MyoungLae Cho

The Antioxidant Properties of Ethanol Extracts and Their Solvent-Partitioned Fractions from Various Green Seaweeds

The antioxidant activities of the ethanol (EtOH) extracts from the green seaweeds Enteromorpha compressa, Capsosiphon fulvescens, Chaetomorpha moniligera, and Ulva pertusa, as well as their solvent-partitioned fractions, were investigated, and their antioxidant activities were correlated with total phenolic and flavonoid contents. The EtOH extracts and their solvent-partitioned fractions showed 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl (OH•) radical scavenging activities with strong reducing ability. The most effective antioxidant properties were observed from the EtOH extracts of E. compressa and C. fulvescens. Among the solvent-partitioned fractions obtained with n-hexane, chloroform (CF), and ethyl acetate, the CF fractions from E. compressa and C. fulvescens exhibited higher radical scavenging activities and stronger reducing ability than other fractions. The OH• radical scavenging capacity and reducing power of these fractions were comparable to those of a positive control, α-tocopherol, at concentrations of 0.06-1.0 mg/mL. Total phenolic contents showed little correlation (r²=0.22-0.42) with the antioxidant properties; however, significant correlation (r² =0.73-0.96) was observed with flavonoid contents, implying that the flavonoid constituents contribute substantially to the antioxidant properties of the extracts. The overall results suggested that the green seaweeds (E. compressa and C. fulvescens), especially their CF fractions, could be good sources of natural antioxidants and of highly beneficial ingredients for healthcare products, such as nutraceuticals, supplements, and cosmeceuticals.

Molecular characterization and immunomodulatory activity of sulfated fucans from Agarum cribrosum.

The sulfated-fucans, known as fucoidans, were isolated from Agarum cribrosum and fractionated using ion-exchange chromatography to determine their molecular characteristics and in vitro immunomodulatory activity. The crude and fractionated fucoidans (F1 and F2) consisted mostly of carbohydrates (52.4-56.0%), sulfates (12.7-23.0%) and uronic acid (14.1-21.8%), with a small amount of proteins (3.9-9.3%), and included various levels of fucose (44.0-46.7%), mannose (18.9-26.8%), galactose (16.8-33.0%), xylose (10.7-17.0%) and glucose (3.5-9.5%). The crude and fractionated fucans contained one or two subfractions with average molecular weights (Mw) ranging from 110.1 × 10(3) to 2420 × 10(3)g/mol. The fractionated fucoidan, especially the F1 fraction, strongly stimulated murine macrophages (Raw 264.7 cells), producing a considerable amount of nitric oxide (NO) and inducing expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2) and interleukin-10 (IL-10) transcripts by activation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) pathways. The maximally immunoenhancing F1 fraction was mainly composed of (1 → 3)-linked fucose, (1 → 2)-linked mannose and (1 → 4)-linked glucuronic acid with sulfates at C-2 or both the C-2 and C-4 positions in (1 → 2,3)- and (1 → 2,3,4)-linked fucose residues.

Molecular cloning and functional characterization of a sucrose isomerase (isomaltulose synthase) gene from Enterobacter sp. FMB-1.

Aims:  Isomaltulose (palatinose) is a slowly digestible sucrose isomer that can reduce both the glycemic and insulinemic response to foods. The aim of this study was to clone and express a sucrose isomerase (SIase) gene and characterize the protein that is responsible for the production of isomaltulose in the micro‐organism Enterobacter sp. FMB‐1.

Production of starch nanoparticles using normal maize starch via heat-moisture treatment under mildly acidic conditions and homogenization

Normal maize starch was subjected to heat-moisture treatment (HMT) under mildly acidic conditions (0.000, 0.050, or 0.075M H2SO4) for various treatment times (3, 5, or 8h) followed by homogenization up to 60min to prepare nanoparticles. The combination of HMT (0.075M, for 8h) and homogenization (60min) produced nanoparticles with diameters of less than 50nm at a yield higher than 80%. X-ray diffractometry and size-exclusion chromatography revealed that HMT under mildly acidic conditions selectively hydrolyzed the starch chains (especially amylose and/or long chains of amylopectin) in the amorphous region of the granules without significant damage to the crystalline structure, however, modification of the molecular structure in the amorphous region increased fragility of the granules during homogenization. Homogenization for 60min caused obvious damage in the long-range crystalline structure of the HMT starch (0.15N, for 8h), while the short-range chain associations (FT-IR) remained intact.

Effect of High Temperature- and High Pressure-Treated Red Ginseng on Lipolysis and Lipid Oxidation in C2C12 Myotubes.

Korean red ginseng (KRG), a highly valuable medicinal herb in oriental societies, has biological activity similar to that of Panax ginseng. Recently, it has been discovered that the biological activities of red ginseng can vary according to heating and steaming processes under different conditions that change the principal components of KRG and result in changes in biological activity. This study evaluated and compared the effects of high temperature- and high pressure-treated red ginseng (HRG) and commercial red ginseng (RG) on β-oxidation in C2C12 myotubes. HRG enhanced the phosphorylation levels of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC), but RG did not affect the phosphorylation of AMPK in C2C12 myotubes. HRG also promoted the nuclear translocation of forkhead box protein O1 (FoxO1), and the translocation exerted an increase in the protein expression of adipose triglyceride lipase (ATGL). As a consequence, HRG increased the mRNA expression level of carnitine palmitoyltransferase 1 (CPT-1) compared to the control. Taken together, our results indicated that HRG promotes the lipolysis of triglycerides and mitochondrial β-oxidation of fatty acids in C2C12 myotubes, suggesting that alterations to the principal components by high temperature and pressure may positively influence the nutraceutical functions of HRG.

Genotoxicity Study from the Extracts of Fermented Acanthopanax koreanum

This study was to determine genotoxicity from the extracts of fermented Acanthopanax koreanum. The bacterial reverse mutation assay, the extracts of fermented A. koreanum did not induce mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA1537 and Escherichia coli WP2uvrA with or without metabolic activation of S-9 mixture. In addition, the micronucleus formation in ICR mice, the extracts of fermented A. koreanum treated with dose of 500, 1,000 and 2,000 mg/kg did not affected micronucleated polychromatic erythrocytes (MNPCE/2,000 PCE) and polychromatic erythrocytes (PCE)/200 polychromatic erythrocyte+normochromatic erythrocyte (RBC). The cytotoxicity effects using CHO-K1 cells observed no significant changes compared with negative control group (p < 0.05). Moreover, the extracts of fermented A. koreanum did not cause a significant chromosome aberration on CHO-K1 cells in the chromosome aberration assay. Therefore, these results suggest that the extracts of fermented A. koreanum did not induce any harmful genotoxic effects.