Design, synthesis, and evaluation of novel O-alkyl ferulamide derivatives as multifunctional ligands for treating Alzheimer’s disease

Figures & data

Figure 1. Candidates have reached testing stage in clinical phase II/III trials.

Figure 2. Design strategy of 2-acetylphenol-O-alkylhydroxyethylamine derivatives.

Scheme 1. Synthesis of 5a–5i. Reagents and conditions: (i) CH₂Cl₂, EDCI, HOBT, room temperature, overnight, yield 40–56%. (ii) RX (4a–4d), K₂CO₃, CH₃CN, 65 °C, 6–10 h, yield 39–76%.

Table 1. Inhibitory activity of MAO-A/MAO-B, antioxidant activity and effects on self-induced Aβ_1-42 aggregation by target compounds and positive compounds.

Compd	NR1R2	R	IC50 ± SD (μM)^a		SI^c	ORAC^d	Self-induced Aβ1-42 aggregation (%)
			hMAO-A	hMAO-B			Inhibition^e	Disaggregation^f
5a			45.2 ± 1.3	0.32 ± 0.02	141	0.4 ± 0.01	52.3 ± 1.3	40.1 ± 1.5
5b			66.1 ± 2.7	1.1 ± 0.07	60	0.3 ± 0.05	n.t.^g	n.t.^g
5c			80.7 ± 3.9	3.8 ± 0.09	21	0.2 ± 0.03	n.t.^g	n.t.^g
5d			63.9 ± 5.1	0.56 ± 0.01	114	0.3 ± 0.03	59.6 ± 2.7	47.2 ± 2.3
5e			64.0 ± 2.9	0.54 ± 0.05	118	0.2 ± 0.03	63.5 ± 3.4	43.8 ± 1.9
5f			11.3 ± 0.08%^b	0.73 ± 0.06	—	0.3 ± 0.02	61.7 ± 2.1	45.9 ± 3.6
5g			20.6 ± 0.15%^b	3.1 ± 0.23	—	0.4 ± 0.02	n.t.^g	n.t.^g
5h			65.3 ± 3.4	0.86 ± 0.09	76	0.2 ± 0.03	n.t.^g	n.t.^g
5i			63.2 ± 4.5	1.9 ± 0.18	33	0.7 ± 0.02	n.t.^g	n.t.^g
FA			n.t.^g	n.t.^g		1.5 ± 0.08	30.6 ± 1.2	48.3 ± 2.6
rasa.^h			0.63 ± 0.05	0.03 ± 0.004		n.t.^g	n.t.^g	n.t.^g
Curc.^i			n.t.^g	n.t.^g		n.t.^g	46.1 ± 1.3	56.7 ± 1.8

^aIC₅₀: 50% inhibitory concentration. The experiment was performed through three independent experiments, and result were presented as the mean ± SEM.

^bMAO-A inhibition rate was tested at 62.5 μM.

^cSI = selectivity index = IC₅₀ (hMAO-A)/IC₅₀ (hMAO-B).

^dThe experiment was performed using ORAC assay, results are expressed as μM of Trolox equivalent/μM of tested compound.

^eInhibition of self-induced Aβ_1-42 aggregation using ThT assay, the inhibition rate was obtained at 25 μM for both tested compounds and Aβ_1-42, data are presented as the mean ± SEM.

^fDisaggregation of Aβ_1-42 aggregates, the concentration of tested compounds and Aβ_1-42 were 25 μM.

^gn.t.: not tested.

^hrasa.: rasagiline mesylate.

ⁱCurc.: Curcumin.

Figure 3. Linewear-Burk plots resulting from the subvelocity curve of the MAO-B activity different substrate concentration in the absence and presence of 5a (0.15, 0.3, and 0.6 μM).

Figure 4. (A) Compound 5a (green stick) interacted with residues in the binding site of hMAO-B (PDB code: 2V60). (B) The selective inhibitor 7-(3-chlorobenzyloxy)-4-carboxaldehyde-coumarin interacted with residues in the binding site of hMAO-B (PDB code: 2V60).

Figure 5. The cell viability of compounds 5a, 5d, 5e, 5f, 5h, and FA on the BV-2 cells were testing using MTT assay. The data were expressed as the mean ± SD through three independent experiments.

Figure 6. Effects of compounds 5a, 5d, 5e, 5f, 5h, and FA on NO release in BV-2 cells and LPS-stimulated BV-2 cells. Data were expressed as mean ± SD through three independent experiments. con. = control; mod. = model. ^##p < 0.01 vs. control; **p < 0.01, *p < 0.05 vs. LPS-induced group.

Figure 7. Effects of compounds 5a, 5d, 5e, 5f, 5h, and FA on TNF-α release in LPS-stimulated BV-2 cells. Data were expressed as mean ± SD through three independent experiments. ^##p < 0.01 vs. control; ***p < 0.01, **p < 0.01, *p < 0.05 vs. LPS-induced group.

Figure 8. TEM images of Aβ species. (A) inhibition experiments of self-induced Aβ_1 − 42 aggregation. (B) disaggregation experiments of self-induced Aβ_1 − 42 aggregation.

Figure 9. The cell viability (%) of compounds 5a, 5d, 5e, 5f, and 5h on Aβ_1-42-induced PC12 cell injury by MTT assay. Percentages of the cell viability were presented as mean ± SD from three independent experiments. ^##p < 0.01 vs. untreated group; **p < 0.01, *p < 0.05 vs. Aβ_1-42-induced group.

Figure 10. Linear correlation between experimental and reported permeability of commercial drugs using the PAMPA-BBB assay. P_e(exp) = 0.9163, P_e(bibl.) −0.2247 (r² = 0.9558).

Table 2. Permeability (P_e × 10⁻⁶cm/s) in the PAMPA-BBB assay for 11 commercial drugs used in the experiment validation.

Commercial drugs	Bibl^a	PBS:EtOH (70:30)^b
Verapamil	16	16.90
Oxazepam	10	9.60
Diazepam	16	11.86
Clonidine	5.3	5.10
Imipramine	13	10.10
Testosterone	17	16.30
Caffeine	1.3	1.28
Enoxacine	0.9	0.47
Piroxicam	2.5	0.72
Norfloxacin	0.1	0.42
Theophylline	0.12	0.10

^aTaken from Ref²⁸.

^bData are the mean ± SD of three independent experiments.

Table 3. The predictive permeation of compounds 5a, 5d, 5e, 5f, and 5h by PAMPA-BBB assay.

Compound	Pe (×10^−6 cm/s)	Prediction
Testosterone	17.3 ± 0.3	CNS+
Diazepam	15.2 ± 0.5	CNS+
Norfloxacin	0.13 ± 0.01	CNS-
5a	14.7 ± 0.76	CNS+
5d	18.2 ± 0.79	CNS+
5e	12.5 ± 0.66	CNS+
5f	20.4 ± 0.81	CNS+
5h	16.7 ± 0.59	CNS+

Table 4. Theoretical prediction of the druglike properties of compounds 5a, 5d, 5e, 5f, and 5h.

Compound	Log P	MW	TPSA (Å^2)	n-ON	n-OHNH	nviolations	nrotb	volume (Å^3)
5a	4.4	389.50	38.78	4	0	0	7	378.22
5d	6.14	433.59	38.78	4	0	1	7	429.16
5e	3.21	347.41	38.78	4	0	0	5	327.79
5f	3.05	323.39	38.78	4	0	0	4	305.29
5h	4.96	391.51	38.78	4	0	0	5	378.73

Scheme 2. Radiosynthesis of [¹¹C]5f. Reagents and conditions: NaOH, DMF, 100 °C, 3 min.

Figure 11. PET/CT (baseline and blocking) images in mice brain (20‒60 min) with [¹¹C]5f after intravenous administration (i.v.) and time-activity curve of the whole brain (n = 4).

Figure 12. Left: the PET/CT imaging of the mice with [¹¹C]5f (whole body, 0–60 min); right: biodistribution of [¹¹C]5f in organs of interest at 5, 15, 30, and 60 min after injection of radioligand (n = 4 for each time point). Error bars represent SEM.

Available from: https://www.molinspiration.com/cgi-bin/properties

 Google Scholar