Spectronic 3000 array spectrophotometer

UV spectra were obtained by a Milton Roy Spectronic 3000 Array spectrophotometer (Rochester, NY, USA). Optical rotations were measured on a JASCO P-2000 polarimeter (Kyoto, Japan). CD spectra were recorded using a Jasco J-815 CD spectrophotometer (Kyoto, Japan). IR spectra were recorded on a Nicolet^TM iS50 FT-IR spectrometer (Thermo Fisher Scientific, Waltham, MA, USA) and Perkin Elmer FT-IR 1760X spectrometer (Boston, MA, USA). HR-ESI spectra were measured on a Bruker APEX II mass spectrometer (Karlsruche, Germany) and Agilent 6540 UHD Accurate-Mass Q-TOF mass spectrometer (CA, USA). NMR was recorded on a Bruker Advance NEO 400 MHz NMR spectrometer (Karlsruche, Germany) and a Varian VNMRS-600 spectrometer (Lexington, MA, USA). Medium-performance liquid chromatography (MPLC) and flash column chromatography (Flash CC) were performed by using a PuriFlash^® XS 420 (Advion Inc., NY, USA), Sepacore^® purification system (Buchi AG, Flawill, Switzerland), or a ceramic pump (VSP-3050; EYELA, Kyoto, Japan). Silica gel 60 (70–230 or 230–400 mesh ASTM, Merck, Darmstadt, Germany), LiChroprep^® RP-18 (25–40 μm, Merck, Darmstadt, Germany), and Sephadex^TM LH-20 (GE Healthcare, Amersham, UK) were used as a stationary phase material for column chromatography (CC). Organic solvents (commercial grade) were redistilled prior to their use as a mobile phase composition.

The relative concentration of Fe²⁺ in the mouse hippocampus tissue lysates was determined using an Iron Assay Kit (MAK025, Sigma-Aldrich, USA) following the manufacturer's instructions. OD values were measured at 593 nm using a Milton Roy Spectronic 3000 Array spectrophotometer. T The total protein content in each sample was determined using the Bradford method.

The relative activity of Superoxide Dismutase (SOD), catalase (CAT), and Glutathione Peroxidase (GPx) in the mouse hippocampus tissues was examined using commercial test kits (S0101S, S0051, and S0056, Beyotime, Shanghai, China) following the manufacturer's protocols. The absorbance was measured at 450 nm for SOD activity, 340 nm for GPx activity, and 520 nm for CAT activity using a Milton Roy Spectronic 3000 Array spectrophotometer. The total protein content in each sample was measured using the Bradford method.

All solvents and chemicals, unless specifically stated, were of analytical grade, purchased commercially and used without further purification. ¹H and ¹³C spectra were measured on Bruker ARX 500 (or 600) NMR spectrometers using DMSO-d₆ and CDCl₃ as the deuterated solvent, respectively. Tetramethylsilane (TMS; δ = 0 ppm) was used as the internal standard. High-resolution mass spectra (HRMS) were recorded on a Finnegan MAT TSQ 7000 Mass Spectrometer System. UV-vis absorption spectra were taken on a PerkinElmer Lambda 950 spectrophotometer. PL spectra were recorded on an Edinburgh FS5 fluorescence spectrophotometer and Milton Roy Spectronic 3000 array spectrophotometer. The absolute PLQY was determined using a Hamamatsu quantum yield spectrometer, C11347 Quantaurus QY. The cell viability was examined by MTT assay. The cellular fluorescence images were taken using a confocal laser scanning microscope (CLSM, ZEISS-LSM880). Compounds 1,^{42 (link)}2,^{43 (link)}3,^{44 (link)} and 6 (ref. 45 (link)) were synthesized according to a literature method.