1,3-Dipolar cycloadditions: Part III-Cycloaddition of C,N-diarylnitrones to N-cinnamoylpiperidines

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Novel lysosome targeted molecular transporter built on a guanidinium-poly-(propylene imine) hybrid dendron for efficient delivery of doxorubicin into cancer cells

An efficient synthetic approach has been adopted to construct a new dendron-based octa-guanidine appended molecular transporter with a lysosomal targeted peptide–doxorubicin conjugate. The transporter alone (G8-PPI-FL) is found to be non-toxic, showed higher cellular uptake compared to Arg-8-mer and exhibited excellent selectivity towards lysosomes in cathepsin B expressing HeLa cells, while the Dox-conjugate showed significant cytotoxicity to cancer cells without affecting the non-cancerous cells

Experimental and DFT studies for substituent effects on cycloadditions of C,N-disubstituted nitrones to cinnamoyl piperidine

108-119Cycloaddition reactions of C-aryl-N-methyl nitrones (with varied electron demand character) to cinnamoyl piperidines have been studied by both experimental and theoretical approaches. The reactions are completely regioselective. Endo/meta selectivity of the major isomer has been confirmed on the basis of UV-Vis, IR, NMR and X-ray studies. Global properties of the reactants have been analyzed. Delocalization and activation energies of the located transition states have been calculated. Concerted mechanism of the reactions has been confirmed from trajectory simulations. Computational studies have rationalized the preferred endo stereoselectivity and have also indicated that increase in electron withdrawing character of nitrone C-aryl substituent decreases the activation energies and increases the diastereomeric excess along the reaction pathway

Novel lipidated sorbitol-based molecular transporters for non-viral gene delivery

In this study, we investigated the possible use of novel lipidated sorbitol-based transporters as functional devices for the improvement of non-viral gene delivery. These transporters are composed of a sorbitol scaffold bearing 8 guanidine moieties that mimic the arginine residues of well-known cell-penetrating peptides. In addition, the transporters carry different lipid groups to aid DNA condensation and facilitate lipid vesicle-binding. We found that the transporters described in this study have the potential to function as plasmid DNA/siRNA-condensers and surface ligands for the enhancement of cellular uptake of lipid vesicles. Shorter lipid chains were found to be better for condensation, whereas longer chains were superior surface ligands. The differential activity of different cores might be explained by facilitated decondensation of cores prepared with transporters comprised of shorter lipid chains. However, we suggest that there is an optimum value of decondensation to achieve higher transfection activities. The proper use of the transporters presented in this study enabled us to prepare a highly efficient non-viral gene delivery system based on a core-shell structure, in which a condensed DNA core is encapsulated by a lipid envelope. A multifunctional envelope-type nano-device prepared with an optimal surface ligand favorably competes with commonly used transfection systems

<i>Curcuma raktakanda</i> Induces Apoptosis and Suppresses Migration in Cancer Cells: Role of Reactive Oxygen Species

Although over 100 species of Curcuma are reported, only Curcuma longa is extensively studied. Curcuma raktakanda, a poorly studied species, is most commonly distributed in the Kerala state of India. For the first time, we examined the efficacy of different fractions (acetone, hexane, and ethyl acetate) of C. raktakanda against glioma, cervical, and breast cancer cell lines. As determined by mitochondrial reductase activity assay, the viability of cancer cells was decreased in a concentration-dependent manner by the three fractions. The half maximal inhibitory concentration (IC-50) values after the treatment of C-6 glioma cells for 48 h was found to be 32.97 &#181;g/mL (acetone extract), 40.63 &#181;g/mL (hexane extract), and 51.65 &#181;g/mL (ethyl acetate extract). Of the three fractions, the acetone fraction was more effective. The long-term colony formation of cancer cells was significantly suppressed by the acetone fraction. Analyses using DAPI (4&#8242;,6-diamidino-2-phenylindole) staining, AO/PI (acridine orange/propidium iodide) staining, DNA laddering, and sub-G1 population revealed that the acetone extract induced apoptosis in glioma cells. The extract induced reactive oxygen species generation and suppressed the expression of cell survival proteins. The migration of cancer cells was also suppressed by the acetone extract. The gas chromatography-mass spectrometry (GC-MS) analysis indicated that tetracontane, dotriacontane, hexatriacontane, pentacosane, hexacosane, and eicosane are the major components in the acetone extract. Collectively, the extract from C. raktakanda exhibited anti-carcinogenic activities in cancer cells. We are exploring whether the phytoconstituents, individually, or collectively contribute to the anti-cancer activities of C. raktakanda

Chemical synthesis and proinflammatory responses of monophosphoryl lipid a adjuvant candidates

Lipopolysaccharides (LPS), which are structural components of the outer-surface membrane of Gram-negative bacteria, trigger innate immune responses through activation of Tolllike receptor 4 (TLR4). Such responses may be exploited for the development of adjuvants and in particular monophosphoryl lipid A (MPLA) obtained by controlled hydrolysis of LPS of Salmonella minnesota, exhibits low toxicity yet possesses beneficial immuno-stimulatory properties. We have developed an efficient synthetic approach for the preparation of a major component of MPLA (1), which has as a key feature the use of allyloxycarbonates (Alloc) as permanent protecting groups for the C-3 and C-4 hydroxy groups of the proximal glucosamine unit. The latter protecting groups greatly facilitated deprotection of the fully assembled compound. Furthermore, the amino functions were protected as N-2,2,2-trichloroethoxycarbamates (Troc), which performed efficient neighboring-group participation to give selectively 1,2-trans-glycosides and could easily be removed under mild conditions without affecting the permanent Alloc carbonates and anomeric dimethylthexylsilyl (TDS) ether. The synthetic methodology was also employed for the preparation of a monophosphoryl lipid A (2) derivative that has the anomeric center of the proximal sugar modified as a methyl glycoside. Compound 1 was not able to induce cytokine production in mouse macrophages whereas methyl glycoside 2 displayed activity, however it has a lower potency and efficacy than lipid A obtained by controlled hydrolysis S. minnesota. This indicates compound 2 is an attractive candidate for adjuvant development and that 1 is not the active substance of MPLA obtained by controlled hydrolysis of LPS

Exploration of Biogenic Nano-chemobiotics Fabricated by Silver Nanoparticle and Galactoxyloglucan with an Efficient Biodistribution in Solid Tumor Investigated by SERS Fingerprinting

An incredible exploration ensued of a dual modality nanocomposite wherein chemotherapy in fusion with antibacterial efficacy is obtained in a biogenic fabrication, which transformed as a novel nano-chemobiotics (NCB) prevailing fundamental molecular level investigation by surface-enhanced Raman scattering (SERS) platform. The nanocomposite is a facile, robust, and ecofriendly constitution between silver nanoparticles (SNPs) and a naturally occurring galactoxyloglucan (PST001) denoted as SNP@PST, which displayed biocompatibility with an upgraded selective cytotoxicity toward cancer cells. The relatively nontoxic nature of the SNP@PST on normal cells and red blood cells was further proved by detailed toxicological profiling on BALB/c mice. As a unique outcome, we observed excellent antibacterial activity, which is complementary to the greater cytotoxicity by the NCB. In diagnostic aspect, SNP@PST was revealed to be a superior SERS substrate with multiscale Raman signal enhancement contributed by homogeneous hot-spot distribution. Finally, the inherent SERS feature enabled us to investigate the biodistribution of the NCB in tumor-challenged mice using Raman fingerprinting and mapping analysis. Hence, the unrevealed SNP@PST orchestrated with the surfactant-free green method resembled a potential theransonstic NCB construct with synergistic anticancer and antibacterial potential in a single platform