Applied Biological Chemistry最新文献

This study aimed to evaluate the neuroprotective effects of mixed extracts from Dioscorea bulbifera and Zingiber officinale (DBZO) against glutamate-induced excitotoxicity in HT-22 cells and to elucidate the associated molecular mechanisms. Neurotoxicity and protective effects were assessed using MTT and LDH assays, while cellular morphology was analyzed via microscopy. DBZO extract significantly restored axonal integrity disrupted by glutamate exposure. A DCFDA assay confirmed that DBZO reduced reactive oxygen species (ROS) generation in a concentration-dependent manner, underscoring its antioxidant capacity. Western blot analysis demonstrated that DBZO markedly decreased glutamate-induced neuronal death at 0.25 and 0.5 mg/mL. The observed neuroprotection was associated with the inhibition of the MAPK signaling cascade and the downregulation of apoptotic markers, including Caspase-3 and PARP. Moreover, DBZO activated the PI3K/Akt/mTOR survival pathway, enhancing neuronal viability. It also boosted antioxidant defenses by modulating Keap1 and NQO1 expression, thereby reducing oxidative damage. Collectively, these findings suggest that DBZO confers neuroprotection by regulating oxidative stress and apoptosis through NRf2/NQO-1 signaling. Due to its strong antioxidant and antiapoptotic properties.

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Benzoic acid, an aromatic compound conventionally obtained from coal tar, can also be produced via microbial biotransformation. The shikimate pathway of Escherichia coli provides a route for the biosynthesis of aromatic acids, with its intermediates serving as valuable starting materials for the synthesis of benzoic acid derivatives. Here, we report the E. coli-based synthesis of three benzoic acid derivatives: 3,4-dihydroxybenzoic acid (protocatechuic acid, 3,4-DHBA), gallic acid (GA), and β-glucogallin. The enzyme QuiC was used to catalyze the conversion of 3-dehydroshikimate to 3,4-DHBA. For GA production, a screening of four pobA mutants was conducted to identify the most efficient mutant. A grape-derived uridine diphosphate-dependent glucosyltransferase (UDP-GT) was utilized for the glucosylation of GA to β-glucogallin. To improve the production titers of 3,4-DHBA and GA, a shikimate pathway gene module and a specifically engineered E. coli mutant were employed, resulting in the accumulation of 451.3 mg/L 3,4-DHBA and 123.4 mg/L GA. β-Glucogallin synthesis was achieved through a stepwise process, wherein one E. coli strain produced GA, and its clarified culture medium was subsequently used by a second E. coli strain for β-glucogallin formation. Optimization of the ratio between the GA-containing supernatant and the second cell culture led to a β-glucogallin yield of 118.5 mg/L.

In this study, a new kind of hawthorn fruit-derived food flavor was developed through Maillard reaction. The reaction conditions were optimized using a combination of single-factor experiments and response surface methodology (RSM). The key flavor compounds were determined by gas chromatography-mass spectrometry (GC-MS) and relative odor activity values (ROAVs). Single-factor experiments indicated that the preferred conditions were glycine supplement amount of 5.0%, reaction temperature of 130 °C, and reaction time of 90 min, which were further optimized by RSM. GC-MS analysis demonstrated a remarkable 2.7-fold increase in total flavor compounds (TFCs) of Maillard reaction samples (MRSs) than those of enzymolysis extract of hawthorn. ROAV analysis indicated 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP), furfural, 2-methylbutyric acid, hexyl acetate, linalool, decanal, and α-ionone were the key flavor compounds of MRSs, which contributed to the sweetness, roasting, fruity, and acidic aromas. The antioxidant activity were obviously enhanced after Maillard reaction that could be associated with the yielded DDMP and 4-vinylphenol.

Spirits exhibit distinct flavors based on variations in raw materials and production methods. This study aimed to evaluate the potential of Korean rice-matured distilled spirits as premium distilled spirits by comparing their volatile compounds with those of commercially available whiskies. Volatile compounds in 17 single malt whiskies (SM), 9 blended whiskies (BL), and 3 rice-matured distilled spirits (RM) were analyzed using gas chromatography/mass spectrometry (GC/MS) combined with headspace solid-phase microextraction arrow (HS-SPME-Arrow). Among the 77 identified volatile compounds, the concentrations of ethyl acetate, ethyl decanoate, and ethyl octanoate tended to increase as SM, BL, and RM matured, and may serve as key volatile compounds for distinguishing spirits. Additionally, ethanol, isoamyl alcohol, 2-methyl-1-butanol, isoamyl acetate, and phenylethyl acetate may function as volatile indicators for predicting the type and aging level of whisky. In this study, we evaluated volatile compounds in 29 spirits and identified eight key compounds that differentiate whisky types. Moreover, ethyl acetate and lactones, closely related to the flavor of whiskies, were remarkably higher in RMs compared to commercial whiskies. These findings could greatly contribute to the development of rice-matured spirits as high-quality Korean whisky and offer significant contributions to the classification of premium whiskies.

Obesity results from various factors, such as menopause, age, physical activity, genetics, and environmental factors. Notably, the risk of obesity in women, especially in the context of menopause, has increased with rising life expectancy. Therefore, preventing and treating menopause-related obesity is crucial. Rice bran, the brown outer layer of the rice kernel, is known to contain nutrients and bioactive compounds. Rice bran supplement (RBS), a byproduct of rice polishing, recognizably treats obesity; moreover, it is also known to increase mitochondrial function. To validate the effect of RBS on menopause-induced obesity, we administered RBS to ovariectomized mice as a menopause model. Ultimately, we aimed to evaluate the potential of RBS as an alternative candidate to hormone replacement therapy for treating menopause-induced obesity. RBS treatment significantly reduced body weight by 20% and retroperitoneal fat by 97% compared to the HFD group. Furthermore, mitochondrial enzyme activities as mitochondrial respiratory function in the brain increased on average by 102% compared to the HFD group and by average by 93% compared to the ND group, highlighting the therapeutic efficacy of RBS in ameliorating metabolic complications associated with menopause, without the use of hormone replacement therapy.

This study investigated the anti-inflammatory effects of pyran derivatives, focusing on compound 19, in LPS-stimulated RAW264.7 macrophages. We screened 19 pyran derivatives for cytotoxicity and nitric oxide (NO) inhibition, and identified compound 19 as the most promising compound owing to its efficacy. Western blot analysis revealed that compound 19 significantly inhibited the expression of key inflammatory mediators such as inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 in LPS-stimulated macrophages in a dose-dependent manner. Furthermore, compound 19 inhibited the phosphorylation of Akt at 12.5 μM, and suppressed JNK and ERK MAPK phosphorylation at both concentrations (12.5 and 6.25 μM), while p38 phosphorylation was not inhibited. These findings suggest that compound 19 exerts its anti-inflammatory action by modulating multiple signaling pathways involved in inflammatory responses. Our results demonstrate that compound 19 is a promising candidate for the development of novel anti-inflammatory agents.

Kimchi, a traditional Korean fermented food, undergoes spontaneous fermentation driven by lactic acid bacteria (LAB), which significantly influences its flavor, texture, and nutritional content. The quality of kimchi is largely determined by the metabolites produced during microbial metabolism, but the relationship between intra- and extra-cellular metabolism of LAB remains unclear. This study aimed to investigate the metabolism of various LAB strains isolated from kimchi, through metabolomic analysis of both their intra- and extra-cellular matrices, and to explore the role of their metabolism during kimchi fermentation. Hetero- and homo-fermentative characters of Leuconstoc and Lactiplantibacillus strains were characterized by production of extracellular mannitol and lactate, respectively. Notably, the rapid growth of Lactiplantibacillus strains was found to associated with a substantial uptake of extracellular glucose and aromatic amino acids, whereas the slow growth of Leuconostoc strains contributed to the production of most extracellular amino acids and a less uptake of extracellular glucose. Indeed, Lactiplantibacillus strains may regulate intracellular pH through the elimination of intracellular acidic amino acids, while Leuconostoc strains possibly protect themselves against osmotic stress by producing intracellular betaine. Moreover, kimchi fermented under slow fermentation conditions contained higher levels of mannitol and amino acids compared to fast fermentation condition, thereby enhancing its nutritional value and overall quality. This study highlights the links between the slow fermentation or metabolic distinction of LAB and the potential contribution to the improvement of fermented food quality.

Liriope platyphylla F. T. Wang & T. Tang (L. platyphylla) is a perennial member of the Liliaceae family, is predominantly found in East Asian regions such as Korea, Taiwan, and Japan. In this study, we investigated the neuroinflammation-modulating potential of an ethanol-based extract from L. platyphylla (LPE) using BV2 microglial cells activated by lipopolysaccharide (LPS). In addition, we examined which bioactive constituents in LPE contribute to its anti-neuroinflammatory effects by isolating and profiling the major compounds. Notably, treating LPE prior to LPS exposure led to a marked decrease in the synthesis of inflammatory mediators, including cyclooxygenase-2 (COX-2), nitric oxide (NO), prostaglandin E2 (PGE₂), inducible nitric oxide synthase (iNOS), and pro-inflammatory cytokines such as IL-6, IL-1β, and tumor necrosis factor-α (TNF-α) in the microglia. Mechanistic studies revealed that suppressive effects of LPE are linked to the downregulation of LPS-triggered signaling pathways, specifically those involving Toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), and the p38 and JNK branches of the mitogen-activated protein kinase (MAPK) cascade. Chemical analysis of the extract identified eight distinct compounds, with methylophiopogonone A (2) and methylophiopogonanone B (3) being primarily responsible for the observed anti-neuroinflammatory activity. Quantitative profiling by ultra-performance liquid chromatography coupled with quadrupole time of flight / mass spectrometry (QTOF/MS) indicated that these two bioactive constituents were present in the ethyl acetate fraction of LPE at concentrations of 0.0007 ± 0.0001 mg/g and 0.0197 ± 0.0009 mg/g, respectively. Collectively, these findings highlight the promise of LPE as a source for developing novel functional ingredients or herbal therapeutics targeting neuroinflammatory conditions.

With the growing prevalence of memory impairment and limited treatment options, this study evaluated the cognitive-enhancing potential of an Omija (Schisandra chinensis (Turcz). Baill) 50% ethanol extract and soybean mixture (OSM). By integrating network pharmacology with in vivo validation, we aimed to elucidate the molecular mechanisms and therapeutic efficacy of OSM. Network pharmacology was used to identify core pathways and targets associated with the memory-enhancing effects of Omija (gomisin, schizandrin) and soybean. To validate these findings, scopolamine-induced memory-impaired rats (2 mg/kg/day for 8 weeks) through the parasympathetic nervous system (PNS) suppression were administered OSM (100, 250, or 750 mg/kg/day) or dextrin (positive control) alongside a high-fat diet. Behavioral, metabolic, and molecular evaluations were conducted. Network analysis identified key targets involved in neuroinflammation including interleukin (IL)-17 and nuclear factor Kappa B (NF-κB) signaling and neurotransmitter regulation (dopamine synapse), including acetylcholinesterase (AChE), prostaglandin-endoperoxide synthase-2 (PTGS2), glycogen-synthase kinase-3beta (GSK-3β), solute carrier family 6 member 3 (SLC6A3; dopamine transporter), and plasminogen activator (PLAU). In vivo, OSM at 250 and 750 mg/kg significantly improved memory performance across passive avoidance, Y-maze, Morris water maze, and novel object recognition tests. These improvements were associated with suppressed neuroinflammatory genes (NF-κB, PTGS2, TNF-α, IL-17, IL-1β), enhanced cholinergic and dopaminergic balance (reduced AChE activity, increased dopamine), improved glucose metabolism, and upregulated neurotrophic factor expression (brain-derived neurotrophic factor, ciliary neurotrophic factor). Furthermore, OSM enhanced hippocampal insulin signaling (increased phosphorylation of Akt and GSK-3β), improved intestinal morphology, and increased portal vein butyrate levels, suggesting modulation of the gut-brain axis. In conclusion, OSM enhances memory through multiple central (cholinergic, dopaminergic, neurotrophic) and peripheral (anti-inflammatory, metabolic) mechanisms via activating the gut-brain axis. These findings support OSM (250–750 mg/kg) as a promising candidate for cognitive enhancement potentially by inhibiting PNS suppression, warranting further clinical investigation.

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