Stereoselective syntheses of cryptocarya diacetate and all its stereoisomers in optically pure forms

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.

Cytotoxic activity of butane type of 1,7-seco-2,7'-cyclolignanes and apoptosis induction by Caspase 9 and 3

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.

Syntheses of all the stereoisomers of butanol type 1,7-seco-2,7'-cyclolignane

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.

Cytotoxic activity of dietary lignan and its derivatives: structure-cytotoxic activity relationship of dihydroguaiaretic acid

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.

Antimicrobiological Activity of Lignan: Effect of Benzylic Oxygen and Stereochemistry of 2,3-Dibenzyl-4-butanolide and 3,4-Dibenzyltetrahydrofuran Lignans on Activity

The effect of oxidation degree at the benzylic position of 2,3-dibenzyl-4-butanolide and 3,4-dibenzyltetrahydrofuran lignans on the antimicrobiological activity was examined. The highest oxidation degree at the benzylic position of 2,3-dibenzyl-4-butanolide gave the greatest activity, and 3,4-dibenzoyltetrahydrofuran showed the highest antifungal activity. The relationship between stereochemistry and activity was also examined. Both enantiomers of cis-matairesinol were synthesized for the first time, one of the cis-matairesinols showing antibacterial activity.

Effect of the Benzylic Structure of Lignan on Antioxidant Activity

The effect of the benzylic structure of lignan on antioxidant activity was evaluated. Secoisolariciresinol (1) and 3,4-bis(4-hydroxy-3-methoxybenzyl)tetrahydrofuran (2), which have two secondary benzylic positions without oxygen, showed the highest antioxidant activity. Optically active verrucosin (4) was synthesized for the first time in this experiment.

Effect of Benzylic Oxygen on the Cytotoxic Activity for Colon 26 Cell Line of Phenolic Lignans

The cytotoxic activity for colon 26 cell line of matairesinol, oxidized matairesinol, 9,9'-epoxylignan and oxidized 9,9'-epoxylignan were examined. (-)-Matairesinol (Mat 1) showed greatest cytotoxic activity (LC(50)=9 microg/ml) of the lactone-type lignans. 7,7'-Oxomatairesinol having same steric configuration as that of (-)-matairesinol showed greater activity (LC(50)=25 microg/ml) than hydroxy or mono-oxomatairesinol. The activities of 9,9'-epoxylignan and 7,7'-oxo-9,9'-epoxylignan having same steric configurations as (-)-matairesinol were weaker than that of corresponding matairesinols. Different activity levels were observed between enantiomers.

Synthesis and Antioxidant Activity of Oxygenated Furofuran Lignans

Nine furofuran compounds having a different type of oxidation were synthesized from one common intermediate in a short series of steps, and the antioxidant activity was evaluated. It was found that the tertiary hydroxy group on the furofuran ring affected the degree of antioxidant activity and that the structure, except for the phenolic part, was important for the antioxidant activity.

Use of the Benzyl Mesylate for the Synthesis of Tetrahydrofuran Lignan: Syntheses of 7,8-trans, 7′,8′-trans, 7,7′-cis, and 8,8′-cis-Virgatusin Stereoisomers

The benzyl mesylate was employed to construct the tetrasubstituted tetrahydrofuran lignan with avoiding Friedel-Crafts type of reaction. The optically pure 7,8-trans, 7',8'-trans, 7,7'-cis, and 8,8'-cis-virgatusin stereoisomers were synthesized. The enantiomeric excess was >>99%.

Synthesis and Antioxidant Activity of Olivil-Type Lignans

Olivil-type lignans, an enantiomeric type of natural olivil, were synthesized for the first time to evaluate the relationship between the structure of olivil and its antioxidant activity. A comparison of the antioxidant activity with that of other synthesized tetrahydrofuran lignans indicated reduced activity with the tertiary hydroxy group. A different effect of the two phenolic groups of olivil on the antioxidant activity was also observed.

Synthesis of an Optically Pure Synthetic Intermediate of Aloperine from a Yeast-Reductive Product

Optically pure (S)- and (R)-vinylpiperidine 2 and (S)- and (R)-(hydroxyethyl)piperidine 3, which were key intermediates for the synthesis of aloperine, were synthesized from yeast-reductive products.

Immunostimulation Effect of Jellyfish Collagen

Certain edible large jellyfishes belonging to the order Rhizostomeae are consumed in large quantities in China and Japan. The exumbrella part of the edible jellyfish Stomolophus nomurai was cut and soaked in dilute hydrochloric acid solution (pH 3.0) for 12 h, and heated at 121 degrees C for 20 min. The immunostimulation effects of the jellyfish extract were examined. The jellyfish extract enhanced IgM production of human hybridoma HB4C5 cells 34-fold. IgM and IgG production of human peripheral blood lymphocytes (PBL) were also accelerated, 2.8- and 1.4-fold respectively. Moreover, production of interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha by human PBL was stimulated 100- and 17-fold respectively. Collagenase treatment inactivated the immunostimulation activity of the jellyfish extract. In addition, purified collagen from bovine Achilles' tendon accelerated IgM production of hybridoma cells. These facts mean that collagen has an immunostimulation effect, and that the active substance in jellyfish extract is collagen.

Synthesis of all stereoisomers of 3,3'-dimethoxy-7,7'-epoxylignane-4,4'-diol and their plant growth inhibitory activity

All stereoisomers of 3,3'-dimethoxy-7,7'-epoxylignane-4,4'-diol were synthesized to examine the effect of stereochemistry on their plant growth inhibitory activity using lettuce and Italian ryegrass. The effect of structural modifications such as dehydroxylation, methoxylation and hydroxylation at the 9- and 9'-positions of the lignans on the activity was also studied. Most of the epoxylignanes showed higher plant growth inhibitory potency against ryegrass than against lettuce, and the inhibitory activity varied depending on the configurations of each position of the tetrahydrofuran ring (7-, 7'-, 8-, and 8'-positions of the epoxylignanes). Among the 9,9'-position-modified derivatives, the dehydroxy derivatives showed the highest potency. These results suggested that the plant growth inhibitory activity should be influenced by the structure of the epoxylignanes.

Structure-plant growth inhibitory activity relationship of lariciresinol

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.

Quantitative structure-activity relationship analysis of antifungal (+)-dihydroguaiaretic acid using 7-phenyl derivatives

The relationship between antifungal activity against Alternaria alternata and structure on the 7-phenyl group of (+)-dihydroguaiaretic acid ((+)-DGA) was clarified by employing 38 synthesized (+)-DGA derivatives. The results were identified by quantitative structure-activity relationship (QSAR) analysis employing the Hansch-Fujita method. Some compounds showed higher activity than (+)-DGA. The compound showing highest activity was 3,5-difluorophenyl derivative 37. It was suggested that the small electron-withdrawing group at the meta-position of the 7-phenyl group is important for the higher activity by antifungal test and Hansch-Fujita analysis. The whitening activity of 3-hydroxy-4-methoxyphenyl derivative 28, 3-hydroxy-4-ethoxyphenyl derivative 29, and 3-hydroxy-4-isopropoxyphenyl derivative 30 against A. alternata Japanese pear pathotype was also discovered.

Structure-cytotoxic activity relationship of sesquilignan, morinol A

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 (IC50=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 (IC50=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.

First discovery of insecticidal activity of 9,9'-epoxylignane and dihydroguaiaretic acid against houseflies and the structure-activity relationship

The insecticidal activity of (-)-(8R,8'R)-3,3'-dimethoxy-9,9'-epoxylignane-4,4'-diol (1) against houseflies was clarified for the first time. The activities of other stereoisomers were weaker than that of the (8R,8'R)-stereoisomer. In the course of research into structure-activity relationships involving 30 newly synthesized (8R,8'R)-derivatives, 5-fold higher activity (ED50 = 0.91 nmol/fly) was observed for (-)-(8R,8'R)-3,3',4-trimethoxy-9,9'-epoxylignan-4'-ol (21) than for the naturally occurring compound (1). The activity of 1 was weaker than that of (-)-(8R,8'R)-dihydroguaiaretic acid ((-)-DGA) (4); however, compound 21 showed almost the same level of activity as 4.

Effect of polyphenols on oxymyoglobin oxidation: prooxidant activity of polyphenols in vitro and inhibition by amino acids

Effects of various plant phenolics, including polyphenols, on the oxidation of oxymyoglobin were investigated. Most phenolics promoted the oxidation of oxymyoglobin at both pH 5.4 and 7.4. Potent oxidation-promoting activity was observed by several efficient antioxidant polyphenols with a catechol moiety. Therefore, effects of the catechol structure were investigated using dihydrocaffeic acid analogues. The results clarified that ortho- or para-substituted diphenol structures were important for promoting the oxidation of oxymyoglobin. Inhibition of such prooxidant activity for oxymyoglobin by dihydrocaffeic acid was also investigated. Although the required concentration was relatively higher than that of dihydrocaffeic acid, several amino acids inhibited the oxidation. Among these, cysteine was the most potent. Although cysteine alone completely inhibited oxidation at a concentration above 1 mmol/L, 0.1 mmol/L cysteine showed oxidation-promoting activity. In the presence of 0.1 mmol/L dihydrocaffeic acid, in the range of 0.01 mmol/L to 1 mmol/L cysteine, 0.1 mmol/L cysteine showed the most efficient inhibition. These results suggest the possibility of the formation of some equimolar complexes of dihydrocaffeic acid and cysteine such as 5'-cysteinyl dihydrocaffeic acid, which may be produced during the prooxidation of dihydrocaffeic acid, contributing to the inhibition of the oxidation of oxymyoglobin.

Stereoselective syntheses of all stereoisomers of lariciresinol and their plant growth inhibitory activities

All stereoisomers of lariciresinol were synthesized to examine the effect of stereochemistry on plant growth. Configuration of benzylic 7-positions was constructed through S(N)1 or S(N)2 intramolecular etherification. 8- and 8'-position configurations were established from the starting material except for all cis stereoisomers, the 8-position configurations of which were achieved by employing stereoselective hydroboration. (-)-Lariciresinol and its 7S,8S,8'R stereoisomer inhibited the root growth of Italian ryegrass to 51-55% relative to the negative control, whereas other stereoisomers had less effect. These results demonstrate that the stereochemistry of lignans is one of the important factors influencing their inhibitory activity.

(-)-Secoisolariciresinol attenuates high-fat diet-induced obesity in C57BL/6 mice

Flaxseed lignan, secoisolariciresinol has been reported to possess health benefits. We previously synthesized each stereoisomer of secoisolariciresinol and found that (-)-secoisolariciresinol reduces lipid accumulation and induces adiponectin production in 3T3-L1 adipocytes. Here we show the effects of (-)-secoisolariciresinol on high-fat diet-induced obesity in C57BL/6 male mice. Oral administration of (-)-secoisolariciresinol for 28 consecutive days significantly suppressed the gain of body weight. Increased serum adiponectin level and decreased gene expression of fatty acid synthase and sterol regulatory element-binding protein-1c in liver, which are related to fatty acid synthesis, were observed in the mice orally administered with (-)-secoisolariciresinol. In addition, subcutaneous injection of (-)-secoisolariciresinol also significantly suppressed the gain of body weight. Serum leptin levels were significantly increased by treating with (-)-secoisolariciresinol or (-)-enterolactone. Subcutaneous injection of (-)-secoisolariciresinol, (-)-enterolactone, or (-)-enterodiol promoted gene expression of acyl-CoA oxidase, carnitine palmitoyl transferase-1, and peroxisome proliferator-activated receptor α, which are related to β-oxidation. Overall results suggest that (-)-secoisolariciresinol exerts a suppressive effect on the gain of body weight of mice fed a high-fat diet by inducing gene expression of adiponectin, resulting in the altered expression of various genes related to the synthesis and β-oxidation of fatty acids.