Synthesis and structure-activity relationships of pirfenidone derivatives as anti-fibrosis agents in vitro.

Pirfenidone (PFD) was the first approved drug by FDA for the treatment of idiopathic pulmonary fibrosis (IPF). However, the rapid metabolism of 5-methyl of PFD increases the risk of side effects in clinics. Thus, in this paper, a common practice that a stable amide bond linking various groups used to replace 5-methyl of PFD in medicinal chemistry was applied, and total 18 PFD derivatives were synthesized. All compounds were investigated for their antiproliferation activities against NIH3T3 cells and the structure-activity relationships of the target compounds were also discussed. Among them, YZQ17 possessed potent antiproliferation activity compared to PFD and better potency in inhibiting TGF-ß-induced migration of NIH3T3 cells at a much lower concentration than that of PFD. In addition, YZQ17 dramatically inhibited the expression levels of fibrotic markers α-SMA, collagen I, and fibronectin. Moreover, further mechanistic studies confirmed that YZQ17 exhibited this considerable anti-fibrosis activity via the TGF-ß/Smad2/3 dependent pathway. Finally, the results of human and rat liver microsomes assay in vitro and pharmacokinetic assay in rats confirmed that YZQ17 showed better pharmacokinetics than that of PFD. Collectively, the preliminary study of PFD derivatives modified by the amide group indicated that YZQ17 could be regarded as a lead compound for further investigation and optimization.

Generation of sodium halide endohedral metallofullerenes in the gas phase.

RATIONALE: Recent theoretical calculations show that ionic bond encapsulated endohedral metallofullerenes (EMFs) have great potential in the application of molecular electronic components. However, experimental study of these species is very limited, due to the difficulty in their generation. Thus, it is important to study the possibility and optimized conditions of these species generated in the gas phase. METHODS: Mixtures of graphene and metal halides (MX), where M = Na, K; and X = Cl, Br, I, were used as the precursors for the experiments. Mass spectra were obtained in positive ion mode by laser irradiation of these mixtures of graphene and metal halides using a 7.0 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer equipped with a 355 nm YAG laser. RESULTS: EMF ions of NaCl@C+ 2n (2n = 120-244), NaBr@C+ 2n (2n = 110-240), and NaI@C+ 2n (2n = 116-198) were observed in the laser ablation mass spectra. However, the encapsulated ion could not be replaced by Li or K in these experiments, indicating that the effects of the metal cation on the EMFs are larger than those of halide anions. CONCLUSIONS: Ionic bond encapsulated EMF ions of NaX@C+ 2n (X = Cl, Br and I, 110 ≤ 2n ≤ 244) were generated by laser ablation of the mixture of graphene and sodium halides, but no species containing lithium or potassium were observed. This work opens the possibilities of using laser ablation for the synthesis of large-sized salt-encaged EMFs. Further study of the mechanism for these processes is important for the generation of the missing species.

Intertidal mussels do not stop metal bioaccumulation even when out of water: Cadmium toxicokinetics in Xenostrobus atratus under influences of simulated tidal exposure.

Intertidal bivalves are periodically exposed in air. It is tempting to speculate that the organisms would temporarily escape from contaminants when they are out of water and thus have lower risks. In this study, we tested this speculation by investigating cadmium (Cd) toxicokinetics in an intertidal mussel, Xenostrobus atratus, under the effects of tidal exposure using simulated tidal regimes. The uptake rate constant (ku) of Cd ranged from 0.045 L g-1 d-1 to 0.109 L g-1 d-1, whereas the elimination rate constant (ke) of Cd ranged from 0.029 d-1 to 0.091 d-1. Cd bioaccumulation was slightly higher in the continuously immersed mussels than the alternately immersed mussels, but much lower than what would be expected if assuming bioaccumulation being proportional to immersion duration. Cd uptake was observed even when mussels were exposed in air, due to uptake of Cd dissolved in mantle cavity fluid and internalization of Cd adsorbed on mussel tissues. Overall, tidal height showed limited effects on Cd bioaccumulation, consistent with the trend of Cd concentrations found in X. atratus collected from different tidal heights. The mantle cavity uptake mechanism is expected to be applicable to other contaminants and bivalves, and should have important implications in risk assessments for intertidal environment.

Greatly Enhanced Electron Affinities of Au2n Cl Clusters (n = 1-4): Effects of Chlorine Doping.

Au2n Cl- (n = 1-4) clusters are investigated by both laser ablation mass spectrometry and theoretical calculations. It is interesting to find that the electron affinities of neutral Au2n Cl (n = 1-4) clusters are much larger than those of corresponding pure Au2n clusters. Among them, the electron affinity of Au2Cl is 4.02 eV, which can be defined as a very unique superhalogen that is quite different from classical ones of M n X m (M = metal, X = halogen, and n < m). Natural bond orbital and highest occupied molecular orbital analyses indicate that the extra electron is predominantly delocalized over the positively charged metal moiety in these anionic Au2n Cl- clusters, which is the main reason for the large electron affinities of the corresponding neutral species.

Size Effect on Aurophilic Interaction in Gold-Chloride Cluster Anions of Au n Cl n+1 - (2 ≤ n ≤ 7).

Aurophilic interaction plays a very important role in gold-related clusters. Here, we investigate the Au n Cl n+1 - (n = 1-7) cluster ions using Fourier transform ion cyclotron resonance mass spectrometry in combination with theoretical calculations. Three cluster ions of Au2Cl3 -, Au3Cl4 -, and Au4Cl5 - show their remarkable intensities in the mass spectrum. Geometric structure optimizations for Au n Cl n+1 - (n = 1-7) were performed on the MP2 level. The results show that the most stable structures of Au n Cl n+1 - (n = 2-7) are all characterized by a zigzag structure. Furthermore, it can be found that the aurophilic interactions containing terminal gold atoms strengthen with the increase of total gold atoms and progressively stabilize for large clusters of Au6Cl7 - and Au7Cl8 -, whereas the aurophilic interactions between nonterminal adjacent gold atoms stabilize at n = 5.

Superhalogen Species of Titanium Oxide Related Clusters Generated by Laser Ablation.

Negative ion mass spectrometry can serve as an effective and easy way to find new candidates of superhalogen species. In order to investigate superhalogen properties of polytitanium clusters, the laser ablation mass spectrum of TiO2 was obtained with a Fourier transform ion cyclotron resonance mass spectrometer. Density functional theory calculations were also performed in this study. Species of [(TiO2)x(H2O)yOH]- (x = 1-8, y = 1-3) were observed in the mass spectrum. Among them, the intensities of [(TiO2)4(H2O)OH]-, [(TiO2)4(H2O)2OH]-, [(TiO2)3(H2O)2OH]-, and [(TiO2)5(H2O)2OH]- are remarkable. The structures of these species and their neutral counterparts are studied on the level of B3LYP/Lanl2dz/6-311++G(2d, 2p). Results show that the electron affinities (EAs) of the neutral clusters are all higher than that of the chlorine atom and (TiO2)4(H2O)2OH has the highest electron affinity value at 6.23 eV. This series of polytitanium superhalogens not only indicate that the OH might be applied as an effective superhalogen ligand but also show the potential of metal titanium in the design of novel superhalogen compounds.

Encapsulation of an Ionic Bond in Fullerenes: What is the Difference?

Endohedral metallofullerene ions containing an ionic bond of Lu-Cl were observed in a mass spectrum for the first time. A theoretical calculation has been performed on the example of LuCl@C90. The two most stable isomers are LuCl@ C2(99917)-C90 and LuCl@ C2(99914)-C90. Interestingly, both encaged Lu-Cl bonds have potential curves quite different from the Morse curve and have some energy-preferential directions relative to their outside carbon cages.