Jung-Suck Lee

Protective effect of a marine polyphenol, dieckol against carbon tetrachloride-induced acute liver damage in mouse

In this study, the hepatoprotective effect of dieckol on carbon tetrachloride (CCl4) induced hepatic damages in ICR mice liver was investigated. Mice were randomly divided into 4 groups such as saline treated (negative control), CCl4 treated (positive control), CCl4+dieckol (5mg/kg mouse) and CCl4+dieckol (25mg/kg mouse), respectively. The body weights and survival rates of mice, followed by dieckol treatments were significantly increased compared to the positive control. The level of GOT, GPT and MDA in the serum of the dieckol treated groups were reduced dose dependently than the control, significantly. The antioxidant enzymes including CAT, and GSH-px levels were increased significantly compared to the positive control. However, no significant differences were observed on hepatic histophathological analysis in dieckol treated groups dose dependently. Down-regulation of Bax and up-regulation of Bcl-xl protein expressions were observed in liver tissues of the dieckol administered groups. These results suggested that, dieckol can be developed as a therapeutic agent for liver disease by oxidative stress.

Sulfated Chitosan Oligosaccharides Suppress LPS-Induced NO Production via JNK and NF-κB Inactivation

Various biological effects have been reported for sulfated chitosan oligosaccharides, but the molecular mechanisms of action of their anti-inflammatory effects are still unknown. This study aimed to evaluate the anti-inflammatory effects of sulfated chitosan oligosaccharides and to elucidate the possible mechanisms of action. The results showed that pretreated low molecular weight sulfated chitosan oligosaccharides inhibited the production of nitric oxide (NO) and inflammatory cytokines such as IL-6 and TNF-α in lipopolysaccharide (LPS)-activated RAW264.7 cells. The sulfated chitosan oligosaccharides also suppressed inducible nitric oxide synthase (iNOS), phosphorylation of JNK and translocation of p65, a subunit of NF-κB, into the nucleus by inhibiting degradation of IκB-α. Our investigation suggests sulfated chitosan oligosaccharides inhibit IL-6/TNF-α in LPS-induced macrophages, regulated by mitogen-activated protein kinases (MAPKs) pathways dependent on NF-κB activation.

Preparative isolation of sargachromanol E from Sargassum siliquastrum by centrifugal partition chromatography and its anti-inflammatory activity

Centrifugal partition chromatography (CPC) can be used to isolate various bioactive compounds from natural materials by one-step. We confirmed antioxidative compounds existed in chloroform (CHCl3) fraction of Sargassum siliquastrum using online-HPLC. Fractions (A, B, C, D and E) were separated from the CHCl3 fraction by preparative CPC (n-hexane:ethyl acetate:methanol:water, 5:5:7:3, v/v). In this study, we proved that the isolated compounds exhibit anti-inflammatory activities using lipopolysaccharide (LPS) stimulated RAW 264.7 macrophages. The fraction A which exhibited the strongest inhibitory effect on nitric oxide (NO) production level, was confirmed as sargachromanol E by LC-MS-ESI, (1)H NMR and (13)C NMR data. The sargachromanol E significantly reduced the inflammatory response in LPS induced macrophages, decreasing LPS-induced transcription factor of pro-inflammatory cyclooxygenase-2, NO synthase, phosphate P38, phosphate ERK1/2, LPS-stimulated tumor-necrosis factor alpha, interleukin-1 beta and prostaglandin E2 release. In conclusion, it was suggested that sargachromanol E inhibited inflammation in LPS induced RAW 264.7 cells via MAPK pathway.

Purification of a novel peptide derived from a shellfish, Crassostrea gigas, and evaluation of its anticancer property.

A novel anticancer peptide was purified from Crassostrea gigas and investigated for its cytotoxic activity. To prepare the peptide, eight proteases were employed for enzymatic hydrolysis. Flavourzyme hydrolysate, which showed clearly superior cytotoxic activity on prostate cancer cells, was further purified using a membrane system and consecutive chromatographic methods. Finally, a novel anticancer peptide was obtained, and the sequence was partially purified as His-Phe-Asn-Ile-Gly-Asn-Arg-Cys-Leu-Cys at the N-terminus. The peptide purified from C. gigas effectively induced the death of prostate, breast, and lung cancer cells but not normal liver cells. This is the first report of an anticancer peptide derived from the enzymatic hydrolysates of C. gigas.

Protective effect of marine brown algal polyphenols against oxidative stressed zebrafish with high glucose

The zebrafish (Danio rerio) is one of the most widely used vertebrate models in research studies in molecular genetics, development biology, drug discovery and human disease. This study has confirmed an increase in the production of reactive oxygen species (ROS) and induction of cell death by high glucose treatment in zebrafish. We observed that exposure to phlorotannins, which include 6,6-bieckol, phloroeckol, dieckol and phlorofucofuroeckol isolated from an edible brown alga, Ecklonia cava, significantly inhibited high glucose induced ROS and cell death. Among the phlorotannins, DK (Dieckol) significantly reduced heart rates, ROS, nitric oxide (NO), lipid peroxidation generation and cell death in high glucose induced oxidative stress. Further, high glucose levels induced the over expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), whereas DK treatment reduced its over expression. These findings indicate that the zebrafish model is an efficient animal model that can be used to investigate hyperglycemia-stimulated oxidative stress. Therefore, this model can be used as an in vivo experiment to confirm the antioxidant properties of functional foods and nutraceuticals.

Protective effect of dieckol isolated from Ecklonia cava against ethanol caused damage in vitro and in zebrafish model

In the present study, the protective effects of phlorotannins isolated from Ecklonia cava against ethanol-induced cell damage and apoptosis were investigated both in vitro and in vivo. Three phlorotannin compounds, namely phloroglucinol, eckol and dieckol, were successively isolated and identified from the extract. Dieckol showed the strongest protective effect against ethanol-induced cell apoptosis in Chang liver cells, with the lowest cytotoxicity. It was observed that dieckol reduced cell apoptosis through activation of Bcl-xL and PARP, and down-regulation of Bax and caspase-3 in Western blot analyses. In the in vivo study, the protective effect of ethanol induced by dieckol was investigated in a zebrafish model. The dieckol treated group scavenged intracellural reactive oxygen species and prevented lipid peroxidation and ethanol induced cell death in the zebrafish embryo. In conclusion, dieckol isolated from E. cava might possess a potential protective effect against ethanol-induced liver diseases.

Rapid preparation of functional polysaccharides from Pyropia yezoensis by microwave-assistant rapid enzyme digest system

This study describes a simple preparation of functional polysaccharides from Pyropia yezoensis using a microwave-assistant rapid enzyme digest system (MAREDS) with various carbohydrases, and evaluates their antioxidative effects. Polysaccharide hydrolysates were prepared using MAREDS under different hydrolytic conditions of the carbohydrases and microwave powers. Polysaccharides less than 10kDa (Low molecular weight polysaccharides, LMWP, ≤10kDa) were efficiently obtained using an ultrafiltration (molecular weight cut-off of 10kDa). MAREDS increases AMG activation via an increased degree of hydrolysis; the best AMG hydrolysate was prepared using a 10:1 ratio of substrate to enzyme for 2h in MAREDS with 400W. LMWP consisted of galactose (27.3%), glucose (64.5%), and mannose (8.3%) from the AMG hydrolysate had stronger antioxidant effects than the high molecular weight polysaccharides (>10kDa). We rapidly prepared functional LMWPs by using MAREDS with carbohydrases, and suggest that LMWP might be potentially a valuable algal polysaccharide antioxidant.

Preparation of Commercial Agarose from Jeju Seaweed, Gelidium amansii using DMSO Extraction and EDTA Washing

Agar was prepared from Gelidium amansii collected from Jeju Island, South Korea. This agar preparation has high gel strength and low sulfate content compared with G. amansii agar from Morocco. Accordingly, agarose was made from the Jeju agar through the consecutive refi ning processes of dimethyl sulfoxide (DMSO) extraction and ethylene diamine tetra acetic acid (EDTA) washing. The physicochemical properties of the resulting agarose were compared with those from agarose prepared using only DMSO extraction. Consecutive DMSO extraction and EDTA washing more strongly affected the physicochemical properties of the agarose (purifi ed agarose) compared with the use of DMSO extraction alone. These properties were similar to those of commercial agarose used for electrophore- sis. In DNA electrophoresis, the separation and movement speed of the purifi ed agarose were similar to those of the commercial agarose. In a 13 C NMR analysis, the purifi ed agarose exhibited the same carbon peak as the commercial agarose. When observed under scanning electron microscopy, the agar had an even and smooth surface without ir- regularities or pores, and the purifi ed agarose had a wide surface area with a large number of pores; the commercial agarose had an irregular surface that would allow the solvent to easily permeate. These results illustrate that the physi- cochemical properties of agarose prepared from DMSO extraction and EDTA washing were more effective than those observed after DMSO extraction alone; thus, these processes used in succession will be useful in agarose industries.

Identification and large isolation of an anti-inflammatory compound from an edible brown seaweed, Undariopsis peterseniana, and evaluation on its anti-inflammatory effect in in vitro and in vivo zebrafish

In this study, we isolated and purified secondary metabolites from an edible brown seaweed, Undariopsis peterseniana, and evaluated their anti-inflammatory effects in vitro and in vivo. Apo-9′-fucoxanthinone (Apo-9′), a main anti-inflammatory compound found in the chloroform fraction of U. peterseniana extracts, was first isolated by one-step centrifugal partition chromatography and identified by nuclear magnetic resonance. Apo-9′ significantly decreased nitric oxide (NO), prostaglandin E2, pro-inflammatory proteins (inducible NO synthase [iNOS] and cyclooxygenase [COX-2]), and pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-6, and interleukin-1β) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells without exhibiting any cytotoxicity. In vivo, Apo-9′ protected LPS-stimulated zebrafish embryos against inflammatory stress and suppressed the expression of pro-inflammatory proteins such as COX-2 and iNOS. These findings suggest that U. peterseniana extract and Apo-9′ could be used as an anti-inflammatory agent in health care.

The Photoheterotrophic Growth of Bacteriochlorophyll Synthase-Deficient Mutant of Rhodobacter sphaeroides Is Restored by I44F Mutant Chlorophyll Synthase of Synechocystis sp. PCC 6803.

Chlorophyll synthase (ChlG) and bacteriochlorophyll synthase (BchG) have a high degree of substrate specificity. The BchG mutant of Rhodobacter sphaeroides, BG1 strain, is photosynthetically incompetent. When BG1 harboring chlG of Synechocystis sp. PCC 6803 was cultured photoheterotrophically, colonies arose at a frequency of approximately 10(-8). All the suppressor mutants were determined to have the same mutational change, ChlGI44F. The mutated enzyme ChlGI44F showed BchG activity. Remarkably, BchGF28I, which has the substitution of F at the corresponding 28(th) residue to I, showed ChlG activity. The Km values of ChlGI44F and BchGF28I for their original substrates, chlorophyllide (Chlide) a and bacteriochlorophyllide (Bchlide) a, respectively, were not affected by the mutations, but the Km values of ChlGI44F and BchGF28I for the new substrates Bchlide a and Chlide a, respectively, were more than 10-fold larger than those for their original substrates, suggesting the lower affinities for new substrates. Taken together, I44 and F28 are important for the substrate specificities of ChlG and BchG, respectively. The BchG activity of ChlGI44F and the ChlG activity of BchGF28I further suggest that ChlG and BchG are evolutionarily related enzymes.