Green synthesis,characterization and anti-cancer capability of Co0.5Ni0.5Nd0.02Fe1.98O4 nanocomposites

In this study, Co_0.5Ni_0.5Nd_0.02Fe_1.98O₄ nanoparticles CoNiNd (NPs) were synthesized by combustion method linked with biosynthesis with and without different plant extracts such as Lavender, Ginger, Flax-Seed, Lemon Juice, Tragacanth Gum, and Dates Fruit. Co_0.5Ni_0.5Nd_0.02Fe_1.98O₄ nanoparticles (NPs) with plant extracts (CoNiNd plant extracts) were analyzed by XRD, TEM and SEM methods. The structure of Co-Ni spinel ferrite was confirmed by XRD and the shape and the size of nanoparticles were examined via SEM and TEM and the size was found between 17 and 25 nm. The anti-cancer activity of NPs on cancer cells such as human colorectal carcinoma (HCT-116) and human cervical cells (Hela) were investigated. The cytotoxicity of was examined by MTT assay and followed by measuring the inhibitory concentration (IC₅₀) values after 48 h treatments. The cell viability assay confirmed a decrease in the cancer cell viability post NPs treatments and showed dose-dependent inhibitory action. The treatments of CoNiNd (NPs) and CoNiNd plant extracts via Lavender plant extract showed most profound inhibitory action on both cancer cells than extracts other plant extracts. The IC₅₀ values were for HCT-116 cells were found to be in range of 15.75–42.55 µg/mL and 13.44 to 35.65 µg/mL for HeLa cells. In contrast, the treatment of CoNiNd (NPs) and CoNiNd plant extracts showed inhibitory action but the percentage of inhibition was higher in HEK-293 cells. Our results showed that CoNiNd (NPs) and CoNiNd plant extracts possess potential application in the colon and cervical cancer treatments and we recommend molecular analysis of NPs mediated cancer cell death for future applications.     

Spectrochemical analysis using LIBS and ICP-OES techniques of herbal medicine (Tinnevelly Senna leaves) and its anti-cancerous/antibacterial applications

Tinnevelly senna leaves are being applied to cure many diseases especially in developing countries and sub-Saharan region due to many bioactive compounds such as sennosides, phenols, and flavonoids. The conventional methods to isolate and analyze plant extracts biomolecules are not very effective as well cost effective as they require hazardous chemical solvents and reagents, which are time-consuming processes. The major objective of the present study is to investigate the feasibility of the Laser induced breakdown spectroscopy (LIBS) technique for rapid, eco-friendly, and multi-elemental analysis of Senna leaves extracts and study their antibacterial and anticancer potentials. The elegant LIBS technique was applied as a qualitative and quantitative method for Senna leaves sample’s elemental analysis and their biological activities were measured by evaluating anti-cancer and anti-bacterial analysis. The quantitative analysis of Senna leaves extracts was done using the calibration-free laser-induced breakdown spectroscopy (CF-LIBS) algorithm showing their appreciable content of several nutrient elements, and the obtained results were in close conformity with these achieved by using the standard analytical ICP OES technique. We studied the bactericidal efficacy of the Senna leaves extract against Staphylococcus aureus (S. aureus) by AWD assays and morphogenesis by scanning electron microscopy (SEM) and the anticancer activity was also investigated where different concentrations of Senna leaves extract were tested on cancer cells (HCT-116 and HeLa) and normal cells (HEK-293) using the cell metabolic activity MTT assay and Propidium iodide (PI) staining. We have also calculated the inhibitory concentration (IC50) value for the various extracts concentrations (25 µg/ml, 50 µg/ml, 100 µg/ml, 150 µg/ml, 200 µg/ml, and 225 µg/ml). We have found that IC₅₀ value for HCT-116 cells were 13.5 µg/ml, 17.5 µg/ml, 21.5 µg/ml, 22.5 µg/ml, 26 µg/ml and 33.5 µg/ml and for HeLa cells 15.25 µg/ml, 21.25 µg/ml, 23.5 µg/ml, 262.5 µg/ml, 36.25 µg/ml, and 39.50 µg/ml. The bactericidal efficacy of the Senna leaves extract showed significant inhibition against Gram-positive bacterium. Both MTT and PI analysis showed that Senna leaves extract induced profound inhibition on HCT-116 growth and proliferation. Additionally, Senna leaves extract did not exert an inhibitory influence on normal (HEK-293), which is non-cancerous cells. We suggest that the extract specifically targets the cancerous cells, which could be highly beneficial for the development of future safe anticancer and antibacterial drugs using these extracts.     

Chitinase inhibits growth of human breast and colorectal cancer cells in vitro and Ehrlich ascites carcinoma cells in vivo

Trichosanthes dioica seed extract was loaded on a QA-cellulose column and the unbound fraction with the chitinase activity was run on SDS-PAGE. Multiple bands were observed and were separated by a Sephadex G-50 column. The combination of the 6 and 33 kDa masses supported the degradation of chitinase as purified earlier. Only the 33 kDa fraction contained sugar and showed chitinase activity. The chitinase was also isolated by using a chitin column. At 200 µg/ml protein concentration, the chitinase inhibited 49.1 %, 48.8 % and 38.12 % of Ehrlich ascites carcinoma, HCT-116 and MCF-7 cells growth, respectively, in a dose-dependent manner. Exactly, 46 % and 82 % EAC cell growth inhibition were observed after treating the EAC cells bearing Swiss albino mice with the chitinase at the doses of 1.0 and 2.0 mg/Kg/day respectively. EAC, HCT-116 and MCF-7 cells growth inhibitions were due to the induction of apoptosis. ROS was accumulated in HCT-116 and MCF-7 cells. After treatment of HCT-116 cells, the expression level of p53 and TNFα genes increased and PARP gene decreased. On the other hand, elevated expression was observed for PARP, MAPK, NFκB, FAS, FADD, and Caspase-8 genes in MCF-7 cells. The induction of apoptosis in HCT-116 was further confirmed by caspase protein expression. The chitinase causes ‘S’ cell cycle arrest in MCF-7 and HCT-116 cells. T. dioica seed chitinase inhibited EAC, HCT-116 and MCF-7 cells by inducing apoptosis in vitro and EAC in vivo in mice. These promising results indicated that T. dioica seed chitinase can be an anticancer agent.     

Determination of 31P,31P coupling constants in cyclotriphosphazenes and their influence on 1H and 13C NMR spectra of phosphorus substituents

¹H and ¹³C NMR spectra of symmetrically substituted cyclotriphosphazenes exhibit second‐order effects. The influence of the ³¹P,³¹P coupling constants between ring phosphorus atoms on these effects was studied. Some values of this coupling constant between phosphorus bearing identical substituents were measured using ¹³C satellites of the ³¹P signals or by introduction of a chiral substituent on the third phosphorus atom. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis and Electronic Properties of 6-Chloro-2-diethylaminoethyl-3(2H)-pyridazinone

6-Chloro-2-diethylaminoethyl-3(2H)-pyridazinone was synthesized by the reaction of 6-chloro-3(2H)-pyridazinone and 2-diethylamionethyl chloride reaction in methylbenzene.Then the structure was characterized by means of ^1H NMR,IR,UV.By the method of ab initio HF and density functional theory(DFT) BeLYP,the geometric structures of the reagent intermediate,the product and its isomer were optimized and their total energies were calculated,The properties for the frontier molecular orbitals and the rules for energy distribution were analyzed systematically.It was shown that the energy of the nitrogen alkyl compound is lower than that of the oxy alkyl compound and the former is stable than the latter.This result is in accordance with the fact that 6-chloro-2-diethylaminoethyl-3(2H)-pyridazinone is synthesized by the reaction of 6-chloride-2-diethylaminoethyl-3(2H)-pyridazinone and 2-diethylaminoethyl chloride.     

Sulfamide-substituted-BODIPY based fluorescence drugs: Synthesis,spectral characteristics,molecular docking,and bioactivity

BODIPY derivatives have attracted much attention in the field of biological probes, but probes with a single imaging function are no longer innovative. In this paper, two multifunctional sulfonamide-BODIPY derivatives were designed and synthesized. Photophysical properties, cytotoxicity, in vitro and in vivo imaging, apoptosis, cell cycle, and molecular docking simulation were studied. The results showed that the compound had low cytotoxicity to normal cells, but had strong inhibitory effect on tumor cells. The IC₅₀ value of compound 3 on HCT-116 cells was 58.61 ± 4.91 μmol/L, and 4 on HeLa cells was 52.29 ± 10.93 μmol/L. Cell imaging and mice experiments demonstrated that the probe had excellent biocompatibility and potential tumor targeting; and in vivo imaging of mice at different time periods showed that the fluorescence intensity of probes in subcutaneous lung tumor gradually increased with the extension of time. In addition, the flow cytometry analysis of 3 showed that the G1 phase of HCT-116 cells was inhibited and apoptosis of tumor cells was promoted. In molecular docking simulation, sulfonamide-BODIPY derivatives had high affinity scores with CDK2: −8.0 and −8.4 kcal·mol⁻¹, and the multiple interactions with receptors provided conditions for the probes to recognize tumor cells.     

187Os subspectra in 1H and 31P{1H} spectra of triosmium carbonyl clusters

A survey of the use of ¹⁸⁷Os satellite subspectra in ¹H and ³¹P{¹H} spectra of triosmium carbonyl clusters is reported. By varying evolution delays in HMQC spectra of [Os₃(µ‐H)₂(CO)₁₀] we have selectively extracted the values for ¹J(Os,H) and ²J(Os,H), respectively. An analysis of the principal modes of phosphine coordination in triosmium clusters demonstrates that ³¹P{¹H}¹⁸⁷Os satellite subspectra are diagnostic for equatorial coordination [¹J(Os,P) = 211–223 Hz] or for axial coordination (perpendicular to the plane of the cluster) [¹J(Os,P) ≈ 147 Hz]. Chelating and bridging diphosphines yield ¹⁸⁷Os satellite subspectra which are the sum of A₂X and AA′X spin systems. If significant P–P coupling is present, the AA′X component requires simulation. All observed ²J(Os,P) trans‐equatorial couplings fall in the range 38–65 Hz. Copyright © 2001 John Wiley & Sons, Ltd.     

Spektroskopische Eigenschaften von Di(phthalocyaninato)metallaten(III) der Seltenen Erden. Teil 2: Die Multikern(1H-, 13C-, 15N-, 17O- und 31P)-NMR-Spektren und Nachweis komplexgebundenen Wassers

Spectroscopical Properties of Di(phthalocyaninato)metalates(III) of the Rare Earth Elements. Part 2: The Multinuclear (¹H, ¹³C, ¹⁵N, ¹⁷O, and ³¹P) NMR Spectra and Determination of Complex Bound Water The ¹H, ¹³C, ¹⁵N, ¹⁷O and ³¹P NMR spectra of (PNP)[Ln(Pc^2?)₂] and (TDOA)[Ln(Pc^2?)₂] (Ln = La …? (—Pm) …? Lu); PNP: di(triphenylphosphine)-iminium; TDOA: Tri(n-dodecyl)n-octylammonium dissolved in CD₂Cl₂ are reported. With the exception of the nitrogen atoms of the cations all light atoms of both homologues complex salt rows have been detected and assigned. Proof of the presence of additional water contained in the (solid) complex salts has been given unambigously. The otherwise strong Fermi contact interactions diminuish rapidly with growing distance from the paramagnetic centre favouring dipolar (pseudo-contact) interactions. As a consequence the mostly element independent paramagnetic shifts of the atoms situated on the periphery of the anion as well as those of the cations and water are determined by the distance factor. Therefore a first glance of the structure of the ion-pair present in solution emerges, in which the water molecule seems to play an important role.     

Large-bite bis(phosphite) ligand containing mesocyclic thioether moieties: synthesis, reactivity, group 11 (Cu(I), Au(I)) metal complexes and anticancer activity studies on a human cervical cancer (HeLa) cell line

The large-bite bis(phosphite) ligand [{(-OC(10)H(6)(mu-S)C(10)H(6)O-)P{mu-(-OC(10)H(6)(mu-S)C(10)H(6)O-)}P(-OC(10)H(6)(mu-S)C(10)H(6)O-)}] (Pinsertion markP) () was obtained by the reaction of PCl(3) and thiobis(2,2'-naphthol) (). The stoichiometric reactions of with elemental sulfur and selenium afforded the corresponding chalcogenide derivatives [(E)Pinsertion markP(E)] (, E = S; , E = Se) in good yield. Treatment of two equivalents of [ClAu(SMe(2))] with afforded a dinuclear complex [ClAu(Pinsertion markP)AuCl] (), whereas the 1 : 1 reaction with CuI yielded the [(Pinsertion markP)CuI] () complex. The copper(i) complex on treatment with various pyridyl derivatives, produced mixed-ligand complexes [(Pinsertion markP)CuI(NC(5)H(5))] (), [(Pinsertion markP)Cu(2,2'-bpy)]I (), [(Pinsertion markP)Cu(1,10-phen)]I () and {[(Pinsertion markP)Cu(4,4'-bpy)]I}(infinity) (). The compounds were tested for their cytotoxic activity on the human cervical cancer (HeLa) cell line. Compounds and were found to inhibit proliferation of HeLa cells significantly. These agents also induced apoptotic cell death in cancer cells. Evidence presented in this study indicated that the compounds and activate the tumor suppressor protein p53 in the colon adenocarcinoma (HCT-116) cell line.     

Complete 1H, 13C{1H}, and 31P NMR spectral parameters of some pyrophosphates

The ¹H, ¹³C{¹H}, and ³¹P NMR spectral parameters of some pyrophosphates were determined in CDCl₃. The most complicated ¹H spectrum can be solved fully only as (A₃MN)R₆XX′R₆′(MNA₃)′, where R₆ (= ―N(CH₃)₂) is coupled only to phosphorus (X). Second‐order coupling between phosphorus was found and solved with iterative analysis. A signal shape of one of the carbon resonance cannot be explained only with couplings. Explanation for exceptional shape was searched from molecular modeling results. Copyright © 2017 John Wiley & Sons, Ltd.     

Diazenyl schiff bases: Synthesis,spectral analysis,antimicrobial studies and cytotoxic activity on human colorectal carcinoma cell line (HCT-116)

A series of diazenyl schiff bases have been synthesized by reaction of salicylaldehyde containing azo dyes with various substituted aniline derivatives in the presence of acetic acid as catalyst. The structures of diazenyl derivatives were determined by FTIR, UV–vis, ¹H NMR, ¹³C NMR, CHN analysis, fluorimetric and mass spectroscopic studies. The synthesized derivatives were screened for their in vitro antimicrobial activity against various Gram-positive (S. aureus, B. subtilis, B. cereus), Gram-negative (S. typhi, S. enterica, E. coli, P. aeruginosa) bacterial and fungal (C. albicans, A. niger and A. fumigatus) strains, using cefadroxil (antibacterial) and fluconazole (antifungal) as standard drugs. The diazenyl schiff bases were also screened for their cytotoxicity against human colorectal carcinoma cell line (HCT-116) using 5-fluorouracil as standard drug by Sulforhodamine-B Stain (SRB) assay. The schiff bases exhibited significant activity toward both Gram-positive, Gram-negative bacterial and fungal strains. Most of the synthesized derivatives showed high activity against S. enterica. 4-((2,5-Dichlorophenyl)diazenyl)-2-((3-bromophenylimino)methyl)phenol (SBN-40) was found to be very active against S. aureus, B. cereus and E. coli, with MIC = 0.69 (µM/ml × 10²). The compound 4-((2-bromophenyl)diazenyl)-2-((4-nitrophenylimino)methyl)phenol (SBN-13) possessed comparable activity (IC₅₀ = 7.5 µg/ml) to the standard drug 5-fluorouracil (IC₅₀ = 3.0 µg/ml) against human colorectal carcinoma cell line (HCT-116).     

Novel Tdp1 Inhibitors Based on Adamantane Connected with Monoterpene Moieties via Heterocyclic Fragments

Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is a promising target for anticancer therapy due to its ability to counter the effects topoisomerase 1 (Top1) poison, such as topotecan, thus, decreasing their efficacy. Compounds containing adamantane and monoterpenoid residues connected via 1,2,4-triazole or 1,3,4-thiadiazole linkers were synthesized and tested against Tdp1. All the derivatives exhibited inhibition at low micromolar or nanomolar concentrations with the most potent inhibitors having IC₅₀ values in the 0.35–0.57 µM range. The cytotoxicity was determined in the HeLa, HCT-116 and SW837 cancer cell lines; moderate CC₅₀ (µM) values were seen from the mid-teens to no effect at 100 µM. Furthermore, citral derivative 20c, α-pinene-derived compounds 20f, 20g and 25c, and the citronellic acid derivative 25b were found to have a sensitizing effect in conjunction with topotecan in the HeLa cervical cancer and colon adenocarcinoma HCT-116 cell lines. The ligands are predicted to bind in the catalytic pocket of Tdp1 and have favorable physicochemical properties for further development as a potential adjunct therapy with Top1 poisons.     

1H and 13C assignments of two new macrocyclic lactones isolated from Streptomyces sp. 211726 and revised assignments of azalomycins F3a, F4a and F5a

Azalomycin F(4a) 2-ethylpentyl ester (1) and Azalomycin F(5a) 2-ethylpentyl ester (2), two new macrocyclic lactones, along with three known compounds of Azalomycins F(3a) (3), F(4a) (4) and F(5a) (5), were identified from metabolites of Streptomyces sp. 211726 isolated from mangrove rhizosphere soil. The complete (1)H and (13)C assignments of these compounds were achieved by using (1)H, (13)C, DEPT, HSQC, (1)H-(1)H COSY and HMBC spectra, and the relative stereochemistry of 5 was first elucidated on the basis of proton-proton coupling constants, NOESY and IR spectra. Moreover, some errors in the (1)H and (13)C assignments published of 3, 4 and 5 were found and revised. 1 and 2 were active against Candida albicans, and exhibited moderate cytotoxicity against HCT-116 cell line.     

Synthesis and antitumor activity of novel pyridino[2,3-d]pyrimidine urea derivatives

A series of novel N-(3-((6-bromopyrido[2,3-d]pyrimidin-4-yl)oxy)phenyl)pyrrolidine-1-carboxamide and 1-(3-((6-bromopyrido[2,3-d]pyrimidin-4-yl)oxy)phenyl)-3-propylurea derivatives were synthesized. Their antitumor activities against human breast carcinoma cells (MCF-7) and human colon cancer cells (HCT-116) in vitro were evaluated, using sorafenib as a positive control drug. Anticancer bioassays indicated that several compounds exhibited appreciable anticancer activity against MCF-7 and HCT-116 cells. Particularly, compounds 9g and 8b demonstrated the most significant inhibitory effect against HCT-116 and MCF-7 cells, with inhibition ratios of 25.56% and 26.46%, respectively. Additionally, the synthesized pyridine[2,3-d]pyrimidine derivatives containing a urea group moieties exhibited antitumor activities against MCF-7 and HCT-116 cells in vitro.     

Magnetic properties,anticancer and antibacterial effectiveness of sonochemically produced Ce3+/Dy3+ co-activated Mn-Zn nanospinel ferrites

Some new types of Ce³⁺ and Dy³⁺ co-doped manganese-zinc nanospinel ferrites (CDMZNSFs) of the form (Mn_0.5Zn_0.5)[Fe_2-2xCe_xDy_x]O₄ (with 0.0 ≤ x ≤ 0.1) were sonochemically produced and characterized. The structure, morphology, optical and magnetic properties of these NSFs were determined as a function of co-dopant (Ce³⁺ and Dy³⁺) contents. The direct optical band gap energies of the studied NSFs were ranged from 1.54 to 1.85 eV. The measurements of magnetization versus magnetic field of the prepared NSFs disclosed a superparamagnetic (SPM) behavior at room temperature (RT). The measurements of temperature-dependent magnetizations revealed a transition from superparamagnetic (SPM) state above blocking temperature T_B to a ferromagnetic (FM) state below T_B. The saturation magnetization and T_B decreased with the increase in co-dopant contents. In addition, the bactericidal (on the gram-positive and gram-negative bacterial strains) and anti-cancerous effectiveness of these NSFs were assessed. The cancer cells' growth inhibitory action of these NSFs was tested against both normal (HEK-293) and cancerous (HCT-116) human cells. After 48 h of treatment of the cancerous cells with the NSFs, their population was significantly dropped as shown by the MTT assay, indicating the selective inhibition of the cancer cells growth by the proposed NSFs. Conversely, the non-cancerous cells (HEK-293) population remained unaffected. The IC₅₀ values of the NSFs-treated cancerous cells (HCT-116) were in the range of 0.74–2.35 µg/mL. The results of the MIC and MBC assays revealed the reasonable antibacterial efficacy (growth inhibitory activity) of these NSFs when tested against the E. coli and S. aureus bacterial strains. It is established that the proposed Ce³⁺/Dy³⁺ co-activated CDMZNSFs may be beneficial for the anti-cancerous and bactericidal applications.     

Green synthesis of Copper oxide nanoparticles decorated with graphene oxide for anticancer activity and catalytic applications

Nanotechnology is an embryonic field that grips countless impacts on the drug delivery system. Nanoparticles as haulers increase the capability of target-specific drug delivery to many folds hence are used in the treatment of dreadful diseases such as cancer, diabetes, etc. This boom has aimed at, to synthesize Copper oxide nanoparticles (CuO-NPs) using Acalypha Indica leaf extract and then incorporated with graphene oxide (GO) to form GO-CuO nanocomposites. Secondly, to sightsee the photocatalytic activity of CuO-NPs and GO-CuO nanocomposites towards the decolorization of methylene blue-dye and to test its activity against HCT-116 Human colon cancer cell lines. Synthesized nanocomposites were characterized using FTIR, UV–vis, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray Photoelectron Spectroscopy (XPS) and transmission electron microscopy (TEM) analysis. The photocatalytic studies revealed that synthesized nanocomposites have the efficiency to degrade methylene blue dye by 83.20% and cytotoxic activity was found to be 70% against HCT-116 Human colon cancer cell lines at 100 μg/ml. GO-CuO nanocomposites have appreciable activity towards cancer cell lines and photocatalytic activity when compared to nanoparticles as such.     

Aminomethylphosphine Oxides: Synthesis,dissociation and stability constants, 31P{1H}-NMR-controlled titrations

The title compounds are prepared via Gabriel-synthesis following known or improved procedures. Novel methods using ³¹P{¹H}-NMR controlled titrations of aminomethylphosphine oxides lead to dissociation constants (given as basicity or acidity constants resp.) and to stability constants. Dynamically averaged and ion specific chemical shifts δ_P were derived.     

Synthesis and in vitro anti-proliferative capabilities of steroidal thiazole and indole derivatives

Derivatives (1–15) of steroidal and indole class were synthesized using different strategies. These compounds were characterized by ¹H NMR spectroscopy and EI-MS, respectively. The synthetic derivatives were examined for their cytotoxic effects on human adenocarcinoma cells (HCT-116) using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and morphometric analysis. The cytotoxic effects of all the compounds were observed after 48 h treatment and it was found that out of fifteen, four compounds 1, 2, 3, and 14 showed inhibitory action on the cancer cells. We have calculated the IC₅₀ values for compounds 1, 2, 3, and 14 which were 22.50 µg/mL, 55.65 µg/mL, 21.35 µg/mL and 58.50 µg/mL, respectively. The compounds 3 (IC₅₀ = 21.35 µg/mL) and 1 (IC₅₀ = 22.50 µg/mL) showed highest inhibitory activities as compared to compounds 2 (IC₅₀ = 55.65 µg/mL) and 14 (IC₅₀ = 58.50 µg/mL). These results suggested that steroidal thiazole and indole derivatives are potent lead molecules having strong anti-cancer proliferative capabilities.     

1H, 13C and 31P NMR spectral analysis of monoalkyl (α‐anilinobenzyl)phosphonates and their dipalladium(II) metallocyclic complexes

A ¹H, ¹³C and ³¹P NMR study of monoethyl (HL1) and monobutyl (HL2) esters of (α‐anilinobenzyl)phosphonic acid and their metallocyclic dipalladium complexes (Pd₂L₄,L = L1, L2) in DMSO‐d₆ was performed, based on 1D and 2D homo‐ and heteronuclear experiments including ¹H,¹³C,³¹P,APT,¹H–¹H COSY, ¹H–¹³C COSY, gs‐HMQC and gs‐HMBC NMR techniques. The results obtained are discussed with respect to those for some palladium(II) complexes reported for various anilinobenzylphosphonate derivatives. Copyright © 2002 John Wiley & Sons, Ltd.     

Concurrent Reactive Oxygen Species Generation and Aneuploidy Induction Contribute to Thymoquinone Anticancer Activity

Thymoquinone (TQ) is the main biologically active constituent of Nigella sativa. Many studies have confirmed its anticancer actions. Herein, we investigated the different anticancer activities of, and considered resistance mechanisms to, TQ. MTT and clonogenic data showed TQ’s ability to suppress breast MDA-MB-468 and T-47D proliferation at lower concentrations compared to other cancer and non-transformed cell lines tested (GI₅₀ values ≤ 1.5 µM). Flow-cytometric analyses revealed that TQ consistently induced MDA-MB-468 and T-47D cell-cycle perturbation, specifically inducing pre-G1 populations. In comparison, less sensitive breast MCF-7 and colon HCT-116 cells exhibited only transient increases in pre-G1 events. Annexin V/PI staining confirmed apoptosis induction in MDA-MB-468 and HCT-116 cells, which was continuous in the former and transient in the latter. Experiments revealed the role of reactive oxygen species (ROS) generation and aneuploidy induction in MDA-MB-468 cells within the first 24 h of treatment. The ROS-scavenger NAD(P)H dehydrogenase (quinone 1) (NQO1; DT-diaphorase) and glutathione (GSH) were implicated in resistance to TQ. Indeed, western blot analyses showed that NQO1 is expressed in all cell lines in this study, except those most sensitive to TQ-MDA-MB-468 and T-47D. Moreover, TQ treatment increased NQO1 expression in HCT-116 in a concentration-dependent fashion. Measurement of GSH activity in MDA-MB-468 and HCT-116 cells found that GSH is similarly active in both cell lines. Furthermore, GSH depletion rendered these cells more sensitive to TQ’s antiproliferative actions. Therefore, to bypass putative inactivation of the TQ semiquinone metabolite, the benzylamine analogue was designed and synthesised following modification of TQ’s carbon-3 atom. However, the structural modification negatively impacted potency against MDA-MB-468 cells. In conclusion, we disclose the following: (i) The anticancer activity of TQ may be a consequence of ROS generation and aneuploidy; (ii) Early GSH depletion could substantially enhance TQ’s anticancer activity; (iii) Benzylamine substitution at TQ’s carbon-3 failed to enhance anticancer activity.