• Korean Chemical Engineering Research
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• v.62 no.2
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• pp.147-152
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• 2024

Most medical sensors are disposable products. In order to reduce inspection and diagnosis costs, it is more important to develop the inexpensive electrode materials. We fabricated the CuO NPs/PANI/E-PGE as an electrode material for disposable electrochemical sensors and applied it to a non-enzymatic glucose sensor. For surface activation of PGE, pretreatment was performed using chemical and electrochemical methods, respectively. Electrochemical properties according to the pretreatment method were analyzed through chronoamperometry (CA), cyclic voltammetry (CV) and electrochemical impedance (EIS). From these analytical results, the electrochemically pretreated PGE (E-PGE) was finally adopted. The non-enzymatic glucose sensor based on CuO NPs/PANI/E-PGE shows sensitivity of 239.18 mA/mM×cm² (in a linear range of 0.282~2.112 mM) and 36.99 mA/mM×cm² (3.75423~50 mM), detection limit of 17.6 μM and good selectivity. Based on the results of this study, it was confirmed that the modified PGE is a high-performance electrode material. Therefore, these electrodes can be applied to a variety of disposable sensors.

• Clean Technology
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• v.30 no.2
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• pp.145-156
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• 2024

Carbon has a large specific area and excellent chemical stability, so research on its use as a catalyst support is actively conducted. When using carbon as a support, the pretreatment process is essential. Through pretreatment of carbon, the growth of metal nanoparticles can be controlled and the bonding strength between the support and metal particles can be improved. In this study, carbon was pretreated for surface modification and 5 wt% Pd/C catalysts were synthesized using it as a support. Catalytic activity was evaluated through phenol hydrogenation. To compare with nitric acid, which is commonly used in carbon pretreatment, carbon pretreatment was performed using organic acid. Pd/C treated with gluconic acid showed the highest activity, with 94.93% phenol conversion and 92.76% cyclohexanone selectivity. Therefore, it is expected that pretreatment of the carbon support using organic acid will not only overcome the disadvantages of inorganic acid treatment but also improve catalyst performance.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.13-18
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• 2024

To develop flexible electrode materials for wearable devices, we investigated the electrochemical characteristics of carbon fibers tow according to pretreatment. And an electrochemical non-enzymatic sensor was fabricated using glucose as a target. The carbon fibers tow was pretreated through desizing and activation processes, and activation was performed in two ways: chemical oxidation and electrochemical oxidation. Surface morphology of carbon fibers tow samples was observed by SEM and their electrochemical characteristics and sensing performance were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Carbon fibers tow samples showed improved electrochemical properties such as reduced R_et, ΔE_p, and increased I_p through pretreatment. And similar electrochemical properties were obtained with both activation methods. We selected electrochemically activated carbon fibers tow as the final electrode material for application of electrochemical sensor. The non-enzymatic glucose sensor based on this electrode has an enhanced sensitivity of 0.744 A/mM (in a linear range of 0.09899~3.75423 mM) and 0.330 mA/mM (3.75423~50 mM), respectively. Through this study, the possibility of using carbon fibers tow was confirmed as an electrode material. It is expected to be used as basic research for development of high-performance flexible electrode materials.

• Research in Plant Disease
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• v.29 no.4
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• pp.390-398
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• 2023

Apple white rot, caused by Botryosphaeria dothidea, is one of the important diseases in Korea. B. dothidea can cause pre- and postharvest decay on apple fruit as well as canker and dieback of apple trees. In this study, we isolated bacteria from the trunk of apple trees and tested their antagonistic activity against B. dothidea. Five bacterial isolates (23-168, 23-169, 23-170, 23-172, and 23-173) were selected that were most effective at inhibiting the mycelial growth of the pathogens. The isolate 23-172 was identified as Bacillus amyloliquefaciens and four isolates 23-168, 23-169, 23-170, and 23-173 were identified as Bacillus velezensis by RNA polymerase beta subunit (rpoB) and DNA gyraseA subunit (gyrA) gene sequencing. All isolates showed strong antagonistic activity against B. dothidiea as well as Colletotrichum fructicola and Diaporthe eres. All isolates exhibited cellulolytic, proteolytic and phosphate solubilizing activities. In particular, two isolates 23-168, 23-169 were shown to significantly reduce the size of white rot lesions in pretreated apple fruits. These results will provide the basis for the development of a fungicide alternative for the control of white rot of apple.

• Journal of Life Science
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• v.34 no.1
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• pp.9-17
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• 2024

Diabetes mellitus (DM) is one of the main global health problems. Chronic exposure to hyperglycemia can lead to cellular dysfunction that may become irreversible over time, a process that is termed glucose toxicity. Our perspective about glucose toxicity as it pertains to the pancreatic β-cell is that the characteristic decreases in insulin secretion are caused by regulated apoptotic gene expression. In this study, we examined whether ferulic acid protects INS-1 pancreatic cells against high glucose-induced apoptosis. High glucose concentration (30 mM) induced glucotoxicity and death of INS-1 pancreatic β cells. However, treatment with 1, 5, 10, or 20 μM ferulic acid increased the cell viability in a concentration-dependent manner. Treatment with ferulic acid dose-dependently decreased the intracellular levels of reactive oxygen species, thiobarbituric acid reactive substances, and nitric oxide in INS-1 pancreatic β cells pretreated with high glucose. These effects influence the apoptotic pathway, increasing the expression of the anti-apoptotic protein Bcl-2 and reducing the levels of pro-apoptotic proteins, including Bax, cytochrome C, and caspase 9. Annexin V/propidium iodide staining indicated that ferulic acid significantly reduced high glucose-induced apoptosis. These results demonstrate that ferulic acid is a potential therapeutic agent to protect INS-1 pancreatic β cells against high glucose-induced apoptosis.

• Food Science and Preservation
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• v.31 no.2
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• pp.298-306
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• 2024

This study evaluated the differentiation and protective effects of mixed plant-extract powder in C2C12 muscle cells. Cells were differentiated into myotubes in 2% horse serum (HS)-containing medium with mixed plant-extract powder (MPEP) for 6 days. Treatment with MPEP increased the expression of myogenin and myosin heavy chain (MHC) protein in cells compared with non-treated cells. Differentiated cells were pretreated with MPEP, and hydrogen peroxide (H₂O₂). Our results revealed that treatment with MPEP before H₂O₂ treatment increased cell viability and decreased H₂O₂-induced lactate dehydrogenase (LDH) and creatine kinase (CK). In addition, MPEP attenuated H₂O₂-induced upregulation of Bax, downregulation of Bcl-2, and activation of caspase-9 and -3. These results suggest the MPEP can stimulate C2C12 muscle cell differentiation into myotubes and observe the protective effect of mixed plant-extract powder against muscle oxidative stress. In conclusion, MPEP may be useful as a prevention and treatment material for skeletal muscle disease caused by age-related diseases.

• Herbal Formula Science
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• v.31 no.4
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• pp.231-243
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• 2023

Objectives : Jasminum officinale L. var. grandiflorum is used as a traditional or folk remedy in China to treat arthritis, hepatitis, duodenitis, conjunctivitis, gastritis, and diarrhea. In this study, we aimed to study the hepatocyte protective activity and molecular mechanism of Jasminum officinale L. var. grandiflorum aqueous extract (JGW) using HepG2 hepatocyte cell lines. Methods : HepG2 cells were pretreated with diverse concentrations of JGW, and then the cells were exposed to tert-butyl hydroperoxide (tBHP) for inducing oxidative stress. Hydrogen peroxide (H₂O₂) production, glutathione (GSH) concentration, mitochondrial membrane potential (MMP) and cell viability were measured to investigate hepato-protective effects of JGW. Phosphorylation of AMP-activated protein kinases (AMPK), acetyl coenzyme A carboxylase (ACC) and effects of compound C on cell viability were examined to observe the role of AMPK on JGW-mediated cytoprotection. Results : Pretreatment with JGW (10-300 ㎍/mL) significantly suppressed cytotoxicity induced by tBHP in a concentration dependent manner and reduced the expression of cleaved PARP and cleaved caspase-3 proteins related to apoptosis in HepG2 cells. In addition, pretreatment with JGW significantly prevented the increase in H₂O₂ production, GSH depletion, and lower MMP induced by tBHP. Treatment with JGW (30 minutes of incubation and concentrations of 100 and 300 ㎍/mL) increased the phosphorylation of AMPK and ACC and treatment with compound C, a chemical inhibitor of AMPK, inhibited the cytoprotective effect of JGW. Conclusions : Our results demonstrated that JGW may protect hepatocytes from oxidative stress via activation of AMPK.

• Biomolecules & Therapeutics
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• v.32 no.1
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• pp.154-161
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• 2024

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disorder that causes progressive paralysis. L-Citrulline is a nonessential neutral amino acid produced by L-arginine via nitric oxide synthase (NOS). According to previous studies, the pathogenesis of ALS entails glutamate toxicity, oxidative stress, protein misfolding, and neurofilament disruption. In addition, L-citrulline prevents neuronal cell death in brain ischemia; therefore, we investigated the change in the transport of L-citrulline under various pathological conditions in a cell line model of ALS. We examined the uptake of [¹⁴C]L-citrulline in wild-type (hSOD1wt/WT) and mutant NSC-34/ SOD1^G93A (MT) cell lines. The cell viability was determined via MTT assay. A transport study was performed to determine the uptake of [¹⁴C]L-citrulline. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was performed to determine the expression levels of rat large neutral amino acid transported 1 (rLAT1) in ALS cell lines. Nitric oxide (NO) assay was performed using Griess reagent. L-Citrulline had a restorative effect on glutamate induced cell death, and increased [¹⁴C]L-citrulline uptake and mRNA levels of the large neutral amino acid transporter (LAT1) in the glutamate-treated ALS disease model (MT). NO levels increased significantly when MT cells were pretreated with glutamate for 24 h and restored by co-treatment with L-citrulline. Co-treatment of MT cells with L-arginine, an NO donor, increased NO levels. NSC-34 cells exposed to high glucose conditions showed a significant increase in [¹⁴C]L-citrulline uptake and LAT1 mRNA expression levels, which were restored to normal levels upon co-treatment with unlabeled L-citrulline. In contrast, exposure of the MT cell line to tumor necrosis factor alpha, lipopolysaccharides, and hypertonic condition decreased the uptake significantly which was restored to the normal level by co-treating with unlabeled L-citrulline. L-Citrulline can restore NO levels and cellular uptake in ALS-affected cells with glutamate cytotoxicity, pro-inflammatory cytokines, or other pathological states, suggesting that L-citrulline supplementation in ALS may play a key role in providing neuroprotection.

• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.246-252
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• 2024

In this study, impurities such as Li and F were removed from waste graphite through citric acid treatment, and changes in structural properties, capacity, and cycle stability of regenerated graphite were observed accordingly. Regenerated graphite pretreated in a nitrogen atmosphere was treated with citric acid, and its structure and characteristics were analyzed through SEM (Scanning Electron Microscope), FT-IR (Fourier Transform Infrared spectroscopy), XRD (X-ray Diffraction), and XPS (X-ray Photoelectron Spectroscopy). Waste graphite that was not treated with acid had a rapid decrease in capacity before 70 cycles, but graphite that had been treated with citric acid showed a capacity of 302.9 mAh g^-1 and a capacity retention rate of 93.1% at 100 cycles. In addition, despite changes in current density in rate performance, samples treated with citric acid showed 340.2 mAh g^-1 performance at 1.0C without change in capacity. As a result, it was confirmed that citric acid treatment not only effectively removed impurities and showed a high capacity retention rate, but also showed stability even at high current densities.

• Journal of Nutrition and Health
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• v.57 no.4
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• pp.403-417
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• 2024

Purpose: This study investigated the anti-inflammatory effects of Evodiae Fructus (EF) on hydrochloric acid (HCl)/ethanol-induced gastritis, focusing on its impact on oxidative stress by analyzing inflammatory cytokines and inflammation-related factors. The total polyphenol and flavonoid contents were determined through in vitro experiments, while the radical scavenging activity was confirmed using 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assays. Methods: In vivo experiments were conducted on rats divided into 5 groups (n = 7/in each group): normal group (Normal), 150 mM HCl/60% ethanol-induced gastritis group (Control), 150 mM HCl/60% ethanol-induced gastritis group administered 10 mg/kg sucralfate (SC), 150 mM HCl/60% ethanol-induced gastritis group administered EF at the doses of 100 mg/kg or 200 mg/kg (EF100 or EF200). The mice were pretreated with the extract (EF) or drug (SC), and after 1 hour, 150 mM HCl/60% ethanol (v/v) mixture was administered orally. Reactive oxygen species (ROS) levels, peroxynitrite (ONOO^-), and pro-inflammatory cytokines including tumor necrosis factor-α and interleukin-1 beta were assessed in serum. Additionally, western blotting of the gastric tissues confirmed the expression of inflammation-related proteins. Results: EF alleviated the gastric mucosal damage caused by 150 mM HCl/60% ethanol. The assessment of oxidative stress in the serum showed that EF significantly reduced ROS and ONOO^- levels and significantly decreased the levels of pro-inflammatory cytokines. Western blot analysis revealed that EF reduced ROS-generating nicotinamide adenine dinucleotide phosphate oxidase subunits, including gp91^phox, p22^phox, and p47^phox. Additionally, EF mitigated the inflammation by inhibiting the mitogen-activated protein kinase signaling pathway. Conclusion: These results indicate that EF is a potential herbal medicine candidate for the treatment of oxidative stress-induced gastritis.