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Kyoung Heon Kim – One of the best experts on this subject based on the ideXlab platform.

  • Different Levels of Skin Whitening Activity among 3,6-Anhydro-l-galactose, Agarooligosaccharides, and Neoagarooligosaccharides
    Marine Drugs, 2017
    Co-Authors: Ji Hye Kim, Eun Ju Yun, Kyoung Heon Kim, Nam Joo Kang
    Abstract:

    3,6-Anhydro-l-galactose (AHG), a major monomeric constituent of red macroalgae (Rhodophyta), was recently reported to possess skin whitening activity. Moreover, AHG-containing oligosaccharides, such as agarooligosaccharides (AOSs) and neoagarooligosaccharides (NAOSs), have various physiological activities, including anti-inflammatory, antioxidant, and skin moisturizing effects. In this study, AHG and NAOSs were produced from Agarose by enzymatic reactions catalyzed by an endo-type β-agarase, an exo-type β-agarase, and a neoagarobiose hydrolase. In a cell prolproliferationay, AHG, AOSs, and NAOSs at 12.5, 25, and 50 μg/mL concentrations did not exhibit cytotoxicity toward murine B16 melanoma cells or human epidermal melanocytes. In an in vitro skin whitening activity assay of AHG, AOSs, and NAOSs at 50 μg/mL, AHG showed the highest skin whitening activity in both murine B16 melanoma cells and human epidermal melanocytes; this activity was mediated by the inhibition of melanogenesis. Neoagarotetraose and neoagarohexaose also exhibited in vitro skin whitening activity, whereas neoagarobiose and AOSs with degrees of polymerization of 3 (agarotriose), 5 (agaropentaose), and 7 (agaroheptaose) did not. Therefore, AHG is responsible for the skin whitening activity of agar-derived sugars, and the structural differences among the AHG-containing oligosaccharides may be responsible for their different skin whitening activities.

  • enzymatic production of 3 6 anhydro l galactose from Agarose and its purification and in vitro skin whitening and anti inflammatory activities
    Applied Microbiology and Biotechnology, 2013
    Co-Authors: Eun Ju Yun, Ji Hye Kim, Nam Joo Kang, In Geol Choi, Saeyoung Lee, Bo Bae Kim, Hee Taek Kim, Sun Hee Lee, Jeffrey G Pelton, Kyoung Heon Kim
    Abstract:

    3,6-Anhydro-l-galactose (L-AHG) constitutes 50 % of Agarose, which is the main component of red macroalgae. No information is currently available on the mass production, metabolic fate, or physiological effects of L-AHG. Here, Agarose was converted to L-AHG in the following three steps: pre-hydrolysis of Agarose into agaro-oligosaccharides by using acetic acid, hydrolysis of the agaro-oligosaccharides into neoagarobiose by an exo-agarase, and hydrolysis of neoagarobiose into L-AHG and galactose by a neoagarobiose hydrolase. After these three steps, L-AHG was purified by adsorption and gel permeation chromatographies. The final product obtained was 95.6 % pure L-AHG at a final yield of 4.0 % based on the initial Agarose. In a cell prolproliferationay, L-AHG at a concentration of 100 or 200 μg/ mL did not exhibit any significant cytotoxicity. In a skin whitening assay, 100 μg/ mL of L-AHG showed significantly lower melanin production compared to arbutin. L-AHG at 100 and 200 μg/ mL showed strong anti-inflammatory activity, indicating the significant suppression of nitrite production. This is the first report on the production of high-purity L-AHG and its physiological activities.

  • production of 3 6 anhydro l galactose from Agarose by agarolytic enzymes of saccharophagus degradans 2 40
    Process Biochemistry, 2011
    Co-Authors: Eun Ju Yun, Minhye Shin, Jeongjun Yoon, Yong Jin Kim, In Geol Choi, Kyoung Heon Kim
    Abstract:

    Abstract Saccharophagus degradans 2-40 is capable of hydrolyzing Agarose, a red macroalgae-derived polymer, into d –galactose and 3,6-anhydro- l –galactose (L-AHG). Its agarase system is receiving much attention because it can be used to produce fermentable sugar from Agarose. L-AHG is commercially unavailable and is considered a rare sugar with a high value. In this study, cells grown on Agarose, agar or red macroalgae biomass were found to have a significantly higher agarase activity and AHG-generating activity than those grown on glucose or galactose. From agar-grown cells, both the volumetric activities of agarases and AHG generation in the cell-free lysate were much higher than in the extracellular fraction. Based on the analyses of the enzyme reacreaction products, from the reaction with the crude enzymes from cell-free lysate, neoagarobiose with a degree of polypolymerization (DP) 2 appeared to be the only major product in the initial reaction period, but sugars with DPs 2, 4 and 6 were found to be all predominantly produced by the extracellular enzymes in the initial reaction period. Quantitative analysis of AHG using gas chromatography–mass spectrometry with a derivatization step was also found to be highly reproducible and reliable. These results will be useful for producing L-AHG as a rare sugar to investigate its metabolic fate and commercial utilization.

Nam Joo Kang – One of the best experts on this subject based on the ideXlab platform.

  • Different Levels of Skin Whitening Activity among 3,6-Anhydro-l-galactose, Agarooligosaccharides, and Neoagarooligosaccharides
    Marine Drugs, 2017
    Co-Authors: Ji Hye Kim, Eun Ju Yun, Kyoung Heon Kim, Nam Joo Kang
    Abstract:

    3,6-Anhydro-l-galactose (AHG), a major monomeric constituent of red macroalgae (Rhodophyta), was recently reported to possess skin whitening activity. Moreover, AHG-containing oligosaccharides, such as agarooligosaccharides (AOSs) and neoagarooligosaccharides (NAOSs), have various physiological activities, including anti-inflammatory, antioxidant, and skin moisturizing effects. In this study, AHG and NAOSs were produced from Agarose by enzymatic reactions catalyzed by an endo-type β-agarase, an exo-type β-agarase, and a neoagarobiose hydrolase. In a cell proliferation assay, AHG, AOSs, and NAOSs at 12.5, 25, and 50 μg/mL concentrations did not exhibit cytotoxicity toward murine B16 melanoma cells or human epidermal melanocytes. In an in vitro skin whitening activity assay of AHG, AOSs, and NAOSs at 50 μg/mL, AHG showed the highest skin whitening activity in both murine B16 melanoma cells and human epidermal melanocytes; this activity was mediated by the inhibition of melanogenesis. Neoagarotetraose and neoagarohexaose also exhibited in vitro skin whitening activity, whereas neoagarobiose and AOSs with degrees of polymerization of 3 (agarotriose), 5 (agaropentaose), and 7 (agaroheptaose) did not. Therefore, AHG is responsible for the skin whitening activity of agar-derived sugars, and the structural differences among the AHG-containing oligosaccharides may be responsible for their different skin whitening activities.

  • enzymatic production of 3 6 anhydro l galactose from Agarose and its purification and in vitro skin whitening and anti inflammatory activities
    Applied Microbiology and Biotechnology, 2013
    Co-Authors: Eun Ju Yun, Ji Hye Kim, Nam Joo Kang, In Geol Choi, Saeyoung Lee, Bo Bae Kim, Hee Taek Kim, Sun Hee Lee, Jeffrey G Pelton, Kyoung Heon Kim
    Abstract:

    3,6-Anhydro-l-galactose (L-AHG) constitutes 50 % of Agarose, which is the main component of red macroalgae. No information is currently available on the mass production, metabolic fate, or physiological effects of L-AHG. Here, Agarose was converted to L-AHG in the following three steps: pre-hydrolysis of Agarose into agaro-oligosaccharides by using acetic acid, hydrolysis of the agaro-oligosaccharides into neoagarobiose by an exo-agarase, and hydrolysis of neoagarobiose into L-AHG and galactose by a neoagarobiose hydrolase. After these three steps, L-AHG was purified by adsorption and gel permeation chromatographies. The final product obtained was 95.6 % pure L-AHG at a final yield of 4.0 % based on the initial Agarose. In a cell proliferation assay, L-AHG at a concentration of 100 or 200 μg/ mL did not exhibit any significant cytotoxicity. In a skin whitening assay, 100 μg/ mL of L-AHG showed significantly lower melanin production compared to arbutin. L-AHG at 100 and 200 μg/ mL showed strong anti-inflammatory activity, indicating the significant suppression of nitrite production. This is the first report on the production of high-purity L-AHG and its physiological activities.

Eun Ju Yun – One of the best experts on this subject based on the ideXlab platform.

  • Different Levels of Skin Whitening Activity among 3,6-Anhydro-l-galactose, Agarooligosaccharides, and Neoagarooligosaccharides
    Marine Drugs, 2017
    Co-Authors: Ji Hye Kim, Eun Ju Yun, Kyoung Heon Kim, Nam Joo Kang
    Abstract:

    3,6-Anhydro-l-galactose (AHG), a major monomeric constituent of red macroalgae (Rhodophyta), was recently reported to possess skin whitening activity. Moreover, AHG-containing oligosaccharides, such as agarooligosaccharides (AOSs) and neoagarooligosaccharides (NAOSs), have various physiological activities, including anti-inflammatory, antioxidant, and skin moisturizing effects. In this study, AHG and NAOSs were produced from Agarose by enzymatic reactions catalyzed by an endo-type β-agarase, an exo-type β-agarase, and a neoagarobiose hydrolase. In a cell proliferation assay, AHG, AOSs, and NAOSs at 12.5, 25, and 50 μg/mL concentrations did not exhibit cytotoxicity toward murine B16 melanoma cells or human epidermal melanocytes. In an in vitro skin whitening activity assay of AHG, AOSs, and NAOSs at 50 μg/mL, AHG showed the highest skin whitening activity in both murine B16 melanoma cells and human epidermal melanocytes; this activity was mediated by the inhibition of melanogenesis. Neoagarotetraose and neoagarohexaose also exhibited in vitro skin whitening activity, whereas neoagarobiose and AOSs with degrees of polymerization of 3 (agarotriose), 5 (agaropentaose), and 7 (agaroheptaose) did not. Therefore, AHG is responsible for the skin whitening activity of agar-derived sugars, and the structural differences among the AHG-containing oligosaccharides may be responsible for their different skin whitening activities.

  • enzymatic production of 3 6 anhydro l galactose from Agarose and its purification and in vitro skin whitening and anti inflammatory activities
    Applied Microbiology and Biotechnology, 2013
    Co-Authors: Eun Ju Yun, Ji Hye Kim, Nam Joo Kang, In Geol Choi, Saeyoung Lee, Bo Bae Kim, Hee Taek Kim, Sun Hee Lee, Jeffrey G Pelton, Kyoung Heon Kim
    Abstract:

    3,6-Anhydro-l-galactose (L-AHG) constitutes 50 % of Agarose, which is the main component of red macroalgae. No information is currently available on the mass production, metabolic fate, or physiological effects of L-AHG. Here, Agarose was converted to L-AHG in the following three steps: pre-hydrolysis of Agarose into agaro-oligosaccharides by using acetic acid, hydrolysis of the agaro-oligosaccharides into neoagarobiose by an exo-agarase, and hydrolysis of neoagarobiose into L-AHG and galactose by a neoagarobiose hydrolase. After these three steps, L-AHG was purified by adsorption and gel permeation chromatographies. The final product obtained was 95.6 % pure L-AHG at a final yield of 4.0 % based on the initial Agarose. In a cell proliferation assay, L-AHG at a concentration of 100 or 200 μg/ mL did not exhibit any significant cytotoxicity. In a skin whitening assay, 100 μg/ mL of L-AHG showed significantly lower melanin production compared to arbutin. L-AHG at 100 and 200 μg/ mL showed strong anti-inflammatory activity, indicating the significant suppression of nitrite production. This is the first report on the production of high-purity L-AHG and its physiological activities.

  • production of 3 6 anhydro l galactose from Agarose by agarolytic enzymes of saccharophagus degradans 2 40
    Process Biochemistry, 2011
    Co-Authors: Eun Ju Yun, Minhye Shin, Jeongjun Yoon, Yong Jin Kim, In Geol Choi, Kyoung Heon Kim
    Abstract:

    Abstract Saccharophagus degradans 2-40 is capable of hydrolyzing Agarose, a red macroalgae-derived polymer, into d -galactose and 3,6-anhydro- l -galactose (L-AHG). Its agarase system is receiving much attention because it can be used to produce fermentable sugar from Agarose. L-AHG is commercially unavailable and is considered a rare sugar with a high value. In this study, cells grown on Agarose, agar or red macroalgae biomass were found to have a significantly higher agarase activity and AHG-generating activity than those grown on glucose or galactose. From agar-grown cells, both the volumetric activities of agarases and AHG generation in the cell-free lysate were much higher than in the extracellular fraction. Based on the analyses of the enzyme reaction products, from the reaction with the crude enzymes from cell-free lysate, neoagarobiose with a degree of polymerization (DP) 2 appeared to be the only major product in the initial reaction period, but sugars with DPs 2, 4 and 6 were found to be all predominantly produced by the extracellular enzymes in the initial reaction period. Quantitative analysis of AHG using gas chromatography–mass spectrometry with a derivatization step was also found to be highly reproducible and reliable. These results will be useful for producing L-AHG as a rare sugar to investigate its metabolic fate and commercial utilization.

Ji Hye Kim – One of the best experts on this subject based on the ideXlab platform.

  • Different Levels of Skin Whitening Activity among 3,6-Anhydro-l-galactose, Agarooligosaccharides, and Neoagarooligosaccharides
    Marine Drugs, 2017
    Co-Authors: Ji Hye Kim, Eun Ju Yun, Kyoung Heon Kim, Nam Joo Kang
    Abstract:

    3,6-Anhydro-l-galactose (AHG), a major monomeric constituent of red macroalgae (Rhodophyta), was recently reported to possess skin whitening activity. Moreover, AHG-containing oligosaccharides, such as agarooligosaccharides (AOSs) and neoagarooligosaccharides (NAOSs), have various physiological activities, including anti-inflammatory, antioxidant, and skin moisturizing effects. In this study, AHG and NAOSs were produced from Agarose by enzymatic reactions catalyzed by an endo-type β-agarase, an exo-type β-agarase, and a neoagarobiose hydrolase. In a cell proliferation assay, AHG, AOSs, and NAOSs at 12.5, 25, and 50 μg/mL concentrations did not exhibit cytotoxicity toward murine B16 melanoma cells or human epidermal melanocytes. In an in vitro skin whitening activity assay of AHG, AOSs, and NAOSs at 50 μg/mL, AHG showed the highest skin whitening activity in both murine B16 melanoma cells and human epidermal melanocytes; this activity was mediated by the inhibition of melanogenesis. Neoagarotetraose and neoagarohexaose also exhibited in vitro skin whitening activity, whereas neoagarobiose and AOSs with degrees of polymerization of 3 (agarotriose), 5 (agaropentaose), and 7 (agaroheptaose) did not. Therefore, AHG is responsible for the skin whitening activity of agar-derived sugars, and the structural differences among the AHG-containing oligosaccharides may be responsible for their different skin whitening activities.

  • enzymatic production of 3 6 anhydro l galactose from Agarose and its purification and in vitro skin whitening and anti inflammatory activities
    Applied Microbiology and Biotechnology, 2013
    Co-Authors: Eun Ju Yun, Ji Hye Kim, Nam Joo Kang, In Geol Choi, Saeyoung Lee, Bo Bae Kim, Hee Taek Kim, Sun Hee Lee, Jeffrey G Pelton, Kyoung Heon Kim
    Abstract:

    3,6-Anhydro-l-galactose (L-AHG) constitutes 50 % of Agarose, which is the main component of red macroalgae. No information is currently available on the mass production, metabolic fate, or physiological effects of L-AHG. Here, Agarose was converted to L-AHG in the following three steps: pre-hydrolysis of Agarose into agaro-oligosaccharides by using acetic acid, hydrolysis of the agaro-oligosaccharides into neoagarobiose by an exo-agarase, and hydrolysis of neoagarobiose into L-AHG and galactose by a neoagarobiose hydrolase. After these three steps, L-AHG was purified by adsorption and gel permeation chromatographies. The final product obtained was 95.6 % pure L-AHG at a final yield of 4.0 % based on the initial Agarose. In a cell proliferation assay, L-AHG at a concentration of 100 or 200 μg/ mL did not exhibit any significant cytotoxicity. In a skin whitening assay, 100 μg/ mL of L-AHG showed significantly lower melanin production compared to arbutin. L-AHG at 100 and 200 μg/ mL showed strong anti-inflammatory activity, indicating the significant suppression of nitrite production. This is the first report on the production of high-purity L-AHG and its physiological activities.

Philip Serwer – One of the best experts on this subject based on the ideXlab platform.

  • The formation of small-pore gels by an electrically charged Agarose derivative.
    Journal of structural biology, 1998
    Co-Authors: Gary A. Griess, Kenneth B. Guiseley, Margaret M. Miller, Renee A. Harris, Philip Serwer
    Abstract:

    Previous studies have shown that, during the formation of an underivatized Agarose gel, Agarose molecules laterally aggregate to form thicker fibers called suprafibers; the suprafibers branch to form a gelled network. In the present study, electron microscopy of thin sections is used to investigate both the thickness and the spacing of the fibers of gels formed by Agarose chemically derivatized with carboxymethyl (negatively charged) groups. For carboxymethyl Agarose, electron microscopy reveals that gels cast in water consist of both fibers narrower and pores smaller than those observed for water-cast underivatized Agarose gels at the same concentration. This result is confirmed by using the electrophoretic sieving of spheres to determine the radius (PE) of the effective pore of the gel. At a given concentration of gel less than 1%, the PE for a water-cast carboxymethyl Agarose gel is 0.25-0.30x the PE for a water-cast underivatized Agarose gel. The value of PE predicts the extent of the electrophoretic sieving that is observed when double-stranded DNA is subjected to electrophoresis through a water-cast carboxymethyl Agarose gel; DNA bands formed in a water-cast carboxymethyl Agarose gel are comparable in quality to DNA bands formed in a water-cast underivatized Agarose gel of equal PE. The following observation supports the hypothesis that electrical charge-charge repulsion among carboxymethyl Agarose molecules inhibits the formation of suprafibers in water-cast carboxymethyl Agarose gels: Increased content of suprafibers in carboxymethyl Agarose gels is observed when the ionic strength is raised by the presence of NaCl, MgCl2, or any of several buffers during gelation of carboxymethyl Agarose.

  • The relationship of Agarose gel structure to the sieving of spheres during Agarose gel electrophoresis
    Biophysical journal, 1993
    Co-Authors: G.a. Griess, K.b. Guiseley, Philip Serwer
    Abstract:

    To understand the organization of fibers in an Agarose gel, digitized electron micrographs are used here to determine the frequency distribution of interfiber distance (2Pc) in thin sections of Agarose gels. For a preparation of underivatized Agarose, a 1.5% gel has a Pc distribution that is indistinguishable from the Pc distribution of a computer-generated, random-fiber gel; the log of the occurrence frequency (F) decreases linearly as a function of Pc. As the Agarose concentration decreases below 1.5%, the semilogarithmic F versus Pc plot becomes progressively less linear. Two straight lines represent the data; the plot is steeper at the lower Pc values. As the percentage of Agarose increases above 1.5%, the semilogarithmic F versus Pc plot becomes steeper at the higher Pc values. This change in the shape of semilogarithmic F versus Pc plots is possibly explained by the existence in Agarose gels of two zones, one whose Pc distribution is more sensitive to the average Agarose concentration than the other. To compare the structure of Agarose gels to their sieving during electrophoresis, the root mean square value of Pc (Pc) is compared to the sieving-based radius of the effective pore (PE; Griess et. al. (16)) for both underivatized Agarose and a derivatized Agarose that has a smaller PE at any given Agarose percentage. For 0.8–2.0% gels of either underivatized or derivatized Agarose, PE/Pc is a constant within experimental error. Deviations from this constant are observed at lower gel percentages. This relationship of PE to Pc constrains theoretical descriptions of the motion of spheres in fibrous networks.