Dicentrine is preferentially antagonistic to rat aortic than splenic alpha 1-adrenoceptor stimulation.
(1/15)
AIM: Dicentrine is a known alpha 1-adrenoceptor antagonist, but its alpha 1-adrenoceptor subtype selectivity has not yet been determined. We therefore, investigated the putative alpha 1-adrenoceptor subtype selectivity of this agent. METHODS: Graded isometric contractile responses of rat aortic rings and spleen to phenylephrine were observed in the absence or presence of various concentrations of dicentrine. The pA2 values for dicentrine were determined. RESULTS: Aortic tissues were more sensitive to phenylephrine-induced contraction than the spleen tissues. Dicentrine was approximately 100 times more potent as an antagonist to the aortic contraction, than it was to the splenic contractions. CONCLUSION: Dicentrine is an alpha 1-adrenoceptor antagonist which is more selective towards the putative alpha 1D-adrenoceptor subtype of the rat aorta than the alpha 1B-adrenoceptor of the spleen. (+info)
Prolyl endopeptidase inhibitors from the roots of Lindera strychnifolia F. Vill.
(2/15)
Prolyl endopeptidase (PEP, EC 3.4.21.26) has been proposed to play a role in degradation of proline-containing neuropeptides involved in the processes of learning and memory, e.g., vasopressin, substance P, and thyrotropin-releasing hormone (TRH). In the course of our search for bioactive constituents in medicinal plants, we studied the PEP inhibitory constituents of the roots of Lindera strychnifolia F. VILL and isolated two known tannins, epicatechin (1) and aesculitannin B (2), and four known sesquiterpenes, linderene (3), linderene acetate (4), linderalactone (5) and isolinderalactone (6) as inhibitors. On the inhibitory activities of six compounds against PEP from Flavobacterium meningosepticum and that from rat brain supernatant, compounds 1, 2 and 4 inhibited the enzyme from Flavobacterium more strongly than that from rat brain supernatant. However, compounds 3, 5 and 6 inhibited the enzymes from both origins to the same extent and furthermore, compound 6 was the strongest natural inhibitor against PEP from rat brain supernatant. The kinetic study of these inhibitors indicated that compounds 1, 2 are noncompetitive inhibitors and compounds 3-6 are competitive inhibitors. This is the first example of non-phenolic constituents showing significant competitive inhibitory activity being isolated from natural medicines. (+info)
Sesquiterpenes and alkaloids from Lindera chunii and their inhibitory activities against HIV-1 integrase.
(3/15)
Three new eudesmane type sesquiterpenoid lindenanolides E (1), F (2) and G (3), and two new aporphine alkaloid lindechunines A (18) and B (20) were isolated from roots of Lindera chunii MERR., together with seven known sesquiterpenes including a new naturally-occurring lindenanolide H (4) and eight known aporphine alkaloids. The structures of these compounds were determined by spectroscopic means. Of the isolated compounds, hernandonine (14), laurolistine (16), 7-oxohernangerine (17) and lindechunine A (18) showed significant anti-human immunodeficiency virus type 1 (HIV-1) integrase activity with IC(50) values of 16.3, 7.7, 18.2 and 21.1 microM, respectively. The major alkaloids presented in the roots of L. chunii were quantitatively analyzed by an HPLC method. (+info)
The potential of NO3--N utilization by a woody shrub species Lindera triloba: a cultivation test to estimate the saturation point of soil NO3--N for plants.
(4/15)
Responses of seedlings of a shrub species, Lindera triloba, grown in perlite culture medium, to nitrate (NO3--N) supply were investigated to estimate the saturating point of available NO3--N for plant utilization. NO3--N concentration and nitrate reductase activity (NRA) in leaves and roots were used as indicators of NO3--N uptake and assimilation by L. triloba. Root NRA increased with NO3--N supply when concentrations were low and reached a plateau at high NO3--N concentrations. On the other hand, root NO3--N concentration increased linearly with NO3--N supply; therefore, it is suggested that NO3--N uptake did not limit NO3--N assimilation by L. triloba. In contrast, leaf NRA and leaf NO3--N concentration were low and were not influenced by NO3--N supply. This may be caused by the lack of transport of NO3--N from roots to leaves. The NO3--N retained in perlite was compared with NO3--N pool sizes in soils from a forest where L. triloba occurs naturally to estimate the level of NO3--N availability to plants in the forest soil. The maximum NO3--N pool size in the forest soil was comparable to concentrations at which root NRA reached a plateau in perlite cultures. These results indicate that soil NO3--N availability is below the saturation point for NO3--N uptake by L. triloba, and it is the limiting factor of NO3--N utilization by L. triloba under field conditions in which this species naturally occurs. (+info)
A new sesquiterpene isolated from Lindera aggregata (SIMS) KOSTERM.
(5/15)
A new sesquiterpene, neolindenenonelactone (1), was first isolated from the dried roots of Lindera aggregata (SIMS) KOSTERM., along with four known compounds, linderane (2), isolinderalactone (3), linderalactone (4), and 8-hydroxylindestenolide (5). Their chemical structures were elucidated using spectral analysis of fast atom bombardment mass spectroscopy, one-dimensional nuclear magnetic resonance spectroscopy and two-dimensional-nuclear magnetic resonance spectroscopy including (1)H-NMR, (13)C-NMR, distortionless enhancement by polarization transfer, heteronuclear multiple-bond coherence, and single-crystal X-ray diffraction techniques. (+info)
Phenolic glycosides from Lindera fruticosa root and their inhibitory activity on osteoclast differentiation.
(6/15)
Two new compounds were found in the phenolic glycosides isolated from the roots of Lindera fruticosa: 5-O-[beta-D-apiofuranosyl-(1''-->2')-O-beta-D-xylopyranosyl]gentisic acid-7,5''-ester (3), named linderofruticoside A; and 5-O-[beta-D-apiofuranosyl-(1''-->3')-O-beta-D-xylopyranosyl]gentisic acid methyl ester (4), linderofruticoside B. Two previously known phenolic glycosides were also identified: beta-D-(3,4-disinapoyl)fructofuranosyl-alpha-D-(6-sinapoyl)glucopyranoside (1) and beta-D-(3-sinapoyl)fructofuranosyl-alpha-D-(6-sinapoyl)glucopyranoside (2). Compounds 1 and 2 inhibited osteoclast differentiation in a dose-dependent manner at concentrations higher than 1.04 microM and 0.132 microM, respectively. (+info)
Inhibition of the human ether-a-go-go-related gene (HERG) K+ channels by Lindera erythrocarpa.
(7/15)