Quantification of trans-1,4-polyisoprene in Eucommia ulmoides by fourier transform infrared spectroscopy and pyrolysis-gas chromatography/mass spectrometry.
(10/18)
Endothelium-derived hyperpolarizing factor (EDHF) mediates endothelium-dependent vasodilator effects of aqueous extracts from Eucommia ulmoides Oliv. leaves in rat mesenteric resistance arteries.
(11/18)
The vascular effects of an aqueous extract prepared from the leaves of Eucommia ulmoides Oliv. (ELE), a medicinal herb commonly used in antihypertensive herbal prescriptions in China, were investigated in rat mesenteric resistance arteries. The mesenteric vascular bed was perfused with Krebs solution and the perfusion pressure was measured with a pressure transducer. In preparations with an intact endothelium and precontracted with 7 microM methoxamine, perfusion of ELE (107102 mg/ml for 15 min) caused a concentration-dependent vasodilatation, which was abolished by chemical removal of the endothelium. The ELE-induced vasodilatation was inhibited by neither indomethacin (INDO, a cyclooxygenase inhibitor) nor NG-nitro-L-arginine-methyl ester (L-NAME, a nitric oxide inhibitor). The ELE-induced vasodilatation was significantly inhibited by tetraethylammonium (TEA, a K channel blocker) and 18alpha-glycyrrhetinic acid (18alpha-GA, a gap-junction inhibitor), and abolished by high K-containing Krebs' solution. Atropine (a muscarinic acetylcholine receptor antagonist) significantly inhibited the vasodilatation induced by ELE at high concentrations. These results suggest that the ELE-induced vasodilatation is endothelium-dependent but nitric oxide (NO)- and prostaglandin I2 (PGI2)-independent, and is mainly mediated by the endothelium-derived hyperpolarizing factor (EDHF) in the mesenteric resistance arteries. Furthermore, the ELE-induced EDHF-mediated response involves the activation of K-channels and gap junctions. (+info)
A high-throughput and solvent-free method for measurement of natural polyisoprene content in leaves by Fourier transform near infrared spectroscopy.
(12/18)
High-throughput and highly sensitive analysis method for polyisoprene in plants by pyrolysis-gas chromatography/mass spectrometry.
(13/18)
Natural polyisoprene is a biopolymer consisting of isoprene units (C(5)H(8)) that is used commercially in household, medical, and industrial materials. For the management of natural polyisoprene production, the selection of high-yield polyisoprene-producing trees, and an understanding of polyisoprene biosynthesis, a high-throughput and highly sensitive screening method for the quantification of polyisoprene is required. In this study, we examined pyrolysates from polyisoprenes, polyprenols, carotenoids, ubiquinone (CoQ-10), and sterols by pyrolysis gas chromatography/mass spectrometry (PyGC/MS) and determined that the amounts of isoprene and limonene released from polyprenols and polyisoprenes were dependent upon their molecular weights. Based on these results, we developed a relative quantification method for polyisoprene in leaves by direct analysis of 1 mg of leaves using PyGC/MS. This novel quantification method eliminated extraction steps and can be used in the measurement of polyisoprene contents in Eucommia ulmoides and Hevea brasiliensis. (+info)
Eucommia ulmoides Oliv. antagonizes H2O2-induced rat osteoblastic MC3T3-E1 apoptosis by inhibiting expressions of caspases 3, 6, 7, and 9.
(14/18)
A clinical trial testing the safety and efficacy of a standardized Eucommia ulmoides Oliver bark extract to treat hypertension.
(15/18)
BACKGROUND: A tea made from Eucommia ulmoides leaves and bark is part of the Japanese diet. Eucommia is an herbal medicine that, by increasing nitric oxide, reduced blood pressure (BP) in rats and humans in an uncontrolled clinical trial. OBJECTIVE: A controlled clinical trial was conducted to evaluate an aqueous bark extract of Eucommia standardized to eight percent pinoresinol di-beta-D-glucoside (PG) for BP reduction in humans. METHODS: Study 1: Twenty-four healthy adult subjects with a BP between 120-160/80-100 mmHg were randomized to Eucommia extract 500 mg three times daily for eight weeks. Automatic 24-hour ambulatory blood pressure monitoring (24-h ABPM) was utilized at baseline and after eight weeks. Study 2: The effect of the Eucommia extract on isoproterenol-stimulated lipolysis was evaluated in a human fat cell assay to determine whether Eucommia was a beta-adrenergic blocker. Study 3: Thirty healthy adult subjects with a BP between 120-160/80-100 mmHg were randomized to 1 g Eucommia extract three times daily for two weeks with 24-h ABPM at baseline and after two weeks. RESULTS: Study 1: There was no toxicity or any difference in BP between the two groups. Study 2: Eucommia at 0.5% w/v reduced isoproterenol-stimulated lipolysis from 2.67 to 1.4 times the buffer control (P<0.001). Study 3: The Eucommia extract was well-tolerated and reduced BP by an average of 7.5/3.9 mmHg (P<0.008). CONCLUSION: The standardized Eucommia extract reduced BP and has beta-adrenergic blocking activity. Eucommia may be an appropriate nutraceutical intervention for prehypertension. (+info)
Overexpression of an isopentenyl diphosphate isomerase gene to enhance trans-polyisoprene production in Eucommia ulmoides Oliver.
(16/18)