Table 2.

AChE and BuChE inhibitory activity of the quinoxaline derivatives.

Code	R	R1	R2	IC50 AChE (µM)	IC50 BChE (µM)(%Inhibition)	Selectivity BChE/AChE
3a	H	H	H	13.22 ± 4.1	40.64 ± 1.6	3.07
3b	H	Ph	H	50.08 ± 2.6	14.91 ± 2.6	0.29
3c	H	CH3	CH3	7.25 ± 1.5	(23.42 ± 1.7%)	-
4a	Cl	H	H	23.87 ± 1.3	(37.42 ± 2.3%)	-
4b	Cl	Ph	H	28.49 ± 1.6	(41.16 ± 1.5%)	-
4c	Cl	CH3	CH3	10.67 ± 1.4	(37.35 ± 1.3%)	-
5a	NO2	H	H	21.31 ± 1.5	42.02 ± 1.0	1.97
5b	NO2	Ph	H	39.0 ± 0.8	60.95 ± 3.4	1.56
5c	NO2	CH3	CH3	8.42 ± 1.8	(32.13 ± 1.9%)	-
6a	NH2	H	H	0.74 ± 0.5	(32.87 ± 2.8%)	-
6b	NH2	Ph	H	1.31 ± 0.2	(44.14 ± 1.0%)	-
6c	NH2	CH3	CH3	0.077 ± 0.01	(29.22 ± 1.95%)	-
Tacrine				0.11 ± 0.01	0.0066 ± 0.001	0.09
Galanthamine				0.59 ± 0.13	11.55 ± 5.5	19.58

IC₅₀ values are expressed as the mean ± SD (n = three independent experiments). %inhibition at 100 µM are shown in square brackets as the mean ± SD (n = three independent experiments). Selectivity index for AChE: IC₅₀ BChE/IC₅₀ AChE.