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At least 109 records · Page 6Linked to original sources
PubMed2002

A new phenanthridine alkaloid from Hymenocallis x festalis.

Investigation of the alkaloid fraction of the bulbs of Hymenocallis x festalis yielded a new natural product, 3-methoxy-8,9-methylenedioxy-3,4-dihydrophenanthridine (1). The structure was elucidated on the basis of spectroscopic data.

Alkaloids↗
PubMed1991

trans-hexahydroindolo[4,3-ab]phenanthridines ("benzergolines"), the first structural class of potent and selective dopamine D1 receptor agonists lacking a catechol group.

In contrast to the many selective dopamine (DA) D2 receptor agonists known, only two prototypes of selective D1 receptor agonists have been described; both show preference for the periphery due to their catechol partial structures. Our search for non-catechol, selective D1 agonists was based on the hypothesis that D1 selectivity could be conferred upon ergolines by annulation with a phenyl ring. The target molecules, trans-4,6,6a,7,8,12b-hexahydroindolo-[4,3-ab]phenanthridi nes ("benzergolines"), were efficiently synthesized by using the Ninomiya enamide photocyclization reaction. These compounds were found to be as active as the most potent D1 agonists in the adenylate cyclase D1 receptor model, but showed no activity in the ACh release D2 receptor assay. The acquired subtype selectivity of the novel structures was accompanied by an enhanced potency and efficacy as compared to the corresponding ergolines. This points to a D1 affinity enhancing, D2 receptor discriminating role for the additional phenyl group and provides further support for the existence of a D1 receptor specific accessory aryl binding site. Thus the benzergolines represent the first structural class of potent and selective D1 agonists lacking a catechol group which should allow an efficient central nervous system penetration. On the basis of these results, the D1 agonist pharmacophore has to be revised in the sense that potent activity requires neither a catechol function nor an orthogonal conformation of the aromatic rings.

Acetylcholine↗
PubMed2002

Inhibitory activity on binding of specific ligands to the human angiotensin II AT(1) and endothelin 1 ET(A) receptors: bioactive benzo[c]phenanthridine alkaloids from the root of Bocconia frutescens.

A bioassay-guided fractionation of the 80 % ethanolic extract from Bocconia frutescens L. roots, showing a dose-dependent inhibitory effect towards both [(3)H]-angiotensin II and [(3)H]-BQ-123 binding to the human angiotensin II AT 1 and endothelin 1 ET(A) receptors, led to an alkaloidal subfraction as the only responsible fraction for the activity of the whole extract. Among the alkaloids present in this fraction sanguinarine and chelerythrine were significant inhibitors of [(3)H]-angiotensin II binding (hAT 1 receptor), with IC(50) values within the micromolar range. On the contrary, the [(3)H]-BQ-123 binding (ET(A) receptor) was only weakly inhibited. Moreover, other members of the isoquinoline alkaloid family such as chelidonine and some protoberberine alkaloids exhibited no affinity for the two receptors. The present work shows the possible structure-activity relationship for these benzophenanthridine alkaloids on a screening bioassay using both stably transfected Chinese hamster ovary (CHO) and the human neuroblastoma SK-N-MC cells. Furthermore, the ability of these compounds to block AT(1) and/or ET(A) receptors may provide some justification for the traditional use of Bocconia frutescens L. to control hypertension.

Alkaloids↗
PubMed2005

New indolopyridoquinazoline, benzo[c]phenanthridines and cytotoxic constituents from Zanthoxylum integrifoliolum.

Three new alkaloids, 7,8-dehydro-1-methoxyrutaecarpine, isodecarine, and 8-demethyloxychelerythrine, together with sixteen known compounds, norchelerythrine, oxychelerythrine, decarine, dihydrocherythrinylacetaldehyde, 6-acetonyldihydrochelerythrine, rutaecarpine, 1-hydroxyrutaecarpine, gamma-fagarine, skimmianine, (-)-matairesinol, (-)-isoarctigenin, (+)-epipinoresinol, d-sesamin, lupeol, canthin-6-one, and arnottianamide have been isolated from the root bark of Zanthoxylum integrifoliolum. The structures of these new compounds were determined through spectral analyses. Among the isolates, 7,8-dehydro-1-methoxyrutaecarpine, norchelerythrine, oxychelerythrine, dihydrocherythrinylacetaldehyde, 6-acetonyldihydrochelerythrine, 1-hydroxyrutaecarpine, gamma-fagarine, skimmianine, (-)-matairesinol, and canthin-6-one exhibited cytotoxicities (ED50 values < 4 microg/mL) against P-388 or HT-29 cell lines in vitro.

Antineoplastic Agents, Phytogenic↗
PubMed2005

Study of the inhibition of alpha-amylase by the benzo[c]phenanthridine alkaloids sanguinarine and chelerythrine.

Inhibition of porcine pancreas and human saliva alpha-amylase (EC 3.2.1.1) by sanguinarine and chelerythrine was studied. The inhibition of alpha-amylase was assayed using a biosensor method which utilises a flow system equipped with a peroxide electrode. 250 microM sanguinarine and 250 microM chelerythrine cause complete inhibition of 1.9 nkat alpha-amylase from porcine pancreas. The same concentration of sanguinarine and chelerythrine caused 23.9% and 7.5% inhibition, respectively, of 1.9 nkat alpha-amylase from human saliva. Mixed type and partially reversible inhibition was found for both alpha-amylases treated with either alkaloid.

Alkaloids↗