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Nishiwaki H.,Ehime University | Hasebe A.,Ehime University | Kawaguchi Y.,Ehime University | Akamatsu M.,Kyoto University | And 3 more authors.
Bioscience, Biotechnology and Biochemistry | Year: 2011

The larvicidal activity against Culex pipiens of all stereoisomers of dihydroguaiaretic acid (DGA) and secoisolariciresinol was measured, and these DGAs were found to be potent. Sixteen (-)-DGA derivatives were then newly synthesized to analyze their structureactivity relationship. Two derivatives monohydroxylated at the 3- or 4-position of the 7-phenyl group of DGA induced acute paralytic activity in the mosquitoes. Derivatives with several hydroxyl groups had lower activity than the natural compound, suggesting that hydrophobicity was probably an important factor for their insecticidal activity.


Yamauchi S.,Ehime University | Yamauchi S.,South Ehime Fisheries Research Center | Isozaki Y.,Ehime University | Nishimura H.,Ehime University | And 3 more authors.
Bioscience, Biotechnology and Biochemistry | Year: 2012

Optically pure (+)- and (-)-boronolides were stereoselectively synthesized from yeast reductive products which had been obtained by yeast reduction of one common racemic substrate. The lactone structure of boronolide was constructed by Baeyer-Villiger oxidation. The stereochemistry of the yeast reduction products was studied to obtain the stereocenters at 5 positions of the dodecanolides of (+)- and (-)-boronolides. The stereochemistry of the 6 and 7 positions was obtained by AD-mix-α or β oxidation. The chiral center at the 8 position was constructed by employing (R)-(+)- or (S)-(-)-2-methyl-CBS- oxazaborolidine reduction or the Mitsunobu reaction. The plant growth-inhibitory activity against Echinochloa crusgalli L. of naturally occurring (+)-boronolide was higher than that of the (-)-boronolide.


Yamauchi S.,Ehime University | Yamauchi S.,South Ehime Fisheries Research Center | Nakayama K.,Ehime University | Nishiwaki H.,Ehime University | Shuto Y.,Ehime University
Bioorganic and Medicinal Chemistry Letters | Year: 2014

The synthesized 7-aryl derivatives of (7R,7′S,8S,8′S)-(+)-verrucosin were applied to growth inhibitory activity test against ryegrass at 1 mM. 7-(3-Ethoxy-4-hydroxyphenyl) derivative 12 and 7-(2-hydroxyphenyl) derivative 4 showed comparable activity to those of (+)-verrucosin against the root (-95%) and the shoot (-60%), respectively. The growth inhibitory activity test against lettuce using synthesized 7-aryl derivatives of (7S,7′R,8R,8′R)-(-)-verrucosin at 1 mM showed that the activities of 7-(3-hydroxyphenyl) derivative 20 and 7-(3-ethoxy-4-hydroxyphenyl) derivative 28 are similar to that of (-)-verrucosin against the root (-95%). Against the shoot, 7-(3-hydroxyphenyl) derivative 20 showed higher activity (-80%) than that of (-)-verrucosin (-60%). As the next step, (7S,7′R,8R,8′R)-7-(3-hydroxyphenyl)-7′-aryl-(-)-verrucosin derivatives, in which the most effective 3-hydroxyphenyl group is employed as 7-aromatic ring, were synthesized for the assay against lettuce. In this experiment, 7′-(2-hydroxyphenyl) derivative 37 and 7′-(3-hydroxyphenyl) derivative 38 showed similar activity to that of derivative 20. The effect of 7- and 7′-aryl structures of 7,7′-epoxylignanes on the plant growth inhibitory activity was clarified. The 7- and 7′-aryl structures were simplified to show comparable activity to or higher activity than that of (-)-verrucosin. The plant growth inhibitory activity of a nutmeg component, (+)-fragransin C3b, was estimated as -80% inhibition at 1 mM against ryegrass roots. © 2014 Elsevier Ltd. All rights reserved.


Yamauchi S.,Ehime University | Yamauchi S.,South Ehime Fisheries Research Center | Tomiyama C.,Ehime University | Wukirsari T.,Ehime University | Nishiwaki H.,Ehime University
Bioscience, Biotechnology and Biochemistry | Year: 2014

All the stereoisomers of butanol type 1,7-seco-2,7′-cyclolignane were stereoselectively synthesized by employing (S)- and (R)-Evans' auxiliaries to construct the stereochemistry. (+)- and (-)-Kadangustin J and their diastereomers were also prepared. The optical purity of the synthesized butanol type 1,7-seco-2,7′-cyclolignane was more than 99%ee. © 2014 Japan Society for Bioscience, Biotechnology, and Agrochemistry.


Wukirsari T.,Ehime University | Nishiwaki H.,Ehime University | Nishi K.,Ehime University | Sugahara T.,Ehime University | And 6 more authors.
Bioorganic and Medicinal Chemistry Letters | Year: 2014

All stereoisomers of methoxybutane and fluorobutane type of 1,7-seco-2,7′-cyclolignane were synthesized and cytotoxic activities of these compounds were compared with those of all stereoisomers of butane and butanol type compounds. Both enantiomers of butane type secocyclolignane showed higher cytotoxic activity (IC50 = 16-20 μM) than methoxy type compounds, whereas none was observed for all the stereoisomers of butanol type secocyclolignane, however, (-)-Kadangustin J showed stereospecific cytotoxic activity (IC50 = 47-67 μM). Since (R)-9′-fluoro derivative 23 was most potent (IC50 = 19 μM) among the corresponding fluoro stereoisomers, (R)-9′-alkyl derivatives were synthesized, hydrophobic 9′-heptyl derivative 27 showing highest activity (IC50 = 3.7 μM against HL-60, IC50 = 3.1 μM against HeLa) in this experiment. Apoptosis induction caused by Caspase 3 and 9 for (R)-9′-heptyl derivative 27 was observed in the research on the mechanism. A degradation of DNA into small fragments was also shown by DNA ladder assay. © 2014 Elsevier Ltd. All rights reserved.


Yamauchi S.,Ehime University | Yamauchi S.,South Ehime Fisheries Research Center | Kumamoto M.,Ehime University | Ochi Y.,Ehime University | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2013

The syntheses of 55 lariciresinol derivatives containing derivatives on the 9-position and an aryl group at both 7- and 7′-positions were successful to examine the effect of structure of (-)-lariciresinol (1) on plant growth regulatory activity. (-)-(7R,8R,8′S)-9-Dehydroxylariciresinol 9 showed activity 2-fold more potent than that of natural (-)-lariciresinol (1) and -95% growth inhibitory activity to negative control against rye grass root at 1 mM. The derivatives bearing hydrophobic and smaller groups at the 9-position showed higher activity. The importance of 4- and 4′-hydroxy groups and 3- and 3′-small hydrophobic groups on 7- and 7′-phenyl groups for higher activity was also suggested. © 2013 American Chemical Society.


Yamauchi S.,Ehime University | Yamauchi S.,South Ehime Fisheries Research Center | Kawahara S.,Ehime University | Wukirsari T.,Ehime University | And 7 more authors.
Bioorganic and Medicinal Chemistry Letters | Year: 2013

The cytotoxic activities of sesquilignans, (7S,8S,7′R,8′R)- and (7R,8R,7′S,8′S)-morinol A and (7S,8S,7′S,8′S)- and (7R,8R,7′R,8′R)-morinol B were compared, showing no significant difference between stereoisomers (IC50 = 24-35 μM). As a next stage, the effect of substituents at 7, 7′, and 7″-aromatic ring on the activity was evaluated to find out the higher activity of (7S,8S,7′R,8′R)-7,7′,7″-phenyl derivative 18 (IC 50 = 6-7 μM). In the research on the structure-activity relationship of 7″-position of (7S,8S,7′R,8′R)-7,7′, 7″-phenyl derivative 18, the most potent compounds were 7,7′,7″-phenyl derivative 18 (IC50 = 6 μM) against HeLa cells. Against HL-60 cells, 7″-(4-nitrophenyl)-7,7′-phenyl derivative 33 and 7″-hexyl-7,7′-phenyl derivative 37 (IC 50 = 5 μM) showed highest activity. We discovered the compounds showed four to sevenfold potent activity than that of natural (7S,8S,7′R,8′R)-morinol A. It was also confirmed that the 7′-benzylic hydroxy group have an important role for exhibiting activity, on the other hand, the resonance system of cinnamyl structure is not crucial for the potent activity. © 2013 Elsevier Ltd. All rights reserved.


Yamauchi S.,Ehime University | Yamauchi S.,South Ehime Fisheries Research Center | Ichikawa H.,Ehime University | Nishiwaki H.,Ehime University | Shuto Y.,Ehime University
Journal of Agricultural and Food Chemistry | Year: 2015

The plant growth regulatory activity of furofuran lignan (7,9′:7′,9-diepoxylignan) was evaluated by employing optically pure synthesized (+)- and (-)-enantiomers. (+)-Sesamin possessing a 3,4-methylenedioxy group on the aromatic rings and 7-aryl structure showed growth promotion activity against lettuce roots (EC50 = 0.50 mM); on the other hand, growth inhibitory activity was observed against lettuce shoots (EC50 = 0.38 mM). Against ryegrass shoots, (-)-sesamolin, which has 3,4-methylenedioxy groups on the aromatic rings and a 7-acetal structure, was effective in showing growth inhibitory activity (EC50 = 0.23 mM). Different activity levels were observed between (+)- and (-)-enantiomers. It was assumed that the 3,4-methylenedioxy group on the aromatic ring was more potent for the plant growth regulatory activity. © 2015 American Chemical Society.


Yamauchi S.,Ehime University | Yamauchi S.,South Ehime Fisheries Research Center | Nishimura H.,Ehime University | Nishiwaki H.,Ehime University
Bioscience, Biotechnology and Biochemistry | Year: 2015

Cryptocarya diacetate and each of its stereoisomers were stereoselectively synthesized in 8-16 steps. One of the three chiral carbons was converted from the chiral center of a yeast-reduction product. The other two chiral carbons were constructed by employing stereoselective allylation and syn-and anti-1,3-reductions. The enantiomeric excesses of the synthesized cryptocarya diacetate and its stereoisomers were determined to be more than 99%ee using a chiral column. © 2014 Japan Society for Bioscience Biotechnology and Agrochemistry.


Wukirsari T.,Ehime University | Nishiwaki H.,Ehime University | Nishi K.,Ehime University | Sugahara T.,Ehime University | And 6 more authors.
Journal of Agricultural and Food Chemistry | Year: 2014

Cytotoxic activities of synthesized lignan derivatives were estimated by WST-8 reduction assay against HL-60 and HeLa cells to show the structure-activity relationship. The activities of some effective compounds were examined against Colon 26 and Vero cells. Dietary secoisolariciresinol (SECO, 1) and its metabolite, 9,9′-anhydrosecoisolariciresinol (2), did not show the cytotoxic activity. On the other hand, all stereoisomers of dihydroguaiaretic acid (DGA, 9,9′-dehydroxysecoisolariciresinol, 3-5) exhibited the activity (IC50: around 30 μM). The IC50 value of (8R,8′R)-9-butyl DGA derivative 13 was around 6 μM. This fact means that the hydrophobic group was advantageous for higher activity at 9- and 9′-positions. By the evaluation of the effect of 7and 7′-aryl group on the activity, we discovered the highest activity of (8R,8′R)-7-(3- hydroxy-4-methoxyphenyl)-7′-(2-ethoxyphenyl) DGA derivative 47 showing around 1 μM of IC50 value, which is about 24-fold higher activity than that of natural (8R,8′R)-DGA. The derivative of dietary lignan showed the high cytotoxic activity. © 2014 American Chemical Society.

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