Byung-Hun Um

Fucoidans from Brown Seaweeds Sargassum hornery, Eclonia cava, Costaria costata: Structural Characteristics and Anticancer Activity

Fucoidans were isolated by water extraction and ion-exchange chromatography from brown algae Eclonia cava, Sargassum hornery, and Costaria costata collected near of Korean coasts. The structures of fucoidans were investigated. Fucoidan from E. cava was mixture of sulfated rhamnogalactofucan and galactofucan. Fucoidan from C. costata was a sulfated galactofucan. Fucoidan isolated from S. hornery was separated into three fractions: a homofucan sulfate, a homofucan but without sulfate groups, and a sulfated rhamnofucan. The results clearly showed that fucoidans play an inhibitory role in colony formation in human melanoma and colon cancer cells and may be effective antitumor agents.

Pressurized liquid method for fucoxanthin extraction from Eisenia bicyclis (Kjellman) Setchell

Optimization of extraction conditions for fucoxanthin from brown algae Eisenia bicyclis was investigated through a pressurized liquid extraction (PLE) method and statistical experimental design. The process was optimized by Plackett-Burman design at first step to screen the most important variables in the extraction of fucoxanthin, and subsequently central composite design was applied to attain the optimum conditions of the selected factors for fucoxanthin extraction. Two factors, temperature and ethanol concentration, significantly influenced the extraction efficiency of fucoxanthin at 95% level (P<0.05). The maximum predicted value of fucoxanthin extraction was 0.42 mg/g at 110 °C and 90% ethanol. The validation of the model was verified by triplicate experiments under the optimal conditions. The results demonstrated that the statistical strategy was successfully applied for optimization of PLE method for fucoxanthin extraction and that PLE can be a powerful method to extract fucoxanthin from E. bicyclis.

Anti-Inflammatory Effects of Gomisin N, Gomisin J, and Schisandrin C Isolated from the Fruit of Schisandra chinensis

Schiandra chinensis is a well-known Chinese traditional medicine for the treatment of hepatic disease. In this study, we investigated whether the nine major compounds of Schiandra chinensis could be applied to suppress lipopolysaccharide (LPS)-induced inflammatory responses in murine macrophages (Raw 264.7 cells). Among the nine lignans, three, gomisin J, gomisin N, and schisandrin C, were found to reduce nitric oxide (NO) production from LPS-stimulated Raw 264.7 cells. These three lignans showed low cytotoxic effects in Raw 264.7 cells. Pre-treatment of Raw 264.7 cells with gomisin J, gomisin N, or schisandrin C reduced the expression of mRNA and the secretion of pro-inflammatory cytokines. These inhibitory effects were found to be caused by blockage of p38 mitogen-activated protein kinase (MAPK), extracellular signal–regulated kinases 1 and 2 (ERK 1/2), and c-Jun N-terminal kinase (JNK) phosphorylation.

Anti-inflammatory activity of hydroxycinnamic acid derivatives isolated from corn bran in lipopolysaccharide-stimulated Raw 264.7 macrophages.

In this study, the effect of the 80% ethanolic extract of corn bran (EECB) on inhibition of nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in lipopolysaccharide (LPS)-stimulated Raw 264.7 cells was investigated. The EECB inhibited LPS-induced NO production and iNOS expression in a dose-dependent manner. Four hydroxycinnamic acid derivatives (HADs), including two free cinnamic acids, p-coumaric acid (CA) and ferulic acid (FA), and their conjugate phenolic amides, p-dicoumaroyl-putrescine (DCP) and diferuloylputrescine (DFP), were found to be present in the EECB by LC-MS analysis, and DFP (378.66 μg/g) was the predominant phenolic compound, followed by DCP (7.83 μg/g)>CA (5.58 μg/g)>FA (1.84 μg/g). The four HADs significantly inhibited NO production and iNOS expression in a dose-dependent manner. Among the four HADs tested, DFP showed the most potent inhibition on NO production and iNOS mRNA and protein expression, followed by DCP>FA ≥ CA. DFP also exhibited the strongest inhibition on LPS-induced iNOS and NF-κB luciferase activity, which was followed by DCP ≥ FA (CA)>CA (FA). Thus, these results suggest that phenolic amides in the corn bran may be a potential source of natural anti-inflammatory agents.

Effect of Pressurized Liquids on Extraction of Antioxidants from Chlorella vulgaris

Chlorella vulgaris is a green microalga that contains various antioxidants, such as carotenoids and chlorophylls. In this study, antioxidants from C. vulgaris were extracted using pressurized liquid extraction (PLE), which has been recently used for bioactive compound extraction. The antioxidant capacity of individual compounds in chlorella was determined by online HPLC ABTS(*+) analysis. According to the antioxidant analysis of total extracts, the extraction yield, radical scavenging activity, and phenolic compounds using PLE were relatively high compared to those obtained using maceration or ultrasound-assisted extraction. On the basis of online HPLC ABTS(*+) analysis, the 15 major antioxidants from chlorella extracts were identified as hydrophilic compounds, lutein and its isomers, chlorophylls, and chlorophyll derivatives. Using PLE at high temperature (85-160 degrees C) significantly increased antioxidant extraction from chlorella, improving the formation of hydrophilic compounds and yielding more antioxidative chlorophyll derivatives. Online HPLC ABTS(*+) analysis was a useful tool for the separation of main antioxidants from PLE extracts and allowed the simultaneous measurement of their antioxidant capacity, which clearly showed that PLE is an excellent method for extracting antioxidants from C. vulgaris.

A preparative method for isolation of fucoxanthin from Eisenia bicyclis by centrifugal partition chromatography

INTRODUCTION Eisenia bicyclis (Kjellman) Setchell (Laminariaceae) is a common brown alga that inhabits around the coast of Korea, Japan and China. It contains fucoxanthin, a major carotenoid of brown algae which shows a variety of pharmaceutical functions. OBJECTIVE The aim of this investigation was the quantification and preparative isolation of fucoxanthin from fresh E. bicyclis using a new separation scheme, centrifugal partition chromatography (CPC). METHODOLOGY The fucoxanthin fraction (Fuco fraction) was prepared by solvent partition method from the acetone extract of fresh E. bicyclis. Fuco fraction was used for CPC using a two-phase solvent system of n-hexane-ethyl acetate-ethanol-water (5:5:7:3, v/v/v/v). The flow rate of mobile phase was 2 mL/min with descending mode while rotating at 1000 rpm. The eluate was monitored at 410 nm. The content and structure of fucoxanthin in the CPC fraction were confirmed with HPLC, UV, APCI/MS and NMR spectra. RESULTS A preparative CPC yielded 20 mg of fucoxanthin (87% recovery from Fuco fraction) in a two-step separation from 516 mg of Fuco fraction containing 4.59% fucoxanthin. The purity of the isolated fucoxanthin was about 81% in the first CPC step and over 98% in the second CPC step based on the calibration curve. The isolated fucoxanthin was identified as all-trans-fucoxanthin with APCI/MS (parent ion at m/z 641 [M + H - H(2) O](+) ) and (1) H, (13) C and 2-D NMR spectra. CONCLUSION High-purity fucoxanthin was successfully isolated from fresh E. bicyclis, suggesting further potential applications in the industrial use of this valuable carotenoid.

Structure, enzymatic transformation and anticancer activity of branched high molecular weight laminaran from brown alga Eisenia bicyclis

The structure of high molecular weight laminaran from brown alga Eisenia bicyclis was investigated by chemical and enzymatic methods, NMR spectroscopy and mass spectrometry. The laminaran from E. bicyclis was characterized as 1,3;1,6-β-D-glucan with the high content of 1,6-linked glucose residues (ratio of bonds 1,3:1,6=1.5:1), which are both in the branches and in the main chain of the laminaran. The degree of polymerization of fragments, building from 1,3-linked glucose residues with single glucose branches at C-6 or without it, was no more than four glucose residues. The main part of 1,3-linked glucose blocks was builded from disaccharide fragments. 1,6-Linked glucose residues were localized basically on non-reduced ends of molecules. The degree of polymerization of 1,6-linked blocks was not greater than three glucose residues. Laminaran contained laminarioligosaccharides, gentiobiose, gentiotriose and single glucose residues in the branches at the C-6. Laminaran and its products of enzymatic hydrolysis inhibited a colony formation of human melanoma SK-MEL-28 and colon cancer DLD-1 cells. It was shown that decreasing the molecular weight of native laminaran to a determined limit (degree of polymerization 9-23) and increasing the content of 1,6-linked glucose residues increased the anticancer effect. Therefore, they may be perspective antitumor agents.

Hepatoprotective Effect of Flavonoid Glycosides from Lespedeza cuneata against Oxidative Stress Induced by tert-Butyl Hyperoxide

The aerial parts of Lespedeza cuneata G. Don, perennial legume native to Eastern Asia, have been used therapeutically in traditional Asian medicine to protect the function of liver, kidneys and lungs. However, little is known about the pharmaceutical effect of extracts from this plant. In the present study, the aerial parts of L. cuneata were used to prepare an ethanol extract, which was then tested for hepatoprotective effects against injury by tert‐butyl hyperoxide (t‐BHP). At a dose of 20 μg/mL, the ethanol extract significantly protected HepG2 cells against the cytotoxicity of t‐BHP. Further fractionation of the extract with ethyl acetate allowed the isolation of five flavonoid compounds that were structurally identified by 1H and 13C NMR spectroscopy as isovitexin, hirsutrin, trifolin, avicularin and quercetin. Hirsutrin, avicularin and quercetin (10 μm) showed clear hepatoprotective activity against injury by t‐BHP in HepG2 cells, whereas isovitexin and trifolin showed no protective effects. The observed hepatoprotective effect of the investigated compounds showed a high correlation with radical scavenging activity, which followed the structure–activity relationships of the flavonoid aglycones. Copyright

Production of Lactosucrose from Sucrose and Lactose by a Levansucrase from Zymomonas mobilis

Lactosucrose (4(G)-beta-D-galactosylsucrose) is an oligosaccharide consisting of galactose, glucose, and fructose. In this study, we prepared lactosucrose from lactose and sucrose using a levansucrase derived from Zymomonas mobilis. Optimum conditions for lactosucrose formation were 23 degrees C, pH 7.0, 18.0% (w/v) lactose monohydrate, and 18% (w/v) sucrose as substrates, and 1 unit of enzyme/ml of reaction mixture. Under these conditions, the lactosucrose conversion efficiency was 28.5%. The product was purified and confirmed to be O-beta-D-galactopyranosyl-(1-->4)-O-beta-D-glucopyranosyl- (1-->2)-beta-D-fructofuranoside, or lactosucrose. A mixed-enzyme system containing a levansucrase and a glucose oxidase was applied in order to increase the efficiency of lactose and sucrose conversion to lactosucrose, which rose to 43.2% as s result.

Rapid identification of furanocoumarins in Angelica dahurica using the Online LC-MMR-MS and their nitric oxide inhibitory activity in RAW 264.7 cells

INTRODUCTION Angelica dahurica (Fisch. Ex hoffm.) Benth. Et Hook. is a perennial herb that grows throughout Korea whose dried roots have been used to treat various diseases in Korean traditional medicine. The root extract contains diverse constituents, and it is necessary to determine the active compounds. OBJECTIVE To investigate the nitric oxide (NO) inhibitory activity in a root extract of A. dahurica and identify the most active compounds using LC-NMR-MS. METHODOLOGY In search of the anti-inflammatory constituents of A. dahurica extract, the HPLC-based activity profiling approach was used to investigate the extracts NO inhibitory activity. To directly identify the compounds, a hyphenated LC-NMR-MS technique was applied. Reversed-phase isocratic chromatography was performed using the acetonitrile-water solvent system on a C(30) column. The identification of the compounds was based on information from ESI/MS and 1H-NMR. RESULTS NO inhibitory activities for five main fractions of the extract were evaluated, which were identified by LC-NMR-MS as containing furanocoumarins: byakangelicol, oxypeucedanin, imperatorin, phellopterin and isoimperatorin. CONCLUSION The results obtained showed that the anti-inflammatory activities of A. dahurica could be linked to imperatorin and phellopterin.