• Journal of Society of Preventive Korean Medicine
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• v.12 no.1
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• pp.103-118
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• 2008

Antioxidants are compounds that protect cells against the damaging effects of reactive oxygen species (ROS). Some ROS, such as superoxide and hydrogen peroxide, are normally produced in cells as by-products of biochemical reactions or as signaling molecules. When ROS-generating reactions are activated excessively, pathological quantities of ROS are released to create an imbalance between antioxidants and ROS, called as oxidative stress. Oxidative stress, which may result in cellular damage, has been linked to cardiovascular disease, diabetes, cancer, and other degenerative conditions. In humans the first line of antioxidant defence are the antioxidant enzymes, especially SOD, glutathione peroxidase (GPX), and to a lesser extent catalase, as well as the tripeptide glutathione(GSH). These enzymes will help destroy ROS(reactive oxygen species) such as hydroxyl radical, $H_2O_2$ and lipid peroxides, while GSH protects against oxidized protein. Many herbal medicines possess antioxidant properties. Herbal antioxidants may protect against these diseases by contributing to the total antioxidant defense system of the human body. Here, many herbal medicines including Ginseng, Licorice, Ligusticum Chuanxiong, Ginkgo biloba and many others was reviewed in terms of anti-oxidant efficiency related to their components.

• Biomolecules & Therapeutics
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• v.22 no.5
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• pp.420-425
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• 2014

Esophageal reflux of gastric contents causes esophageal mucosal damage and inflammation. Recent studies show that oxygen-derived free radicals mediate mucosal damage in reflux esophagitis (RE). Chlorogenic acid (CGA), an ester of caffeic acid and quinic acid, is one of the most abundant polyphenols in the human diet and possesses anti-inflammatory, antibacterial and anti-oxidant activities. In this context, we investigated the effects of CGA against experimental RE in rats. RE was produced by ligating the transitional region between the forestomach and the glandular portion and covering the duodenum near the pylorus ring with a small piece of catheter. CGA (10, 30 and 100 mg/kg) and omeprazole (positive control, 10 mg/kg) were administered orally 48 h after the RE operation for 12 days. CGA reduced the severity of esophageal lesions, and this beneficial effect was confirmed by histopathological observations. CGA reduced esophageal lipid peroxidation and increased the reduced glutathione/oxidized glutathione ratio. CGA attenuated increases in the serum level of tumor necrosis factor-${\alpha}$, and expressions of inducible nitric oxide synthase and cyclooxygenase-2 protein. CGA alleviates RE-induced mucosal injury, and this protection is associated with reduced oxidative stress and the anti-inflammatory properties of CGA.

• BMB Reports
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• v.44 no.3
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• pp.170-175
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• 2011

We identified a bovine $B_{12}$ trafficking chaperone bCblC in Bos taurus that showed 88% amino acid sequence identity with a human homologue. The protein bCblC was purified from E. coli by over-expression of the encoding gene. bCblC bound cyanocobalamin (CNCbl), methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl) in the base-off states and eliminated the upper axial ligands forming aquo/hydroxocobalamin ($OH_2$/OHCbl) under aerobic conditions. A transition of $OH_2$/OHCbl was induced upon binding to bCblC. Interestingly, bCblC-bound $OH_2$/OHCbl did not react with reduced glutathione (GSH), while the reaction of free$OH_2$/OHCbl with GSH resulted in the formation of glutathionylcobalamin (GSCbl) and glutathione disulfide (GSSG). Furthermore we found that bCblC eliminates the GSH ligand of GSCbl forming $OH_2$/OHCbl. The results demonstrated that bCblC is a $B_{12}$ trafficking chaperone that binds cobalamins and protects $OH_2$/OHCbl from GSH, which could be oxidized to GSSG by free $OH_2$/OHCbl.

• Proceedings of the Microbiological Society of Korea Conference
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• 2000.10a
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• pp.24-31
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• 2000

In order to find out SoxR-reducing system in E. coli, we generated Tn10-insertion mutants and screened for constitutive expression of SoxS in a soxS-lacZ fusion strain. One mutation was mapped in rseB, a gene in rseABC (Regulation of SigmaE) operon. The constitutive soxS-expressing phenotype was due to the polar effect on the downstream gene, rseC. RseC is likely to function as a component of SoxR reduction system because SoxR was kept in oxidized form to activate soxS expression in rseC mutant. RseC is an integral membrane protein with an N-terminal cysteine-rich domain in the cytoplasm. The functionally critical cysteines were determined by substitution mutagenesis. The truncated N-terminal domain of RseC reduced the soxS transcription by $50\%$ as judged by in vitro transcription assay. Currently RseC is believed to be a reducing factor for SoxR. However, the mechanism for the reduction needs further investigation.

• Journal of Microbiology and Biotechnology
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• v.25 no.8
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• pp.1361-1370
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• 2015

A blue laccase was purified from a white rot fungus of Trametes trogii, which was a monomeric protein of 64 kDa as determined by SDS-PAGE. The enzyme acted optimally at a pH of 2.2 to 4.5 and a temperature of 70℃ and showed high thermal stability, with a half-life of 1.6 h at 60℃. A broad range of substrates, including the non-phenolic azo dye methyl red, was oxidized by the laccase, and the laccase exhibited high affinity towards ABTS and syringaldazine. Moreover, the laccase was fairly metal-tolerant. A high-molecular-weight kraft lignin was effectively polymerized by the laccase, with a maximum of 6.4-fold increase in weight-average molecular weight, as demonstrated by gel permeation chromatography. Notable structural changes in the polymerized lignin were detected by Fourier transform infrared spectroscopy and ¹H NMR spectroscopy. This revealed an increase in condensed structures as well as carbonyl and aliphatic hydroxyl groups. Simultaneously, phenolic hydroxyl and methoxy groups decreased. These results suggested the potential use of the laccase in lignin modification.

• International Journal of Industrial Entomology and Biomaterials
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• v.43 no.2
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• pp.45-51
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• 2021

High blood cholesterol levels and oxidized cholesterol are risk factors for cardiovascular disease, which displays high annual incidence. Although studies on sericulture products, including pupae, silk protein, and blood lymph, as hypocholesterolemic substances have been reported, insufficient research in this field has been focused on silkworm larvae. Six larval extracts (Low temperature distilled water, LW; hot temperature distilled water, HW; and 30-100% ethanol, E30-E100) were prepared, and their effects on cholesterol metabolism were examined. LW most potently reduced the risk of cholesterol-related disorders. Polyphenols were highly represented in LW, corresponding with its increased antioxidant potency. The cholesterol biosynthesis enzyme, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) was strongly inhibited by LW. Hepatocytes over-expressed LDL receptor (LDLR) after LW stimulation, promoting cholesterol elimination from plasma. LW also increased ATP binding cassette transporter 1 (ABCA1) gene expression, upregulating HDL biogenesis. In conclusion, LW exhibited strong antioxidant activity, suppressed cholesterol biosynthesis, improved LDL uptake from plasma, and upregulated HDL biosynthesis. In aggregate, these activities could reduce blood cholesterol levels and prevent cardiovascular disease.

• Journal of Microbiology and Biotechnology
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• v.32 no.11
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• pp.1406-1415
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• 2022

The formation of macrophage foam cells stimulated by oxidized low-density lipoprotein (ox-LDL) is deemed an important cause of atherosclerosis. Transcription factor Yin Yang 1 (YY1), which is a universally expressed multifunctional protein, is closely related to cell metabolism disorders such as lipid metabolism, sugar metabolism, and bile acid metabolism. However, whether YY1 is involved in macrophage inflammation and lipid accumulation still remains unknown. After mouse macrophage cell line RAW264.7 cells were induced by ox-LDL, YY1 and proprotein convertase subtilisin/kexin type 9 (PCSK9) expressions were found to be increased while low-density lipoprotein receptor (LDLR) expression was lowly expressed. Subsequently, through reverse transcription-quantitative polymerase chain reaction (RT-qPCR), Western blot analysis, Oil Red O staining and cholesterol quantification, it turned out that silencing of YY1 attenuated the inflammatory response and lipid accumulation in RAW264.7 cells caused by ox-LDL. Moreover, results from the JASPAR database, chromatin immunoprecipitation (ChIP) assay, luciferase reporter assay and Western blot analysis suggested that YY1 activated PCSK9 by binding to PCSK9 promoter and modulated the expression of LDLR in the downstream of PCSK9. In addition, the results of functional experiments demonstrated that the inhibitory effects of YY1 interference on ox-LDL-mediated macrophage inflammation and lipid accumulation were reversed by PCSK9 overexpression. To sum up, YY1 depletion inhibited its activation of PCSK9, thereby reducing cellular inflammatory response, cholesterol homeostasis imbalance, and lipid accumulation caused by ox-LDL.

• Molecules and Cells
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• v.46 no.8
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• pp.486-495
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• 2023

Lipofuscins are oxidized lipid and protein complexes that accumulate during cellular senescence and tissue aging, regarded as markers for cellular oxidative damage, tissue aging, and certain aging-associated diseases. Therefore, understanding their cellular biological properties is crucial for effective treatment development. Through traditional microscopy, lipofuscins are readily observed as fluorescent granules thought to accumulate in lysosomes. However, lipofuscin granule formation and accumulation in senescent cells are poorly understood. Thus, this study examined lipofuscin accumulation in human fibroblasts exposed to various stressors. Our results substantiate that in glucose-starved or replicative senescence cells, where elevated oxidative stress levels activate autophagy, lipofuscins predominately appear as granules that co-localize with autolysosomes due to lysosomal acidity or impairment. Meanwhile, autophagosome formation is attenuated in cells experiencing oxidative stress induced by a doxorubicin pulse and chase, and lipofuscin fluorescence granules seldom manifest in the cytoplasm. As Torin-1 treatment activates autophagy, granular lipofuscins intensify and dominate, indicating that autophagy activation triggers their accumulation. Our results suggest that high oxidative stress activates autophagy but fails in lipofuscin removal, leaving an abundance of lipofuscin-filled impaired autolysosomes, referred to as residual bodies. Therefore, future endeavors in treating lipofuscin pathology-associated diseases and dysfunctions through autophagy activation demand meticulous consideration.

• Journal of Life Science
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• v.9 no.4
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• pp.439-452
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• 1999

This study was designed to investigate the effects of sea tangle (Laminaria japonica) extract and fucoidan components on anti-aging action. Sprague-Dawley(SD) male rats (210$\pm$5g) were fed experimental diets Dasi-Ex group: sea tangle extract powder of 4.0% added to control diet; Fuco-I, II and III groups: funcoidan powder of 1, 2 and 3% added to Dasi-Ex group for 45 days. Hydroxyl radical (.OH) formations were significantly inhibited (10-20% and 25-30%) in serum and brain mitochondria of Dasi-Ex and Fuco-I, II and III groups compared with control group. Significant differences in .OH formations of brain mitochondria in Dasi-Ex and Fuco-I groups could not be obtained, but.OH formations of brain microsomes resulted in a significant decrease (15-20%) in Fuco-II and III groups compared with control group. Basal oxygen radical (BOR) formations were significantly decreased about 10% and 13-15% in brain mitochondria of Dasi-Ex and Fuco-I group, and Fuco-II, III groups, and also decreased about 10% and 15-20% in brain microsomes of Dasi-Ex and Fuco-I groups, and Fuco-II, III groups. LPO levels of brain mitochondria and microsomes were significantly inhibited about 10% in Dasi-Ex and Fuco-I, II groups and 15% in Fuco-III groups. Oxidized proteins (>C=O) were significantly inhibited about 10% in serum of Dasi-Ex and Fuco-I, II, III groups and brain mitochondria of Dasi-Ex group, while remarkably inhibited (30~35%) in brain mitochondria of Fuco-I, II and III groups. Nitric oxide (NO) levels were significantly inhibited (12~15%) in serum of Fuco-I, II and III groups, but there no significant difference in serum NO levels of Dasi-Ex group. Superoxide dismutase (SOD) activities were remarkably increased (30~ 60%) in serum of Fuco-I, II and III groups, but there were no significant differences in SOD activities in serum of Dasi-Ex group. Catalase (CAT) activities were significantly increased about 20% in serum of Dasi-Ex and Fuco-I, II, III groups. Mn-SOD activities in brain mitochondria were significantly increased about 17% in Dasi-Ex group, while remarkably increased 26~36% in Fuco-I, II, III groups. Cu,Zn-SOD activities in brain cytosol were dose-dependently of fucoidan increased 10%, 12% and 18%, respectively, compared with control group. These results suggest that anti-aging effects of fucoidan may play a pivotal role in attenuating a various age-related changes such as chronic degenerative disease and senile dementia.