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Low molecular weight fucoidan (LMWF) is widely used to treat metabolic disorders, but its physiologic effects have not been well determined. In the present study, we investigated the metabolic effects of LMWF in obese diabetic mice (leptin receptor-deficient db/db mice) and the underlying molecular mechanisms involved in endoplasmic reticulum (ER) stressresponsive L6 myotubes. The effect of LMWF-mediated AMP-activated protein kinase (AMPK) activation on insulin resistance via regulation of the ER stress-dependent pathway was examined in vitro and in vivo. In db/db mice, LMWF markedly reduced serum glucose, triglyceride, cholesterol, and low-density lipoprotein levels, and gradually reduced body weights by reducing lipid parameters. Furthermore, it effectively ameliorated glucose homeostasis by elevating glucose tolerance. In addition, the phosphorylation levels of AMPK and Akt were markedly reduced by ER stressor, and subsequently, glucose uptake and fatty acid oxidation were also reduced. However, these adverse effects of ER stress were significantly ameliorated by LMWF. Finally, in L6 myotubes, LMWF markedly reduced the ER stress-induced upregulation of the mammalian target of rapamycin-p70S61 kinase network and subsequently improved the action of insulin via AMPK stimulation. Our findings suggest that AMPK activation by LMWF could prevent metabolic diseases by controlling the ER stress-dependent pathway and that this beneficial effect of LMWF provides a potential therapeutic strategy for ameliorating ER stress-mediated metabolic dysfunctions.

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-In order to investigate the preliminary repeat oral dose toxicity and to determine the highest dosage for further 4-week repeated dose toxicity test, Low Molecular Weight Fucoidan (LMF) has been showed various pharmacological effects, was orally administered to female and male rats, once a day for 14 days at dose levels of 2,000, 1,000, 500 and 0 (vehicle control) mg/kg (body weights) in a volume of 10 ml/kg. The mortality and changes on the body weights, clinical signs, hematology, serum biochemistry and gross observations were monitored with organ weight and histopathology of principle organs. As the results of 14-day repeated oral treatment of LMF, no LMF treatment related mortalities were detected up to 2,000 mg/kg in both male and female rats, respectively. In addition, no noticeable changes on the body weight and clinical signs were detected except for significant decreases on the body weights and gains restricted to male 2,000 mg/kg treated groups as compared with male vehicle control. No meaningful changes on the organ weights, hematological, serum biochemistrical, gross and histopathological findings were observed. Therefore the highest dosage in the 4-week repeated dose toxicity test is suggested as 2,000 mg/kg in both female and male rats, respectively.

Bitter gourd is the fruit of a tropical vine in Asia, Africa, and South America where it is commonly used in traditional medicine. Our study tested the effects of a fermented extract of the bitter gourd on the inflammatory activities of the human monocytic leukemia cell line, THP-1. Treatment with the extract resulted in the suppression of phagocytic as well as lipopolysaccharide (LPS)-induced adhesion activity. Interestingly, the LPS-induced expression of matrix metalloproteinase-9 (MMP-9) and tumor necrosis factor-α (TNF-α) was suppressed by the extract while the expression of Interleukin-8 (IL-8) was upregulated. The extract inhibited the LPS-induced activation of p38 mitogen-activated protein kinase (MAPKs) and nuclear factor-κB (NF-κB), both of which are well known to be required for the expression of MMP-9 and TNF-α. In contrast, the expression of interferon regulatory factor (IRF) 1, a transcription factor involved in the expression of IL-8, but not TNF-α, was enhanced by the extract. Suppression of IRF-1 expression resulted in the elimination of the extract's interleukin-8 (IL-8) enhancing effect. These results indicate that the fermented bitter gourd extract has general anti-inflammatory effects, with a differential effect on the expression of cytokines through modulation of NF-κB and IRF-1 activities.