Effects of substitution and conjugation on photophysical properties of ESIPT-based fluorophores with the core of 4-aminophthalimide.

4-Aminophthalimide is a highly fluorescent signaling unit with excellent photophysical properties and wide application foregrounds. Based on this, a range of theoretical investigations are conducted on the fluorescent probe (E)-5-((2-hydroxybenzylidene) amino) isoindoline-1, 3-dione (HID) with the core of 4-aminophthalimide using density functional theory (DFT) and time-containing density functional theory (TD-DFT) methods in this paper. The optimized configurations, vertical excitation and emission energies, electronic characteristics and excited-state intramolecular proton transfer (ESIPT) behaviors of the probe HID are discussed in detail. Furthermore, to enhance the luminescent properties of HID, five novel compounds have been designed based on the structure of HID by introducing amino, methoxy and naphthalene groups (-NH2, -OMe and C10H8). Our work thoroughly explores how the property and position of substituents and conjugation affect photophysical characteristics and ESIPT processes. We find that the ESIPT dynamics can be modulated by the substitution and conjugation effects. Specifically, the introduction of amino and methoxy groups at the ortho-position and the introduction of the naphthalene group promote the ESIPT behavior of HID1, whereas the introduction of amino and methoxy groups at the meta-position exhibits the contrary impact. Therefore, we boldly infer that the introduction of electron-donating groups in the ortho-position and the introduction of the conjugated group make the ESIPT process more effortless to occur, whereas the introduction of substituents with opposing natures in the meta-position makes the ESIPT process more difficult to occur. In addition, the ionization potentials (IP), electron affinities (EA) and reorganization energies (λh and λe) of molecules are calculated to assess their potential as luminescent materials. Our work not only reveals the luminescence and ESIPT mechanism of the probe HID1, but also proposes to modulate the ESIPT process through the substitution and conjugation effects. In particular, the designed molecules have better photoelectric properties as a result of their red-shifted absorption and fluorescence spectra, smaller energy gaps, larger transferred charges and greater charge transferred distances, which offers some valuable ideas for the experimental development of more efficient organic luminescent materials with ESIPT properties.

Sesquiterpene lactones from Artemisia vulgaris L. as potential NO inhibitors in LPS-induced RAW264.7 macrophage cells.

Twelve new guaianolide sesquiterpene lactones (1-12), along with ten known analogs (13-22) were isolated from an EtOH extract of the dried aerial parts of Artemisia vulgaris L. The new structures were elucidated via abundant spectroscopic data analyses (HRESIMS, IR, 1D, and 2D NMR), and the absolute configurations of these compounds were determined by X-ray crystallography and ECD calculations. The compounds (1-22) were identified as guaiane-type sesquiterpenes with characteristic α-methylene-γ-lactone and α,ß-unsaturated carbonyl moieties. All compounds were tested for their inhibitory activity against NO production in lipopolysaccharide-stimulated RAW264.7 macrophages. The isolated sesquiterpenoids dose-dependently exhibited an NO production inhibitory activity by inhibiting the expression of inducible NO oxidase (iNOS) and cyclooxygenase-2 (COX-2) with IC50 values ranging from 1.0 to 3.6 µM. The inhibitory effect on the NO production of the compounds (1-4 and 6-22) is better than that of the positive control (dexamethasone). The different substitutions of compounds on C-8 influence anti-inflammatory effects, as evidenced by the in silico analysis of related binding interactions of new compounds (1-12) with iNOS.

LINC00943 knockdown attenuates MPP+-induced neuronal damage via miR-15b-5p/RAB3IP axis in SK-N-SH cells.

OBJECTIVES: Parkinson's disease (PD) is a neurodegenerative problem correlated with neuronal damage. Long noncoding RNAs (lncRNAs) are implicated in neuronal damage in PD development. This research aims to analyze the function and mechanism of LINC00943 in 1-methyl-4-phenylpyridinium (MPP+)-caused neuronal injury. METHODS: MPP+-challenged SK-N-SH cells served as a PD-like model of neuronal damage. LINC00943, microRNA-15b-5p (miR-15b-5p) and RAB3A interacting protein (RAB3IP) abundances were examined via quantitative reverse transcription polymerase chain reaction or western blot. MPP+-caused neuronal damage was assessed via cell viability, apoptosis, inflammatory injury and oxidative injury. The association between miR-15b-5p and LINC00943 or RAB3IP was determined via dual-luciferase reporter analysis and RNA immunoprecipitation. RESULTS: LINC00943 abundance was up-regulated in MPP+-challenged SK-N-SH cells. LINC00943 silence alleviated MPP+-caused decrease of cell viability and elevation of apoptosis, inflammatory injury and oxidative injury. miR-15b-5p was inhibited via LINC00943, and miR-15b-5p inhibition reversed knockdown of LINC00943-mediated suppression of MPP+-induced neuronal damage. RAB3IP was targeted via miR-15b-5p, and LINC00943 could regulate RAB3IP via miR-15b-5p. miR-15b-5p addition mitigated MPP+-induced neuronal damage through decreasing RAB3IP. CONCLUSION: LINC00943 inhibition alleviated MPP+-induced neuronal injury via miR-15b-5p/RAB3IP axis, indicating a potential target for treatment of PD.