Eui Jeong Han

Hepatoprotective Effects of Xylose-Taurine Reduced Against Hydrogen Peroxide-Induced Oxidative Stress in Cultured Hepatocytes

In this study, Xylose-Taurine reduced (X-T-R) was synthesized to enhance biological activities. Hence, we investigated the hepatoprotective effects of X-T-R against H2O2-induced hepatocyte damage and apoptosis. The results showed that X-T-R led to the cytoprotective effect against H2O2-induced oxidative stress in cultured hepatocytes such as the improvement of cell viability and the reduction of reactive oxygen species (ROS) production. Additionally, pre-treatment with X-T-R increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), NAD(P)H dehydrogenase:quinone 1 (NQO1) and heme oxygenase 1 (HO-1) in cultured hepatocytes. Furthermore, X-T-R protected the cells against apoptosis via regulating the expression level of Bcl-2/Bax as well as the activation of caspase-3. According to the results obtained, X-T-R may be a bio-material for the therapy of hepatic diseases.

Hepatoprotective effect of chitosan-caffeic acid conjugate against ethanol-treated mice

The chitosan-caffeic acid (CCA) conjugate shows a hepatoprotective effect against oxidative stress-induced hepatic damage in cultured hepatocytes. The objective of this study is the verification of the hepatoprotective effect of the CCA in vivo against ethanol-induced liver injury in mice. The administration of ethanol resulted in the increase of the serum-aminotransferase activities (AST and ALT), triglycerides, total cholesterol, and lipid peroxidation. The CCA co-administration, however, significantly (p<0.05) ameliorated these serum biomarkers. The antioxidant-enzyme activities in the liver tissue, including those of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), were significantly decreased by a chronic ethanol administration, whereas the hepatic lipid-peroxidation level was increased. Moreover, the chronic ethanol administration elevated the gene expression of pro-inflammatory cytokines such as tumor-necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the liver tissue. The CCA co-administration, however, significantly (p<0.05) increased the activities of the SOD, CAT, and GPx and caused the down-regulation of the TNF-α- and IL-6-gene expressions in the liver tissue. An histopathologic evaluation also supported the hepatoprotective effect of the CCA against ethanol-induced hepatotoxicity in the mice.

Anti-inflammatory Effects of Galactose-Taurine Sodium Salt: A Taurine Derivate in Zebrafish In Vivo Model

Taurine, the plentiful amino acids in mammalian cells exerts various biological activities including antioxidant and anti-inflammatory effects. Inflammation can cause several diseases such as cancer, heart disease, rheumatoid arthritis and immune system reactions. Here, we investigated anti-inflammatory effects of Galactose-Taurine sodium salt (Gal-Tau), a newly synthesized taurine derivate in LPS-stimulated zebrafish embryos in vivo model. The result showed that Gal-Tau improved the survival rate and the edema in LPS-treated zebrafish embryos. Also, Gal-Tau effectively reduced the productions of nitric oxide (NO), reactive oxygen species (ROS) and cell death induced by LPS in zebrafish embryos. In addition, Gal-Tau regulated the expression levels of inflammatory mediators such as inducible NOS (iNOS) and cycloxygenase 2 (COX-2) as well as IL-6 and TNF-α, inflammatory cytokines known as important key mediators of inflammation. Taken together, this study first indicates that Gal-Tau could be considered as an effective anti-inflammatory material with its anti-inflammatory activity.

Protective Effects of An Enzymatic Hydrolysate from Octopus ocellatus Meat against Hydrogen Peroxide-Induced Oxidative Stress in Chang Liver Cells and Zebrafish Embryo

Octopus ocellatus, a marine cephalopod distributed in the coast of South Korea, China, Japan and tropical sea, contains high amounts of taurine. In this study, an enzymatic hydrolysate obtained from O. ocellatus meat was evaluated for its antioxidant effects using a human liver cell line and zebrafish embryo model. Enzymatic hydrolysates of the O. ocellatus meat (OOM) were prepared using six different enzymes. Among the enzymatic hydrolysates, Alcalase hydrolysate of OOM (OOMAH) showed the highest scavenging effects against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radicals and hydrogen peroxide (H2O2). Moreover, it showed a high oxygen radical absorbance capacity (ORAC). OOMAH treatment effectively reduced the hydroxyl radical-induced DNA damage. OOMAH reduced the production of reactive oxygen species (ROS) in H2O2-treated hepatocytes without cytotoxicity. Furthermore, OOMAH improved the survival rate and reduced the intracellular ROS levels in H2O2-treated zebrafish embryos. Compositional analysis of amino acids indicated a high content of taurine in OOMAH. Current results suggest that OOMAH possesses antioxidant bioactivities and could provide protective effects against H2O2-induced oxidative stress. Therefore, OOMAH might be used as a potential resource of functional foods.

Anti-inflammatory Effects of Galactose-Taurine Sodium Salt in LPS-Activated RAW 264.7 Cells

In this study, we synthesized Galactose-Taurine sodium salt (G-T) as a functional food ingredient to enhance biological activities of taurine. Also, anti-inflammatory effects of G-T were investigated in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. G-T found to reduce the generations of the LPS-stimulated nitric oxide (NO) and prostaglandin E2 (PGE2) via down-regulating the expression levels of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2). Also, G-T reduced the secretion of inflammatory cytokines including interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF-α) in LPS-treated RAW 264.7 cells. Finally, we identified that G-T inhibits the activation of nuclear factor-κB (NF-κB) and the phosphorylation of inhibitor κB (IκB)-α. From these results, this study first suggests that G-T could be considered as an effective anti-inflammatory agent.

Protective Effects of An Water Extracts Prepared from Loliolus beka Gray Meat Against H 2 O 2 -Induced Oxidative Stress in Chang Liver Cells and Zebrafish Embryo Model

In this study, we first evaluated protective effects of Loliolus beka in a human liver cell line and zebrafish embryo model with its anti-oxidant activity. First, we prepared the water extract from L. beka meat (LBMW) at room temperature for 24 h and revealed it consisted of a rich taurine. LBMW exhibited the scavenging effects against 2,2-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and hydrogen peroxide (H2O2) as well as the high value of oxygen radical absorbance capacity (ORAC). Also, the hydroxyl radical-induced DNA damage was dose-dependently reduced by the treatment of LBMW. In addition, LBMW showed no cytotoxicity and reduced the production of reactive oxygen species (ROS) in H2O2-treated hepatocytes. Moreover, LBMW regulated the expression of an anti-apoptotic molecule, Bcl-2 and the expression of pro-apoptotic molecules, Bax and PARP in H2O2-treated hepatocytes as well as the increment of antioxidant mediated-HO-1 and Nrf2 protein expression. In further study, LBMW improved the survival rate and decreased the production of ROS in H2O2-treated zebrafish embryo model. Therefore, our results suggest that Loliolus beka has protective effects against H2O2-induced oxidative stress and may be used as a potential source for functional foods.

Radio-Protective Effects of Octopus ocellatus Meat Consisted of a Plentiful Taurine Against Damages Caused by Gamma Ray Irradiation

Gamma ray irradiation causes immune suppressive responses by inducing oxidative stress such as reduction of cell viability and damages in immune cells. In this present study, we investigated whether Octopus ocellatus meet (OM) consisted of a plentiful taurine has protective effects against damages caused by oxidative stress in murine splenocytes. First of all, we prepared the aqueous extract from OM (OMA) and identified it contained a plentiful taurine content. The result also showed that OMA exhibited the antioxidant activity by scavenging DPPH and ABTS+ radicals and hydrogen peroxide. In addition, OMA improved the cell viability without cytotoxicity in gamma ray-irradiated murine splenocytes. Moreover, OMA significantly reduced the production of reactive oxygen species (ROS) in gamma ray-irradiated splenocytes. In further study, we identified that OMA protected zebrafish embryo via improving the reduced survival rate and decreasing the formation of deformity caused by the exposure of gamma ray irradiation. Also, OMA decreased the production of NO and ROS in gamma ray-irradiated zebrafish embryos as well as the induction of cell death. In these results, this study suggests that the consumption of taurine-rich foods, such as O. ocellatus, may be useful for the useful material for the protection against oxidative stress.

Anti-inflammatory Effects of Ecklonia cava by the Regulation of TSLP in TNF-α/IFN-γ-Stimulated Keratinocytes

이전 연구를 통해 제주 자생해조류인 감태의 에탄올 추출물인 ECE가 TNF-α/IFN-γ로 염증을 유도한 피부각질형성세포에서 염증성 사이토카인과 케모카인의 발현을 억제함을 확인하였다. 그러나 초기 피부염증성 자극 인자로 알려진 TSLP와의 연관성에 대해서는 보고된 바가 없다. 따라서 이번 연구에서 TSLP의 발현 및 분비에 ECE가 미치는 영향에 대하여 확인하였다. 그 결과, ECE는 TNF-α/IFN-γ의 자극에 의해 증가된 TSLP의 발현과 분비를 억제함으로써 염증성 사이토카인인 IL-4, IL-5, IL-13 및 TNF-α의 발현 또는 분비를 억제하였다. 또한, ECE는 피부각질형성세포에서 분비되어 Th2 세포를 염증 부위로 이동시키는 케모카인인 TARC의 발현을 억제하였다. 뿐만 아니라 아토피성 피부염이 자연유발되는 NC/Nga 동물모델에서 ECE는 아토피성 피부염의 대표적인 증상인 가려움 빈도를 감소시켰다. 이 모든 결과를 종합해보면, ECE는 TSLP를 하향 조절함으로써 피부염증 억제 효능과 가려움을 억제 효능을 가진다고 할 수 있으며, 이 결과는 ECE의 비정상적인 면역반응에 의한 피부염증 개선용 천연 기능성 식품 소재로써 활용이 가능하다는 것을 시사하고 있다.