Interaction Of Sanguinarine Research Articles

Competitive binding assay for G-quadruplex DNA and sanguinarine based on room temperature phosphorescence of Mn-doped ZnS quantum dots

Abstracts G-quadruplex DNA is an effective target for anticancer drug, and investigation of the G-quadruplex DNA with natural compounds plays a key role in the development of anticancer drugs. In this article, room temperature phosphorescence sensing system based on l -cysteine-capped Mn-doped ZnS QDs has been established. Sanguinarine can adsorb on the surface of Mn-doped QDs and quenched the phosphorescence emission of the sensor. When the G-quadruplex sequences combined with the sanguinarine of the QDs-sanguinarine system, the phosphorescence intensities of the QDs sensors would be restored, and the binding abilities of the G-quadruplex DNA with the sanguinarine can be evaluated by the phosphorescence recoveries of the sensor system. Based on the developed approach, the interaction of sanguinarine and six G-quadruplex DNA with various sequences (tel24-1, tel24-2, tel22, k-ras, HIF-1α and c-kit1) has been investigated. The results showed that the binding abilities of the G-quadruplex DNA with sanguinarine were related to their number of bases and conformations. The conformational changes of the six G-quadruplex DNA, after binding with sanguinarine, have also been probed by circular dichroism. Combining the changes of the phosphorescence lifetime, the binding mechanism of the G-quadruplex DNA and sanguinarine has been discussed. The developed method was simple, rapid and specific, and can avoid fluorescence interferences of the system, and it would be prospective to evaluate the interaction of the drug with different G-quadruplexes.

Binding of nucleosides with the cytotoxic plant alkaloid sanguinarine: Spectroscopic and thermodynamic studies

In spite of a large number of studies of the interaction of the cytotoxic plant alkaloid sanguinarine (SAN) with nucleic acids, the anticancer mechanism of SAN is still not clear. In contrast to the large number of studies of the interaction mechanism of SAN with DNA, there have been relatively few studies of the interaction of SAN with nucleosides. In this work, the interaction of SAN with three nucleosides—thymidine (T), uridine (U), and adenosine (A)—was investigated using a combination of conventional fluorescence and UV-vis spectroscopic techniques; thermodynamic calculations were also carried out at physiological pH 7.2. The binding processes of SAN with the different nucleosides were characterized by hypochromic and bathochromic effects in the absorption spectra of SAN and by the quenching of the fluorescence intensity of SAN. The measurements of fluorescence lifetime, the variations of the absorption spectra of the fluorophore, and the dependence of the quenching on the temperature indicated that the fluorescence quenching is static. The Stern-Volmer plot is nonlinear and approximately quadratic showing that, in this process, one SAN molecule can bind with two nucleoside molecules. These studies, together with our earlier studies of the binding of SAN with cytidine (C) and guanosine (G), showed that the binding constants of SAN with the five nucleosides at T = 308.15, 318.15, and 328.15 K decreased in the order C > G > T > U > A and at T = 298.15 K decreased in the order G > C > T > U > A, and that the binding of SAN with the various nucleosides is not only slightly exothermic but also entropy-driven. All these results together with fluorescence quenching experiments advance good evidence concerning the interaction of SAN with various nucleosides. Such studies of the interaction mechanism of alkaloids with DNA may promote the development of new drugs.

Interaction of sanguinarine and its dihydroderivative with the Na +/K +-ATPase. Complex view on the old problem

The effects of sanguinarine (SG) and its metabolite dihydrosanguinarine (DHSG) on Na +/K +-ATPase were investigated using fluorescence spectroscopy. The results showed that the enzyme in E1 conformation can bind both charged and neutral (pseudobase) forms of SG with a K D = 7.2 ± 2.0 μM or 11.7 ± 0.9 μM, while the enzyme in E2 conformation binds only the charged form of SG with a K D = 4.7 ± 1.1 μM. Fluorescence quenching experiments suggest that the binding site in E1 conformation is located on the surface of the enzyme for both forms but the binding site in E2 conformation is protected from the solvent. We found no evidence for interaction of Na +/K +-ATPase and DHSG. This implies that any in vivo effect of SG attributable to inhibition of Na +/K +-ATPase can be considered only prior to SG → DHSG transformation in the gastro-intestinal tract and/or blood. Hence, Na +/K +-ATPase inhibition will be effective in SG topical application but its duration will be very limited in SG oral or parenteral administration.

Interaction of Sanguinarine Alkaloid, Isolated From Argemone Oil, With Hepatic Cytochrome P450 in Rats

ABSTRACTPrior studies have shown that argemone oil (AO), responsible for ‘Epidemic dropsy’, causes inhibition of catalytic activities of Cytochrome P450 (P450). In this study interaction of sanguinarine (SAN) alkaloid, isolated from AO, with rat hepatic P450 was investigated. Hepatic microsomes prepared from 3-methylcholantherene (3MC) treated rats when incubated with SAN (1–3 μM) resulted in a spectral peak at 385 nm and a trough at 415 nm, indicative of Type I binding. Incubation of SAN (50–200 μM) with hepatic microsomes prepared from phenobarbitone (PB) treated rats also showed a Type I spectra with a peak at 395 nm and a trough at 420 nm. Relative binding efficiency (ΔAmax/Ksapp factor) of SAN with P450 was found to be 1540 and 1030 absorbance units/nmol CYP/M for 3MC and PB induced microsomes, respectively. In a P450 spectral inhibition study SAN showed higher affinity towards 3MC eliciting inhibition at much lesser concentrations (0.25–5 μM) as compared to PB (100–300 μM). The IC50s of SAN with different catalytic markers of P450 isoforms, i.e. ethoxyresorufin-O-deethylase (EROD) for CYP1A1, was 2.8 μM and for methoxyresorufin-O-deethylase (MROD) for CYP1A2 was 2.2 μM in 3MC induced microsomes, while benzoyloxyresorufin-O-deethylase (BROD) for CYP 2B1/1A1 showed an IC50 of 50 μM but pentoxyresorufin-O-deethylase (PROD) for CYP2B1 showed no inhibition even at higher concentrations of SAN (> 60 μM) in PB-induced microsomes. These results indicate that higher affinity of SAN binding towards the CYP1A family may have a role in SAN toxicity.

Interactions of sanguinarine and chelerythrine with molecules containing a mercapto group

AbstractCapillary zone electrophoresis was applied to the investigation of the interaction of sanguinarine and chelerythrine with mercapto compounds including albumins at pH 7.4. Mercaptoethanol and L‐cysteine were chosen for the identification of the type of interaction and for the identification of the interacting chemical form of these alkaloids. It was evidenced that sanguinarine and chelerythrine do not react chemically with these mercapto compounds at pH 7.4 and that non‐covalent products form in this interaction. Their interaction is a fast and reversible complexation and is based on non‐bonding intermolecular interactions. Conditional binding constants measured at pH 7.4 and 5.0 indicate that only uncharged forms of sanguinarine and chelerythrine (pseudobases) participate in complexation. A negatively charged group, either bound to the mercapto ligand or supplied by the solution, enters in the complexation. The simple 1 : 1 interaction scheme holds, therefore, only for mercapto compounds bearing an anionic group. Constants corrected for the abundance of the uncharged alkaloid form are of the order of magnitude of 104 l mol−1 and depend on the chemical composition of buffer. Interaction of sanguinarine and chelerythrine with human or bovine serum albumins is qualitatively identical with interaction of these alkaloids with simple mercapto compounds. Constants for the binding of uncharged form of sanguinarine with human and bovine serum albumins in sodium phosphate buffer at pH 7.4, corrected for abundance of the interacting uncharged form, are 332 000±38 400 and 141 000±14 400 l mol−1, respectively. The former agrees well with the value K=385 000 (or log K=5.59) reported from static experiments. For the uncharged form of chelerythrine, the constants are 2 970 000±360 000 and 1 380 000±22 600 l mol−1 for human and bovine serum albumins, respectively. Copyright © 2003 John Wiley & Sons, Ltd.

Spectroscopic and Thermodynamic Studies on the Binding of Sanguinarine and Berberine to Triple and Double Helical DNA and RNA Structures

A comparative study on the interaction of sanguinarine and berberine with DNA and RNA triplexes and their parent duplexes was performed, by using a combination of spectrophotometric, UV thermal melting, circular dichroic and thermodynamic techniques. Formation of the DNA and RNA triplexes was confirmed from UV-melting and circular dichroic measurements. The interaction process was characterized by increase of thermal melting temperature, perturbation in circular dichroic spectrum and the typical hypochromic and bathochromic effects in the absorption spectrum. Scatchard analysis indicated that both the alkaloids bound to the triplex and duplex structures in a non-cooperative manner and the binding was stronger to triplexes than to parent duplexes. Thermal melting studies further indicated that sanguinarine stabilized the Hoogsteen base paired third strand of both DNA and RNA triplexes more tightly compared to their Watson-Crick strands, while berberine stabilized the third strand only without affecting the Watson-Crick strand. However, sanguinarine stabilized the parent duplexes while no stabilization was observed with berberine under identical conditions. Circular dichroic studies were also consistent with the observation that perturbations of DNA and RNA triplexes were more compared to their parent duplexes in presence of the alkaloids. Thermodynamic data revealed that binding of sanguinarine and berberine to triplexes (T·AxT and U·AxU) and duplexes (A·T and A·U) showed negative enthalpy changes and positive entropy changes but that of sanguinarine to C·GxC+ triplex and G·C duplex exhibited negative enthalpy and negative entropy changes. Taken together, these results suggest that both sanguinarine and berberine can bind and stabilize the DNA and RNA triplexes more strongly than their respective parent duplexes.

Conversions of the left-handed form and the protonated form of DNA back to the bound right-handed form by sanguinarine and ethidium: A comparative study

The interaction of sanguinarine and ethidium with right-handed (B-form), left-handed (Z-form) and left-handed protonated (designated as H L-form) structures of poly(dG–dC)·poly(dG–dC) and poly(dG–me 5dC)·poly(dG–me 5dC) was investigated by measuring the circular dichroism and UV absorption spectral analysis. Both sanguinarine and ethidium bind strongly to the B-form DNA and convert the Z-form and the H L-form back to the bound right-handed form. Circular dichroic data also show that the conformation at the binding site is right-handed, even though adjacent regions of the polymer have a left-handed conformation either in Z-form or in H L-form. Both the rate and extent of B-form to Z-form transition were decreased by sanguinarine and ethidium under ionic conditions that otherwise favour the left-handed conformation of the polynucleotides. The rate of decrease is faster in the case of ethidium as compared to that of sanguinarine. Scatchard analysis of the spectrophotometric data shows that sanguinarine binds strongly to both the polynucleotides in a non-cooperative manner under B-form conditions, in sharp contrast to the highly-cooperative binding under Z-form and H L-form conditions. Correlation of binding isotherms with circular dichroism data indicates that the cooperative binding of sanguinarine under the Z-form and the H L-form conditions is associated with a sequential conversion of the polymer from a left-handed to a bound right-handed conformation. Determination of bound alkaloid concentration by spectroscopic titration technique and the measurement of circular dichroic spectra have enabled us to calculate the number of base pairs of Z-form and H L-form that adopt a right-handed conformation for each bound alkaloid. Analysis reveals that 2–3 base pairs (bp) of Z-form of poly(dG–dC)·poly(dG–dC) and poly(dG–me 5dC)·poly(dG–me 5dC) switch to the right-handed form for each bound sanguinarine, while approximately same number of base pairs switch to the bound right-handed form in complexes with H L-form of these polynucleotides. Comparative binding analysis shows that ethidium also converts approximately 2 bp of Z-form or H L-form to bound right-handed form under same experimental conditions. Since sanguinarine binds preferentially to alternating GC sequences, which are capable of undergoing the B to Z or B to H L transition, these effects may be an important part in understanding its extensive biological activities.

Interactions of Sanguinarine and Zinc on Oral Streptococci and Actinomyces Species

Sanguinaria extract, which contains benzophenanthridine alkaloids, has been used as a folk medicine for many years. Minimum inhibitory and minimum bactericidal concentrations (MIC and MBC values) for sanguinarine were determined for common and etiologically important plaque bacteria. Because the efficacy of sanguinarine is believed to be enhanced by zinc, isobolograms were assessed to determine their mode(s) of interaction. Hydrogen ion concentration influenced the inhibitory activity of both sanguinarine and zinc. For sanguinarine, at the optimum pH (6.5), MIC values were 4 or 8 micrograms/ml for Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguis, Actinomyces viscosus and Actinomyces naeslundii. MIC values were 0.125-0.50 mmol Zn/ml. MBC values ranged from 1 to 8 mmol Zn/ml at pH 5.5. Isobologram data revealed that sanguinarine and zinc interacted synergistically. Viadent oral rinse, which contained 300 micrograms sanguinaria extract/ml and 0.2% zinc chloride (14.9 mmol Zn/l), was inhibitory to all strains tested. MIC values were 1 or 2% (ml Viadent oral rinse/100 ml aqueous solution) for all strains except A. viscosus for which the MIC value was 12% (vol/vol).

EFFECTS OF IONIC STRENGTH and pH ON THE BINDING OF SANGUINARINE TO DEOXYRIBONUCLEIC ACID

Abstract— The interaction of sanguinarine with DN A has been studied in buffers of various ionic strengths and pH values where the physicochemical properties of DNA remain unchanged. Spectrophotometric analysis using absorption and fluorescence techniques indicates that the complex formed between sanguinarine and DNA is a function of ionic strength and pH. Increasing the salt concentration minimizes the importance of intercalator charge and extrapolation to 1 M [Na+] salt reveals the intercalative abilities, as reflected in binding constants, to be of the same order of magnitude as that of ethidium bromide. The fluorescence of sanguinarine bound to DNA is quenched and can be decreased by [Na +], [Mg2+] and [Ca2+] ions. The influence of pH on the fluorescence spectrum of sanguinarine with increasing concentration of DNA was studied. It is concluded that the binding of sanguinarine to DNA contains a large favourable non‐electrostatic interaction and the alkaloid binds more DNA in buffer of low ionic‐strength and acidic pH.