Chemical structures of compounds (a) 1, (b) 2, (c) 3, (d) 4, (e) 5, and (f) 6.

PL spectra of compounds (a) 1, (b) 2, (c) 3, (d) 4, (e) 5, and (f) 6 in CH₃OH/H₂O mixed solutions (c = 2.07 × 10⁻⁵ M) with different water fractions (0–90%).

UV–vis absorption spectra of compounds (a) 1, (b) 2, and (c) 3 in pure CH₃OH solution and CH₃OH/H₂O mixed solution with 90% water contents.

Fluorescence photographs of compounds (a) 1, (b) 2, and (c) 3 in CH₃OH/H₂O mixed solution (with various water fractions) under 365 nm wavelength UV light.

(a–c), (d–f) and (g–i) are SEM images of compound 1, 2, and 3, respectively; and the first column is of CH₃OH/H₂O (5:5 v:v), the second (4:6 v:v), and the third (1:9 v:v).

Fluorescence intensity of compounds (a) 1, (b) 2, and (c) 3 in CH₃OH/EG mixed solutions with different EG fractions (0–50%).

Cell viabilities of A549 cells co-incubated with different concentrations of compounds 1–3.

The imaging figures of A549 cells incubated with compounds (a) 1, (d) 2, and (g) 3 for 30 min with excitation at 405 nm. The bright-field images of A549 cells incubated with (b) 1, (e) 2, and (h) 3. The merged images incubated with (c) 1, (f) 2, and (i) 3.

The morphological images of A549 cells. (a,e,i) The images of untreated control. The imaging figures of A549 cells incubated with compounds 1 (b,f,j), 2 (c,g,k), and 3 (d,h,l) for 24 h. (a–d) were taken with a fluorescence microscope under a 10-fold lens, (e–h) were taken under a 20-fold lens, and (i–l) were taken under a 40-fold lens. No difference in morphology was observed before or after incubating with compounds.

(a,e) The bright-field images of A549 cells incubated with compound 1. Co-localized images of A549 cells incubated with compound 1 (20 µM) (b,f) and Mito Tracker Red (200 nM) (c,g) for 30 min. (d,h) The merged images co-cultured with compound 1. The excitation wavelength of compound 1 was 405 nm. The excitation wavelength of Mito Tracker Red was 578 nm. (a–d) were taken with the confocal laser scanning microscope under a 60-fold lens, and (e–h) were taken under a 100-fold oil immersion lens. (e–h) are enlarged images of the dashed-square in (a). Scale bars, 50 µm.

(a,e) The bright-field images of A549 cells incubated with compound 2. Co-localized images of A549 cells incubated with compound 2 (20 µM) (b,f) and Mito Tracker Red (200 nM) (c,g) for 30 min. (d,h) The merged images co-cultured with compound 2. The excitation wavelength of compound 2 was 405 nm. The excitation wavelength of Mito Tracker Red was 578 nm. (a–d) were taken using the confocal laser scanning microscope under a 60-fold lens, and (e–h) were taken under a 100-fold oil immersion lens. (e–h) are enlarged images of the dashed-square in (a). Scale bars, 50 µm.

(a,e) The bright-field images of A549 cells incubated with compound 3. Co-localized images of A549 cells incubated with compound 3 (20 µM) (b,f) and Mito Tracker Red (200 nM) (c,g) for 30 min. (d,h) The merged images co-cultured with compound 3. The excitation wavelength of compound 3 was 405 nm. The excitation wavelength of Mito Tracker Red was 578 nm. (a–d) were taken using the confocal laser scanning microscope under a 60-fold lens, and (e–h) were taken under a 100-fold oil immersion lens. (e–h) are enlarged images of the dashed-square in (a). Scale bars, 50 µm.

The Plot Profile of compounds 1–3.

Experimental procedure.

Structural sketch of zebrafish. DLAV, dorsal longitudinal anastomotic vessels; ICV, intercostal vessels; VTA, vertebral arteries; ISV, intersegmental vessels; DA, dorsal aorta; PCV, posterior cardinal vein; CVP, caudal vein capillary plexus.

The fluorescence images of Tg(fli1a:EGFP) after incubation, respectively, with DAPI (10 µg/mL) (a–c) and compound 2 (40 µM) (d–f) for 1 h at 48 hpf. Compound 2 and DAPI exhibit similar permeability and both emit strong blue fluorescence. Zebrafish blood vessels are characterized by green fluorescence. Scale bars, 100 µm (a,d), 50 µm (b,c,e,f).

(a) The 3D images of zebrafish trunk vessels. (b–g) and (h,i) are enlarged images of areas 1 and 2 in (a), respectively. (b–d) Fluorescence images of Tg(fli1a:EGFP) after incubation with compound 2 (40 µM) for 1 h in 48 hpf larvae. In (c), most of the compounds adhere to the surface of the blood vessels, and a few enter the blood vessels. (e–g) Fluorescence images of Tg(fli1a:EGFP) after incubation with compound 2 (40 µM) for 2 h at 48 hpf. Arrowheads in (c,f) indicate that compound 2 adheres to the surface of the blood vessels. In (f), the amount of compound absorbed into the blood vessels is greatly increased. In (h,i), compound 2 enters the CVP. Zebrafish blood vessels are characterized by green fluorescence. Scale bars, 500 µm (a), 200 µm (b,e,h), 100 µm (c,f), and 50 µm (d,g,i).

Fluorescence intensity of compound 2 cycled for 1 h and 2 h, respectively, and fluorescence area of compound 2 cycled for 1 h and 2 h, respectively. The number of dots in Figure 18 corresponds to the red triangles in Figure 17.

(a) The fluorescence images of Tg(fli1a:EGFP) after incubation with compound 2 (40 µM) for 2 h at 168 hpf. (b) and (c) are enlarged images of areas 1 and 2 in (a), respectively. Zebrafish blood vessels are characterized by green fluorescence. Scale bars, 500 µm (a), 100 µm (b,c).

Synthetic route and chemical structures of 4′-methyflavanone.