEE) has been confirmed to exert a significant protective effect on vascular endothelial injury. However, the universal action patterns and underlying mechanisms of AEE across different pathological scenarios have not been systematically elucidated. This study aimed to investigate the effect and mechanism of AEE in alleviating multiple vascular endothelial injury models. Nine vascular endothelial injury models were established by treating bovine aortic endothelial cells (BAECs), mouse aortic endothelial cells (MAECs), and human umbilical vein endothelial cells (Huvecs) with ethanol (EtOH), hydrogen peroxide (H₂O₂), and copper sulfate (CuSO₄), respectively. The protective effects of AEE were systematically evaluated via morphological observation, detection of inflammatory responses, and oxidative stress markers. Furthermore, metabolomics was employed to identify and analyze differentially expressed metabolites between the nine model groups and AEE groups. AEE exerted protective effects on all nine vascular endothelial injury models, inhibiting inflammation and oxidative stress induced by all inducers. Metabolomic analysis revealed that the differentially expressed metabolites modulated by AEE in most models were primarily enriched in lipid metabolism, amino acid metabolism, coenzyme biosynthesis, and other related pathways. AEE could improve vascular endothelial injury by upregulating antioxidant substance which included eicosapentaenoic acid (EPA), choline, coenzyme A (CoA), glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD), as well as downregulating substances that cause endothelial oxidative damage, including phytosphingosine (PS), palmitic acid (PA), and arachidonic acid (AA). Full article

Recent studies have shown that the use of non-Saccharomyces yeasts, either alone or in co-fermentation with Saccharomyces cerevisiae, can enhance the development of specialty beers with distinctive compositional characteristics. This study aimed to evaluate the main compositional and sensory differences between American Pale Ale (APA) beers produced using the commercial strain S. cerevisiae US-05 as a single starter (Test 1), and those produced through sequential inoculation with Metschnikowia pulcherrima 62 followed by S. cerevisiae US-05 (Test 2). Analyses focused on key chemical parameters and volatile compounds at the end of primary fermentation (F1) and after 20 days of refermentation at 20 °C (F2). After F1, Test 2 samples showed higher concentrations of glycerol and higher alcohols (isoamyl alcohol, benzeneethanol) and lower concentrations of esters (isoamyl acetate, ethyl hexanoate, ethyl octanoate) compared to Test 1. After F2, the differences in higher alcohol content became less significant, whereas ester concentrations, particularly ethyl acetate and ethyl octanoate, were significantly higher in Test 2. Sensory evaluation revealed that beers from Test 2 exhibited more pronounced floral and fruity notes and achieved higher overall scores in the panel assessment. These findings indicate that sequential inoculation with M. pulcherrima 62 followed by S. cerevisiae enhances both the chemical complexity and sensory appeal of APA beers, highlighting the strain’s potential as a valuable tool for developing specialty beers with unique aromatic profiles. Full article