Chang-Suk Kong

Flavonoid glycosides isolated from Salicornia herbacea inhibit matrix metalloproteinase in HT1080 cells

Flavonoid glycosides, isorhamnetin 3-capital O, Cyrillic-beta-d-glucoside, and quercetin 3-O-beta-d-glucoside were isolated from Salicornia herbacea and their inhibitory effects on matrix metalloproteinase-9 and -2 (MMP-9 and -2) were evaluated in human fibrosarcoma cell line (HT1080). In zymography experiments, these flavonoid glycosides led to the reduction of the expression levels and activities of MMP-9 and -2 without any significant difference between these flavonoid glycosides. Protein expression levels of both MMP-9 and MMP-2 were inhibited and TIMP-1 (tissue inhibitor of metalloproteinase-1) protein level was enhanced by these flavonoid glycosides. Moreover, a transfection study carried out with AP-1 reporter construct revealed that the reporter activity was suppressed by treatment with isorhamnetin 3-capital O, Cyrillic-beta-d-glucoside. Therefore, these results suggested that these flavonoid glycosides have a potential as valuable natural chemopreventive agents for cancer.

Anti-adipogenic effect of dioxinodehydroeckol via AMPK activation in 3T3-L1 adipocytes

Dioxinodehydroeckol (DHE) isolated from Ecklonia cava, has previously been investigated for its inhibition of the differentiation of 3T3-L1 preadipocytes into adipocytes. Levels of lipid accumulation were measured, along with changes in the expression of genes and proteins associated with adipogenesis and lipolysis. Confluent 3T3-L1 preadipocytes in medium with or without different concentrations of DHE for 7 days were differentiated into adipocytes. Lipid accumulation was quantified by measuring direct triglyceride contents and Oil-Red O staining. The expression of genes and proteins associated with adipogenesis and lipolysis was measured using RT-PCR, quantitative real-time RT-PCR and Western blotting analysis. It was found that the presence of DHE significantly reduced lipid accumulation and down-regulated the expression of peroxisome proliferator-activated receptor-gamma (PPARgamma), sterol regulatory element-binding protein 1 (SREBP1) and CCAAT/enhancer-binding proteins (C/EBPalpha) in a dose-dependent manner. Moreover, DHE suppressed regulation of the adipocyte-specific gene promoters such as fatty acid binding protein (FABP4), fatty acid transport protein (FATP1), fatty acid synthase (FAS), lipoprotein lipase (LPL), acyl-CoA synthetase 1 (ACS1), leptin, perilipin and HSL compared to control adipocytes. The specific mechanism mediating the effects of DHE was confirmed by activation of phosphorylated AMP-activated protein kinase (pAMPK). Therefore, these results suggest that DHE exerts anti-adipogenic effect on adipocyte differentiation through the activation and modulation of the AMPK signaling pathway.

Anti-inflammatory effect of coumarins isolated from Corydalis heterocarpa in HT-29 human colon carcinoma cells.

We investigated anti-inflammatory effects of two coumarins, columbianetin (A) and libanoridin (B), isolated from Corydalis heterocarpa in lipopolysaccharide (LPS)-stimulated HT-29 human colon carcinoma cells. Treatment with compound B inhibited the protein expression levels of inflammatory mediators such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 beta (IL-1 beta) in a dose-dependent manner in LPS-stimulated HT-29 cells, but compound A did not. Also, compound B had a higher inhibitory effect on production of cytokines such as IL-1 beta and TNF-alpha in LPS-stimulated HT-29 human colon carcinoma cells than those of compound A. Furthermore, we confirmed that LPS-induced transcription activity of NF-kappaB was inhibited by compound B. As a result of this study, compound B can be considered as a potential anti-inflammatory agent.

Protective effect of isorhamnetin 3-О-β-d-glucopyranoside from Salicornia herbacea against oxidation-induced cell damage

Isorhamnetin 3-O-beta-D-glucopyranoside (1) was isolated from Salicornia herbacea. The inhibitory effects of compound 1 on oxidative stress were evaluated in free-cellular and cellular systems. An increased concentration of compound 1 not only exhibited dose-dependent scavenging activities on the generation of 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and carbon-centered radicals, but also significantly decreased levels of intracellular reactive oxygen species (ROS) in a dose-dependent manner. Further, antioxidative mechanisms by compound 1 were examined by measuring the intracellular glutathione (GSH) level and expression levels of antioxidant enzymes such as superoxide dismutase (SOD), catalase, glutathione reductase and heme oxygenase-1 (HO-1). Compound 1 significantly elevated GSH level as well as expression levels of antioxidant enzymes which were closely related with amount of cellular ROS. In addition, it significantly inhibited oxidative damage of purified genomic DNA and suppressed activity of myeloperoxidase (MPO), a generator of potent oxidant (hypochlorous acid), in tumor necrosis factor-alpha (TNF-alpha) stimulated human myeloid cells. Therefore, these results suggested that compound 1 has a therapeutic effectiveness in prevention of ROS-induced cellular damage and is a candidate worthy of being developed as a potential natural antioxidant related to oxidative stress.

Evaluation of novel antioxidant triterpenoid saponins from the halophyte Salicornia herbacea.

As a part of an ongoing search for novel antioxidants from the salt marsh plants, bioactivity-isolation and structure determination of constituents from Salicornia herbacea were performed. One new triterpenoid saponin (4), along with three known saponins (1-3), has been isolated from n-BuOH fraction of S. herbacea. On the basis of the spectroscopic methods, the structure of the new saponin 4 was elucidated as 3β-hydroxy-23-oxo-30-noroleana-12, 20(29)-diene-28-oic acid 3-O-β-D-glucuronopyranosyl-28-O-β-d-glucopyranoside. Scavenging effects of saponins 1-4 were examined on 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical and peroxynitrite. Particularly, saponin 3 exerted significant antioxidant activity on both authentic peroxynitrite and peroxynitrite generated from morpholinosydnonimine (SIN-1).

Anti-obesity effect of sulfated glucosamine by AMPK signal pathway in 3T3-L1 adipocytes

In this study, we investigated the effect of sulfated glucosamine (SGlc) on adipogenesis of 3T3-L1 adipocytes during differentiation of preadipocytes into adipocytes by measuring lipid accumulation and adipogenesis related factors. Treatment with SGlc reduced the triglyceride content in Oil-Red O staining and enhanced glycerol secretion in adipocytes in a dose-dependent manner. In addition, SGlc induced the down-regulation of adipogenesis related factors and adipocyte specific gene promoters. Moreover, treatment of 3T3-L1 adipocytes with SGlc activated the phosphorylated adenosine monophosphate-activated protein kinase (AMPK) alpha and beta along with their substrate, acetyl-CoA carboxylase (ACC). These results suggest that inhibitory effect of SGlc on adipocyte differentiation might be mediated through the up-regulation of AMPK pathway.

1-(3′,5′-dihydroxyphenoxy)-7-(2″,4″,6-trihydroxyphenoxy)-2,4,9-trihydroxydibenzo-1,4-dioxin Inhibits Adipocyte Differentiation of 3T3-L1 Fibroblasts

In this study, we isolated the phloroglucinol derivative, 1-(3′,5′-dihydroxyphenoxy)-7-(2″,4″,6-trihydroxyphenoxy)-2,4,9-trihydroxydibenzo-1,4-dioxin (1), from Ecklonia cava and evaluated its potential inhibition on adipocyte differentiation in 3T3-L1 cells. Lipid accumulation along with the expression of several genes associated with adipogenesis and lipolysis was examined at the end of differentiation. Lipid accumulation level was examined by measuring triglyceride content and Oil-Red O staining. The expression levels of several genes and proteins were examined using reverse-transcription polymerase chain reaction (RT-PCR), real-time RT-PCR, and Western blot analysis. Compound 1 significantly reduced lipid accumulation and downregulated peroxisome proliferator-activated receptor-γ, sterol regulatory element-binding protein 1c, and CCAAT/enhancer-binding proteins α in a dose-dependent manner. Moreover, the presence of compound 1 induced downregulation of adipogenic target genes such as fatty acid binding protein 4, fatty acid transport protein 1, fatty acid synthase, acyl-CoA synthetase 1, lipoprotein lipase, and leptin. According to the lipolytic response, compound 1 downregulated perilipin and hormone-sensitive lipase while upregulating tumor necrosis factor alpha. Therefore, these results suggest that compound 1 might decrease lipid accumulation during adipocyte differentiation by modulating adipogenesis and lipogenesis. Furthermore, compound 1 could be developed as a functional agent effective in improving obesity.

Evaluation of Salicornia herbacea as a Potential Antioxidant and Anti-Inflammatory Agent

In this study, the antioxidant and anti-inflammatory activities of Salicornia herbacea were evaluated. The crude CH(2)Cl(2)/methanol extract of S. herbacea showed 52% and 86% scavenging activities of the authentic ONOO(-) and ONOO(-) from 3-morpholinosydnomimine (SIN-1) at a concentration of 50 microg/mL, respectively, and was subjected to a further fractionation with n-hexane, 85% aqueous methanol, n-butanol, and water. Additional purification of the n-butanol fraction revealed that the most potent scavenging activity led to the isolation of isorhamnetin 3-O-beta-d-glucopyranoside as the active principle. The structure of isorhamnetin 3-O-beta-d-glucopyranoside was elucidated by extensive two-dimensional nuclear magnetic resonance experiments such as (1)H correlation spectroscopy nuclear Overhauser effect spectroscopy, heteronuclear single quantum correlation, and heteronuclear multiple-bond correlation as well as by comparison with the published spectral data. Isorhamnetin 3-O-beta-d-glucopyranoside exhibited dose-dependent scavenging activities of the authentic ONOO(-) and ONOO(-) from SIN-1. The electron spin resonance spin-trap techniques confirmed that reactive oxygen species, including the hydroxyl, superoxide, carbon-centered, and 1,1-diphenyl-2-picrylhydrazyl radicals, were actively quenched by addition of isorhamnetin 3-O-beta-d-glucopyranoside. In addition, isorhamnetin 3-O-beta-d-glucopyranoside suppressed the lipopolysaccharide-induced nitric oxide production and the expression of cytokines such as inducible nitric oxide synthase, tumor necrosis factor-alpha, and interleukin-1beta in Raw 264.7 cells. Findings from this study should underscore the nutraceutical value of S. herbacea-derived isorhamnetin 3-O-beta-d-glucopyranoside as a potent antioxidative and anti-inflammatory agent via alleviation of radical-induced toxicities and pro-inflammatory responses.

Anti-obesity effect of carboxymethyl chitin by AMPK and aquaporin-7 pathways in 3T3-L1 adipocytes

The aim of this study was to investigate the anti-obesity effect of carboxymethyl-chitin (CM-chitin), a water-soluble derivative of chitin, by measuring lipid accumulation and adipogenesis related factors in 3T3-L1 adipocytes. CM-chitin was synthesized by means of carboxymethylation reaction. Its inhibitory effect on lipid accumulation was investigated by measuring triglyceride content and glycerol release level. The gene and protein levels associated with adipogenesis were determined using reverse transcriptase-polymerase chain reaction and Western blot analysis. Treatment with CM-chitin reduced triglyceride content and enhanced glycerol secretion in a dose-dependent manner. CM-chitin induced the down-regulation of adipogenesis related transcriptional factors and adipocyte specific gene promoters. Moreover, the specific mechanism by CM-chitin was confirmed by transcriptional activations of the phosphorylated adenosine monophosphate-activated protein kinase (AMPK) and aquaporin-7. These results suggest that CM-chitin exerts anti-adipogenic effect on lipid accumulation through modulations of AMPK and aquaporin-7 signal pathways.

Phosphorylated glucosamine inhibits adipogenesis in 3T3-L1 adipocytes.

Phosphorylated glucosamine (glucosamine-6-phosphate, PGlc) was synthesized using methanesulfonic acid, phosphorus pentoxide (P(2)O(5)), NH(2)NH(2) and DMF. Its inhibitory effect on lipid accumulation in cultured 3T3-L1 adipocytes was investigated by measuring triglyceride contents and Oil Red O staining. In order to understand the mechanism by which lipid accumulation in adipocytes is decreased by PGlc, we examined the expression levels of several genes and proteins associated with adipogenesis and lipolysis using reverse transcription polymerase chain reaction, real-time polymerase chain reaction and Western blot analysis. Treatment with PGlc significantly reduced lipid accumulation during adipocyte differentiation and induced down-regulation of peroxisome proliferator-activated receptor-gamma, sterol regulatory element binding protein 1 and CCAAT/enhancer binding protein-alpha in a dose-dependent manner. Moreover, treatment with PGlc during adipocyte differentiation induced significant up-regulation of preadipocyte factor 1 mRNA and down-regulation of such adipocyte-specific gene promoters as adipocyte fatty acid binding protein, fatty acid synthase, lipoprotein lipase and leptin. According to the lipolytic response, PGlc up-regulated hormone-sensitive lipase mRNA expression and suppressed the expression levels of tumor necrosis factor-alpha mRNA compared with fully differentiated adipose tissue. These results suggest that the inhibitory effect of PGlc on adipocyte differentiation might be mediated through the down-regulation of adipogenic transcription factors, such as peroxisome proliferator-activated receptor-gamma, sterol regulatory element binding protein 1 and CCAAT/enhancer binding protein-alpha, which are related to the downstream adipocyte-specific gene promoters.