A NIR-controlled cage mimicking system for hydrophobic drug mediated cancer therapy.

Most chemotherapeutic drugs commonly suffer from several shortcomings, including the lack of aqueous solubility, limited stability and adverse side effects. Although caging strategy has recently been employed as an effective approach to conceal and stabilize these drugs to achieve light-activated cancer therapy, it is plagued by the sophisticated drug modification process and deleterious solvent usage. In addition, using UV or Visible light to remove photocaged group is restricted to its limited tissue penetration ability in and phototoxicity. In this paper, by anchoring photochromic spiropyran on the mesoporous silica coated upconversion nanoparticles (UCNP-SP), we design a NIR-controlled cage mimicking system. Our results indicate that hydrophobic drug can be concealed inside the channels of the nanocarrier with high stability and "uncaged" via NIR irradiation-triggered hydrophobicity-hydrophilicity switch of the spiropyran molecules, finally inducing drug release and recovering their bioactivity. Moreover, under NIR illumination, the UV/Visible emissions from UCNP can also efficaciously initiate the generation of reactive oxygen species (ROS) by Curcumin, further improving the therapeutic efficiency. Both in vitro and in vivo experimental results validate that NIR irradiated nanosystem can produce remarkably enhanced antitumor efficiency.

Aqueous extract from seeds of Silybum marianum L. as a green material for preparation of the Cu/Fe3O4 nanoparticles: A magnetically recoverable and reusable catalyst for the reduction of nitroarenes.

In this paper, we report the green synthesis of the Cu/Fe3O4 nanoparticles using Silybum marianum L. seeds extract and their application as magnetically separable nanocatalyst for the reduction of nitroarenes. Our method is clean, nontoxic and environment friendly. The synthesized nanocatalyst is characterized by XRD, TEM, EDS and UV-visible techniques. UV-visible spectroscopy is used to monitor the kinetics of the Cu/Fe3O4 nanoparticles formation. The results from Fourier transform infrared spectroscopy showed that the C=O and C-O groups in the plant seeds extract played a critical role in capping the nanoparticles. The expected reaction mechanism in the formation of nanoparticles is also reported. The catalyst is recoverable by magnetic decantation and could be reused several times without significant loss in catalytic activity.

Synthesis and evaluation of bifunctional nitrocatechol inhibitors of pig liver catechol-O-methyltransferase.

Bifunctional compounds were tested in vitro as potential inhibitors of pig liver catechol-O-methyltransferase (COMT) with respect to the catechol substrate 4-[(3,4-dihydroxyphenyl)azo]benzenesulfonate. The bifunctional compounds were a composite of either two nitrocatechols or one nitrocatechol and one phenol, linked by amide bonds to a spacer unit comprising two to five methylene groups. The unsymmetrical compounds N-[2-(4-hydroxybenzoylamine)ethyl]-3,4-dihydroxy-5-nitrobenzamide], N-[3-(4-hydroxybenzoyl-amine)propyl]-3,4-dihydroxy-5-nitrobenzamide] and N-[5-(4-hydroxybenzoylamine)pentyl]-3,4-dihydroxy-5-nitrobenzamide] demonstrated strong inhibitory action against COMT with K(i) values in the 100 nM range. In comparison, the monofunctional nitrocatechol analogues of these compounds had K(i) values that were significantly higher.

Synthesis and antiviral properties of arabino and ribonucleosides of 1,3-dideazaadenine, 4-nitro-1,3-dideazapurine and diketopiperazine.

Different arabinosides and ribosides, viz. Ara-DDA or 9(1-beta-D-arabinofuranosyl) 1,3-dideazaadenine (6), Ara-NDDP or 9(1-beta-D-arabinofuranosyl) 4-nitro-1,3-dideazapurine (7), Ara-DKP or 1(1-beta-D-arabinofuranosyl) diketopiperazine (8), Ribo-DDA or 9(1-beta-D-ribofuranosyl) 1,3-dideazaadenine (9) and Ribo-NDDP or 9(1-beta-D-ribofuranosyl) 4-nitro-1,3-dideazapurine (10) have been synthesized as probable antiviral agents. The arabinosides have been synthesized using the catalyst TDA-1 that causes stereospecific formation of beta-nucleosides while a one-pot synthesis procedure was adopted for the synthesis of the ribonucleosides where beta-anomers were obtained in higher yields. All the five nucleoside analogs have been screened for antiviral property against HIV-1 (IIIB), HSV-1 and 2, parainfluenza-3, reovirus-1 and many others. It was observed that arabinosides had greater inhibitory action than ribosides. The compound 7 or Ara-NDDP has shown maximum inhibition of HIV-1 replication than the rest of the molecules with an IC50 of 79.4 microg/mL.

Studies on nitrophenylfuran derivatives part Xii. synthesis, characterization, antibacterial and antiviral activities of some nitrophenylfurfurylidene-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines.

Synthesis of four 1-aryl-3-[5-(p-nitrophenyl)-2-furyl]-2-propen-1-ones starting from substituted acetophenones and p-nitrophenylfurfuraldehyde is described. These propenones were then converted into corresponding dibromo derivatives which on dehydrobromination afforded alpha-bromopropenones rather than acetylenic ketones. Condensation of these dibromopropanones with 4-amino-5-mercapto-1,2,4-triazoles yielded a new class of nitrophenylfurfurylidene-1,2,4-triazolothiadiazines. The structures of nitrophenylfurfurylidene-1,2,4-triazolothiadiazines were established on the basis of analytical, IR, NMR and mass spectral studies. The formation of 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines rather than 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazepines in the above condensation was unambiguously confirmed by X-ray crystallographic analysis of one of them. A possible mechanism is proposed to account for the formation of nitrophenylfurfurylidene-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines. Some of the newly synthesized triazolothiadiazines were screened for their antibacterial and antiviral properties.

[Synthesis and biological activity of isomeric 5- and 6-nitro-1-alkylbenzimidazoles]. / Synteza i dzialanie biologiczne izomerycznych 5- i 6-nitro-1-alkilobenzimidazoli.

Either the alkylation of 5(6)-nitro-benzimidazoles (R = H, CH3) or the nitration of 1-alkyl-benzimidazoles afforded corresponding mixtures of 1-alkyl-5-nitro- and 1-alkyl-6-nitro-benzimidazoles (III, IV, VII, VIII, XI). Fractional crystallization from water was employed for isolation of 6-nitro isomers V, VI and IX from mixtures III, IV and VII. On the other hand, application of this isolation method to mixtures VIII and XI proved unsuccessful. 6-Nitro-compound X and 5-nitro derivatives XIII and XV were obtained by direct syntheses. From calibration curves depicting dependence of absorbance of the mixtures upon their composition, percentage ratios of 5-nitro to 6-nitro isomers in the mixtures were estimated. Usefulness of thin-layer chromatography, and UV and IR spectrometry for identification of 5-nitro and 6-nitro isomers was stated; e. g. 5-nitro isomers have higher epsilon values, while 6-nitro isomers exhibit two vmax values of the benzene ring. Compounds IV, IX and X proved to exert antihelminthic, antibacterial and antiphlogistic activities.