Non-cancerous Human Embryonic Kidney Cells Research Articles

Gold(I) and gold(III) complexes of 1,2,4-triazole-derived N-heterocyclic carbenes: Synthesis, characterization, in-vitro anticancer and anti-inflammatory studies

Two gold(I) and two gold(III) complexes featuring 1,2,4-triazole derived carbenes ([AuCl(Cy-tazy)] and [AuCl(Bn-tazy)]) have been successfully synthesized via a silver-carbene transfer pathway. Subsequent metal oxidations of using PhICl2 resulted in gold(III) complexes [AuCl3(Cy-tazy)] and [AuCl3(Bn-tazy)], respectively. All the complexes have been characterized by elemental analysis, multinuclear NMR spectroscopy, (ESI) mass spectrometry, single crystal X-ray diffraction and DFT calculations. In addition, all the four gold complexes exhibit high antiproliferative activities against KB, MCF-7 and HT-29 cancerous cell lines. The most active compound is also potent to Hela and leukemia (HL-60) cells but shows lower degree of cytotoxicity toward non-cancerous human embryonic kidney cells (HEK-293). Our preliminary studies also reveal that the two gold(III) complexes are capable of stabilizing red blood cell membrane and suppressing the NO production in RAW264.7 macrophages induced by lipopolysaccharides, suggesting their potential anti-inflammatory activities. Interestingly, there have hardly been any reports on anti-inflammatory activities of gold(III) complexes of N-heterocyclic carbenes.

Synthesis of M-Ag3PO4, (M = Se, Ag, Ta) Nanoparticles and Their Antibacterial and Cytotoxicity Study.

Silver Phosphate, Ag3PO4, being a highly capable clinical molecule, an ultrasonic method was employed to synthesize the M-Ag3PO4, (M = Se, Ag, Ta) nanoparticles which were evaluated for antibacterial and cytotoxicity activities post-characterization. Escherichia coli and Staphylococcus aureus were used for antibacterial testing and the effects of sonication on bacterial growth with sub-MIC values of M-Ag3PO4 nanoparticles were examined. The effect of M-Ag3PO4 nanoparticles on human colorectal carcinoma cells (HCT-116) and human cervical carcinoma cells (HeLa cells) was examined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay and DAPI (4′,6-diamidino-2-phenylindole) staining. Additionally, we analyzed the effect of nanoparticles on normal and non-cancerous human embryonic kidney cells (HEK-293). Ag-Ag3PO4 exhibited enhanced antibacterial activity followed by Ta-Ag3PO4, Ag3PO4, and Se-Ag3PO4 nanoparticles against E. coli. Whereas the order of antibacterial activity against Staphylococcus aureus was Ag3PO4 > Ag-Ag3PO4 > Ta-Ag3PO4 > Se-Ag3PO4, respectively. Percentage inhibition of E. coli was 98.27, 74.38, 100, and 94.2%, while percentage inhibition of S. aureus was 25.53, 80.28, 99.36, and 20.22% after treatment with Ag3PO4, Se-Ag3PO4, Ag-Ag3PO4, and Ta-Ag3PO4, respectively. The MTT assay shows a significant decline in the cell viability after treating with M-Ag3PO4 nanoparticles. The IC50 values for Ag3PO4, Se-Ag3PO4, Ag-Ag3PO4, and Ta-Ag3PO4 on HCT-116 were 39.44, 28.33, 60.24, 58.34 µg/mL; whereas for HeLa cells, they were 65.25, 61.27, 75.52, 72.82 µg/mL, respectively. M-Ag3PO4 nanoparticles did not inhibit HEK-293 cells. Apoptotic assay revealed that the numbers of DAPI stained cells were significantly lower in the M-Ag3PO4-treated cells versus control.

Pincer–dipeptide and pseudodipeptide conjugates: Synthesis and bioactivity studies

Following a recent trend on the application of different pincer scaffolds for the development of new metal-based antitumor agents, in this work, dipeptides and dipeptide surrogates based on picolinyl- and 4-chloropicolinylamides with S-donor amino acid residues (cysteine, homocysteine, or methionine) bearing glycinate, alaninate, or phosphonate moieties either at the C-terminus or in the S-donor side arm have been designed as nonclassical pincer ligands with central amide units and shown to smoothly undergo site-selective direct cyclopalladation under mild conditions, affording the target Pd(II) pincer complexes in good to high yields. The realization of S,N,N-coordination through the sulfur atom of the thioether group and nitrogen atoms of the pyridine and deprotonated amide units was unambiguously confirmed using different NMR techniques (1H, 13C, 31P, and 2D NMR methods, including 1H15N HMBC) and IR spectroscopy; the structure of one representative was elucidated by X-ray crystallography. The resulting pincer–(pseudo)dipeptide conjugates were screened for cytotoxicity against several cancer cell lines and noncancerous human embryonic kidney cells and at least some of them provided an appreciable level of activity comparable to that of cisplatin. The S-modified homocysteine-based derivatives exhibited also significant antiproliferative effects against doxorubicin-resistant transformed breast cells HBL100/Dox, implying the possibility of overcoming drug resistance. The complexes can induced apoptosis but did not affect mitochondria. The comparative DNA/protein binding studies of one of the most active pincer–(pseudo)dipeptide conjugates with the monoamino acid-based prototype revealed certain advantages of the former and gave further insights into the potential of this type of palladium-based antitumor agents.

Role of the ancillary ligand in determining the antimicrobial activity of Pd(II) complexes with N^N^N-tridentate coligand

Two [PdN3L]PF6 complexes (L = 2,6-bis(1-ethyl-benzimidazol-2́-yl)pyridine (LBZ) and 4-(2-pyridyl)-2,2′:6′,2′'-terpyridine (LPY)) underwent catalyst-free 1,3-dipolar cycloaddition coupling with phenyl isothiocyanate at the room temperature giving the corresponding tetrazole–thiolato complexes. 1H NMR studies showed that the N1-isomer appeared first in the catalyst-free coupling, then gradually isomerized to the more stable tetrazole–thiolato isomer. The interconversion of N1-isomer into the S-isomer is accompanied by a decrease of the greater steric demand of the 5-membered ring. Tetrazolate complex of LBZ displayed higher antifungal activity (MIC ≤ 0.25 μg/mL) than the chloride analogue (MIC = 0.5–1.0 μg/mL) and the reference drug, Fluconazole (MIC = 0.125–8.0 μg/mL) against Candida albicans and Cryptococcus neoformans. The treated non-cancerous human embryonic kidney cells (HEK293) showed no cytotoxicity and no haemolysis release at the measured concentrations of the chloride complex of LBZ and tetrazolate complex of LPY.

Nanoparticle-Mediated Routing of Antibiotics into Mitochondria in Cancer Cells.

In recent years, antibiotics have emerged as alternative medicines in cancer therapy due to their capability of mitochondrial dysfunction in cancer cells. However, antibiotics render collateral damage in noncancerous cells by targeting mitochondrial transcription and translational machinery. To address this, herein, we have engineered three different mitochondria-targeted cationic antibiotic (tigecycline)-loaded nanoparticles from cholesterol conjugates. Dynamic light scattering and electron microscopy confirmed the spherical morphology and a less than 200 nm hydrodynamic diameter for these nanoparticles. The triphenylphosphine-coated tigecycline-loaded nanoparticle (Mito-TPP-Tig-NP) was shown to be homed into the mitochondria of A549 lung cancer cells compared to the other cationic nanoparticles. These Mito-TPP-Tig-NPs indeed triggered mitochondrial morphology damage and generation of reactive oxygen species (ROS). All the mitochondria-targeted tigecycline-loaded nanoparticles showed improved cancer cell killing ability in A549 and HeLa cervical cancer cells compared to free tigecycline. Moreover, Mito-TPP-Tig-NPs showed much less toxicity toward noncancerous human embryonic kidney cells (HEK293) compared to free tigecycline. These antibiotic-loaded mitochondria-targeted nanoparticles can open up an avenue toward anticancer therapy.

1,2,4-triazole-derived N-heterocyclic carbene complexes of platinum(II) as catalysts for hydroamination reactions and active anticancer agents

A series of five platinum(II) complexes of 1,2,4-triazole derived N-heterocylcic carbenes (R-tazy) with generic formula cis-[PtCl2(R-tazy)(DMSO)] (DMSO = dimethyl sulfoxide) have been successfully synthesized. The complexes feature the carbenes with the same benzyl wingtip, but are differed by their N-4 substituent (R = isopropyl (1), cyclohexyl (2), phenyl (3), mesityl (4) and 2,6-diisopropylphenyl (5)). The two new compounds 1 and 2 were characterized by means of multinuclear (1H, 13C{1H}) magnetic resonance spectroscopy, mass spectrometry, elemental analysis and single crystal X-ray diffraction (for 2). The hindered rotations of the benzyl and κ-S-dimethyl sulfoxide were elucidated using NMR spectroscopy and rationalized with density functional theory (DFT) calculation. Notably, the five complexes were found active catalysts for intermolecular hydroamination of phenylacetylene using aromatic amines in the presence of silver(I) triflate additive. In addition, all the five complexes display high cytotoxicity toward human carcinoma in the mouth (KB), human breast carcinoma (MCF-7) and human colorectal carcinoma (HT-29) cell lines with IC50 concentration in the 3.0 ± 0.4–14.3 ± 1.3 μM range. Interestingly, compound 1 and 3 display lower cytotoxicity toward non-cancerous human embryonic kidney cell (HEK-293A).

Human serum albumin interaction, in silico and anticancer evaluation of Pine-Gold nanoparticles

Abstract Unique characteristics displayed by phytoconstituent conjugated nanoparticles and their crucial interactions with proteins serve to develop nanoparticle-bio-interface platform. Gold nanoparticles of 16 nm in size were generated using aqueous extracts of pine bark and further conjugated to human serum albumin. The gold nanoparticles-protein complex was characterized by surface plasmon resonance, UV–vis and emission spectroscopy techniques. Further, it was characterized for surface morphology and elemental composition, crystallographic quality, nanoparticles size, shape, stability, structural determination and the identification of capping agent. Moreover, the interaction of gold nanoparticles with human serum albumin was investigated using conventional spectroscopy techniques. Fluorescence quenching and absorption studies demonstrated an effective binding of human serum albumin with oleamide capped gold nanoparticles. The molecular docking study showed a binding affinity of -6.1 kcal/mol whereas the molecular dynamics simulation indicated that the binding of oleamide to human serum albumin. A biological evaluation of pine bark extract-gold nanoparticles showed cytotoxicity with increased cell mortality in lung cancer cells and minimal toxicity on non-cancerous human embryonic kidney cells, respectively.

Coupling the near-infrared fluorescent dye IR-780 with cabazitaxel makes renal cell carcinoma chemotherapy possible

Renal cell carcinoma (RCC) has always been considered resistant to chemotherapy. IR-780 is a near-infrared fluorescent (NIRF) dye that can be efficiently taken up by RCC cells. Cabazitaxel is a cytotoxic drug that interferes with mitosis by acting on tubulin. We chemically fused IR-780 and cabazitaxel into a new drug, Caba-780, which is expected to increase the sensitivity of RCC to chemotherapy. Infrared spectrum, nuclear magnetic resonance spectra, high-resolution mass spectra, and IR spectra were used for detecting structural characterization of the new synthetic drug Caba-780. The RCC cells lines ACHN and 786-O, as well as the non-cancerous human embryonic kidney cell line HEK293, were used to assess the cytotoxicity and tumor-efficient uptake of Caba-780 in vitro. The xenograft tumor-bearing mice and C57 mice were used to estimate the tumor-efficient imaging of Caba-780 as well as the safety and efficacy of its anti-tumor effects in vivo. The new synthetic drug Caba-780 retains the NIRF properties of IR-780. In vitro, Caba-780 was efficiently absorbed by the RCC cell lines ACHN and 786-O, and had an inhibitory effect on their growth, clonogenicity migration, and invasion. At the same time, Caba-780 retained the anti-tumor effect of cabazitaxel, which can inhibit the growth of tumor cells and promote apoptosis by inhibiting mitosis. In vivo experiments showed that Caba-780 can be taken up and imaged in tumor tissue, whereby it inhibits tumor growth. The novel fused molecule Caba-780 has application prospects in the diagnosis and treatment of RCC and makes RCC chemotherapy possible.

Green‐Light‐Induced PhotoCORM: Lysozyme Binding Affinity towards MnI and ReI Carbonyl Complexes and Biological Activity Evaluation

Reaction of N‐(2‐pyridylmethylene)benzene‐1,4‐diamine (L) with [MBr(CO)5] (M = MnI and ReI) affords complexes of the type [MBr(CO)3L] [M = MnI (1) and ReI (2)]. Complex 1 releases CO upon illumination with light in the range of 525–468 nm. No photo induced CO release is detected from 2. Reactive azide complex 3, obtained by bromide's ligand exchange, reacts with the electron‐poor alkyne dimethyl acetylene dicarboxylate giving triazolato complex 4 ([Mn(triazolateCOOMe,COOMe)(CO)3L]) via the free catalyst [3+2] cycloaddition coupling. Complex 1 exhibits interesting antifungal activity (MIC = 30 nM) against Candida albicans and Cryptococcus neoformans as well as cytotoxic activity of 12.56 µg/mL against noncancerous human embryonic kidney cells. Reactivity of the complexes towards hen egg white lysozyme is studied by electrospray ionization mass spectrometry.

Tricarbonylrhenium(I) complexes with the N,6-dimethylpyridine-2-carbothioamide ligand: combined experimental and calculation studies

A new series of tricarbonyl complexes of rhenium(I) in the “2 + 1” system with the bidentate ligand N,6-dimethylpyridine-2-carbothioamide ((CH3)NC5H4-CS-NH-CH3, MeLH(Me)NS) and a monodentate ligand (halides Cl, Br, or I, and the pseudohalide NCS anion) was synthesized. The use of mixed ligands led to the formation of neutral tricarbonylrhenium(I) complexes [Re(CO)3(MeLH(Me)NS)X] (X = Cl, Br, I, NCS) (1–4). Single-crystal X-ray diffraction was used to determine the crystal structures of all four compounds and those results were compared with molecular structures obtained from DFT calculations using the PBE0/def2-TZVPD approach. The complexes were also characterized by spectroscopic (FT-IR, NMR, and UV–vis) and analytical (HPLC, TGA, EA, ESI-MS) techniques. IR and UV–vis spectra were also calculated by DFT and TD-DFT methods. The cytotoxicity of these complexes was estimated using human ovarian cancer cell lines (A2780 and A2780cis), cervical cancer cells (HeLa), and non-cancerous human embryonic kidney cells (Hek-293). The toxicity of most complexes was moderate or low toward cancer cell lines (IC50 = 46–231 μM) and similar against non-cancerous cells (IC50 = 41-121 μM). Only the complex with chlorido ligand remarkably inhibited growth of ovarian cancer cells (IC50 = 3 and 12 μM for A2780 and A2780cis, respectively). The cytotoxicity of 1 was higher than that of cisplatin.

Tricarbonylrhenium(I) complexes with the N-methylpyridine-2-carbothioamide ligand – Synthesis, characterization and cytotoxicity studies

A new series of tricarbonyl complexes of rhenium(I) in the ‘2 + 1’ system with the bidentate ligand N-methylpyridine-2-carbothioamide (NC5H4-CS-NH-CH3, LH(Me)NS) and a monodentate ligand, being either an anion (Cl, Br, I or SCN) or a neutral molecule (3,5-dimethylpyrazole (Hdmpz) or imidazole (Him)), was synthesized. The use of mixed ligands leads to the formation of neutral or cationic (in the form of PF6− salts) tricarbonylrhenium(I) complexes: [Re(CO)3(LH(Me)NS)X] (X = Cl, Br, I, NCS) (complexes 1–4) and [Re(CO)3(LH(Me)NS)Y]+ (Y = Hdmpz, Him) (5 and 6), respectively. In case of the [Re(CO)3(LH(Me)NS)NCS] complex two polymorphic forms (4a and 4b) have been distinguished. Crystal structure of all complexes was determined by single-crystal X-ray diffraction method and the results were compared with the molecular structures obtained from DFT calculations. The compounds were characterized by FT-IR, NMR, UV-Vis and HPLC techniques. IR and UV-Vis spectra were also simulated by DFT and TD-DFT methods. Cytotoxicity of the complexes was estimated using human ovarian cancer cell line (A2780), its cisplatin resistant cell line (A2780cis) and non-cancerous human embryonic kidney cells (Hek-293). The toxicity of newly synthesized complexes was comparable to cisplatin when tested against both cancerous cell lines (IC50 = 2–49 μM), but lower than cisplatin towards non-cancerous cells (IC50 = 6–63 μM). Among them, the complexes with chloride and iodide anions exhibit remarkable cytotoxicities.

Synthesis, characterization, anticancer and antimicrobial study of arene ruthenium(II) complexes with 1,2,4-triazole ligands containing an α-diimine moiety

Abstract The reaction of the ruthenium arene dimers [(η 6-arene)Ru(μ-Cl)Cl]2 (where arene=benzene or p-cymene) with the ligands 4-benzylidene-3,5-di(2′-pyridyl)-4-amino-1,2,4-triazole (L1 ), 2-methoxybenzylidene-3,5-di(2′-pyridyl)-4-amino-1,2,4-triazole (L2 ), 4-methylbenzylidene-3,5-di(2′-pyridyl)-4-amino-1,2,4-triazole (L3 ) and indole-3-carbaldehyde-3,5-di(2′-pyridyl)-4-amino-1,2,4-triazole (L4 ) in a 1:2 ratio gives the new complexes [(η 6-arene)RuCl(L)]+ [arene=C6H6 (with L=L1(1), L2(3), L4(7), with PF6 − as a counter ion, and L4 (6), with Cl− as a counter ion) or p-cymene with L=L1(2), L2(4), L3(5), L4(8) with PF6 − as a counter ion]. All complexes were fully characterized using 1H and 13C NMR, elemental analyses, UV/Vis and IR spectroscopy. The single crystal X-ray structures of ligand L2 and complex 1 have been determined. The structure of 1 has the Ru atom coordinated with the arene group and to the N,N′-bidentate ligand and to the Cl atom. The arene group occupies the apex, while the ligand and the Cl atom are at the base of a pseudo-octahedral three-legged piano stool. The cytotoxicity of these mononuclear complexes was established in the human epithelial colorectal adenocarcinoma cell line (Caco-2) and for selectivity in the non-cancerous human embryonic kidney cell line (HEK293), using 5-fluorouracil (5-FU) as the reference anticancer drug. Compounds 1 and 7 were relatively inactive toward the Caco-2 tumor cells (IC50>200), while complexes 2–5 showed moderate anti-proliferative properties (IC50>100–200). Compound 6, however, displayed better anti-proliferative properties with an IC50 value lower than that of the reference drug, 5-FU, and was therefore further investigated for its antimicrobial activity against six Gram-positive and four Gram-negative bacteria.

RuII–Carbonyl photoCORMs with N,N‐Benzimidazole Bidentate Ligands: Spectroscopic, Lysozyme Binding Affinity, and Biological Activity Evaluation

The photoinduced carbon monoxide releasing properties of pyridylbenzimidazole‐based RuII–carbonyl complexes functionalized with alkylated sulfonate (LSO3H), phthalimide (LPhth), and morpholine (Lmorph) moieties, [RuCl(CO)3LSO3H]Cl (1) and [RuCl2(CO)2L] {where L = LPhth (2) and Lmorph (3)}, are reported. The geometrical stereochemistry and electronic transitions are assigned with the aid of DFT and TDDFT calculations. The compounds are evaluated for potential antimicrobial and cytotoxic active properties [against noncancerous human embryonic kidney cells (HEK293)]. Complex 2 shows interesting antifungal activity towards Candida albicans and Cryptococcus neoformans, with a similar MIC value of 24 nm. Metalation of hen egg‐white lysozyme (HEWL), as a biocompatible carrier, is studied in the dark and upon exposure to light. Stable protein adducts, capable of release CO upon illumination, are formed.

Mechanism of apoptosis induction in human breast cancer MCF-7 cell by Ruviprase, a small peptide from Daboia russelii russelii venom

Ruviprase, a 4.4 kDa peptide isolated from Daboia russelii russelii venom demonstrated antiproliferative activity against EMT6/AR1, U-87MG, HeLa and MCF-7 cancer cells with an IC50 value of 23.0, 8.8, 5.8 and 4.0 μg ml−1, respectively. However, it was nontoxic to non-cancerous human embryonic kidney cell and human peripheral blood lymphocytes. Flow-cytometric analysis confirmed the apoptosis induction in MCF-7 cells by Ruviprase where it induced DNA condensation but did not cause mitotic blockage or chromosomal aberration in treated-cells. Immunofluorescence microscopic analysis indicated Ruviprase induced apoptosis in MCF-7 cells through p53 and p21-mediated pathways. Ruviprase generated reactive oxygen species (ROS), altered the mitochondrial transmembrane potential, and significantly decreased the cellular glutathione (GSH) content of MCF-7 cells. Immunoblotting and quantitative real-time PCR (qRT-PCR) analyses suggested that Ruviprase down-regulated the expression of anti-apoptotic protein Bcl-2, increased cleavage of poly (ADP-ribose) polymerase (PARP) protein, and up-regulated the expression of pro-apoptotic protein Bax, as well as executer protein caspase-7 to induced apoptosis in MCF-7 cells via intrinsic pathway. This is the first report on the characterization of the anticancer potential of a small, non-toxic and anticoagulant peptide purified from Russell's viper venom.

Cytotoxic and immunomodulatory effects of Ebenus boissieri Barbey on breast cancer cells.

We aimed to determine the cytotoxic and immunomodulatory effects of hydroalcoholic extracts of the roots and aerial parts of Ebenus boissieri (EB) on breast cancer MDA-MB231 cells and the non-cancerous human embryonic kidney cell line, 293T. Cell viability was determined by MTT assay, trypan blue exclusion, and Live/Dead Viability/Cytotoxicity assay. Apoptosis was evaluated by measuring the activity of caspase-2, 3, 6, 8, and 9. Tumor necrosis factor (TNF)-α and interferon (IFN)-g release was assayed by ELISA, and protein expression of caspase-3, TNF-a, and IFN-g was determined by western blot. The results of this study revealed that MDA-MB231 cell viability was reduced in a dose-dependent manner by the aerial and root extract of EB at 72 h with a half-maximal inhibitory concentration (IC50) of 41.1 ± 2.76 and 65 ± 1.09 μg/mL, respectively. In contrast, neither the aerial nor the root extracts of this plant inhibited the proliferation of 293T cells at doses up to 1000 μg/mL. There was a time-dependent increase in caspase activity, especially caspase-3 and caspase-9. The levels of TNF-aand IFN-g significantly increased in MDA-MB231 cells treated with aerial extract. In conclusion, the extracts of EB induced apoptosis in breast cancer cells by altering the levels of caspases, TNF-a, and IFN-g. The components and precise modes of action of EB have not yet been determined. However, potential antitumor and immunomodulatory activity was observed along with selectivity against cancer cells in vitro, suggesting that hydroalcoholic extracts of this plant are worthy of additional study.

Bioengineered quantum dot/chitosan-tripeptide nanoconjugates for targeting the receptors of cancer cells

Nanobiomaterials can be engineered to recognize cancer-specific receptors at the cellular level for diagnostic and therapeutic purposes. In this work, we report the synthesis of novel multifunctional nanoconjugates composed of fluorescent inorganic semiconductor quantum dot (QD) cores and tripeptide-modified polysaccharide organic shells. These structures were designed for targeting and imaging the αvβ3 integrin receptors of cancer cells. Initially, chitosan was covalently bound with the RGD peptide using a crosslinker to form bioconjugates (RGD-chitosan), which were later utilized as capping ligands for the production of surface-functionalized CdS QDs via a single-step process in aqueous media at room temperature. These core-shell nanostructures were extensively characterized by UV–vis spectroscopy, photoluminescence (PL) spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), zeta potential (ZP) and dynamic light scattering (DLS). The TEM images and the UV–vis absorption results indicated the formation of ultra-small CdS QD nanocrystals with average diameters between 2.0 and 3.0nm. In addition, the PL results demonstrated that the nanobioconjugates exhibited intense green fluorescence under excitation. The CdS-RGD-chitosan systems were effective at specific targeting integrin when assayed in vitro using two model cell cultures, HEK 293 (non-cancerous human embryonic kidney cell) and SAOS (cancerous sarcoma osteogenic-derived cells) imaged using fluorescence microscopy.

Investigation of the mechanism and apoptotic pathway induced by 4β cinnamido linked podophyllotoxins against human lung cancer cells A549.

Apoptosis is essential for normal development and the maintenance of homeostasis. It plays a necessary role to protect against carcinogenesis by eliminating damaged cells. Many studies have demonstrated that the dysregulation of apoptosis results in cancer and this provides an approach to develop therapeutic agents via inducing apoptosis. In our previous studies 4β-cinnamido linked podophyllotoxin conjugates were synthesized and evaluated for their cytotoxic activity in a panel of five human cancer cell lines and the new molecules like 17a and 17f were considered as potential leads. The cytotoxic activity was comparable to etoposide. These observations prompted us to investigate the mechanism underplaying the cytotoxic activity and apoptotic pathway induced by these compounds in human lung cancer cells A459. The results of the present study revealed that these compounds exhibited DNA topoisomerase IIα inhibition and induced mitochondrial mediated apoptosis. It was further confirmed by Mitochondrial membrane potential, Cytochrome c release, cleavage of poly (ADP-ribose) polymerase (PARP), Reactive oxygen species (ROS) generation, regulation of antiapoptotic protein Bcl-2 and pro apoptotic protein Bax studied by Western blot analysis. Annexin V-FITC assay also suggested that these compounds induced cell death by apoptosis. Pretreatment with N-acetyl-L-cysteine (NAC) prevented the generation of ROS. Further, pretreatment with NAC significantly inhibited 17a and 17f induced apoptosis, suggesting that ROS are the key mediators for 17a and 17f induced apoptosis. These data indicate that these compounds might induce apoptosis in A549 cells through a ROS mediated mitochondrial dysfunction pathway. Moreover, these compounds did not significantly inhibit the noncancerous human embryonic kidney cells, HEK-293. Docking studies also elucidate the potential of these molecules to bind to the DNA topoisomerase II. Podophyllotoxin analogs were investigated for their mechanism and apoptotic pathway against lung cancer cell line, A549. These podophyllotoxin analogs inhibited DNA topoisomerase IIα and induced mitochondrial mediated apoptosis in lung cancer cell line, A549. Western blot analysis suggested that these compounds inhibited the DNA topoisomerase IIα. Studies like, Measurement of mitochondrial membrane potential (∆Ψm), Generation of intracellular reactive oxygen species (ROS) and Annexin V-FITC assay suggested that these compounds induced mitochondrial mediated apoptosis. Pretreatment with N-acetyl-L-cysteine (NAC) suggested that ROS plays a role in 17a and 17f induced apoptosis. Further the apoptotic effect of these compounds was confirmed by western blot analysis of pro apoptotic protein Bax and antiapoptotic protein Bcl-2, Cytochrome c release and cleavage of poly (ADP-ribose) polymerase (PARP). Moreover, these compounds did not significantly inhibit the noncancerous human embryonic kidney cells, HEK-293.

PEG-SO 3H catalyzed synthesis and cytotoxicity of α-aminophosphonates

One pot three-component PEG-SO 3H catalyzed reaction of 4-(Pyridin-4-yl)benzaldehyde and triethyl phosphite with various primary amines afforded α-aminophosphonates with high yields by the Kabachnik–Field’s reaction. These new structurally diversified set of α-aminophosphonates ( 4a–j) were evaluated for their anti-tumor activity on human chronic myeloid leukemia cells ( K 562), human colon carcinoma cells ( Colo 205) along with non-cancerous human embryonic kidney cells ( HEK 293). They showed moderate activity on both cancerous cells and non-cancerous cells.

Cytotoxic alkaloids from stems, leaves and twigs of Dasymaschalon blumei

Bioassay-guided fractionation of the cytotoxic ethyl acetate extract from the stems of Dasymaschalon blumei (Annonaceae) led to the isolation of four aristololactam alkaloids, including the hitherto unknown 3,5-dihydroxy-2,4-dimethoxyaristolactam (1), as well as the three known compounds, aristolactam BI, goniopedaline, and griffithinam. Additionally, the cytotoxic extract from the combined leaves and twigs of the same plant yielded three known oxoaporphine alkaloids, oxodiscoguattine, dicentrinone, and duguevalline. The structures of aristolactams and oxoaporphine alkaloids were elucidated on the basis of spectroscopic methods. All isolates were evaluated for cytotoxicity against a panel of mammalian cancer cell lines and a noncancerous human embryonic kidney cell Hek 293.