Phenanthridine Alkaloids Research Articles

Quaternary benzo[c]phenathridine alkaloids sanguinarine and chelerythrine do not affect transcriptional activity of aryl hydrocarbon receptor: Analyses in rat hepatoma cell line H4IIE.luc

Quaternary benzo[c]phenanthridine alkaloids (QBAs) sanguinarine and chelerythrine exert a plethora of biological activities. Nevertheless, the specific cellular target for these alkaloids within the cell was not identified as far. Several literary data indicate that biological effects of QBAs could be associated with aryl hydrocarbon receptor (AhR) signaling pathway, including cytochrome P450 CYP1A, however, available information are controversial. In this work we analyzed the effects of sanguinarine and chelerythrine on AhR activity in rat hepatoma cells HII4E. luc stably transfected with dioxin responsive element fused to luciferase gene (DRE-LUC). Studied QBAs were tested in submicromolar concentration range (0.0001–1 μM) and in incubation times 6, 24 and 48 h. Transcriptional activity of AhR was monitored by chemiluminiscence measurement of luciferase catalytic activity. Sanguinarine and chelerythrine did not activated AhR in any time or dose tested. Chelerythrine (1 μM) but not sanguinarine caused moderate inhibition of AhR activation by 10 picomolar dioxin (exponential phase of receptor activation). In contrast, AhR activation by 2.5 nM dioxin (saturated receptor) was not affected by either alkaloid tested. In conclusion, the findings presented here favor rather for inactivity or modest inhibitory effect of QBAs on AhR signaling pathways in vitro than for the activation of the receptor. Regarding the concentrations of QBAs occurring in vivo, the use of products containing sanguinarine and/or chelerythrine has low toxicological potential in terms of the interactions with AhR signaling pathways.

Safety assessment of sanguiritrin, alkaloid fraction of Macleaya cordata, in rats

The subchronic safety of sanguiritrin, a mixture of sanguinarine (SA) and chelerythrine (CHE) quaternary benzo[c]phenanthridine alkaloids (QBA), obtained from Macleaya cordata was assessed. Rats were fed a diet containing 120 ppm sanguiritrin (100 ppm QBA) for 109 days. The feed consumption and the animal weight were monitored. The content of QBA in selected tissues and plasma was determined using HPLC. It was evidenced that 2% of QBA were absorbed through the GIT while 98% were excreted in the feces. In plasma, bilirubin, urea, creatinine, glomerular filtration, AST, ALT, GMT, ALP and total antioxidant capacity were determined. In liver, GSH level, lipoperoxidation products, SOD and GPx activities and total amount of cytochrome P450 were evaluated. Damage to nuclear DNA was assessed; a <sup>32</sup>P-postlabeling assay proved that no DNA-adducts were detected in nuclear and mitochrondrial DNA in liver. No adverse effects were observed on rat organism. QBA had no influence on the gut mucosal epithelium, liver tissue and any biochemical parameters tested. Oxidative stress was not manifested during the experiment.

A New Radical-Based Route to Calothrixin B

[structure: see text] A high-yielding totally regioselective intramolecular homolytic acylation of a quinoline ring constitutes the key step in a new synthesis of the pentacyclic indolo[3,2-j]phenanthridine alkaloid calothrixin B.

Total Synthesis of Oxyfagaronine, Phenolic Benzo[c]phenanthridine and General Synthetic Way of 2,3,7,8- and 2,3,8,9-Tetrasubstituted Benzo[c]phenanthridine Alkaloids

Benzo[c]phenanthridine alkaloids such as oxynitidine, oxysanguinarine, oxyavicine and phenolic oxyfagaronine were synthesized from easily available starting benzonitriles 5 and toluamides 6 using a lithiated toluamide-benzonitrile cycloaddition reaction. The coupling reaction provided 3-arylisoquinolinones that were transformed to the benzo[c]phenanthridones. This method is highly efficient and could be useful for preparing diverse substituted aromatic benzo[c]phenanthridine compounds on a multi gram scale.

Investigation of sanguinarine and chelerythrine effects on CYP1A1 expression and activity in human hepatoma cells

Quaternary benzo[ c]phenanthridine alkaloids (QBA) sanguinarine and chelerythrine exhibit a wide spectrum of biological activities whence they are used in dental care products. Recent studies indicated that cytochrome P450 CYP1A attenuates sanguinarine toxicity both in vivo [Williams, M.K., Dalvi, S., Dalvi, R.R., 2000. Influence of 3-methylcholanthrene pretreatment on sanguinarine toxicity in mice. Vet. Hum. Toxicol. 42, 196–198] and in vitro [Vrba, J., Kosina, P., Ulrichová, J., Modrianský, M., 2004. Involvement of cytochrome P450 1A in sanguinarine detoxication. Toxicol. Lett. 151, 375–387]. However, CYP1A converts sanguinarine to the products that form DNA adducts [Stiborová, M., Šimánek, V., Frei, E., Hobza, P., Ulrichová, J., 2002. DNA adduct formation from quaternary benzo[ c]phenanthridine alkaloids sanguinarine and chelerythrine as revealed by the 32P-postlabeling technique. Chem. Biol. Interact. 140, 231–242]. In our work we examined the effects of sanguinarine and chelerythrine on CYP1A1 expression and catalytic activity in human hepatoma cells—HepG2. Sanguinarine and chelerythrine did not affect basal and dioxin-inducible expression of CYP1A1 mRNA and protein in HepG2 cells. The enzymatic activity of CYP1A1 was assessed by the fluorescent measurement of 7-ethyxoresorufin- O-deethylase (EROD) activity. We observed a slight decrease of dioxin-induced EROD activity in HepG2 cells by sanguinarine and chelerythrine. This decrease was attributed to the inhibition of CYP1A1 catalytic activity, as revealed by enzyme kinetic studies on recombinant CYP1A1 protein. The IC50 values for the inhibition of CYP1A1 by sanguinarine and chelerythrine were 2.1 and 1.9 μM, respectively. In conclusion, albeit the CYP1A modulates QBA cytotoxicity and genotoxicity, the QBA themselves do not affect CYP1A1 expression. The data indicate that studied alkaloids do not have specific cellular target and their biological effects are rather pleiotropic.

Synthesis of Oxychelerythrine Using Lithiated Toluamide‐Benzonitrile Cycloaddition.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Phenanthridine alkaloids from Zanthoxylum madagascariense

Four benzo[c]phenanthridine alkaloids have been isolated from the stem bark of Zanthoxylum madagascariense. These compounds were identified by extensive use of NMR spectroscopy.

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

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

Synthesis of Benzo[c]phenanthridine Alkaloids Using a Palladium‐Catalyzed Aryl‐Aryl Coupling Reaction

AbstractFor Abstract see ChemInform Abstract in Full Text.

The Benzo[c]phenanthridine Alkaloid, Sanguinarine, Is a Selective, Cell-active Inhibitor of Mitogen-activated Protein Kinase Phosphatase-1

Mitogen-activated protein kinase phosphatase-1 (MKP-1) is a dual specificity phosphatase that is overexpressed in many human tumors and can protect cells from apoptosis caused by DNA-damaging agents or cellular stress. Small molecule inhibitors of MKP-1 have not been reported, in part because of the lack of structural guidance for inhibitor design and definitive assays for MKP-1 inhibition in intact cells. Herein we have exploited a high content chemical complementation assay to analyze a diverse collection of pure natural products for cellular MKP-1 inhibition. Using two-dimensional Kolmogorov-Smirnov statistics, we identified sanguinarine, a plant alkaloid with known antibiotic and antitumor activity but no primary cellular target, as a potent and selective inhibitor of MKP-1. Sanguinarine inhibited cellular MKP-1 with an IC50 of 10 microM and showed selectivity for MKP-1 over MKP-3. Sanguinarine also inhibited MKP-1 and the MKP-1 like phosphatase, MKP-L, in vitro with IC50 values of 17.3 and 12.5 microM, respectively, and showed 5-10-fold selectivity for MKP-3 and MKP-1 over VH-1-related phosphatase, Cdc25B2, or protein-tyrosine phosphatase 1B. In a human tumor cell line with high MKP-1 levels, sanguinarine caused enhanced ERK and JNK/SAPK phosphorylation. A close congener of sanguinarine, chelerythrine, also inhibited MKP-1 in vitro and in whole cells, and activated ERK and JNK/SAPK. In contrast, sanguinarine analogs lacking the benzophenanthridine scaffold did not inhibit MKP-1 in vitro or in cells nor did they cause ERK or JNK/SAPK phosphorylation. These data illustrate the utility of a chemical complementation assay linked with multiparameter high content cellular screening.

Synthesis of Benzo[c]phenanthridine Alkaloids Using a Palladium-catalyzed Aryl-Aryl Coupling Reaction

A synthesis of (fully aromatized) benzo[c]phenanthridine alkaloids was accomplished using an intramolecular palladium-catalyzed aryl-aryl coupling reaction of halo- or triflyloxyarenes.

Synthesis of Oxychelerythrine Using Lithiated Toluamide-Benzonitrile Cycloaddition

Oxychelerythrine, benzo[c]phenanthridine alkaloid, was synthesized from easily available starting toluamide 5 and benzonitrile 6 using toluamide-benzonitrile cycloaddition reaction in 6 steps.

A Highly Efficient Synthesis of Trispheridine through a Construction of Tetrahydrophenanthridine Based on a Microwave-assisted Thermal Electrocyclic Reaction of an Aza 6π-Electron System

A highly efficient synthesis of a phenanthridine alkaloid, trispheridine (1) has been achieved in a 74% overall yield in a four-step sequence. The key step is the construction of a tetrahydrophenanthridine based on a microwave -assisted thermal electrocyclic reaction of an aza 631-electron system including the benzene double bond.

Synthesis and Antiviral Effect against Herpes Simplex Type 1 of 12-substituted Benzo[c]phenanthridinium Salts

The synthesis of benzo[c]phenanthridine alkaloid derivatives is described. In vitro antiviral activity against herpes simplex type 1 (HSV1) has been investigated. Contrary to the natural product fagaronine, which did not have any activity in the HSV1 antiviral tests, four 12-alkoxy derivatives showed good activity demonstrating the importance of the 12-substitution in the structure-activity relationships.

Molecular and crystal structures of (+)-homochelidonine, (+)-chelamine, and (−)-norchelidonine

The molecular and crystal structures of three hexahydrobenzo[ c]phenanthridine alkaloids (+)-homochelidonine ( 1), (+)-chelamine ( 2), and (−)-norchelidonine ( 3) have been examined by X-ray single crystal diffraction and by CD spectroscopy. All alkaloids 1–3 possess the cis-junction of B/C rings and the C11-hydroxyl in axial position on the half-chair-conformated B ring. The dihedral angles between the aromatic planes A, D are 51.9, 55.0/44.8, and 22.0° in 1, 2, and 3, respectively. In all compounds 1– 3, there is intramolecular H-bonding between C11–OH group and nitrogen. Using a combined approach of X-ray diffraction and CD spectra correlations the absolute configurations of the title alkaloids have been determined as (+)-11 S,13 R,14 S-homochelidonine ( 1), (+)-11 R,12 R,13 R,14 S-chelamine ( 2), and (−)-11 R,13 S,14 R-norchelidonine ( 3).

Synthesis of Benzo[c]Phenanthridine Alkaloids, Using a Novel Palladium-Phosphine Combination System - Pd(OAc)2, DPPP, and Bu3P

Total synthesis of several benzo[c]phenanthridine alkaloids was accomplished via an aryl-aryl coupling reaction using a novel Pd reagent prepared from Pd(OAc) 2 , DPPP, and Bu 3 P. This is a versatile method for the coupling reactions of not only aryl triflates and arenes hut also aryl halides and arenes.

A Versatile Total Synthesis of Benzo[c]phenanthridine (IX) and Protoberberine (V) Alkaloids Using Lithiated Toluamide—Benzonitrile Cycloaddition.

A Versatile Total Synthesis of Benzo[c]phenanthridine (IX) and Protoberberine (V) Alkaloids Using Lithiated Toluamide—Benzonitrile Cycloaddition.

A Facile Synthesis of Benzo[c]phenanthridine Alkaloids: Oxynitidine and Oxysanguinarine Using Lithiated Toluamide—Benzonitrile Cycloaddition.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Involvement of cytochrome P450 1A in sanguinarine detoxication

Sanguinarine (SA), a member of the benzo[c]phenanthridine alkaloids, is a potent anti-microbial agent with anti-inflammatory and anti-neoplastic properties. However, toxicity of the alkaloid severely limits its medical applications. Recent report by Williams et al. [Vet. Hum. Toxicol. 42 (2000) 196] implicated rat hepatic cytochrome P450 (CYP) 1A2 as a likely modulator of SA toxicity. Indeed, the in vitro toxicity of SA in primary culture of rat hepatocytes and human hepatic cell line HepG2, demonstrated as lactate dehydrogenase leakage and metabolic capability (MTT assay), was diminished following induction of CYP1A by 2,3,7,8-tetrachlorodibenzo- p-dioxin, 3-methylcholanthrene, and β-naphtoflavone. Using microsomes containing recombinant CYP1A1 or CYP1A2 we show that SA causes non-competitive inhibition of the former and competitive inhibition of the latter as assessed by ethoxyresorufin de-ethylation (EROD). In human hepatic microsomes SA exhibits competitive inhibition of EROD activity with apparent K i of 2 μM, a value identical to that observed for CYP1A2 inhibition in recombinant system. Pre-incubation of SA with human liver microsomes resulted in time-dependent, but not dose-dependent decline in EROD activity suggesting CYP1A2 inhibition is not mechanism based. SA also inhibits activity of NADPH:CYP reductase, an enzyme required for CYP activity, with IC 50 very similar to that observed for EROD inhibition. Tentative mechanism for CYP1A involvement in decreased in vitro SA toxicity is discussed.

A versatile total synthesis of benzo[c]phenanthridine and protoberberine alkaloids using lithiated toluamide-benzonitrile cycloaddition.

A new versatile synthesis of benzo[c]phenanthridine and protoberberine alkaloids using lithiated toluamide-benzonitrile cycloaddition was carried out. The coupling reaction between benzonitrile 6 with o-toluamides (8a-c) afforded 3-arylisoquinolines (9a-c) that were transformed to the protoberberines (11a-c) or benzo[c]phenanthridines (14a-c). These compounds were synthesized by ring closure of the two-carbon chain on either position 2 or 4 of the 3-arylisoquinolinone (9a-c). Several kinds of substituted benzo[c]phenanthridine alkaloids such as oxysanguinarine, oxyavicine, and oxynitidine as well as protoberberines such as 8-oxocoptisine, 8-oxopseudoberberine, and 8-oxopseudocoptisine were synthesized.