Table 1.

In vitro inhibition of AChE from human erythrocytes and serum hBChE by compounds with 6-methyluracil, quinazoline-2,4-dione moieties, varied polymethylene chains, amino groups, and substituents at benzene rings compared to donepezil hydrochloride ^a.

Compound	IC50 [nM]		AChE Selectivity b	LD50, mg/kg c
	AChE	BChE
1a d	47 ± 3	50,000 ± 3000	1064	281
1b d	3.5 ± 0.3	35,000 ± 500	10,000	51
1c d	83 ± 10	90,000 ± 3000	1084	93
1d d	67 ± 8	20,000 ± 150	298	59
1e d	5.6 ± 0.7	20,000 ± 2000	35,714	49
1f d	1400 ± 90	200,000 ± 2000	143	58
2a	7 ± 0.5	65,000 ± 500	9285	284
2b	7.3 ± 0.6	100,000 ± 12,000	14,286	138
2c	29 ± 0.3	10,000 ± 150	345	282
3	480 ± 30	1800 ± 170	3.8	146
13	2320 ± 170	2160 ± 150	0.9	10
4a	5520 ± 400	2620 ± 200	0.5	107
4b	38 ± 3	30,000 ± 500	789	1.1
2b·2HBr	1.7 ± 2	942 ± 12	5541	13.1
2c·2HBr	24 ± 2	10,000 ± 700	417	11.3
4b·2HBr	46 ± 5	3920 ± 200	85	265
Donepezil	48 ± 3	7900 ± 600	165	5

IC₅₀ values are expressed as mean of three independent measurements, each performed in duplicate; ^a the acetylthiocholine and butyrylthiocholine concentration was 1 millimole/L (mM); ^b (IC₅₀hBChE)/(IC₅₀hAChE); ^c mice, intraperitoneal injection; ^d data for compounds 1a–f were taken from reference [25].