The uptake of , a metal cofactor Mn-SOD, by rice seedings resulted in not only a substantial incr... more The uptake of , a metal cofactor Mn-SOD, by rice seedings resulted in not only a substantial increase in SOD activity in leaf tissues of the plants, but also a significant enhancement of their cold tolerance : the relative extent of the cold tolerance appeared to accord with relative level of the SOD activity. In contrast, and , which are the cofactors of Fe-SOD and Cu/Zn-SOD, were found to be ineffective for increasing the SOD activity as well as for improving the chilling-resistant capacity of the plants. The results suggest that Mn-SOD, which is most likely induced by its substrate(superoxide) and activated by the presence of a at high level, is the enzyme acting as an active component of the defense system against low temperature stress in rice plants. In addition, the application of abscisic acid which has been know to protect to some extent certain plants from chilling injury brought about an increase in SOD activity in rice tissues, providing another affirmative information f...
Two lipid peroxidation inhibitors, designated as betulinans A (1) and B (2), were isolated from t... more Two lipid peroxidation inhibitors, designated as betulinans A (1) and B (2), were isolated from the MeOH extract of Lenzites betulina. The structures of these compounds have been determined to be 2,5-diphenyl-3,6-dimethoxy-p-benzoquinone and 2-phenyl-3-methoxy-[1H-2-benzopyran][4,3-e][p]benzoquinone, respectively, on the basis of various spectral data. Betulinans A and B inhibited lipid peroxidation with IC50 values of 0.46 and 2.88 micrograms/mL, respectively.
Journal of Korean Society of Agricul Chem Biot, 1996
During the screening of herbicidal substances from microbial secondary metabolites using photoaut... more During the screening of herbicidal substances from microbial secondary metabolites using photoautotrophic cells, a strain of ME-13 with strong herbicidal activity was isolated from soil. Based on the taxonomic studies, the strain was identified as Streptomyces. Two active compounds were purified from the culture broth through the column chromatographies using active charcoal, silica gel, MCI gel, and ODS HPLC. The compounds were identified as AB3217-A and B, respectively, related to anisomycin by spectroscopic methods. AB3217-A and B completely suppressed the germination of radish and barnyard grass at 25 ppm. In comparison to anisomycin, they showed the 6 times higher inhibitory activities against the growth of shoot and root of radish and barnyard grass with EC5O of around 6 ppm.
Plant mitochondria, irradiated with blue-colored under aerobic and anaerobic conditions, were ass... more Plant mitochondria, irradiated with blue-colored under aerobic and anaerobic conditions, were assayed as to the electron transfer activity of respiratory enzyme system, and compared with those irradiated with orange-colored light(white sunlight minus blue-colored light). The respiratory activity of mitochondria was most seriousely inhibited by illumination with blue-colored light under aerobic condition. Deaeration of mitochondrial suspension resulted in substantial decrease of the photoinhibition by blue-colored light. Meanwhile, orange-colored light demonstrated much less effectiveness-almost ineffectiveness-in causing the inhibition of mitochondrial respiration system. The results of enzymatic assay revealed a strong possibility that FMN in NDH and heme group at least in cytochrome c oxidase, but not FAD in SDH, are the photodynamic sensitizers in mitochondrial inner membrane. Also worthwhile to note is the significant difference from the others of SDH in its photoinhibitory resp...
In an attempt to explore the mechanistic aspects of chilling injury in plants and their defensive... more In an attempt to explore the mechanistic aspects of chilling injury in plants and their defensive measures against the low temperature stress, the time sequential measurements of pyruvate, superoxide radicals and antioxygenic enzymes during whole period of injury-inducing treatment were performed using mostly rice seedlings. Pyruvate was substantialy accumulated in leaf tissues during the exposure period to of the seedlings ; the relative extent of the accumulation was increased with increasing time of the cold treatment. When the cold-treated plants were translocated to ambient temperature, the accumulation started to dissipate, concomitantly accompaning a remarkable increase in the level of tissues. Superoxide dismutase(SOD) and catalase were also activated during post-chilling period, although they showed a considerable lag time for activation. In contrast, glutathione peroxidase, another antioxygenic enzyme in cells, was not activated at all by preceding cold treatment of plants...
Journal of The Korean Society for Applied Biological Chemistry, 2005
Three antioxidants, Sa-1, Sa-2 and Sa-3, were isolated from the MeOH extract of the mushroom Sarc... more Three antioxidants, Sa-1, Sa-2 and Sa-3, were isolated from the MeOH extract of the mushroom Sarcodon aspratus through EtOAc extraction, silica gel and Sephadex LH-20 column chromatography, and HPLC. The structures of the compounds were determined mainly by NMR and mass spectroscopic data analyses. Sa-1, Sa-2 and Sa-3 were identified as diketopiperazines, and their structures were determined to be cyclo(prolyl-valyl), cyclo(prolyl-leucyl) and cyclo(prolyl-isoleucyl), respectively. This is the first time that these compounds were isolated from this mushroom. They showed antioxidant activity by scavenging DPPH radical and superoxide radical .
During the screening of herbicidal substances from microbial secondary metabolites using photoaut... more During the screening of herbicidal substances from microbial secondary metabolites using photoautotrophic cells, a strain of ME-13 with strong herbicidal activity was isolated from soil. Based on the taxonomic studies, the strain was identified as Streptomyces. Two active compounds were purified from the culture broth through the column chromatographies using active charcoal, silica gel, MCI gel, and ODS HPLC. The compounds were identified as AB3217-A and B, respectively, related to anisomycin by spectroscopic methods. AB3217-A and B completely suppressed the germination of radish and barnyard grass at 25 ppm. In comparison to anisomycin, they showed the 6 times higher inhibitory activities against the growth of shoot and root of radish and barnyard grass with EC5O of around 6 ppm.
To obtain a natural antioxidant from a marine biomass, this study investigated the antioxidative ... more To obtain a natural antioxidant from a marine biomass, this study investigated the antioxidative activity of methanolic extracts from the marine brown alga, Ishige okamurae collected off Jeju Island. A potent free radical scavenging activity was detected in the ethyl acetate fraction containing polyphenolic compounds, and the potent antioxidant elucidated as a kind of phlorotannin, diphlorethohydroxycarmalol, by NMR and mass spectroscopic data. The free radical scavenging activities of the diphlorethohydroxycarmalol were investigated in relation to 1,1-diphenyl-2-picrylhydrazyl (DPPH), alkyl, and hydroxyl radicals using an electron spin resonance (ESR) system. The diphlorethohydroxycarmalol was found to scavenge DPPH (IC50=3.41 microM) and alkyl (IC50=4.92 microM) radicals more effectively than the commercial antioxidant, ascorbic acid. Therefore, these results present diphlorethohydroxycarmalol as a new phlorotannin with a potent antioxidative activity that could be useful in cosme...
Three new chlorinated sesquiterpenes, named lepistatins A-C, were isolated from the culture broth... more Three new chlorinated sesquiterpenes, named lepistatins A-C, were isolated from the culture broth of Basidiomycete Lepista sordida. The structures were determined by the analysis of spectroscopic data including HREIMS and 1D and 2D NMR. The absolute configuration of lepistatin B was determined by comparing the specific rotation and circular dichroism spectrum with those of known structurally related compounds bearing the same chiral carbon. The structures of lepistatins A-C feature the indanone core structure, but differ from other indanone-containing sesquiterpenes of fungal origin by the alkyl substitution pattern. This indicates that lepistatins A-C probably possess a new sesquiterpene scaffold derived from the common precursor, trans-humulyl cation, by an alternative cyclization.
Three sesquiterpene ortho-naphthoquinones were isolated from the methanolic extract of root bark ... more Three sesquiterpene ortho-naphthoquinones were isolated from the methanolic extract of root bark of Ulmus davidiana Planch whose stem and root bark have been used as an oriental medicine for the treatment of edema, mastitis, gastric cancer and inflammation. The structures of these compounds were established on the basis of spectral data obtained from UV-vis, IR, HR-EIMS and NMR spectrometry, including the pulse field gradient (PFG)-HMQC and HMBC techniques. Their structures were determined as 2,3-dihydro-3,6,9-trimethylnaphtho(1,8-b,c)pyran-7,8-dione, 3,6,9-trimethylnaphtho(1,8-b,c)pyran-7,8-dione and 2,3-dihydro-4-hedroxy-3,6, 9-trimethylnaphtho(1,8-b,c)pyran-7,8-dione, which were identified as mansonones E. F and H, respectively. These compounds have originally been isolated from Mansonia altissima Chev, but have never been isolated from Ulmus davidiana Planch. Especially, mansonone H was isolated for the first time from Ulmaceae. The mismatched carbon chemical shifts of mansonone...
Structurally new antioxidative metabolite was isolated from mycelial culture of mushroom Stereum ... more Structurally new antioxidative metabolite was isolated from mycelial culture of mushroom Stereum hirsutum. Culture broth was subjected to Diaion HP-20 column chromatography, and 70% aqueous MeOH eluent was extracted with EtOAc. EtOAc extract was purified through silica gel and Sephadex LH-20 column chromatographies, and reversed phase C18 HPLC. Compound was revealed to be new dihydroxylated derivative of sterin B with molecular formula of C12H16O5 (MW 240) by MS and various NMR spectral data analyses, and designated as sterin C. Sterin C showed superoxide radical-scavenging activity with EC50 value of 0.31 mM.
The uptake of , a metal cofactor Mn-SOD, by rice seedings resulted in not only a substantial incr... more The uptake of , a metal cofactor Mn-SOD, by rice seedings resulted in not only a substantial increase in SOD activity in leaf tissues of the plants, but also a significant enhancement of their cold tolerance : the relative extent of the cold tolerance appeared to accord with relative level of the SOD activity. In contrast, and , which are the cofactors of Fe-SOD and Cu/Zn-SOD, were found to be ineffective for increasing the SOD activity as well as for improving the chilling-resistant capacity of the plants. The results suggest that Mn-SOD, which is most likely induced by its substrate(superoxide) and activated by the presence of a at high level, is the enzyme acting as an active component of the defense system against low temperature stress in rice plants. In addition, the application of abscisic acid which has been know to protect to some extent certain plants from chilling injury brought about an increase in SOD activity in rice tissues, providing another affirmative information f...
Two lipid peroxidation inhibitors, designated as betulinans A (1) and B (2), were isolated from t... more Two lipid peroxidation inhibitors, designated as betulinans A (1) and B (2), were isolated from the MeOH extract of Lenzites betulina. The structures of these compounds have been determined to be 2,5-diphenyl-3,6-dimethoxy-p-benzoquinone and 2-phenyl-3-methoxy-[1H-2-benzopyran][4,3-e][p]benzoquinone, respectively, on the basis of various spectral data. Betulinans A and B inhibited lipid peroxidation with IC50 values of 0.46 and 2.88 micrograms/mL, respectively.
Journal of Korean Society of Agricul Chem Biot, 1996
During the screening of herbicidal substances from microbial secondary metabolites using photoaut... more During the screening of herbicidal substances from microbial secondary metabolites using photoautotrophic cells, a strain of ME-13 with strong herbicidal activity was isolated from soil. Based on the taxonomic studies, the strain was identified as Streptomyces. Two active compounds were purified from the culture broth through the column chromatographies using active charcoal, silica gel, MCI gel, and ODS HPLC. The compounds were identified as AB3217-A and B, respectively, related to anisomycin by spectroscopic methods. AB3217-A and B completely suppressed the germination of radish and barnyard grass at 25 ppm. In comparison to anisomycin, they showed the 6 times higher inhibitory activities against the growth of shoot and root of radish and barnyard grass with EC5O of around 6 ppm.
Plant mitochondria, irradiated with blue-colored under aerobic and anaerobic conditions, were ass... more Plant mitochondria, irradiated with blue-colored under aerobic and anaerobic conditions, were assayed as to the electron transfer activity of respiratory enzyme system, and compared with those irradiated with orange-colored light(white sunlight minus blue-colored light). The respiratory activity of mitochondria was most seriousely inhibited by illumination with blue-colored light under aerobic condition. Deaeration of mitochondrial suspension resulted in substantial decrease of the photoinhibition by blue-colored light. Meanwhile, orange-colored light demonstrated much less effectiveness-almost ineffectiveness-in causing the inhibition of mitochondrial respiration system. The results of enzymatic assay revealed a strong possibility that FMN in NDH and heme group at least in cytochrome c oxidase, but not FAD in SDH, are the photodynamic sensitizers in mitochondrial inner membrane. Also worthwhile to note is the significant difference from the others of SDH in its photoinhibitory resp...
In an attempt to explore the mechanistic aspects of chilling injury in plants and their defensive... more In an attempt to explore the mechanistic aspects of chilling injury in plants and their defensive measures against the low temperature stress, the time sequential measurements of pyruvate, superoxide radicals and antioxygenic enzymes during whole period of injury-inducing treatment were performed using mostly rice seedlings. Pyruvate was substantialy accumulated in leaf tissues during the exposure period to of the seedlings ; the relative extent of the accumulation was increased with increasing time of the cold treatment. When the cold-treated plants were translocated to ambient temperature, the accumulation started to dissipate, concomitantly accompaning a remarkable increase in the level of tissues. Superoxide dismutase(SOD) and catalase were also activated during post-chilling period, although they showed a considerable lag time for activation. In contrast, glutathione peroxidase, another antioxygenic enzyme in cells, was not activated at all by preceding cold treatment of plants...
Journal of The Korean Society for Applied Biological Chemistry, 2005
Three antioxidants, Sa-1, Sa-2 and Sa-3, were isolated from the MeOH extract of the mushroom Sarc... more Three antioxidants, Sa-1, Sa-2 and Sa-3, were isolated from the MeOH extract of the mushroom Sarcodon aspratus through EtOAc extraction, silica gel and Sephadex LH-20 column chromatography, and HPLC. The structures of the compounds were determined mainly by NMR and mass spectroscopic data analyses. Sa-1, Sa-2 and Sa-3 were identified as diketopiperazines, and their structures were determined to be cyclo(prolyl-valyl), cyclo(prolyl-leucyl) and cyclo(prolyl-isoleucyl), respectively. This is the first time that these compounds were isolated from this mushroom. They showed antioxidant activity by scavenging DPPH radical and superoxide radical .
During the screening of herbicidal substances from microbial secondary metabolites using photoaut... more During the screening of herbicidal substances from microbial secondary metabolites using photoautotrophic cells, a strain of ME-13 with strong herbicidal activity was isolated from soil. Based on the taxonomic studies, the strain was identified as Streptomyces. Two active compounds were purified from the culture broth through the column chromatographies using active charcoal, silica gel, MCI gel, and ODS HPLC. The compounds were identified as AB3217-A and B, respectively, related to anisomycin by spectroscopic methods. AB3217-A and B completely suppressed the germination of radish and barnyard grass at 25 ppm. In comparison to anisomycin, they showed the 6 times higher inhibitory activities against the growth of shoot and root of radish and barnyard grass with EC5O of around 6 ppm.
To obtain a natural antioxidant from a marine biomass, this study investigated the antioxidative ... more To obtain a natural antioxidant from a marine biomass, this study investigated the antioxidative activity of methanolic extracts from the marine brown alga, Ishige okamurae collected off Jeju Island. A potent free radical scavenging activity was detected in the ethyl acetate fraction containing polyphenolic compounds, and the potent antioxidant elucidated as a kind of phlorotannin, diphlorethohydroxycarmalol, by NMR and mass spectroscopic data. The free radical scavenging activities of the diphlorethohydroxycarmalol were investigated in relation to 1,1-diphenyl-2-picrylhydrazyl (DPPH), alkyl, and hydroxyl radicals using an electron spin resonance (ESR) system. The diphlorethohydroxycarmalol was found to scavenge DPPH (IC50=3.41 microM) and alkyl (IC50=4.92 microM) radicals more effectively than the commercial antioxidant, ascorbic acid. Therefore, these results present diphlorethohydroxycarmalol as a new phlorotannin with a potent antioxidative activity that could be useful in cosme...
Three new chlorinated sesquiterpenes, named lepistatins A-C, were isolated from the culture broth... more Three new chlorinated sesquiterpenes, named lepistatins A-C, were isolated from the culture broth of Basidiomycete Lepista sordida. The structures were determined by the analysis of spectroscopic data including HREIMS and 1D and 2D NMR. The absolute configuration of lepistatin B was determined by comparing the specific rotation and circular dichroism spectrum with those of known structurally related compounds bearing the same chiral carbon. The structures of lepistatins A-C feature the indanone core structure, but differ from other indanone-containing sesquiterpenes of fungal origin by the alkyl substitution pattern. This indicates that lepistatins A-C probably possess a new sesquiterpene scaffold derived from the common precursor, trans-humulyl cation, by an alternative cyclization.
Three sesquiterpene ortho-naphthoquinones were isolated from the methanolic extract of root bark ... more Three sesquiterpene ortho-naphthoquinones were isolated from the methanolic extract of root bark of Ulmus davidiana Planch whose stem and root bark have been used as an oriental medicine for the treatment of edema, mastitis, gastric cancer and inflammation. The structures of these compounds were established on the basis of spectral data obtained from UV-vis, IR, HR-EIMS and NMR spectrometry, including the pulse field gradient (PFG)-HMQC and HMBC techniques. Their structures were determined as 2,3-dihydro-3,6,9-trimethylnaphtho(1,8-b,c)pyran-7,8-dione, 3,6,9-trimethylnaphtho(1,8-b,c)pyran-7,8-dione and 2,3-dihydro-4-hedroxy-3,6, 9-trimethylnaphtho(1,8-b,c)pyran-7,8-dione, which were identified as mansonones E. F and H, respectively. These compounds have originally been isolated from Mansonia altissima Chev, but have never been isolated from Ulmus davidiana Planch. Especially, mansonone H was isolated for the first time from Ulmaceae. The mismatched carbon chemical shifts of mansonone...
Structurally new antioxidative metabolite was isolated from mycelial culture of mushroom Stereum ... more Structurally new antioxidative metabolite was isolated from mycelial culture of mushroom Stereum hirsutum. Culture broth was subjected to Diaion HP-20 column chromatography, and 70% aqueous MeOH eluent was extracted with EtOAc. EtOAc extract was purified through silica gel and Sephadex LH-20 column chromatographies, and reversed phase C18 HPLC. Compound was revealed to be new dihydroxylated derivative of sterin B with molecular formula of C12H16O5 (MW 240) by MS and various NMR spectral data analyses, and designated as sterin C. Sterin C showed superoxide radical-scavenging activity with EC50 value of 0.31 mM.
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