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At least 55 records · Page 3Linked to original sources
PubMed1994

Dopaminergic benzo[a]phenanthridines: resolution and pharmacological evaluation of the enantiomers of dihydrexidine, the full efficacy D1 dopamine receptor agonist.

Racemic trans-10,11-dihydroxy-5,6,6a,7,8,12b- hexahydrobenzo[a]phenanthridine (2, dihydrexidine) was shown previously to be the first bioavailable full efficacy agonist at the D1 dopamine receptor. In addition to its full D1 agonist properties, 2 also is a good ligand for D2-like dopamine receptors. The profound anti-Parkinsonian actions of this compound make determination of its enantioselectivity at both D1 and D2 receptors of particular importance. To accomplish this, the enantiomers were resolved by preparation of diastereomeric (R)-O-methylmandelic acid amides of racemic trans-10,11-dimethoxy-5,6,6a,7,8,12b- hexahydrobenzo[a]phenanthridine 4 that were then separated by centrifugal chromatography. An X-ray analysis of the (-)-N-(R)-O-methylmandel diastereoamide revealed the absolute configuration to be 6aS,12bR. Removal of the chiral auxiliary and O,O-deprotection afforded enantiomeric amines that were then tested for biological activity. In striatal membranes, the (6aR,12bS)-(+)-enantiomer 2 had about twice the affinity of the racemate and 25-fold greater affinity than the (-)-enantiomer at the D1 receptor labeled by [3H]SCH23390 (K0.5s of 5.6, 11.6, and 149 nM, respectively). Similarly, the (+)-enantiomer 2 had about twice the affinity of the racemate for human D1 receptors expressed in transfected Ltk- cells. Functionally, the (+)-enantiomer of 2 was a full agonist, with an EC50 of 51 nM in activating striatal dopamine-sensitive adenylate cyclase versus 2.15 microM for the (-)-enantiomer. With respect to D2-like receptors, (+)-2 had a K0.5 of 87.7 nM in competing with [3H]spiperone at D2 binding sites in rat striatal membranes versus about 1 microM for the (-)-enantiomer. Together, these data demonstrate that both the D1 and D2 activities of dihydrexidine reside principally in the (6aR,12bS)-(+)-enantiomer. The results are discussed in the context of structure-activity relationships and conceptual models of the D1 receptor.

Animals↗
PubMed1993

Synthesis and evaluation of new 6-amino-substituted benzo[c]phenanthridine derivatives.

Different 7,8,9,10-tetrahydrobenzo[c]phenanthridin-6(5H)-ones (10a-e) were prepared by using a one-pot procedure which includes the preparation of various 6- and 7-alkoxy-1-naphthylisocyanates from 1-naphthylamines and triphosgene, followed by addition of 1-N-morpholino-1-cyclohexenes, and cyclization of the resulting amides upon heating in the presence of hydrogen chloride. Subsequent aromatization, chlorination, and substitution with (dimethylamino)alkylamines, followed by a demethylation or a selective desisopropylation, allowed us to synthesize the derivatives 6a-i and 7a-h bearing a [(dimethylamino)alkyl]amino side chain at their 6-position. These compounds, as the other analogs 5a-b, were devised to further study the structure-activity relationships in the benzo[c]phenanthridine family of antitumor alkaloids led by fagaronine (1a) and nitidine (1b). Topoisomerases I and II cleavable complex assay and evaluation of the cytotoxicity and antitumor properties were performed. In vitro cytotoxicity (L1210 and Calc 18) shows a relationship between the cytotoxicity of these compounds and their topoisomerase poisoning properties. However, all these compounds were devoid of significant antitumor effect on the P388 murine leukemia system.

Adenocarcinoma↗
PubMed1999

Structural considerations of NK109, an antitumor benzo[c]phenanthridine alkaloid.

The antitumor activities of a synthetic benzo[c]phenanthridine, NK109 (7-hydroxy-2, 3-methylenedioxy-5-methyl-8-methoxybenzo[c]phenanthridinium hydrogensulfate dihydrate), and of natural benzo[c]phenanthridines were tested in vitro and in vivo. NK109 (3) had the highest activity among them. NK109 is similar in structure to fagaronine and fagaridine; however, it has a phenolic-OH at C-7. NK109 exists as a resonance hybrid, the keto-amine and zwitterionic forms in neutral media. The resonance hybrid is cationic and has molecular planarity; these have been considered to be essential for the antitumor activity of the benzo[c]phenanthridinium salts. On the other hand, the structurally similar benzo[c]phenthridine alkaloids, chelerythrine and sanguinarine, exist as pseudobases under the same conditions. The latter do not exhibit antitumor activity in vivo, probably because they lose both the immonium region and molecular planarity. Thus, 3 may be considered to be novel category of benzo[c]phenanthridinium salt from the viewpoint of its structure under biological conditions.

Animals↗
PubMed2005

A novel bis-phenanthridine triamine with pH controlled binding to nucleotides and nucleic acids.

The new bis-phenanthridine triamine is characterised by three pK(a) values: 3.65; 6.0 and >7.5. A significant difference in the protonation state of at pH = 5 (four positive charges) and at pH = 7 (less than two positive charges) accounts for the strong dependence of -nucleotide binding constants on nucleotide charge under acidic conditions, whereas at neutral pH all -nucleotide complexes are of comparable stability. All experimental data point at intercalation as the dominant binding mode of to polynucleotides. However, there is no indication of bis-intercalation of the two phenanthridine subunits in binding to double stranded polynucleotides, the respective complexes being most likely mono-intercalative. Thermal stabilisation of calf thymus DNA (ct-DNA) and poly A-poly U duplexes upon addition of is significantly higher at pH = 5 than at neutral conditions. This is not the case with poly dA-poly dT, indicating that the specific secondary structure of the latter, most likely the shape of the minor groove, plays a key role in complex stability. At pH = 5 acts as a fluorimetric probe for poly G (emission quenching) as opposed to other ss-polynucleotides (emission increase), while at neutral conditions this specificity is lost. One order of magnitude higher cytotoxicity of compared to its "monomer" can be accounted for by cooperative action of two phenanthridinium units and the charged triamine linker. The results presented here are of interest to the development of e.g. sequence-selective cytostatic drugs, and in particular for the possibility to control the drug activity properties over binding to DNA and/or RNA by variation of the pH of its surrounding.

Amination↗
PubMed2002

Convergent synthesis of 6-substituted phenanthridines via anionic ring closure.

[reaction: see text] The addition of organometallic derivatives to the cyano group of 2-(2-fluorophenyl)benzonitrile followed by intramolecular nucleophilic substitution produces 6-substituted phenanthridines. Alkyllithiums, aryllithiums, and sterically nondemanding lithium amides reacted at -78 degrees C to produce the 6-substituted phenanthridines in 82-98% yield upon warming to room temperature. The addition of the corresponding Grignard reagents requires an excess of the organometallic reagent and extented reaction times at elevated temperature.

Journal Article↗
PubMed2002

A one-pot access to 6-substituted phenanthridines from fluoroarenes and nitriles via 1,2-arynes.

[reaction: see text] A one-pot, t-BuLi-induced synthesis of 6-substituted phenanthridines from fluoroarenes and nitriles via 1,2-arynes is reported. Aryl- and hetaryl nitriles, cyanamides, and trimethylacetonitrile gave phenanthridine products. The method was extended to provide bisphenanthridine 10 by a one-pot bis-cyclization, using 1,3-dicyanobenzene and PhF in 1:5 ratio. Reaction of 1-fluoronaphthalene and 4-chlorofluorobenzene with benzonitrile afforded the regioisomerically pure products 11 and 12, respectively.

Journal Article↗
PubMed2000

Structure-activity relationships of synthetic analogs of jasmonic acid and coronatine on induction of benzo[c]phenanthridine alkaloid accumulation in Eschscholzia californica cell cultures.

A facile test system based on the accumulation of benzo[c]phenanthridine alkaloids in Eschscholzia californica cell suspension culture (an indicator of defense gene activation) has been used to analyze a series of synthetic compounds for elicitor-like activity. Of the 200 jasmonic acid and coronatine analogs tested with this system, representative results obtained with 49 of them are presented here. The following can be summarized concerning structure-activity relationships: there is a large degree of plasticity allowed at the C-3 of jasmonic acid in the activation of defense genes. The carbonyl moiety is not strictly required, but exocyclic double bond character appears necessary. The pentenyl side chain at C-2 cannot tolerate bulky groups at the terminal carbon and still be biologically active. Substitutions to the C-1' position are tolerated if they can potentially undergo beta-oxidation. Either an alkanoic acid or methyl ester is required at C-1, or a side chain that can be shortened by beta-oxidation or by peptidase hydrolysis. Coronatine and various derivatives thereof are not as effective as jasmonic acid, and derivatives in inducing benzo[c]phenanthridine alkaloid accumulation. Jasmonic acid rather than the octadecanoic precursors is therefore considered to be a likely signal transducer of defense gene activation in planta.

Alkaloids↗
PubMed1995

[Cell cultured of Macleaya cordata--a producer of antimicrobial benzo[c]phenanthridine alkaloids].

It was shown that a suspension culture of Macleaya cordata accumulated benzo(c)phenanthridine alkaloids in the cell biomass. By the composition of the alkaloids and their content the cell culture markedly differed from the intact plant and callus tissue. The benzo(c)phenanthridine compounds in the cell culture were mainly represented by the reduced forms: dihydrosanquinarin and dihydrochelirubin. In the green plant they were mainly represented by the oxidized forms: sanquinarin and chelerithrin. The cell culture practically contained no chelerithrin characteristic of the intact plant.

Alkaloids↗
PubMed2002

Quaternary benzo[c]phenanthridine alkaloids as inhibitors of aminopeptidase N and dipeptidyl peptidase IV.

Chelerythrine, sanguinarine and an alkaloid extract from Macleaya cordata--sanguiritrin--were found to be inhibitors of aminopeptidase A and dipeptidyl peptidase IV, while fagaronine inhibited dipeptidyl peptidase IV only. At 50 microM, chelerythrine, sanguinarine and sanguiritrin inhibited aminopeptidase N by 82%, 82%, 88%, DPP IV by 38%, 62%, 57%, and fagaronine by 34%, respectively. When bovine serum albumin (500 microg/mL) was added, the inhibition of both proteases by quaternary benzo[c]phenanthridine alkaloids (QBA) (50 microM) was significantly diminished. Strong interaction of chelerythrine and sanguinarine with bovine and human serum albumin was proved by electrophoretic determination of their respective conditional binding constants.

Alkaloids↗
PubMed2000

Benzo[c]phenanthridine alkaloids from Corydalis incisa.

Six benzo[c]phenanthridine alkaloids, corynoline (1), acetylcorynoline (2), corynoloxine (3), luguine (4), 6-oxocorynoline (5), and 12-hydroxycorynoloxine (6) were isolated from the aerial parts of Corydalis incisa, and 6 was isolated for the first time from nature. The structure was elucidated by NMR techniques.

Alkaloids↗
PubMed1993

Hexahydrobenzo[a]phenanthridines: novel dopamine D3 receptor ligands.

We report that certain substituted hexahydrobenzo[a]phenanthridines are novel high affinity ligands selective for the dopamine D3 receptor. These data demonstrate that substitutions on the heterocyclic nitrogen and the pendant phenyl ring of this nucleus cause a marked increase in both affinity and selectivity for dopamine D3 vs. D2 receptors. Thus, these compounds represent important new tools to study the pharmacology of dopamine D3 receptors, and may also provide an opportunity for the synthesis of new radioligands for dopamine D3 receptors.

Animals↗
PubMed2004

Dimethoxybenzo[i]phenanthridine-12-carboxylic acid derivatives and 6H-dibenzo[c,h][2,6]naphthyridin-5-ones with potent topoisomerase I-targeting activity and cytotoxicity.

The exceptional TOP1-targeting activity and antitumor activity of ARC-111, 1, prompted studies on similarly substituted benzo[i]phenanthridine-12-carboxylic ester and amide derivatives. These studies were extended to include 6-substituted 8,9-dimethoxy-2,3-methylenedioxy-dibenzo[c,h][2,6]naphthyridin-5-ones, which represent reversed lactam analogues of 1. Several of these analogues retained the potent TOP1-targeting activity and cytotoxicity observed for ARC-111.

Antineoplastic Agents↗
PubMed2002

Metabolism and distribution of phenanthridine trypanocides in Trypanosoma brucei.

Phenanthridine trypanocides (isometamidium chloride hydrochloride, ISM, and Ethidium bromide, EBr) have been widely used to treat African trypanosomiasis in livestock for more than 40 years. Their main action is to inhibit nucleic acid synthesis in trypanosome parasites, by intercalation between the DNA base pairs. They can also linearise selectively kinetoplast DNA minicircles; a form of mitochondrial DNA unique to this group of parasites. However, the metabolism of these compounds by trypanosomes has not been reported. Indeed, it is not known whether or not their metabolism by the parasite contributes to their activity, selective toxicity for these parasites or to the development of chemoresistance. Therefore, we studied the metabolism of EBr and ISM, and their distribution in Trypanosoma brucei (TREU 927) using high performance liquid chromatography (HPLC), liquid chromatography combined with mass spectrometry (LC-MS) and confocal laser scanning microscopy (CLSM). Incubation of EBr with trypanosomes led to the formation of a small amount (0.606+/-0.191%) of one metabolite (MI). Ion chromatograms extracted from an LC-MS analysis using electrospray ionisation (ESI), showed that the difference in mass between the parent compound and its metabolite was 30. This may correspond to the addition of a hydroxyl and a methyl group. No metabolites could be detected for ISM. The distribution of the two drugs in trypanosomes was investigated by CLSM, using their intrinsic fluorescence. ISM and EBr showed differences in their distribution in trypanosomes. ISM had a greater affinity for the kinetoplast than EBr and it stained other organelles like the flagellum; in contrast the distribution of EBr was more diffuse.

Animals↗
PubMed2002

DNA adduct formation from quaternary benzo[c]phenanthridine alkaloids sanguinarine and chelerythrine as revealed by the 32P-postlabeling technique.

Using the 32P-postlabeling assay, we investigated the ability of quaternary benzo[c]phenanthridine alkaloids, sanguinarine, chelerythrine and fagaronine, to form DNA adducts in vitro. Two enhanced versions of the assay (enrichment by nuclease P1 and 1-butanol extraction) were utilized in the study. Hepatic microsomes of rats pre-treated with beta-naphthoflavone or those of uninduced rats, used as metabolic activators, were incubated in the presence of calf thymus DNA and the alkaloids, with NADPH used as a cofactor. Under these conditions sanguinarine and chelerythrine, but not fagaronine, formed DNA adducts detectable by 32P-postlabeling. DNA adduct formation by both alkaloids was found to be concentration dependent. When analyzing different atomic and bond indices of the C11-C12 bond (ring B) in alkaloid molecules we found that fagaronine behaved differently from sanguinarine and chelerythrine. While sanguinarine and chelerythrine showed a preference for electrophilic attack indicating higher potential to be activated by cytochrome P450, fagaronine exhibited a tendency for nucleophilic attack. Our results demonstrate that sanguinarine and chelerythrine are metabolized by hepatic microsomes to species, which generate DNA adducts.

Alkaloids↗
PubMed2000

Distribution of morphinan and benzo[c]phenanthridine alkaloid gene transcript accumulation in Papaver somninferum.

The opium poppy Papaver somniferum L. produces the antimicrobial benzo[c]phenanthridine alkaloid sanguinarine and the narcotic analgesic morphinan alkaloid morphine. Transcripts of three genes of alkaloid biosynthesis in P. somniferum in developing seedlings, mature plants and plant cell suspension culture were monitored for temporal/spatial or for methyl jasmonate-induced accumulation by RNA gel blot analysis. These genes encoded (S)-N-methylcoclaurine 3'-hydroxylase (CYP80B1) that is common to morphine and sanguinarine biosynthesis, the berberine bridge enzyme (BBE) that lies on the pathway to sanguinarine, and codeinone reductase (COR) the penultimate enzyme of morphine biosynthesis. In developing P. somniferum seedlings, the morphine precursor thebaine was present throughout the first twenty days of germination. In contrast, sanguinarine was present in detectable quantities only after day five after germination and continued to increase at least until day twenty. Accumulation of cyp80b1, bbe1 and cor1 gene transcripts paralleled these differences. In the mature poppy plant, cyp80b1, bbe1 and cor1 gene transcripts were detected in the root, the stem, the leaf lamina and the leaf mid rib. Only cyp80b1 and cor1, however, were found in the flower bud and the capsule. Consistent with the fact that sanguinarine accumulation, but not that of morphine, can be induced in opium poppy cell suspension culture by addition of methyl jasmonate to the culture medium, cyp80b1 and bbe1, but not cor1 transcript accumulated in response to elicitor treatment.

Alkaloids↗
PubMed2001

Cytotoxicity of natural compounds in hepatocyte cell culture models. The case of quaternary benzo[c]phenanthridine alkaloids.

The quaternary benzo[c]phenanthridine alkaloids (QBA) produce a plethora of species- and tissue-specific effects but the molecular basis of their biological activities remain mysterious. The objective of the present study was to investigate the cytotoxicity of QBA alkaloids, sanguinarine (SA), chelerythrine (CHE), fagaronine (FA), and the extract from Macleaya cordata in primary cultures of human and porcine hepatocytes. The cellular damage was assessed by the MTT assay, lactate dehydrogenase (LDH) leakage and the determination of intracellular glutathione (GSH) levels. The results are summarised as follows: (i) The alkaloids tested in doses 0.1 and 10 microM did not display statistically significant cytotoxicity for 0-3 h incubation; (ii) SA and CHE showed the dose- and time-dependent toxicity within the range 25-100 microM whereas FA was not toxic; (iii) the LDH leakage into the medium was higher for SA than for CHE, thus revealing a potent potential of SA to disturb cell-membrane integrity; (iv) after 3 h incubation with 100 microM SA/CHE, mitochondrial dehydrogenase activity (MTT assay) and the cellular GSH levels decreased to residual values of about 40% suggesting that mitochondria are unlikely to be a primary target for SA/CHE in the cell; (v) no differences were found in the response to QBA application in human vs porcine hepatocyte.

Alkaloids↗