[Quantitative determination of aucubin in Eucommiaceae].
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Eucommiaceae↗
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A new monoterpene from the bark of Eucommia ulmoides.
A new monoterpene, eucommidiol (1), was isolated from the bark of Eucommia ulmoides Oliv. (Eucommiaceae), together with a known compound 1,4a,5,7a-tetrahydro-7-hydroxymethyl-cyclopenta[c]pyran-4-carboxylic methyl ester. The structure of 1 was characterized as 6,6a-di(hydroxymethyl)-3,3a,4,6a-tetrahydro-2H-cyclopenta[b]furan-2-one on the basis of chemical and spectral evidence including 2DNMR studies.
Eucommiaceae↗
Relationship between endogenous indole-3-acetic acid and abscisic acid changes and bark recovery in Eucommia ulmoides Oliv. after girdling.
Eucommia ulmoides (Eucommiaceae), a traditional Chinese medicinal plant, is often subjected to severe manual peeling of its bark. If the girdled trunk is well protected from desiccation, new bark forms within 1 month. It has been proposed that phytohormones play a key role in this process. Research has been conducted to determine the distribution of endogenous indole-3-acetic acid (IAA) and abscisic acid (ABA) during the bark recovery, using high-performance liquid-chromatography (HPLC) and fluoro-immuno-localization techniques. Results showed that, from 2 d after girdling, the IAA content in the recovering bark (RB) increased markedly while that of ABA decreased. The opposite pattern was observed during progressive re-establishment of the tissues. Immuno-localization showed that most of the IAA was located in the RB tissue layers undergoing cell division, dedifferentiation and (re)differentiation, such as xylary rays, immature xylem, phellogen and cambial regions. This study also provides evidence that IAA and ABA are involved in the bark reconstitution.
Abscisic Acid↗
Constituents and pharmacological effects of Eucommia and Siberian ginseng.
The bark and leaves of Eucommia ulmoides Oliv (Eucommiaceae) and "Siberian ginseng" (Ezoukogi in Japanese) prepared from the root bark or stem bark of Eleutherococcus senticosus Maxim (Acanthopanax senticosus Harms) have been used as tonic and anti-stress drug. The extracts of Eucommia showed anti-hypertensive, anti-complementary, anti-oxidative, and anti-gastric ulcer effects, and promoting collagen synthesis, accelating granuloma formation, and other pharmacological effects. The Siberian ginseng exhibited anti-fatigue, anti-stress, immuno-enhancing effect, CNS activity, and anti-depressive effect. By now, 40, 28, and 10 compounds have been isolated from Eucommia ulmoides bark, Eucommia ulmoides leaves, and Siberian ginseng, respectively, and their structures were elucidated. Their pharmacological activities were mainly due to lignans and iridoid glycosides.
Adjuvants, Immunologic↗
The promoting effects of geniposidic acid and aucubin in Eucommia ulmoides Oliver leaves on collagen synthesis.
We have reported that collagen synthesis was stimulated by the administration of a hot water extract from the leaves of Eucommia ulmoides OLIVER, Eucommiaceae (Du-Zhong leaves) in false aged model rats. In this paper, we set out to examine the compounds in Du-Zhong leaves that stimulated collagen synthesis in false aged model rats. In experiment 1, a methanol extract of Du-Zhong leaves also stimulated collagen synthesis in aged model rats. An acetone fraction was derived from the methanol extract by silica gel chromatography in experiment 2. The acetone fraction mainly contained iridoides mono-glycosides such as geniposidic acid and aucubin. The administration of geniposidic acid or aucubin stimulated collagen synthesis in aged model rats in experiments 3 and 4 (significance (p<0.05)). The reported pharmacological effects of Du-Zhong leaves, including healing organs and strengthening bone and muscle, are closely related to collagen metabolism. It appears that geniposidic acid and aucubin are the actual compounds in Du-Zhong which caused the effect in our experiments.
Aging↗
Isolation and identification of alpha-glucosidase inhibitors from tochu-cha (Eucommia ulmoides).
alpha-Glucosidase inhibitory activity was found in aqueous methanol extracts of tochu-cha, dried leaves of Eucommia ulmoides (Eucommiaceae). Five active principles against yeast enzyme were isolated and characterized. Among them, quercetin (1, Ki: 8.5 x 10(-6) M) was considered to contribute mostly to the activity of the tochu leaves. In regard to an animal alpha-glucosidase, rat intestinal sucrase activity was also inhibited by 1.
Animals↗
Solvent effects on focused microwave assisted extraction of polyphenolic acids from Eucommia ulmodies.
An open microwave-assisted extraction system was used to extract gallic acid, protocatechuic acid, chlorogenic acid and caffeic acid from Eucommia ulmodies. The effect of extraction variables, especially solvent, on the recoveries of these polyphenolic compounds was investigated using factorial design. As extracting solvent for these compounds, methanol produced a higher recovery than pure water. For straight chain alcohol solvents, the lower the carbon number, the higher the recoveries of the polyphenolic acids. The optimal ratio of methanol:water:glacial acetic acid in the solvent mixture used in microwave-assisted extraction was 2:8:0.3 (v/v) and this solvent could be directly used as the mobile phase in HPLC separation without additional intermittent treatment as reported in literature. The extraction under the condition of 50% microwave power and 30 s irradiation at a solvent:sample ratio of 10 (mL/g) was found to be the most advantageous. The repeatability test of extraction and chromatographic analysis was satisfactory for the analysis of these polyphenolic compounds.
Chemistry Techniques, Analytical↗
Inhibitory effect of Eucommia ulmoides Oliv. on oxidative DNA damage in lymphocytes induced by H2O2.
This study used the alkaline single cell gel electrophoresis assay (comet assay) to investigate the effect of water extracts of roasted cortex and leaves from Du-zhong on DNA damage in lymphocytes induced by H(2)O(2). The results showed that the DNA damage in human lymphocytes increased with an increase in the concentration of H(2)O(2) (0-200 micro;M), but that the water extracts from Du-zhong (0-2 g l(-1)) only slightly affected DNA damage. The inhibitory effect of leaf extract on DNA damage induced by H(2)O(2) in lymphocytes was more significant (P<0.05) than that of roasted cortex. Leaf extract showed a rather significant inhibitory effect in a concentration-dependent manner. At a concentration of 2 g l(-1), the leaf extract inhibited 37.9% DNA oxidative damage in human lymphocytes. In order to elucidate the mechanism of the leaf extract suppression effect on DNA damage induced by H(2)O(2) in lymphocytes, an experiment was divided with six groups (A-F). Group A was used to evaluate the repair ability of the leaf extract for DNA damage; Group B was employed to determine the scavenging ability on H(2)O(2); and Group C was studied to assess the ability of leaf extract to increase the defense capability. Groups D-F were negative controls and blank. The results showed that group B had the best inhibitory effect. Also, leaf extract had significant ability to scavenge H(2)O(2) in an in vitro HRP-phenol red test. Thus, it appears that H(2)O(2) scavenging potency may be the major mechanism whereby leaf extract inhibits oxidative DNA damage induced by H(2)O(2).
Comet Assay↗
Effects of Eucommiae Cortex on osteoblast-like cell proliferation and osteoclast inhibition.
Methanol extract (MeOH), n-hexane (Hx), chloroform (CHCl3), ethyl acetate (EA), butanol (BuOH) and aqueous (H2O) fractions of Eucommiae Cortex including geniposidic acid (GA), geniposide (GP) and aucubin (AU) were tested for their therapeutic efficacy on osteoporosis. The contents of GA, GP and AU in the cortex and leaf of Eucommia ulmoides Oliver were quantified by HPLC. The effect of Eucommiae Cortex on the induction of growth hormone (GH) release was studied by using rat pituitary cells. The proliferation of osteoblast-like cells increased by herbal extracts was assayed using a tetrazolium (MTT), alkaline phosphatase (ALP) activity, and [3H]-proline incorporation assays. The inhibition of osteoclast was studied by using the coculture of mouse bone marrow cells and ST-2 cells. As a result, the GA, GP and AU were present in the cortex more than in the leaf of E. ulmoides Oliver. The MeOH (1 mg/mL), Hx, CHCl3 and EA fractions (each 20 microg/mL) had potent induction of GH release. The CHCl3 exhibited the potent proliferation of osteoblasts. The AU, GP and GA were increased proliferation of osteoblasts. In addition, GA (IC50: 4.43 x 10(-7) M), AU and GP were significantly inhibited proliferation of osteoclast. In summary, it is thought that the components in a part of the fractions of Eucommiae Cortex participate in each step of mechanism for activating osteoblast to facilitate osteogenesis, and suppress osteoclast activity to inhibit osteolysis.
Animals↗
Endothelium-dependent vascular relaxation induced by Eucommia ulmoides Oliv. bark extract is mediated by NO and EDHF in small vessels.
The vasorelaxant effects of the aqueous extract prepared from the bark of the Chinese medicinal herb, Eucommia ulmoides Oliv. (also referred to as Tu-Chung or Du-Zhong), which is a common active ingredient in traditional antihypertensive herbal prescriptions in China, have recently been characterized in rat aorta and dog carotid artery. The vasorelaxant effect of eucommia bark extract on these large elastic arteries was found to be entirely endothelium-dependent and nitric oxide (NO)-mediated. Since smaller muscular arteries play a more dominant role in the change of peripheral resistance and thus the regulation of blood pressure, we have now compared the relaxant effects of eucommia bark extract using aorta and the proximal as well as the distal ends of the superior mesenteric arteries from the rat, with a specific objective to investigate whether smaller muscular arteries also elicit endothelium-dependent vascular relaxation (EDVR) in response to eucommia bark extract. We have also determined whether the EDVR, if indeed occurring in the mesenteric arteries, is mediated entirely by NO, or whether it also involves endothelium-derived hyperpolarizing factor (EDHF). We found that all three types of vessel preparations elicit EDVR in response to the eucommia bark extract concentration-dependently in a similar manner to the relaxant responses to carbachol (CCh). Although the NO synthase inhibitor L-NAME totally abolished the EDVR in aorta, it only partial abolished EDVR in mesenteric arteries isolated from each end, the distal end being more resistant to L-NAME. However, the residual L-NAME-resistant relaxation of the rat mesenteric arteries could be further inhibited by preincubation of the vessels with the combination of L-NAME and 15-20 mM KCl (KCl itself at this low concentration caused little or no contraction). Therefore, the EDVR induced by the eucommia extract and CCh in aorta is mediated entirely by NO, and that in mesenteric arteries by NO as well as EDHF, with the EDHF component (inhibited by KCl) larger in the smaller distal end of the rat mesenteric artery. Results of our study offer a plausible mechanistic basis for the vasorelaxing action of Eucommia ulmoides Oliv., which may account for its well-documented antihypertensive action.
Animals↗
In-situ chemical analyses of trans-polyisoprene by histochemical staining and Fourier transform infrared microspectroscopy in a rubber-producing plant, Eucommia ulmoides Oliver.
The localization of polyisoprene in young stem tissues of Eucommia ulmoides Oliver was investigated by histochemical staining and Fourier transform infrared (FT-IR) microspectroscopy. The fibrous structures were stained with Oil Red O. FT-IR microspectroscopic analysis proved that the fibrous structures were trans-polyisoprene. Granular structures stained with the dye, and characteristic absorptions at 2,960 cm(-1) and 1,430 cm(-1) in FT-IR suggested that trans-polyisoprene accumulated in the vicinity of the cambium layer. We have thus successfully shown for the first time the localization of trans-polyisoprene in plant tissues, and our histological investigation allowed us to presume the main sites of biosynthesis and accumulation of trans-rubber. Furthermore, a new technical approach, the preparation of sections using an electronic freezing unit and the in situ analysis of polyisoprene using FT-IR microspectroscopy, is demonstrated to be a promising method for determining the accumulation of polyisoprene as well as other metabolites.
Azo Compounds↗
Time-course of programmed cell death during leaf senescence in Eucommia ulmoides.
Leaves of Eucommia ulmoidesOliv. harvested between April to November were examined for programmed cell death (PCD) during growth and senescence. Leaves developed in April, becoming fully expanded in late May, remaining unchanged until November when they started to dehisce. Falling leaves retained a green color. Our results showed that (1) mesophyll cells gradually reduced their nuclei from September to November, (2) positive TUNEL signals appeared on the nuclei from August, (3) ladder-like DNA fragmentation occurred in September and October, and (4) a 20-kDa Ca(2+)-dependent DNase appeared in these same months. In fallen leaves, intact mesophyll cell nuclei could not be detected, but a few cells around the vascular bundle had nuclei. Therefore, (1) programmed cell death (PCD) of leaf cells occurred in the leaves of E. ulmoides, (2) the progress of mesophyll cell PCD lasted for more than 2 months, and (3) PCD of leaf cells was asynchronous in natural senescing leaves.
Apoptosis↗
Molecular cloning of a HMG-CoA reductase gene from Eucommia ulmoides Oliver.
The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) catalyzes the conversion of HMG-CoA to mevalonate, which is the first committed step in the pathway for isoprenoid biosynthesis in plants. A full-length cDNA encoding HMGR (designated as EuHMGR, GenBank Accession No. AY796343) was isolated from Eucommia ulmoides by rapid amplification of cDNA ends (RACE). The full-length cDNA of EuHMGR comprises 2281 bp with a 1770-bp open reading frame (ORF) encoding a 590-amino-acid polypeptide with two trans-membrane domains revealed by bioinformatic analysis. Molecular modeling showed that EuHMGR is a new HMGR with a spatial structure similar to other plant HMGRs. The deduced protein has an isoelectric point (pI) of 6.89 and a calculated molecular weight of about 63 kDa. Sequence comparison analysis showed that EuHMGR had highest homology to HMGR from Hevea brasiliensis. As expected, phylogenetic tree analysis indicated that EuHMGR belongs to plant HMGR group. Tissue expression pattern analysis showed that EuHMGR is strongly expressed in the leaves and stems whereas it is only poorly expressed in the roots, which implies that EuHMGR may be a constitutively expressing gene. Functional complementation of EuHMGR in HMGR-deficient mutant yeast JRY2394 demonstrated that EuHMGR mediates the mevalonate biosynthesis in yeast.
Amino Acid Motifs↗
Yo Jyo Hen Shi Ko (YHK) improves transaminases in nonalcoholic steatohepatitis (NASH): a randomized pilot study.
NASH is a common condition with a rising incidence. There is progression to cirrhosis in some cases and the potential for mortality or requirement of liver transplantation. Currently, there is no approved therapy for NASH. The natural compound YHK has both anti-inflammatory and antifibrotic properties, and can lead to improvement in transaminases in viral hepatitis. Improvement in transaminases may correlate with improved histology in NASH and hence may impact on the natural history. We sought to determine the effects of YHK on NASH. We performed a randomized, double-blind, placebo-controlled pilot study to determine the effects of YHK on transaminases and on quality of life (QoL) in patients with biopsy-confirmed NASH and a persistently abnormal ALT or AST. Eight patients were randomized to YHK or placebo for 8 weeks. The ALT and AST were measured at baseline and weeks 4, 8, and 12. SF-36 surveys were serially completed. All five patients in the YHK group but none in the placebo group had a marked decrease in ALT at both week 4 and week 8 compared to baseline. After discontinuing YHK the ALT returned toward baseline at week 12. The mean decrease in ALT compared to baseline was significantly greater in the YHK group than in the placebo group at both week 4 (-42.8+/-23.2 vs. -6.3+/-6.7 U/L; P=0.036) and week 8 (-45.4+/-23.4 vs. 6.0+/-24.6 U/L; P=0.036). There was also a nonsignificant decrease in AST in the YHK group compared to placebo. QoL was not affected and no severe adverse events were reported. In this controlled pilot study we found the novel nutraceutical agent YHK to be effective at reducing ALT values in patients with NASH. YHK is well tolerated. Further studies are justified to assess the impact of YHK in the natural history of NASH.
Adult↗
Separation and purification of chlorogenic acid by molecularly imprinted polymer monolithic stationary phase.
Separation and purification of chlorogenic acid by removal of the impurities compounds co-existed in the product using molecular imprinting technique was firstly reported. In this work, an in situ synthesis method was utilized for the preparation of molecularly imprinted polymer monolithic stationary phase using the impurity molecule (caffeic acid) as template, the mixture of tetrahydrofuran and isooctane as solvent, and methacrylic acid and ethyl glycol dimethacrylate as functional monomer and cross-linker, respectively. The retention behavior of the monolithic polymer to chlorogenic acid molecule, the template and several main impurities compounds in the product was studied and the adsorption capacity of compounds on the stationary phase determined by frontal chromatographic technique. A relatively weak retention of the target product molecule (chlorogenic acid) on the polymer and a strong adsorption capability of the monolith to the template and several main impurities were observed. This might mainly result from the 'shape' difference of chlorogenic acid molecule with the impurities compounds molecules. This approach was shown to be successful for the separation and purification of chlorogenic acid from the extract of Eucommia ulmodies leaves.
Adsorption↗
Hypoglycemic effect of Du-zhong (Eucommia ulmoides Oliv.) leaves in streptozotocin-induced diabetic rats.
The current study investigated whether Du-zhong (Eucommia ulmoides Oliv.) leaves could improve the hyperglycemia in streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were divided into a non-diabetic group (NDM), diabetic group (DM), diabetic group supplemented with powdered Du-zhong leaves (DM-PDZ) and diabetic group supplemented with a water extract of the powdered Du-zhong leaves (DM-WDZ). Diabetes was induced by injecting STZ (70 mg/kg B.W., i.p.). The powdered Du-zhong leaves or its powdered water extract was add to a standard diet based on 1% dried Du-zhong leaves (1 g PDZ/100 g diet and 0.187 g WDZ/100 g diet, respectively) for 3 weeks. Body weight was significantly higher in both types of Du-zhong leaves supplemented groups than in the DM group. The blood glucose levels were significantly lower in the DM-PDZ and DM-WDZ groups than in the DM group (20.05+/-0.88 and 18.96+/-1.23 mmol/l versus 24.42+/-1.07 mmol/l, P<0.05), whereas the plasma insulin and C-peptide levels were significantly higher in the PDZ and WDZ supplemented groups than in the DM group (7.45+/-0.27 and 7.62+/-0.69 microl U/ml versus 3.75+/-0.27 microl U/ml for the plasma insulin, and 224.52+/-14.6 and 239.76+/-15.52 pmol/l versus 166.5+/-10.4 pmol/l for the plasma C-peptide, respectively, P<0.05). The supplementation of PDZ and WDZ also resulted in lower plasma urea nitrogen levels compared to the DM group. Du-zhong leaves supplement seemed to be helpful to preserve the normal histological appearance of pancreatic islets as well as to preserve insulin-positive beta-cells but it did not reverse the effect of STZ to a great extent. Accordingly, the reduction in plasma glucose by the powdered Du-zhong leaves and its water extract is quite small but significant, nevertheless, this was occurred with simultaneous the increase in plasma insulin and C-peptide. They improved hyperglycemia and seemingly enhance the function of pancreatic beta-cells in STZ-induced diabetic rats.
Animals↗
Du-Zhong (Eucommia ulmoides Oliv.) leaves inhibits CCl4-induced hepatic damage in rats.
The protective effects of water extract of Du-Zhong (Eucommia ulmoides Oliv.) leaves (WEDZ) and its active compound (protocatechuic acid; PCA) on liver damage were evaluated by carbon tetrachloride (CCl4)-induced chronic hepatotoxicity in rats. Wistar rats were orally treated with WEDZ (0.1, 0.5, and 1.0 g/kg bw) or PCA (0.1 g/kg bw) with administration of CCl4 (0.5 ml/rat, 20% CCl4 in olive oil) for 28 consecutive days. It showed that CCl4-treated rats increased the relative organ weights of liver and kidney. CCl4-induced rats liver damage and significantly (p<0.05) increased the GOT, GPT, LDH and ALP levels in serum as compared with the control group. Treatment with WEDZ or PCA could decrease the GOT, GPT, LDH and ALP levels in serum when compared with CCl4-treated group. CCl4-treated rats also significantly (p<0.05) decreased the GSH content in liver and trolox equivalent antioxidant capacity (TEAC) in serum whereas increased (p<0.05) MDA content in liver as compared with the control group. Treatment with WEDZ or PCA also significantly (p<0.05) increased the GSH content and significantly (p<0.05) decreased the MDA content in liver. Administration of WEDZ or PCA could increase the activities of GPx, GRd and GST in liver. Liver histopathology showed that WEDZ or PCA reduced the incidence of liver lesions including hepatic cells cloudy swelling, lymphocytes infiltration, cytoplasmic vacuolization, hepatic necrosis and fibrous connective tissue proliferated induced by CCl4 in rats. The data suggest that oral administration with WEDZ for 28 consecutive days significantly decrease the intensity of hepatic damage induced by CCl4 in rats.
Animals↗
Flavonol glycosides from the leaves of Eucommia ulmoides O. with glycation inhibitory activity.
Eucommia ulmoides leaves have been used as a folk remedy for the treatment of diabetes in Korea. The aim of this study was to isolate and identify the compounds which inhibited advanced glycation end-product formation, one of main molecular mechanisms implicated in diabetic complications. A new flavonol glycoside, quercetin 3-O-alpha-L-arabinopyranosyl-(1-->2)-beta-D-glucopyranoside (1), and known flavonols kaempferol 3-O-beta-D-glucopyranoside (astragalin) (2), quercetin 3-O-beta-D-glucopyranoside (isoquercitrin) (3) were isolated from the leaves of Eucommia ulmoides. These compounds exhibited glycation inhibitory activity comparable to that of aminoguanidine, a known glycation inhibitor. The results suggest that the flavonol glycosides with glycation inhibitory activity could be attributed to the anti-diabetic action of Eucommia ulmoides leaves.
Animals↗