A brief introduction was given to the Eucommia ulmoides from the aspects of distribution, pharmaceutical values, and current situation regarding the utilization of E. ulmoides in China. Problems existed and suggestions were also put forward.

抄録全体を表示

The vascular effects of three extract preparations from Eucommia ulmoides Oliv., which is historically an active ingredient commonly used in antihypertensive herbal prescriptions in China, were investigated with isometric contraction using isolated rat aortic and dog carotid rings. Both aqueous extracts isolated from Eucommia leaf (L) and bark (B) concentration dependently caused endothelium-dependent relaxation in vessels precontracted with 1 μM phenylephrine (PE), but the methanol extract of the leaf (M) had no effect. Vessels precontracted with KCl and de-endothelialized vessels pre-contracted with PE were not affected by B or L. The endothelium-dependent relaxation evoked by B and L was either abolished or substantially inhibited by N^G-nitro-L-arginine methyl ester (L-NAME) and methylene blue (MB), indicating the involvement of the nitric oxide (NO) synthase pathway in the vasorelaxant action of B and L. The relaxation to the aqueous extract of Eucommia bark was not inhibited with 1 μM atropine, but was inhibited by 3-5 mM tetraethylammonium (TEA) and 3 mM 4-aminopyridine. This suggests that the endothelium-dependent, NO-mediated relaxation evoked by the aqueous Eucommia extracts was not mediated via the activation of endothelium muscarinic receptors and may involve the activation of K⁺ -channels. In smaller muscular artery, like rat mesenteric artery, the action of Eucommia extract also involves endothelium derived hyperpolarizing factor in addition to NO. Endothelium-dependent relaxation elicited by Eucommia extract also occur in dog carotid artery. This vasodilatory action of E. ulmoides Oliv. provides a pharmacological basis for its well-documented antihypertensive action.

抄録全体を表示

This paper briefly discusses the current status of the studies and utilization of Eucommia ulmoides Oliv. as feed additives for animals in China. It comprises the following 3 parts:
1. Studies on the nutritional and medicinal components in the leaves and seeds of E. ulmoides trees.
2. Studies on the effects of the use of E. ulmoides leaves or their extracts as supplementary feed additives on the health and performance of laying hens and broilers. The efficacy of the extracts obtained from E. ulmoides leaves with regard to inhibiting fungal growth in animal feeds is also discussed in this part.
3. Analysis of the market for E. ulmoides as feed additives, and studying or solving current and potential problems.

抄録全体を表示

Eucommia bark contains lignans such as (+)-pinoresinol, (+)-1-hydroxypinoresinol, (+)-medioresinol, (+)-syringaresinol and (-)-olivil, and their glucosides. Each lignan was metabolized to enterodiol and enterolactone by human and rat intestinal bacteria. The structures of intermediate metabolites were elucidated and metabolic pathway was proposed. Each (-)-olivil and (+)-1-hydroxypinoresinol was converted to (-)-carinol, which to a new compound, (-)-2-hydroxyenterodiol, and successively to (-)-enterolactone by human intestinal bacteria. Oral administration of pinoresinol diglucoside in ovariectomized rats inhibited increase of body weight due to ovariectomy and exhibited a tendency to increase of uterine weight.

抄録全体を表示

The materials engineering of Eucommia ulmoides gum (EU gum) and the development of its new products are briefly described. This is followed by introduction of the development of low molecular weight EU gum and EU resin, the damping properties of rubbers blended with EU gum, and the dynamic mechanical properties of PBA/PS binary- and EU gum/PBA/PS-ternary-interpenetrating polymer networks. Finally, their prospective applications are discussed.

抄録全体を表示

Methods: The amounts of eucommiol and aucubin in the leaves and barks of Eucommia ulmoides were detected by HPLC.
Results: (1) The amount of eucommiol in E. ulmoides leaves peaked in mid-September (1.450%); the amount was lowest in May (0.133%). (2) Changes in the amounts of eucommiol and aucubin in the cortexes of E. ulmoides were determined. (3) A possible biotransformation pathway that converts aucubin to eucommiol in the leaves and barks of E. ulmoides was suggested.

抄録全体を表示

A simple and rapid analytical method of the three iridoids compounds, geniposidic acid (GPA), geniposide (GP) and aucubin (AU), which are naturally occurring bioactives were determined in Eucommia samples simultaneously by isocratic reverse phase high performance liquid chromatograph (RP-HPLC) using UV detection. All of these iridoids were identified with standard samples. A C₁₈ column was used as the stationary phase, and the mobile phase was methanol-water-acetic acid=24.5:75:0.5 (V/V/V) at the flow rate of 1ml · min^-1. The detection wavelength was set at 220 nm, and the column temperature was 25 °C. Three calibration curves were obtained, and the mean recoveries of GPA, GP and AU were 99.10%, 98.06% and 96.07% respectively.

抄録全体を表示

The hypotensive effects and safety aspect of beverages containing Eucommia leaf glycosides were examined in a randomized double-blind, placebo-controlled, parallel group study. The subjects were high normotensive and mild hypertensive adult male and female subjects. Test or placebo meals were given one time per a day for 12 weeks.
The results revealed that the systolic blood pressure (SBP) was significantly reduced after 4 weeks of intake in the test-meal group. The diastolic blood pressure (DBP) was also significantly reduced after 6 weeks of intake. In contrast, no changes in blood pressure were observed during the trial in the placebo group. Between the two groups, there was a significant difference in SBP at 8, 10, and 12 weeks and in DBP at 10 and 12 weeks. No significant abnormal changes were observed in the results of blood examination, urinalysis, and physical examination. Additionally, clinically relevant adverse effects such as digestive tract symptoms, dry cough, or allergic phenomena were not observed in association with test-meal intake. Thus, these results demonstrated the benefits and safety of beverages containing Eucommia leaf glycosides in high normotensive and mild hypertensive subjects.

抄録全体を表示

The antihypertensive effects of the Eucommia ulmoides leaf extract (ELE) and its methanol-eluted fraction (MeOH ext, Eucommia leaf (EL) glycoside) and water-eluted fraction (H₂O ext), fractionated using a Diaion HP-20 column, were studied in spontaneously hypertensive rats (SHR) by intravenous (i.v.) administration. Additionally, to clarify the oral antihypertensive effect, a single oral (p.o.) administration of ELE, MeOH ext, and H₂O ext as well as geniposidic acid (GA) and chlorogenic acid (CA)—the major component of the ELE and MeOH ext—were performed in SHR. The i.v. administration of the ELE and MeOH ext showed significant transient antihypertensive effects, which were attenuated with atropine pretreatment in SHR, implying that the effect was mediated via an agonistic action on the muscarinic acetylcholine receptors. In a similar manner, p.o. administration of both ELE and MeOH ext showed significant antihypertensive effects. Although both the components also showed antihypertensive effects, the effect of GA was more potent than that of CA. On the other hand, the H₂O ext showed a persistent antihypertensive effect with i.v. administration, which remained unaffected on atropine pretreatment, although such an effect was not observed with p.o. administration. The findings mentioned above imply that the MeOH ext (EL glycoside) contributes to the ELE-induced antihypertensive effect, with GA contributing more to the effect than CA.

抄録全体を表示

In this paper, we have examined the anti-obesity effects of Eucommia ulmoides leaves in rats and mice.
A high fat diet was orally administered to rats. In addition to this diet, a water solution of E. ulmoides leaf extract was administered. After 60 min, the levels of serum triglyceride decreased significantly in the 400 mg/kg E. ulmoides leaf extract group as compared with that in the high-fat diet group.
A diet of 40% beef tallow was fed to rats. These rats were divided into three groups; the E. ulmoides leaf extract powder (E-EP) group received 10% E-EP, the E. ulmoides leaf green powder (E-GP) group received 10% E-GP and the E. ulmoides leaf powder (E-LP) received 10% E-LP in addition to the beef tallow. Food and water were fed ad libitum. After 4 weeks, the body weight, visceral fat, and serum of triglyceride levels of the E-E and E-L groups were significantly lower than those of rats in the 40% beef tallow group.

抄録全体を表示

The aim of this study is to investigate the pharmacological effect of Eucommia ulmoides Oliv. and its components as prophylactics against restraint stress in water (RSW)-induced gastric erosion. In the test, an extract of E. ulmoides bark prepared using hot water was dissolved in water and used to assay its protective effect against gastric erosion in rats exposed to RSW for 7 h. Oral administration of the E. ulmoides extract (500 mg/kg per day) dissolved in 1 ml distilled water demonstrated a 44.9% protective effect against RSW-induced gastric erosion. The protective effect observed following the oral administration of the extract (50 and 500 mg/kg per day) for 2 weeks was dose-dependent. Oral administration of a 500 mg/kg dose of E. ulmoides extract increased the circulating prolactin (PRL) level and the expression level of the hypothalamic PRL receptor long form (PRLR(L)) mRNA in rats. Chlorogenic acid (CHA, 30 mg/kg per day) and geniposidic acid (GEA, 30 mg/kg per day), the major components of the E. ulmoides extract, showed a significant inhibitory effect on gastric erosion (20.9% and 21.8%, respectively) and an increase in the circulating PRL level and the expression level of the receptor mRNA in the hypothalamus. We showed that the protective effect of the E. ulmoides extract against gastric erosion may be partially due to the effects of CHA and GEA. E. ulmoides extract and its components enhance the circulating PRL level and stimulate hypothalamic PRLR(L) to produce an anti-stress effect. These results suggest that the PRLR(L)-driven actions in the hypothalamus that are induced by E. ulmoides extract and its components are important for coping with acute stress.

抄録全体を表示

Eucommia ulmiodes Oliv. calli were induced on an MS medium supplemented with 2.0 mg l^-1 2,4-dichlorophenoxy acetic acid (2,4-D), and a good suspension was obtained in a liquid medium after 3 rounds of subculturing. The suspension cells were transformed by particle bombardment using the pBY520 plasmid containing the late embryogenesis abundant protein gene from barley (Hordeum vulgare L.), namely, the LEA3 gene. After 4 rounds of selection culturing on a medium containing phosphinothricin, 338 resistant calli were obtained.

抄録全体を表示

A rapid and efficient method for the regeneration of Eucommia ulmoides Oliver, a rare Tertiary species surviving only in China, has been developed. Hypocotyl segments exscinded from 2 -week-old seedlings were chosen as explants. Multiple shoot buds were more significantly induced on medium containing MS basal medium supplemented with 10 μM BAP alone than on other media. The addition of NAA resulted in callus enlargement, but it did not promote the production of multiple shoot buds. However, the adventitious shoots became cirrhotic and stunted after subculturing on an identical medium supplemented with BAP alone. It was found that the addition of 10 μM GA3 to the medium was the most suitable for the stimulation of shoot elongation and further growth. Shoots longer than 2 cm cultured on the medium supplemented with 0.5 μM NAA and 0.1 μM ABA were highly responsive and produced the maximum number of roots per shoot. Regenerated plantlets with expanded leaves and well-developed roots could be successfully transferred to a pot containing vermiculite for acclimatization and then to a greenhouse. The regeneration protocol developed in this study provides the basis for E. ulmoides germplasm conservation, rapid propagation, and further genetic alteration for medicinal compound and EU-rubber production.

抄録全体を表示

Antimicrobial peptides can inhibit the growth of bacteria, fungi, plant pathogens, and even viruses. They have potent pharmaceutical effects. Plant antimicrobial peptides may be the new source of antibiotics. The bark of Eucommia ulmoides Oliv. is used in traditional Chinese medicine. The Eucommia antifungal peptide, termed EAFP, was isolated using a procedure involving 0.5 M NaCl extraction and gel filtration chromatography on a Sephadex G-50 column. SDS-PAGE revealed that the molecular weight of the EAFP was 4.2 kDa, and its partial amino acid sequence is PCNAGLCCSIYGYCGSGNAYCGAGNCR; this was determined by high performance liquid chromatography coupled with mass spectrometry (LC/MS). The EAFP exerted an inhibitory effect against Candida albicans in vitro, and its minimal inhibitory concentration (MIC) was 156 μg/ml. The research results suggest that the EAFP may be used as a novel antibiotic drug of plant origin for the prevention of candidiasis.

抄録全体を表示

By using the tissue isolation method, a total of 80 endophytic fungal strains were isolated from the roots, stems, and leaves of Eucommia ulmoides. Of these, 72 strains that belonged to 13 genera were identified based on their morphological characteristics. The results showed that the Alternaria, Fusarium, and Phoma spp. are the dominant endophytic fungal population found on E. ulmoides, and they comprise 52.78% of the 72 strains. Roots are the most preferred location for most endophytic fungal strains.

抄録全体を表示

Eucommia ulmoides Oliver is a tree indigenous to China. E. ulmoides rubber (EU rubber) is a type of white filamentous natural polymer occurring in the bark, seed coat, and leaf of the plant. In order to increase EU rubber production, the mechanisms of its synthesis and accumulation were studied. The results are as follows. The network structure of the rubber filament coincides with that of the leaf veins, the length and density of the rubber-bearing cells are in significant positive correlation with the rubber content in the leaf (leaf area, however, is in significant negative correlation with the length and density of the rubber-bearing cells and rubber content in the leaf), the absolute content of the rubber in a leaf is the highest when the leaves mature completely (May to June), and the rubber content in different organs of the plant is in the following decreasing order: seed coat > bark > leaf. Therefore, choosing an appropriate period (June) to collect the leaves, selecting and breeding varieties with small leaf area, and using seeds comprehensively are biological approaches to increase EU rubber production.

抄録全体を表示

We attempted to elucidate the biosynthetic mechanism for trans-polyisoprene and create a transgenic plant with enhanced rubber content. For this, it was important to collect various cultivars having different varieties of trans-polyisoprene. We investigated the trans-polyisoprene content and molecular-weight distribution based on biomass and bark appearance in 24 cultivars collected from the Shaanxi, Hunan, Guizhou, and Sichuan provinces of China. These cultivars were planted in Northwest Agriculture & Forest University in China. The leaves of the 24 cultivars were harvested in Oct. 2004. In conclusion, the average trans-polyisoprene content in the 24 cultivars was approximately 3%-4%; the highest content was over 6%, and the lowest content was below 2%. The molecular-weight distribution showed a bimodal distribution.

抄録全体を表示

In order to develop an efficient method for the evaluation of the trans-polyisoprene gene functions at the early stage of transgenic plant growth, in this study, we established a rapid root culture system from plantlets and estimated the quantity of EU rubber from cultured roots under different culture conditions. The results revealed that there was no significant difference between the root cultures grown under a photoperiod (16-h light and 8-h dark/day) and those grown under dark conditions with regard to polyisoprene content and molecular weight distribution. It is clear that the production of polyisoprene is not influenced by the light conditions under which the E. ulmoides root culture is grown. Thus, the root culture system can be used to evaluate polyisoprene biosynthesis and its quality in transgenic plants under different conditions.

抄録全体を表示

The use of monolithic silica gel columns for the analysis of natural polyprenols have been described. Separation of natural polyprenols by high-performance liquid chromatography (HPLC) using the Chromolith Performance octadecylsilyl (ODS) monolithic silica column (Merck) was compared with that using a conventional microparticulate ODS-bonded silica column. A system comprising two connected monolithic columns afforded an equivalent separation at half the analysis time of the conventional method. Furthermore, ten connected columns achieved a tremendously high-resolution separation; complicated series of homologous polyprenols having geometric isomers were separated completely. Additionally, we attempted the analysis of naturally occurring polyprenols and dolichols using a monolithic silica capillary column for HPLC. First, separation of the polyprenol mixture alone was performed using a 250 × 0.2 mm i.d. ODS-monolith silica capillary column. The separation resolution (R_S) between octadecaprenol (prenol 18) and nonadecaprenol (prenol 19) was two time or more higher than that recorded when a conventional ODS-silica particle-packed column (250 × 4.6 mm i.d.) was used under identical elution conditions. Next, a mixture of the prenol type (polyprenol) and dolichol type (dihydropolyprenol) was subjected to analysis using this capillary HPLC system, and each homologue was separated successfully. During analysis of the polyprenol fraction derived from Eucommia ulmoides leaves, in addition to the all-trans-polyprenol and cis-polyprenol that were previously identified, dolichols were observed as a single peak. This high-resolution and sensitive system is very useful for the analysis of compounds that are structurally similar to polyprenols and dolichols and have small amounts of these alcohols.

抄録全体を表示

The use of supercritical fluid chromatography (SFC) for the analysis of plant polyprenols has been described. Compared with conventional high-performance liquid chromatography, the use of SFC markedly improved the chromatographic resolution of polyprenol homologues and their geometric isomers. Under optimized SFC conditions, individual homologues from 10 to 100 mers were separated. It was also possible to isolate each geometric isomer of polyprenol homologues from 13 to 20 mers by fractionation by using SFC. The chain-length distributions of polyprenol samples determined by SFC essentially agreed with those determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. SFC analysis of the polyprenols extracted from the leaf, root, and seed coat of the rubber-producing plant Eucommia ulmoides revealed the presence of all trans polyprenols with degrees of polymerizations greater than 10 for the first time in nature. The all trans polyprenols had broad distributions of chain-length leading to high molecular weight; this suggests that the polyprenols act as biosynthetic intermediates for the high molecular weight trans-1,4-polyisoprene in this plant. The chain-length distributions of the trans polyprenols from the leaf, root, and seed coat differed from each other, suggesting the presence of site-specific control mechanisms for chain termination. On the other hand, cis polyprenols have been found to occur in all parts of E. ulmoides. They had narrow chain-length distributions similar to those of dolichols.

抄録全体を表示

The localization of polyisoprene in the young stem tissues of Eucommia ulmoides was investigated by histochemical staining and Fourier transform infrared microspectroscopy (FT-IR). The fibrous structures were stained using Oil Red O. FT-IR microspectroscopy analysis proved that the fibrous structures were indeed trans-polyisoprene. The presence of granular structures clearly stained by the dye and having a characteristic absorption at 2960 cm-¹ in the FT-IR analysis suggested that trans-polyisoprene accumulated in the vicinity of the cambium layer. We have successfully demonstrated the localization of trans-polyisoprene in plant tissues for the first time, and our histological investigation has allowed us to deduce the main sites of biosynthesis and rubber accumulation.

抄録全体を表示

We studied the induction of polyploid in Eucommia ulmoides, which produces trans-polyisoprene (EU rubber), and compared its hydrophilic low molecular metabolites and EU rubber contents with diploid. Seeds were submerged in 0.05% colchicine solution for 72 h. Ploidy levels were investigated by flow cytometry measurement and Giemsa staining. As a result, 15 tetraploids and 3 chimeras were selected from 144 seedlings. The characteristic morphological features of the tetraploid leaves were round shape, deep dentation, and dark green color. The hydrophilic low molecular metabolites in the leaves of the diploids and tetraploids were analyzed by gas chromatography-mass spectrometry (GC/MS). During principal component analysis (PCA) of the GC/MS data, the leaves were separated into two groups, and we concluded that some metabolites had changed due to chromosome doubling. However, there were no significant differences with regard to the content and molecular weight distribution of EU rubber.

抄録全体を表示

The damping properties of Eucommia ulmoides gum (EU gum) and its rubber blends were systematically studied using hysteresis loss ratio and dynamic mechanical tests. The former method indicates that the hysteresis loss ratio of EU gum is much higher than that of other rubbers. Because the residual deformation of EU gum is very large, it cannot be directly used as an elastic damping material; it can only be used as a modifier of other rubbers to obtain elastic damping materials. The results show that EU gum can increase the hysteresis loss ratio of a number of rubbers. The latter method shows that EU gum can also increase E'' (loss modulus) of blended rubber; this is consistent with the results of the former method. A blend of EU gum/Nitrile -Butadiene rubber (NBR) is the best elastic damping material with the largest hysteresis loss ratio, E'', and low residual deformation (less than 20%). The contribution of EU gum to the damping property of blended rubber might be associated with the influence of the crystallinity of EU gum.

抄録全体を表示

This work describes a series of novel Eucommia ulmoides gum (EUG)-based damping materials with excellent damping properties by using the interpenetrating polymer network (IPN) method for the first time; this is an innovative application of EUG. The novel core-shell structure of an EUG-based multicomponent latex interpenetrating polymer network (LIPN) can be controlled by selecting a suitable initiator system, emulsification method, and polymeric sequence and by regulating the miscibility among the components. The damping properties and morphology of multicomponent LIPNs were investigated by dynamic mechanical analysis (DMA) and transmission electron microscope (TEM) in order to reveal the relationship between structure and performance. The results show that some LIPNs that use EUG as the seed in the multicomponent core-shell structure have a high damping factor (tanδ) at a broader temperature range. For example, the EUG/PS/PBA LIPN (1/1/1 by weight) possesses excellent damping properties; its temperature range for tanδ>0.3 extends to almost 130°C. EUG-based LIPNs, particularly the trinary EUG-based LIPNs are novel damping materials with good potential for development.

抄録全体を表示

In the present paper, we studied the mechanical modification caused by the mixing of Eucommia ulmoides resin (EU resin) into three general rubbers (BR, SBR and NR) and found that while EU resin can improve the mechanical properties of SBR and BR; it has no effect on those of NR. By measuring the torque during the mixing process, we found that EU resin can improve the processing properties of the three general rubbers and decrease their energy cost. Plastification of EU resin occurs due to its high aliphatic oil content and EU resin reinforcement may be relative to the amount of EU resin still contains some short chain E. ulmoides gum (EUG).

抄録全体を表示