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1.
Coumarins are the most important class of natural compounds found widely in various plants. Many coumarin derivatives with different biological and pharmacological activities have been synthesized. In this study, the antiapoptotic and cytotoxic effects and DNA‐binding properties of some synthetic coumarin derivatives (4b, 4d, 4f, 4 g (DBP‐g), 4 h and 4j) against K562 cell lines were investigated using different techniques. MTT assay indicated that the DBP‐g compound was more active than other derivatives, with a IC50 value of 55 μM, and therefore this compound was chosen for further investigation. Apoptosis induction was assessed using acridine orange/ethidium bromide double‐staining and cell‐cycle analysis. In addition, in vitro DNA‐binding studies were carried out using ultraviolet–visible light absorption and fluorescence spectroscopy, as well as viscosity measurement and molecular modelling studies. In vitro results indicated that DBP‐g interacted with DNA through a groove‐binding mode with a binding constant (Kb) of 1.17 × 104 M?1. In agreement with other experimental data, molecular docking studies showed that DBP‐g is a minor groove binder. Overall, it can be concluded that DBP‐g could be used as an effective and novel chemotherapeutic agent.  相似文献   

2.
A copper complex of carmoisine dye; [Cu(carmoisine)2(H2O)2]; was synthesized and characterized by using physico-chemical and spectroscopic methods. The binding of this complex with calf thymus (ct) DNA was investigated by circular dichroism, absorption studies, emission spectroscopy, and viscosity measurements. UV-vis results confirmed that the Cu complex interacted with DNA to form a ground-state complex and the observed binding constant (2× 104 M?1) is more in keeping with the groove bindings with DNA. Furthermore, the viscosity measurement result showed that the addition of complex causes no significant change on DNA viscosity and it indicated that the intercalation mode is ruled out. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrogen bonds and van der Waals interactions played major roles in the reaction. The results of circular dichroism (CD) suggested that the complex can change the conformation of DNA from B-like form toward A-like conformation. The cytotoxicity studies of the carmoisine dye and its copper complex indicated that both of them had anticancer effects on HT-29 (colon cancer) cell line and they may be new candidates for treatment of the colon cancer.  相似文献   

3.
Novel N-(1-(4-(dibenzo[b,f][1,4]thiazepin-11-yl)piperazin-1-yl)-1-oxo-3-phenylpropan-2-yl derivatives were designed, synthesized and their chemical structures were confirmed by 1H NMR, 13C NMR and Mass spectra. The anticancer activities of the newly synthesized compounds were evaluated in vitro against three human cancer cell lines including K562, Colo-205 and MDA-MB 231 by MTT assay. The screening results showed that five compounds (16b, 16d, 16i, 16p and 16q) exhibited potent cytotoxic activities with IC50 values between 20 and 40 μM. Further in vitro studies revealed that inhibition of sirtuins could be the possible mechanism of action of these molecules.  相似文献   

4.
Interaction of the food additive tartrazine with double-stranded DNA was studied by spectroscopic and calorimetric techniques. Absorbance studies revealed that tartrazine exhibited hypochromism in the presence of DNA without any bathochromic effects. Minor groove displacement assay of DAPI and Hoechst 33258 suggested that tartrazine binds in the minor groove of DNA. The complexation was predominantly entropy driven with a smaller but favorable enthalpic contribution to the standard molar Gibbs energy. The equilibrium constant was evaluated to be (3.68?±?.08)?×?104?M?1 at 298.15?K. The negative standard molar heat capacity value along with an enthalpy–entropy compensation phenomenon proposed the involvement of dominant hydrophobic forces in the binding process. Tartrazine enhanced the thermal stability of DNA by 7.53?K under saturation conditions.  相似文献   

5.
A series of novel ethyl 2,7‐dimethyl‐4‐oxo‐3‐[(1‐phenyl‐1H‐1,2,3‐triazol‐4‐yl)methyl]‐4,5‐dihydro‐3H‐pyrano[2,3‐d]pyrimidine‐6‐carboxylate derivatives 7a – 7m were efficiently synthesized employing click chemistry approach and evaluated for in vitro cytotoxic activity against four tumor cell lines: A549 (human lung adenocarcinoma cell line), HepG2 (human hematoma), MCF‐7 (human breast adenocarcinoma), and SKOV3 (human ovarian carcinoma cell line). Among the compounds tested, the compounds 7a , 7b , 7f , 7l , and 7m have shown potential and selective activity against human lung adenocarcinoma cell line (A549) with IC50 ranging from 0.69 to 6.74 μm . Molecular docking studies revealed that the compounds 7a , 7b , 7f , 7l , and 7m are potent inhibitors of human DNA topoisomerase‐II and also showed compliance with stranded parameters of drug likeness. The calculated binding constants, kb, from UV/VIS absorptional binding studies of 7a and 7l with CT‐DNA were 10.77 × 104, 6.48 × 104, respectively. Viscosity measurements revealed that the binding could be surface binding mainly due to groove binding. DNA cleavage study showed that 7a and 7l have the potential to cleave pBR322 plasmid DNA without any external agents.  相似文献   

6.
Four complexes [Pd(L)(bipy)Cl]·4H2O (1), [Pd(L)(phen)Cl]·4H2O (2), [Pt(L)(bipy)Cl]·4H2O (3), and [Pt(L)(phen)Cl]·4H2O (4), where L = quinolinic acid, bipy = 2,2’-bipyridyl, and phen = 1,10-phenanthroline, have been synthesized and characterized using IR, 1H NMR, elemental analysis, and single-crystal X-ray diffractometry. The binding of the complexes to FS-DNA was investigated by electronic absorption titration and fluorescence spectroscopy. The results indicate that the complexes bind to FS-DNA in an intercalative mode and the intrinsic binding constants K of the title complexes with FS-DNA are about 3.5?×?104 M?1, 3.9?×?104 M?1, 6.1?×?104 M?1, and 1.4?×?105 M?1, respectively. Also, the four complexes bind to DNA with different binding affinities, in descending order: complex 4, complex 3, complex 2, complex 1. Gel electrophoresis assay demonstrated the ability of the Pt(II) complexes to cleave pBR322 plasmid DNA.  相似文献   

7.
Abstract

The chemistry of Co(II) complexes showing efficient light induced DNA cleavage activity, binding propensity to calf thymus DNA and antibacterial PDT is summarized in this article. Complexes of formulation [Co(mqt)(B)2]ClO4 1–3 where mqt is 4-methylquinoline-2-thiol and B is N,N-donor heterocyclic base, viz. 1,10-phenanthroline (phen 1), dipyrido[3,2-d:2′,3′-f]quinoxaline (dpq 2) and dipyrido[3,2-a:2′,3′-c]phenazine (dppz 3) have been prepared and characterized. The DNA-binding behaviors of these three complexes were explored by absorption spectra, viscosity measurements and thermal denaturation studies. The DNA binding constants for complexes 1, 2 and 3 were determined to be 1.6?×?103?M?1, 1.1?×?104?M?1 and 6.4?×?104?M?1 respectively. The experimental results suggest that these complexes interact with DNA through groove binding mode. The complexes show significant photocleavage of supercoiled (SC) DNA proceeds via a type-II process forming singlet oxygen as the reactive species. Antimicrobial photodynamic therapy was studied using photodynamic antimicrobial chemotherapy (PACT) assay against E. coli and all complexes exhibited significant reduction in bacterial growth on photoirradiation.  相似文献   

8.
Abstract

Two new 10-methoxydibenzo[b,h][1,6]naphthyridine-2-carboxamide derivatives (R1 and R2) have been synthesized and characterized using different spectral techniques. The binding of these probes with DNA was investigated using spectral (Electronic, fluorescence, 1H NMR and circular dichroism) and molecular docking studies. These probes exhibited a strong fluorescence around 440?nm upon excitation around 380?nm. Electronic and competitive fluorescence titration studies, in HEPES [(4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid)] buffer/dimethyl sulfoxide (pH 7.4) medium, suggest that these probes bind strongly to DNA, which is substantiated by 1H NMR study. The binding constants are calculated to be 5.3?×?107 and 6.8?×?106 M?1 for R1 and R2, respectively. From the results of spectral studies, it is proposed that the mechanism of binding of these probes with DNA is through minor groove binding mode, which is further confirmed by circular dichroism and molecular docking studies. Initial cell viability screening using MTT (3-[4,5-methylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) assay shows that normal Vero cells are viable towards these probes at nano molar concentration, which is the concentration range employed in the present study for DNA staining (IC50 in the order of 0.023?mM). The enhancement in fluorescence intensity of these probes upon binding with DNA enables the staining of DNA in agarose gel in gel electrophoresis experiment. The sensitivity of these probes is comparable with that of ethidium bromide and DNA amounts as low as 4 nano gram are detectable.

Communicated by Ramaswamy H. Sarma  相似文献   

9.
The interaction of anticancer drug cytarabine with calf thymus DNA (CT-DNA) was investigated in vitro under simulated physiological conditions by multispectroscopic techniques and molecular modeling study. The fluorescence spectroscopy and UV absorption spectroscopy indicated drug interacted with CT-DNA in a groove-binding mode, while the binding constant of UV-vis and the number of binding sites were 4.0 ± 0.2 × 104 L mol?1 and 1.39, respectively. The fluorimetric studies showed that the reaction between the drugs with CT-DNA is exothermic. Circular dichroism spectroscopy was employed to measure the conformational change of DNA in the presence of cytarabine. Furthermore, the drug induces detectable changes in its viscosity for DNA interaction. The molecular modeling results illustrated that cytarabine strongly binds to groove of DNA by relative binding energy of docked structure ?20.61 KJ mol?1. This combination of multiple spectroscopic techniques and molecular modeling methods can be widely used in the investigation on the interaction of small molecular pollutants and drugs with biomacromolecules for clarifying the molecular mechanism of toxicity or side effect in vivo.  相似文献   

10.
Novel enamine derivatives were synthesized from the reaction of lactone and chalcones and their antiproliferative and cytotoxic activities against six cancer cell lines (e. g., HeLa, HT29, A549, MCF7, PC3 and Hep3B) and one normal cell lines (e. g., FL) were investigated along with their mode of interactions with CT‐DNA. Most of the enamine derivatives with IC50 values of 86–168 μM demonstrated much stronger antiproliferative activity than the starting molecules against the cancer cells. While, among the enamine derivatives, four compounds displayed higher cytotoxic potency than the control drugs (5‐fluorouracil and cisplatin) against the Hep3B cell lines, these compounds did not exhibit any significant toxicity against normal cells, FL. The UV/VIS spectral data suggest that eight compounds cause hypochromism with a slight bathochromic shift (~6 nm), indicating that they bind to the DNA by way of an intercalative or minor groove binding mode. The binding constants of the compounds are in the range of 0.1×103 M?1–2.3×104 M?1. The antiproliferative activity of studied enamine derivatives could possibly be due to their DNA binding as well as their cytotoxic properties. In addition to these assays, the chalcones and enamine derivatives were investigated by molecular docking to calculate the synergistic effect of antiproliferative activities against six human cancer cell lines.  相似文献   

11.
Abstract

Flavonoids are strong antioxidants that prevent DNA damage. The anticancer and antiviral activities of these natural products are implicated in their mechanism of actions. However, there has been no information on the interactions of these antioxidants with individual DNA at molecular level. This study was designed to examine the interaction of quercetin (que), kaempferol (kae), and delphinidin (del) with calf-thymus DNA in aqueous solution at physiological conditions, using constant DNA concentration (6.5 mmol) and various drug/DNA(phosphate) ratios of 1/65 to 1. FTIR and UV-Visible difference spectroscopic methods are used to determine the drug binding sites, the binding constants and the effects of drug complexation on the stability and conformation of DNA duplex.

Structural analysis showed quercetin, kaempferol, and delphinidin bind weakly to adenine, guanine (major groove), and thymine (minor groove) bases, as well as to the backbone phosphate group with overall binding constants Kque = 7.25 × 104M?1, Kkae = 3.60 × 104M?1, and Kdel = 1.66 × 104M?1. The stability of adduct formation is in the order of que>kae>del. Delphinidin with a positive charge induces more stabilizing effect on DNA duplex than quercetin and kaempferol. A partial B to A-DNA transition occurs at high drug concentrations.  相似文献   

12.
Abstract

In this study, the interaction of Holmium (Ho) complex including 2, 9-dimethyl-1,10-phenanthroline, also called Neocuproine (Neo), [Ho(Neo)2Cl3.H2O], as fluorescence probe with fish-salmon DNA (FS-DNA) is studied during experimental investigations. Multi-spectroscopic methods are utilized to determine the affinity binding constants (Kb) of complex–FS-DNA. It is found that fluorescence of Ho complex is strongly quenched by the FS-DNA through a static quenching procedure. Under optimal conditions in Tris(trishydroxymethyl-aminomethane)–HCl buffer at 25?°C with pH?≈?7.2, intrinsic binding constant Kb of Ho complex is 6.12?±?0.04?×?105 M?1. Also, the binding site number and Stern–Volmer quenching constant are calculated. There are different approaches, including iodide quenching assay, salt effect and thermodynamical assessment to determine the features of the binding mode between Ho complex and FS-DNA. Also, the parent and starch and lipid nanoencapsulated Ho complex, as potent antitumor candidates, were synthesized. The main structure of Ho complex is maintained after encapsulation using starch and lipid nanoparticles. 3-[4,5-Dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method was used to assess the anticancer properties of Ho complex and its encapsulated forms on human cancer cell lines of human lung carcinoma cell line and breast cancer cell line. In conclusion, these compounds could be considered as new antitumor candidates.

Communicated by Ramaswamy H. Sarma  相似文献   

13.
Herein, we investigated new phthalimide‐based Schiff base molecules as promising DNA‐binding and free radical scavenging agents. Physicochemical properties of these molecules were demonstrated on the basis of elemental analysis, ultraviolet–visible (UV–Vis), infra‐red (IR), 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. All spectral data are agreed well with the proposed Schiff base framework. The DNA‐binding potential of synthesized compounds were investigated by means of UV–visible, fluorescence, iodide quenching, circular dichroism, viscosity and thermal denaturation studies. The intrinsic binding constants (K b) were calculated from absorption studies were found to be 1.1 × 104 and 1.0 × 104 M?1 for compounds 2a and 2b suggesting that compound 2a binding abilities with DNA were stronger than the compound 2b. Our studies showed that the presented compounds interact with DNA through groove binding. Molecular docking studies were carried out to predict the binding between Ct‐DNA and test compounds. Interestingly, in silico predictions were corroborated with in vitro DNA‐binding conclusions. Furthermore, the title compounds displayed remarkable antioxidant activity compared with reference standard.  相似文献   

14.
Forty four di- or trisubstituted novel isatin derivatives were designed and synthesized in 5–6 steps in 25–45% overall yields. Their structures were confirmed by 1H NMR and 13C NMR as well as LC–MS. The anticancer activity of these new isatin derivatives against three human tumor cell lines, K562, HepG2 and HT-29, were evaluated by MTT assay in vitro. SAR studies suggested that the combination of 1-benzyl and 5-[trans-2-(methoxycarbonyl)ethen-1-yl] substitution greatly enhance their cytotoxic activity, whereas an intact carbonyl functionality on C-3 as present in the parent ring is required to such a potency. This study leads to the identification of two highly active molecules, compounds 2h (IC50 = 3 nM) and 2k (IC50 = 6 nM), against human leukemia K562 cells.  相似文献   

15.
Cisplatin is one of the most effective chemotherapy drugs, and has been widely employed for more than four decades in the treatment of different forms of human tumors. In recent years, various examples of metal complex-based compounds have been used for medicinal purposes. In this context, the novel palladium(II) complex, [Pd(non-dtc)(bpy)]NO3, (non-dtc = nonyldithiocarbamate and bpy = 2,2′- bipyridine) has been synthesized and characterized by means of elemental analysis, conductivity measurements, FT-IR, 1H NMR, 13C NMR, and electronic spectroscopy studies. The 50% cytotoxic concentrations (Ic50) of this Pd(II) complex (0.53 mM) and cisplatin (154 mM) against human cell tumor line (K562) indicates its interaction with DNA of cancer cell at quite low concentration. Thus, binding characteristics of this compound to calf thymus DNA (CT-DNA) has been investigated by UV–vis absorption spectroscopy and fluorescence spectra. The exciting observation of this work in the UV–visible studies was that the Pd(II) complex exhibit two or more types of interaction with CT-DNA. Such properties have rarely been observed in the literature. This complex cooperatively binds with DNA and denatures it too. Fluorescence studies proved the intercalation mode of binding and the other modes seems to be hydrophobic and electrostatic interactions. Binding parameters and thermodynamics of the interaction with CT-DNA are also described. Finally, multifunctional interactions of [Pd(non-dtc)(bpy)]NO3 make it suitable to interact with DNA of cancer cell at quite low concentration and if it is used as anticancer agent, very low doses will be needed which may have fewer side effects.  相似文献   

16.
In this paper, based on Plastoquinone (PQ) analogs possessing substituted aniline containing alkoxy group(s), new 2,3-dimethyl-5-amino-1,4-benzoquinones (PQ1-15) were designed and synthesized in either two steps or one-pot reaction. Specifically, the substituted amino moiety containing mono or poly alkoxy group(s) with various positions and groups were mainly explored to understand the structure-activity relationships for the cytotoxic activity against three human cancer cell lines (K562, Jurkat, and MT-2) and human peripheral blood mononuclear cells (PBMC). PQ2 was found to be most effective anticancer compound on K562 and Jurkat cell lines with IC50 values of 6.40 ± 1.73 μM and 7.72 ± 1.49 μM, respectively. Interestingly, the compound was non-cytotoxic to normal PBMC and also MT-2 cancer cells. PQ2 which showed significant selectivity in MTT assay was chosen for apoptotic/necrotic evaluation and results exhibited that it induced apoptosis in K562 cell line after 6 h of treatment. PQ2 showed anti-Abelson kinase 1 (Abl1) activity with different inhibitory profile than Imatinib in the panel of eight kinases. The binding mode of PQ2 into Abl ATP binding pocket was predicted in silico showing the formation of some key interactions. In addition, PQ2 induced Bcr-Abl1 mediated ERK pathway in human chronic myelogenous leukemia (CML) cells. Furthermore, DNA-cleaving capability of PQ2 was clearly enhanced by iron (II) complex system. Afterward, a further in silico ADMET prediction revealed that PQ2 possesses desirable drug-like properties and favorable safety profile. These results indicated that PQ2 has multiple mechanism of action and two of them are anti-Bcr-Abl1 and DNA-cleaving activity. This study suggests that Plastoquinone analogs could be potential candidates for multi-target anticancer therapy.  相似文献   

17.
Three series of γ-carboline derivatives were designed and synthesized. All the compounds were tested for their cytotoxic activities in vitro against five human tumor cell lines (A549, SGC, HCT116, MCF-7, K562) and one multi-drug resistant subline (K562R). Most compounds showed moderate to potent cytotoxic activities against the tested cell lines. Sulfonate 11f exhibited more potent cytotoxic activities against almost all of the tested cells in comparison with the positive control, taxol, with IC50 values ranging from 0.15 to 4.5 μM. The structure–activity relationships were discussed and a statistically reliable QSAR model (r2 = 0.936, q2 = 0.581) was established by the CoMFA analysis performed using the cytotoxic data against K562 cell line as a template.  相似文献   

18.
In this work, a pair of new palladium(II) complexes, [Pd(Gly)(Phe)] and [Pd(Gly)(Tyr)], (where Gly is glycine, Phe is phenylalanine, and Tyr is tyrosine) were synthesized and characterized by UV–Vis, FT-IR, elemental analysis, 1H-NMR, and conductivity measurements. The detailed 1H NMR and infrared spectral studies of these Pd(II) complexes ascertain the mode of binding of amino acids to palladium through nitrogen of -NH2 and oxygen of -COO? groups as bidentate chelates. The Pd(II) complexes have been tested for in vitro cytotoxicity activities against cancer cell line of K562. Interactions of these Pd(II) complexes with CT-DNA and human serum albumin were identified through absorption/emission titrations and gel electrophoresis which indicated significant binding proficiency. The binding distance (r) between these synthesized complexes and HSA based on Forster?s theory of non-radiation energy transfer were calculated. Alterations of HSA secondary structure induced by complexes were confirmed by FT-IR measurements. The results of emission quenching at three temperatures have revealed that the quenching mechanism of these Pd(II) complexes with CT-DNA and HSA were the static and dynamic quenching mechanism, respectively. Binding constants (Kb), binding site number (n), and the corresponding thermodynamic parameters were calculated and revealed that the hydrogen binding and hydrophobic forces played a major role when Pd(II) complexes interacted with DNA and HSA, respectively. We bid that [Pd(Gly)(Phe)] and [Pd(Gly)(Tyr)] complexes exhibit the groove binding with CT-DNA and interact with the main binding pocket of HSA. The complexes follow the binding affinity order of [Pd(Gly)(Tyr)] > [Pd(Gly)(Phe)] with CT-DNA- and HSA-binding.  相似文献   

19.
In vitro assay for cytotoxic activity of glands/hairs obtained from the fruits of Mallotus philippinensis has been carried out against 14 human cancer cell lines from nine different origins via 95% ethanolic, 50% ethanolic and aqueous extract at the concentration of 100 μg/ml. Results revealed that the 95% ethanolic extract showed highest in vitro cytotoxic effect against all the 14 human cancer cell lines. The fractions of the same extract i.e. 95% ethanolic were obtained and it was found that the significant cytotoxic potential was produced by the chloroform soluble fraction at 100 μg/ml as this fraction inhibited the growth of ten human cancer cell lines from seven different tissues. Further, the chromatographic analysis of the said fraction afforded a polyphenolic molecule rottlerin. This drug at the concentration of 1?×?10?5M and 1?×?10?4M suppressed the proliferation of eight human cancer cell lines from six different tissues and proved its exceptionally remarkable in vitro anticancer efficiency.  相似文献   

20.
Pyrazolealdehydes (4ad), Knoevenagel’s condensates (5ad) and Schiff’s bases (6ad) of curcumin-I were synthesized, purified and characterized. Hemolysis assays, cell line activities, DNA bindings and docking studies were carried out. These compounds were lesser hemolytic than standard drug doxorubicin. Minimum cell viability (MCF-7; wild) observed was 59% (1.0 μg/mL) whereas the DNA binding constants ranged from 1.4 × 103 to 8.1 × 105 M?1. The docking energies varied from ?7.30 to ?13.4 kcal/mol. It has been observed that DNA-compound adducts were stabilized by three governing forces (Van der Wall’s, H-bonding and electrostatic attractions). It has also been observed that compounds 4ad preferred to enter minor groove while 5ad and 6ad interacted with major grooves of DNA. The anticancer activities of the reported compounds might be due to their interactions with DNA. These results indicated the bright future of the reported compounds as anticancer agents.  相似文献   

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