Mi-Jin Kwon

A polysaccharide of the marine alga Capsosiphon fulvescens induces apoptosis in AGS gastric cancer cells via an IGF-IR-mediated PI3K/Akt pathway

Because seaweed extracts have recently been found to have antioxidant and anti‐tumor activities, we analyzed a hot‐water‐soluble polysaccharide (PS) of the marine alga Capsosiphon fulvescens for its potential as a functional foodstuff by determining its effects on cell growth and DNA synthesis. MTS assays showed that the C. fulvescens PS (Cf‐PS) significantly inhibited the proliferation of cultured human cancer cells in a dose‐dependent manner. Cf‐PS‐treated AGS cells exhibited a marked increase in caspase‐3 activation and a decrease in Bcl‐2 expression. In addition, phosphorylation of insulin‐like growth factor‐I receptor (IGF‐IR) was decreased in Cf‐PS‐treated AGS cells as compared to non‐treated control cells, which is consistent with PI3‐kinase (PI3K)/Akt activation. Cf‐PS also decreased IGF‐I‐stimulated recruitment of p85 to IGF‐IR and IRS‐1. These results indicate that Cf‐PS inhibits cell proliferation and induces apoptosis by inhibiting IGF‐IR signaling and the PI3K/Akt pathway.

The effect of polysaccharide extracted from the marine alga Capsosiphon fulvescens on ethanol administration

Seaweed extracts have recently been found to have antioxidant and antitumor activities. Capsosiphon fulvescens (Cf) is a green alga and nutrient-dense food source. In a previous study, we extracted polysaccharide from Cf (Cf-PS) and demonstrated its antitumor effect in gastric cancer cells. In this report, we describe the protective effect of Cf-PS against alcohol-induced gastric injury in rats and adenocarcinoma (AGS) cells. In vivo assay revealed stomach damage in rats treated with alcohol alone; however, the stomach condition of rats co-treated with Cf-PS and alcohol matched that of the control group. Cf-PS also inhibited alcohol-induced cell death in AGS cells. Compared with alcohol treatment alone, Cf-PS and alcohol co-treatment increased phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt but inhibited poly-ADP-ribose polymerase (PARP) cleavage. Thus, ERK1/2 and Akt activation are instrumental in the protective effect of Cf-PS against alcohol-induced cell death in AGS cells. Moreover, Cf-PS treatment reduced the expressions of cyclooxygenase-2 (COX-2) and the inducible form of nitric oxide (iNOS), proteins related to ulcers. These results suggest that Cf-PS could help protect against alcohol-induced peptic ulcers.

Chemoprotective effects of a protein from the red algae Porphyra yezoensis on acetaminophen-induced liver injury in rats.

Seaweeds contribute to the maintenance of health through their nutritional and medicinal properties. The effects of PYP, a 14 kDa protein isolated from a hot‐water extract of the marine alga Porphyra yezoensis, on AAP‐induced liver injury in rats was evaluated. AAP induced acute liver injury and AAP‐induced hepatotoxicity is the leading cause of liver failure. In this study, male Sprague–Dawley rats were assigned to one of three treatment groups: control, AAP, or AAP + PYP. Compared with the control group, liver tissue from the AAP group showed increased levels of caspase‐3 activity and DNA fragmentation, decreased levels of GSH and increased serum GOT/GPT levels. In contrast, treatment with AAP + PYP produced levels of caspase‐3 activity, DNA fragmentation, GSH and GOT/GPT that matched the values seen in the control group. It is concluded that PYP may prevent AAP‐induced liver injury. Copyright

Nrf2 and NF-κB Signaling Pathways Contribute to Porphyra-334-Mediated Inhibition of UVA-Induced Inflammation in Skin Fibroblasts

In this study, we examined the protective effects of porphyra-334 against UVA-irradiated cellular damage and elucidated the underlying mechanisms. Porphyra-334 prevented UVA-induced cell death and exhibited scavenging activities against intracellular oxidative stress induced by UVA irradiation in skin fibroblasts. We found that porphyra-334 significantly reduced the secretion and expression of IL-6 and TNF-α, reduced nuclear expression of Nuclear factor-κB (NF-κB), and sustained NF-E2-related factor 2 (Nrf2) activation. Further mechanism research revealed that porphyra-334 promoted the Nrf2 signaling pathway in UVA-irradiated skin fibroblasts. Our results show that the antioxidant effect of porphyra-334 is due to the direct scavenging of oxidative stress and its inhibitory effects on NF-κB-dependent inflammatory genes, such as IL-6 and TNF-κ. Therefore, we hypothesize that boosting the Nrf2- NF-κB-dependent response to counteract environmental stress is a promising strategy for the prevention of UVA-related damage.

Protective Effects of Mesangi (Capsosiphon fulvecens) on Hepatotoxicity in Carbon Tetrachloride (CCI 4 )-Intoxicated Rats

This study investigated the hepatoprotective effects of mesangi (Capsosiphon fulvecens) in carbon tetrachloride (CCl₄)-induced liver injury. Thirty healthy male Sprague-Dawley rats were divided into three groups : the normal (Normal), CCl₄-treated (CCl₄), and mesangi-treated (Exp-CF) groups. Administration of CCl₄ increased the levels of GOT, GPT, and LDH in serum, while the levels were significantly decreased by the addition of mesangi. Higher levels of HDL-cholesterol were found in the Normal and Exp-CF groups, which has lower levels of total and LDL-cholesterol. Administration of CCl₄ also increased IGFBP-1 expression in serum, but it was decreased in the Exp-CF group. This suggests that CCl₄ is involved in the change in IGFBP-1 expression via its hepatotoxicity. The results indicate that mesangi has a hepatoprotective effect in rats given CCl₄.

Dietary Effects of Polymannuronate Added to Hamburger Buns on Lipid Metabolism in Rats

우리나라 식생활 변화는 사회의 다변화, 국제화, 기계문명화, 환경오염 등의 문제와 관련하여 점점 그 양상이 가속화되고 있 다. 식생활 패턴이 양적으로나 질적으로 다양하고 풍요로운 식 단을 선호하는 경향도 높아졌을 뿐만 아니라, 동물성 식품의 섭 취가 크게 증가하여 지방섭취와 열량은 높아진 반면 활동 부족 과 에너지 소비는 감소되어 비만의 경향이 높아졌다. 특히 즉석 식품 문화가 번창함에 따라 햄버거를 포함한 패스트푸드가 식 사 대용식으로 차지하는 비중이 증대하고 있다. 그러나, 햄버거 를 포함한 패스트푸드는 장기간 섭취하게 되면, 동물성 지방과 에너지, 식염의 과잉 섭취뿐 아니라 비타민과 무기질의 섭취부 족 등 영양소 섭취의 불균형을 초래하게 된다. 그 결과, 체지방 의 과다 축적으로 인한 체형의 변화 및 비만증이 점차적으로 증 가하고 있으며, 고지혈증, 지방간 및 심순환기계 질환에 대한 위험이 높아짐에 따라 사망의 원인과도 직결되어 있어 현대인 에게 비만 예방에 대한 개선책은 사회적 차원에서도 그 필요도 가 높아지고 있다. 식이섬유는 소화되지 않아 영양적 가치가 없고 영양소의 흡 수를 저해하는 단점이 있으나, 비만 • 고지혈증 • 동맥경화 변 비 및 대장암 등을 예방하는 것으로 알려져 있다. 이러한 이유 로 가공식품에는 식이섬유를 첨가하고 있고, 식이섬유의 생리 작용에 대한 연구가 많이 진행되어 왔다(Choi, 1991; Huh et al., 1993; Zhu et al., 2015). 수용성 식이 섬유의 일종인 알긴산은 Polymannuronate 첨가에 의한 햄버거빵이 흰쥐의 지질대사에 미치는 영향