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

Chemico-Biological Interactions 140 (2002) 231– 242

www.elsevier.com/locate/chembiont

DNA adduct formation from quaternary benzo[c]phenanthridine alkaloids sanguinarine and chelerythrine as revealed by the 32 P-postlabeling technique Marie Stiborova´ a,*, Vilı´m S& ima´nek b, Eva Frei c, Pavel Hobza d, Jitka Ulrichova´ b a

Department of Biochemistry, Faculty of Science, Charles Uni6ersity, Alberto6 2030, 128 40 Prague 2, Czech Republic b Institute of Medical Chemistry and Biochemistry, Palacky´ Uni6ersity, 775 15 Olomouc, Czech Republic c Department of Molecular Toxicology, German Cancer Research Center, Im Neuenheimer Feld 280, 69 120 Heidelberg, Germany d Heyro6sky Institute of Physical Chemistry and Center for Complex Molecular Systems and Biomolecules, Academy of Sciences of the Czech Republic, Dolejsko6a 3, 182 23 Prague 8, Czech Republic Received 21 February 2002; received in revised form 23 April 2002; accepted 29 April 2002

Abstract 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 b-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 C11C12 bond (ring B) in alkaloid molecules we found that fagaronine behaved differently from sanguinarine and chelerythrine. While sanguinarine and chelerythrine showed a preference

* Corresponding author. Tel.: + 420-2-21952333; fax: +420-2-21952331 E-mail address: [email protected] (M. Stiborova´). 0009-2797/02/$ - see front matter © 2002 Elsevier Science Ireland Ltd. All rights reserved. PII: S0009-2797(02)00038-8

232

M. Stiboro6a´ et al. / Chemico-Biological Interactions 140 (2002) 231–242

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. © 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Quaternary benzo[c]phenenthridine alkaloids; Enzymatic activation; DNA adduct formation; 32 P-postlabeling; Genotoxicity; Quantum chemical calculations

1. Introduction Several plant extracts and their components exhibit toxic side effects in addition to their desired pharmacological activities. Many adverse effects are due to selective interaction of specific structures (e.g. ion pumps, intracellular receptors) or as a result of metabolic activation to reactive intermediates, which are capable of covalent binding to cellular macromolecules. Covalent binding to proteins can cause cell death by disturbing essential biochemical processes or immunological reactions. Furthermore, a large body of evidence in experimental systems suggests that DNA adduct formation is a critical event in the initiation stage of carcinogenesis [1]. Indeed, some of the most potent known carcinogens are natural products [2]. Among those identified in plants, safrole, aflatoxins, cycasin, aristolochic acids and pyrrolizidine alkaloids have attracted considerable attention [2–4]. Quaternary benzo[c]phenanthridine alkaloids (QBA) represent another group of natural products exhibiting a wide spectrum of pharmacological activities and numerous toxic side effects [5– 8]. QBA were found in plants of Caprifoliaceae, Fumariaceae, Meliaceae, Papaveraceae, and Rutacea families [6]. They belong to the elicitor-inducible secondary metabolites and are called phytoallexines because of their anti-microbial and anti-fungal activities [5–8]. Sanguiritrin, a QBA extract from Macleya cordata (a mixture of sanguinarine, chelerythrine (Fig. 1) and three minor QBAs), is used as an anti-microbial agent and for treatment of myopathy [5,9]. Sanguinaria, extracted from Sanguinaria cadanensis (a mixture of sanguinarine, chelerythrine and four minor QBAs), is used as the antiplaque component in toothpaste and oral rinses manufactured in Europe and USA [10]. Sanguinarine may have an antitumor potential [11]. Another QBA, fagaronine (Fig. 1), demonstrates antileukemic activity [5], inhibits HIV-1 and HIV-2-reverse transcriptase [12], and DNA topoisomerase I and II [13]. Fagaronine is considered a potential novel antitumor drug [5]. A well-known toxic effect of QBA is the epidemic dropsy syndrome, which is associated with consumption of plant oil contaminated by alkaloids of Argemone mexicana [14]. Damm et al. [15] have reported that the long-term use of oral products containing sanguinaria appears to be associated with an increased prevalence of leukoplakia of maxillary vestibule. Furthermore, sanguinarine and chelerythrine have demonstrated toxicity in rat hepatocytes [16], cultured human and mouse fibroblasts [17] and/or in the porcine and human hepatocyte primary cultures [18]. The sanguinarine-mediated cytotoxicity in mice was reduced by

M. Stiboro6a´ et al. / Chemico-Biological Interactions 140 (2002) 231–242

233

pretreatment with 3-methylcholanthrene, an inducer of cytochrome P450 enzymes [19]. In addition to cytotoxicity, sanguinarine elicited positive mutagenic responses in the Salmonella mutagenicity test after metabolic activation [20] and chelerythrine induced respiration-deficient mutants in Saccharomyces cere6isieae [21]. However, neither teratogenicity nor increases in preneoplastic or neoplastic lesions have been shown following treatment with a mixture of sanguinarine and chelerythrine in long-term rat bioassays [5]. Sanguinarine forms a molecular complex with DNA by intercalation [22– 25]. Whereas, DNA intercalation of this alkaloid is well understood [22–25], other types of DNA modification by QBA remain to be explored. Therefore, the objective of this study was to investigate whether other types of in vitro DNA modification by

Fig. 1. Structure of sanguinarine, chelerythrine, and fagaronine alkaloids.

234

M. Stiboro6a´ et al. / Chemico-Biological Interactions 140 (2002) 231–242

sanguinarine, chelerythrine and fagaronine are generated. The detection of DNA adducts derived from sanguinarine and chelerythrine by 32P-postlabeling analysis [26] is reported herein for the first time.

2. Materials and methods

2.1. Alkaloids and chemicals Sanguinarine and chelerythrine were isolated from the alkaloid extract of Macleaya cordata (Papaveraceae) using column chromatography on alumina [27]. Sanguinarine in 98.1% purity, MP 279– 282 °C (Ref. 277– 280 °C [28]) and chelerythrine in 95% purity, MP 200– 204 °C [27] were obtained. Fagaronine in 96.2% purity was synthesized by S& midrkal [29], MP 203–206 °C (Ref. 202 °C [28]). IR, UV, MS and NMR spectra were consistent with the structures of the above alkaloids. Chemicals were obtained from the following sources: NADPH and nuclease P1 from Sigma Chemical Co. (St. Louis, MO); b-naphthoflavone (b-NF) and bicinchoninic acid from Aldrich Chemical Co. (Milwaukee, WI) and calf thymus DNA (CT-DNA) from Roche Mannheim (Germany). All other chemicals were of analytical purity or better. Enzymes and chemicals for the 32P-postlabeling assay were obtained commercially from previously described sources [4].

2.2. Preparation of microsomes and assays Hepatic microsomes of uninduced male Sprague–Dawley rats and those of rats pre-treated with b-NF [30] were prepared as described previously [31]. Protein concentrations in the microsomal fractions were assessed using the bicinchoninic acid protein assay with serum albumin as a standard [32]. The concentration of cytochrome P450 (CYP) was estimated according to Omura and Sato [33] based on the complex of reduced cytochrome P450 with carbon monoxide. Specific contents of cytochromes P450 were 0.609 0.12 and 1.309 0.43 nmol/mg protein for microsomes of control (uninduced) rats and those of rats pre-treated with b-NF (10 rats/group), respectively. All results are presented as means9 SD (n =10).

2.3. Incubations The incubation mixtures contained in a final volume of 0.75 ml: 50 mM potassium phosphate buffer (pH 7.4), 1 mM NADPH, microsomes containing 1 nmol cytochrome P450 (1.7 and 0.8 mg protein of control and b-NF microsomes, respectively), 1– 100 mM sanguinarine, chelerythrine or fagaronine as chloride salts dissolved in water and 1 mg of CT-DNA (4 mM). The reaction was initiated by addition of NADPH. Incubations were carried out at 37 °C for 60 min. Control incubations were performed either without NADPH or with the

M. Stiboro6a´ et al. / Chemico-Biological Interactions 140 (2002) 231–242

235

whole activating system and QBA but without DNA, or with the activating system and DNA but without QBA. After incubation (37 °C, 60 min), the mixtures were extracted twice with ethyl acetate (2× 2 ml). DNA was isolated from the residual water phase by the phenol/chloroform extraction method as described earlier [30,31]. The content of DNA was determined spectrophotometrically.

2.4.

32

P-postlabeling analysis

The nuclease P1 enrichment version [34] and the 1-butanol extraction-mediated enrichment procedure [35] of the 32P-postlabeling assay [26] were performed by digesting DNA samples (12.5 mg) with micrococcal nuclease (750 mU) and spleen phosphodiesterase (12.5 mU) in digestion buffer (20 mM sodium succinate, 8 mM CaCl2, pH 6.0) for 3 h at 37 °C in a total volume of 12.5 ml. Here, 2.5 ml of the digests were removed and diluted 1:1500 to determine the amount of normal nucleotides. In the nuclease P1 version, digests (10 ml) were enriched for adducts by incubation with 5 mg (5 U) of nuclease P1 in 3 ml of a buffer containing 0.8 M sodium acetate, pH 5.0, 2 mM ZnCl2 for 30 min at 37 °C. The reaction was stopped by adding 3 ml of 427 mM Tris base. The extraction with 1-butanol to enrich adducts was carried out as described earlier [35]. Four microliters of labeling mix consisting of 400 mM bicine pH 9.5, 300 mM dithiothreitol, 200 mM MgCl2, 10 mM spermidine, 100 mCi [g-32P]-ATP (15 pmol), 0.5 ml of 90 mM ATP and 10 U T4 polynucleotide kinase were added. After incubation for 30 min at room temperature, 20 ml were applied to a polyethylenimine (PEI)-coated cellulose thin-layer chromatography (TLC) plate (Macherey-Nagel, Du¨ ren, Germany) and separated as described [4,31]. For determination of the amount of normal nucleotides 5 ml of the 1:1500 dilution of digests were mixed with 2.5 ml of Tris buffer (10 mM, pH 9.0) and 2.5 ml of labeling mix (see above) and incubated for 30 min at room temperature. The labeling mixture was diluted by mixing 4 ml with 750 ml of 10 mM Tris buffer, pH 9.0. This solution (5 ml) was applied to a PEI-cellulose TLC plate and run in 0.28 M (NH4)2SO4, 50 mM NaH2PO4, pH 6.5. Adducts and normal nucleotides were detected and quantified by storage phosphor imaging on a Packard Instant Imager. Count rates of adducted fractions were determined from triplicate maps after subtraction of count rates from adjacent blank areas. Excess [g-32P]ATP after the postlabeling reaction was confirmed. Adduct levels were calculated in units of relative adduct labeling (RAL) which is the ratio of counts per minute (cpm) of adducted nucleotides to cpm of total nucleotides in the assay.

2.5. Quantum chemical calculations All ab initio calculations were performed for the optimized structures of compound molecules studied, gradient optimization were performed at the HartreeFock/6-31G** level of theory as described elsewhere [36].

236

M. Stiboro6a´ et al. / Chemico-Biological Interactions 140 (2002) 231–242

3. Results The 32P-postlabeling technique [26] represents a suitable method for the analysis of different types of DNA modification generated with toxic compounds in vivo and in vitro, and is used mainly for detection of covalent DNA adducts [37]. Therefore, this technique was employed for investigation of in vitro interactions between DNA and alkaloids sanguinarine, chelerythrine and fagaronine. In the presence of microsomes of uninduced rats and NADPH, one major and two minor DNA adduct spots were detected in DNA reacted with sanguinarine and chelerythrine (Fig. 2). Besides these three DNA adducts, two additional radioactive adduct spots (4 and 5 in Fig. 2) were formed by sanguinarine in the presence of b-NF microsomes in incubation mixtures. All sanguinarine and chelerythrinederived DNA adducts migrated primarily along a diagonal zone on the TLC plate at approximately 45° to elution directions D3 and D4. In contrast to these results, no DNA adduct spots were found in DNA exposed to fagaronine (Fig. 2). Adduct level is a function of ratio of DNA and test compound concentrations used. A lower DNA concentration in a reaction for the same concentration of test QBA is likely to result in much higher DNA adduction. Based on this argument, in the case of fagaronine, we also incubated this compound in the presence of microsomes with 10-fold lower DNA concentrations (0.4 mM, instead of 4 mM used in the other experiments) to determine if fagaronine is indeed negative in producing DNA damage. Even under these conditions, no fagaronine-derived DNA adduct spots were detected. Likewise, control incubations carried out either without test compounds, or without NADPH, or without DNA were free of adduct spots detected by the 32P-postlabeling assay (not shown). DNA adducts were quantified to evaluate quantitative aspects of both microsomal systems to induce adducts in DNA by the compounds tested. The levels of adducts were determined by measurement of the adduct count rates and expressed as RAL (Table 1). Quantitative analysis of DNA adducts (Table 1) revealed a 4-fold increase in levels of DNA adducts induced by sanguinarine incubated with b-NF microsomes compared to sanguinarine incubated with control (uninduced) microsomes. Total adduct levels (RALs) were 36.39 3.0 and 8.990.8 adducts per 108 normal nucleotides for sanguinarine incubated with b-NF microsomes and microsomes of uninduced rats, respectively. In contrast, there was no effect on the levels and pattern of adducts when chelerythrine was reacted with both types of microsomes and DNA (Table 1 and Fig. 2). Incubation of decreasing amounts of sanguinarine and chelerythrine with b-NF microsomes resulted in the same adduct pattern. Total adduct levels as well as individual adduct levels showed a dose-dependent formation. The presence of one order of magnitude lower concentrations of sanguinarine and chelerythrine in incubations (10 mM) resulted in one order of magnitude lower levels of DNA adducts. Under these conditions, the values of RALs were 3.29 0.4 and 1.590.2 adducts per 108 normal nucleotides for sanguinarine and chelerythrine, respectively. Because adduct spots were undetectable at the lowest concentration of test compounds (1 mM), they could not be quantified.

M. Stiboro6a´ et al. / Chemico-Biological Interactions 140 (2002) 231–242

237

Fig. 2. Autoradiographic profiles of DNA adducts obtained from in vitro incubation of calf thymus DNA with sanguinarine (A), chelerythrine (B) and fagaronine (C) activated with hepatic microsomes of untreated rats (Aa, Ba, Ca) and b-NF microsomes (Ab, Bb, Cb). The nuclease P1-enrichment version of 32 P-postlabeling assay was used for analysis. Screen enhanced autoradiography was at − 80 °C 2 h for (A, B) and 6 h for (C). Chromatographic conditions: D1, 1 M sodium phosphate, pH 6.8; D3, 3.5 M lithium formate, 8.5 M urea, pH 4.0; D4, 0.8 M LiCl, 0.5 M Tris – HCl, 8.5 M urea, pH 9.0; D5, 1.7 M NaH2PO4, pH 6.0. Origins, in the bottom left-hand corner, were cut-off before exposure; D3 direction from bottom to top and D4 direction on four directional TLC on PEI-cellulose from left to right.

In parallel incubations containing sanguinarine or chelerythrine, b-NF microsomes, NADPH and DNA, the version of the 32P-postlabeling assay using the 1-butanol extraction [35] was also used. No differences in patterns and levels of sanguinarine- and chelerythrine-derived adducts detected by both enhanced version of the 32P-postlabeling assay were observed (results not shown).

238

M. Stiboro6a´ et al. / Chemico-Biological Interactions 140 (2002) 231–242

In order to shed more light on the differential potency of sanguinarine, chelerythrine and fagaronine to form reactive species generating DNA adducts we performed quantum chemical ab initio calculations in the attempt to determine molecular characteristics as well as the various reactivity indices. All calculations were performed for the optimized structures of compound molecules studied, gradient optimization were performed at the Hartree-Fock/6-31G** level of theory [36]. Investigating the molecular properties of QBA we found that they all possessed a relatively small dipole moment (3.5– 4.0 D) and had comparable donor–acceptor properties (energies of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were comparable for all three systems). Thus, the molecular properties of QBA cannot explain their different reactivity in the experiments testing their activation by cytochromes P450 to form DNA adducts. We therefore considered various bonding characteristics at critical part of all three molecular systems, in ring B at the positions C11 and C12 (Fig. 1). From the total C11C12 bond order it follows that fagaronine should preferentially undergo nucleophilic attack. Furthermore, the C11C12 bond is strongest in fagaronine, i.e. reactivity of this bond with respect to attack of oxygen during the cytochrome P450-catalyzed reactions, will be easier in sanguinarine and cheleryTable 1 Quantitative analysis of DNA adducts derived from sanguinarine, chelerythrine and fagaronine activated with rat liver microsomal enzyme systems (RAL, adducts per 108 nucleotides) Compound

Adduct levels: adducts per 108 nucleotides Activation with b-NF microsomes

Control microsomes

Sanguinarine Spot 1a Spot 2 Spot 3 Spot 4 Spot 5 Total

19.99 2.0 4.5 9 0.4 5.99 0.5 3.59 0.4 2.59 0.2 36.3 9 3.0

5.3 90.6 1.8 90.2 1.8 9 0.2 n.d.b n.d. 8.9 9 0.8

Chelerythrine Spot 1 Spot 2 Spot 3 Total

7.190.7 2.890.3 3.89 0.3 13.79 1.2

6.9 9 0.7 2.9 9 0.3 4.0 9 0.3 13.8 91.2

Fagaronine

n.d.

n.d.

a

See Fig. 2. n.d., not detected. RAL values represent mean ( 9SD) from three determinations of two independent incubations. Background levels were subtracted from identical regions on the PEI-cellulose plates in the control. DNA samples isolated from the reaction mixtures were analyzed by nuclease P1 version of the 32 P-postlabeling assay. b

M. Stiboro6a´ et al. / Chemico-Biological Interactions 140 (2002) 231–242

239

thrine. Analyzing the HOMO contribution to the C11C12 bond order we again found the susceptibility of fagaronine to nucleophilic attack. A very similar picture was obtained analyzing the HOMO and LUMO contributions to C11H bond order, both indices supported nucleophilic attack on fagaronine. It is important to note that analysis of the C12H bond revealed no clear differences between the different molecular systems studied. Finally, analysis of the HOMO contribution to C11 atomic charge showed it was lowest for fagaronine, supporting a nucleophilic attack in this alkaloid.

4. Discussion The results presented in this paper clearly show that DNA adducts are formed by sanguinarine and chelerythrine in the presence of rat hepatic microsomes. These results are in favor of a potential genotoxic effect of both alkaloids, after metabolic conversion, confirming previous finding [20,21]. Sanguinarine elicits positive mutagenic response in Salmonella typhimurium (Ames) assay after metabolic activation [20] and chelerythrine has been reported to induce respiration-deficient mutants in Saccharomyces cere6issie [21]. Nevertheless, it should be noted that the genotoxic effect of both compounds remains questioned, since metabolites of sanguinarine and chelerythrine reacting with DNA have yet to be detected and because DNA adducts could also be formed via secondary pathways. This has been found for reactive oxygen species [38] and malondialdehyde generated during lipid peroxidation, which may be enhanced by certain xenobiotics [39,40]. However, lipid peroxidation assessed by malondialdehyde formation was not elicited by sanguinarine and chelerythrine in hepatocytes, which excludes oxidative injury by these compounds [18,20]. Taken together, it is likely that covalent binding of sanguinarine and chelerythrine activated by microsomal cytochrome P450, rather than lipid peroxidation or oxidative stress, gives rise to the DNA adduct formation detected by the 32P-postlabeling technique. Under the experimental conditions used, sanguinarine and chelerythrine occurred in the pseudobase (alkanolamine) form [5], the actual species forming a complex with proteins including cytochromes P450 [5,18,41,42]. On the other hand, because fagaronine has a different substitution pattern (Fig. 1), and is a quaternary cation at physiological pH as only, it does not readily interact with cytochromes P450 [42]. Experiments with human liver microsomes have shown that sanguinarine and chelerythrine interact with cytochrome P450, producing a strong inhibition of the 7-ethoxyresorufin O-deethylase activity, a marker for cytochrome P450 1A [43]. Chelerythrine also inhibits the cytochrome P450 2C-dependent reactions in human microsomes [43]. Furthermore, Williams et al. [19] demonstrated that sanguinarine decreases the activity of cytochrome P450 1A-dependent aminopyrine N-demethylase in mice pre-treated with 3-methylcholanthrene, an inducer of cytochromes P450 of a 1A subfamily. The results of our present study correlate with those in Refs. [19] and [43]. Herein, we show that sanguinarine and chelerythrine are activated by cytochromes P450 to reactive species forming DNA adducts. In the case of

240

M. Stiboro6a´ et al. / Chemico-Biological Interactions 140 (2002) 231–242

sanguinarine, enzymes of the cytochrome P450 1A subfamily are more effective than other cytochromes P450, because the b-NF microsomes rich in these two isoforms yielded more DNA adducts than uninduced microsomes. We can only speculate, which sites in QBA molecules are responsible for DNA binding. There are two possible reactive sites in QBA molecule, the iminium bond C6N+ and the C11C12 bond in the ring B (Fig. 1). Nevertheless, the QBA substituted at the C6 position in solution is in equilibrium with its cationic form, while the substitution at C11 is stable under such conditions. With respect to different atomic and bond indices of the C11C12 bond, fagaronine differed from sanguinarine and chelerythrine. While sanguinarine and chelerythrine exhibited a tendency for electrophilic attack indicating higher potential to be activated by cytochromes P450, fagaronine showed a susceptibility to nucleophilic attack. Indeed, the C11C12 epoxide of sanguinarine has also been described to exist [45]. Nevertheless, the question whether QBA are activated during their metabolism in organisms in a similar way to other polycyclic aromatic compounds (such as benzo(a)pyrene), due to formation of reactive diol-epoxides [44], remains to be answered. Further testing of sanguinarine and chelerythrine in vivo is required to fully assess their potential genotoxicity. Nevertheless, because of the extent of DNA adducts detected by the 32P-postlabeling assay is indicative of genotoxic potential, caution should be exercised in recommending the use of sanguinarine and chelerythrine in human and veterinary applications.

Acknowledgements The financial support of German Cancer Research Center, the Grant Agency of the Czech Republic (203/01/0996, 203/00/0633), the Grant Agency of the Ministry of Health (NL 5267-3/1999) and Ministry of Education of the Czech Republic (MSM 1131 00001 and 1511 00003) is greatly acknowledged.

References [1] M.C. Portier, A. Weston, Human DNA adduct measurements: state of the art, Environ. Health Perspect. 104 (1996) 883 –893. [2] Y.-T. Woo, D.Y. Lai, J.C. Arcos, M.F. Argus, Chemical Induction of Cancer IIIc, Academic Press, San Diego, CA, 1988. [3] C.P. Wild, B. Chapot, E. Scherer, L. Den Engelse, R. Montesano, Application of antibody methods to the detection of aflatoxin in human body fluids, in: H. Bartsch, K. Hemminki, I.K. O’Neill (Eds.), Methods for Detecting DNA Damaging Agents in Humans: Applications in Cancer Epidemiology and Prevention, IARC Lyon, 1988, pp. 67 – 74 IARC Sci. Public. No. 89. [4] C.A. Bieler, M. Stiborova´ , M. Wiessler, J.-P. Cosyns, C. van Ypersele de Strihou, H.H. Schmeiser, 32 P-post-labelling analysis of DNA adducts formed by aristolochic acid in tissues from patients with Chinese herbs nephropathy, Carcinogenesis 18 (1997) 1063 – 1067. [5] D. Walterova´ , J. Ulrichova´ , I. Va´ lka, J. Vicar, C. Vavreckova´ , E. Ta´ borska´ , R.J. Harkrader, D.L. Mezer, H. Cerna´ , V. S& ima´ nek, Benzo[c]phenanthridine alkaloids sanguinarine and chelerythrine:

M. Stiboro6a´ et al. / Chemico-Biological Interactions 140 (2002) 231–242

[6] [7] [8] [9] [10] [11] [12]

[13] [14] [15]

[16] [17] [18]

[19] [20]

[21]

[22] [23] [24]

[25]

[26] [27]

241

biological activities and dental care applications, Acta Univ. Palacki. Olomouc (Olomouc), Fac. Med. 139 (1995) 7 –16. V. S& ima´ nek, Benzophenanthridine alkaloids, in: A. Brossi (Ed.), The Alkaloids, vol. 26, Academic Press, Orlando, 1985, pp. 185 –240. M. Wink, T. Schmeller, B. Latz-Bruning, Modes of action odf allelochemical alkaloids: interaction with neuroreceptors, DNA and other molecular targets, J. Chem. Ecol. 24 (1998) 1881 – 1934. R. Verpoorte, Antimicrobially active alkaloids, in: M.F. Roberts, M. Wink (Eds.), Alkaloids. Biochemistry, Ecology and Medicinal Applications, Plenum Press, New York, 1998, pp. 397 – 426. S.A. Vichkanova, O.H. Tolkachev, R.G. Martynova, E.V. Arzamaciev, Sanguiritrin-novyi lekarstvenyi preparat protivomikrobnogo deistviya, Khim-Farm. Zh. 16 (1982) 1515 – 1520. H. Tennenbaum, N. Dahan, M. Soell, Effectiveness of a sanguinarine regimen after scaling and root planing, J. Periodontol. 70 (1999) 307 –311. M.D. Faddeeva, T.N. Beliaeva, Sanguinarine and ellipticine cytotoxic alkaloids isolated from well-known antitumor plants. Intracellular targets of their action, Tsitologia 39 (1997) 181 – 208. G. Tan, J.F. Miller, A.D. Kinghorn, S.H. Hughes, J.M. Pezzuto, HIV-1 and HIV-2 reverse transcriptase: a comparative study of sensitivity to inhibition by selected natural products, Biochem. Biophys. Res. Commun. 185 (1992) 370 –378. L.K. Wang, R.K. Johnson, S.M. Hecht, Inhibition of toposisomerase I function by nitidine and fagaronine, Chem. Res. Toxicol. 6 (1993) 813 –818. M. Das, S.K. Khanna, Clinicoepidemiological, toxicological, and safety evaluation studies on argemone oil, Crit. Rev. Toxicol. 27 (1997) 273 – 297. D.D. Damm, A. Curraan, D.K. White, D.K. White, J.F. Drummond, Leukoplakia of the maxillary vestibule —an association with Viadent?, Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 87 (1999) 61 – 66. J. Ulrichova´ , D. Walterova´ , C. Vavreckova´ , V. Kamara´ d, V. S& ima´ nek, Cytotoxicity of benzo[c]phenanthridium alkaloids in isolated rat hepatocytes, Phytother. Res. 10 (1996) 220 – 223. J. Vicar, V. S& ima´ nek, J. Ulrichova´ , Toxicity of quarternary benzophenenthridine alkaloids in a fibroblast cell culture model, Phytomedicine 7 (II) (2000) 71. J. Ulrichova´ , Z. Dvora´ k, J. Vicar, J. Lata, J. Smrzova´ , A. S& edo, V. S& ima´ nek, Cytotoxicity of natural compounds in hepatocyte cell culture models. The case of quarternary benzo[c]phenenthridine alkaloids, Toxicol. Lett. 125 (2001) 125 –132. M.K. Williams, S. Dalvi, R.R. Dalvi, Influence of 3-methylcholanthrene pretreatment on sanguinarine toxicity in mice, Vet. Hum. Toxicol. 42 (2000) 196 – 198. V.H. Frankos, D.J. Brusick, E.M. Johnson, H.I. Maibach, I. Munro, R.A. Squire, C.S. Weil, Safety of sanguinaria extract as used in commercial toothpaste and oral rinse products, J. Can. Dent. Assoc. 56 (Suppl. 7) (1990) 41 –47. V. Krivjansky´ , M. Obernauerova´ , J. Ulrichova´ , V. S& ima´ nek, J. S& ubı´k, Induction of respiration-deficient mutants in Saccharomyces cere6isies by chelerythrine, FEMS Microbiol. Lett. 120 (1994) 87 – 92. M. Maiti, R. Nandi, K. Chaudhuri, Sanguinarine: a monofunctional intercalation alkaloids, FEBS Lett. 142 (1982) 280 – 284. A. Sen, M. Maiti, Interaction of sanguinarine iminium and alkanolamine form with calf thymus DNA, Biochem. Pharmacol. 48 (1994) 2097 –2102. S. Das, G.S. Kumar, M. Maiti, Conversion of the left-handed form and the protonated from of DNA back to the bound right-handed from by sanguinarine and ithidium: a comparative study, Biophys. Chem. 76 (1999) 199 – 218. S. Das, A. Banerjee, A. Sen, M. Maiti, Interaction of sanguinarine with A-form and protonated form of ribonucleic acid structure: spectroscopic, viscometric and thermodynamic studies, Curr. Sci. 79 (2000) 82 – 87. K. Randerath, M.V. Reddy, R.C. Gupta, 32P-labeling test for DNA damage, Proc. Natl. Acad. Sci. USA 78 (1981) 6126 –6129. J. Dosta´ l, E. Ta´ borska´ , J. Slavı´k, Preparative column chromatography of quarternary benzophenenthridine alkaloids of Dicranostigma lactuoides, Fitoterapia 63 (1992) 67 – 70.

242

M. Stiboro6a´ et al. / Chemico-Biological Interactions 140 (2002) 231–242

[28] I.W. Southon, J. Buckingham, Dictionary of Alkaloids, Chapman and Hall, London, 1989, p. 215 and 940. [29] J. S& midrkal, Synthesis of fagaronine, Collect. Czech Chem. Commun. 53 (1988) 3184 – 3192. [30] M. Stiborova´ , B. Asfaw, E. Frei, H.H. Schmeiser, M. Wiessler, Benzenediazonium ion derived from Sudan I forms an 8-(phenylazo)guanine adduct in DNA, Chem. Res. Toxicol. 8 (1995) 489 – 498. [31] M. Stiborova´ , E. Frei, M. Wiessler, H.H. Schmeiser, Human enzymes involved in metabolic activation of carcinogenic aristolochic acids: evidence for reductive activation by cytochromes P450 1A1 and 1A2, Chem. Res. Toxicol. 14 (2001) 1128 – 1137. [32] K.J. Wiechelman, R.D. Braun, J.D. Fitzpatrick, Investigation of the bicinchoninic acid protein assay: identification of the groups responsible for color formation, Anal. Biochem. 175 (1988) 231 – 237. [33] T. Omura, R. Sato, The carbon monoxide-binding pigment of liver microsomes. I. Evidence for its hemoprotein nature, J. Biol. Chem. 239 (1964) 2370 – 2378. [34] M.V. Reddy, K. Randerath, Nuclease P1-mediated enhancement of sensitivity of 32P-postlabelling test for structurally diverse DNA adducts, Carcinogenesis 7 (1986) 1543 – 1551. [35] R.C. Gupta, K. Early, 32P-adduct assay comparative recoveries of structurally diverse DNA adducts in the various enhancement procedures, Carcinogenesis 8 (1988) 1687 – 1693. [36] D.D. Fitts, Principles of Quantum Mechanics, Cambridge University Press, Cambridge, 1999. [37] K. Randerath, E. Randerath, 32P-postlabeling methods for DNA adduct detection: overview and critical evaluation, Drug Metab. Rev. 26 (1994) 67 – 85. [38] H. Seto, S.M. Okura, T. Takesue, T. Ikemura, Reaction of malondialdehyde with nucleic acid. Formation of fluorescent pyrimido[1,2-a]purin-10(3H)-one nucleotides, Bull. Chem. Soc. Jpn 56 (1983) 1799 – 1802. [39] A.K. Basu, S.M. O’Hara, P. Valldier, K. Stone, O. Mols, L.J. Marnett, Identification of adducts formed by reaction of guanine nucleosides with malondialdehyde and structurally related aldehydes, Chem. Res. Toxicol. 1 (1988) 53 –59. [40] S. Obrecht-Pflumio, G. Dirheimer, In vitro DNA and dGMP adducts formation caused by ochratoxin A, Chem.-Biol. Interact. 127 (2000) 29 –44. [41] R.R. Dalvi, Sanguinarine: its potential as a liver toxic alkaloid present in the seeds of Agremone mexicana, Experientia 41 (1985) 77 – 78. [42] A. Peeples, R.R. Dalvi, Toxic alkaloids and their interaction with microsomal cytochrome P-450 in vitro, J. Appl. Toxicol. 2 (1982) 300 –302. [43] M. Modriansky, P. Kosina, M. Kesselova´ , D. Walterova´ , V. S& ima´ nek, J. Ulrichova´ , Interactions of sanguinarine and chelerythrine with selected human cytochrome P450 isoforms. 12th International Conference on Cytochrome P450, 11 –15.9.2001, Le Grande Motte, Abstract Book, p. 158. [44] F.P. Guengerich, T. Shimada, Activation of procarcinogens by human cytochrome P450 enzymes, Mutat. Res. 400 (1998) 201 –213. [45] M. Suffness, G.A. Cordel, Antitumor alkaloids, Alkaloids 25 (1985) 186.