Table 1. Inhibition of hAChE and hBuChE by tacrine–neocryptolepines 1–3, tacrine, bis(7)tacrine, and highly potent tacrine heterodimers 8–18 available from the literature.

Compound	hAChE (IC50, nM) a	hBuChE (IC50, nM) a	hAChE selectivity b	Aβ1–42 self-aggregation (% inhibition) c
1	53.0 ± 2.7	21.8 ± 1.3	0.41	19.7 ± 1.5
2	1.25 ± 0.12	9.00 ± 0.43	7.20	25.9 ± 2.4
3	0.95 ± 0.04	2.29 ± 0.14	2.41	26.5 ± 4.2
Tacrine	350 ± 10	40 ± 2	0.11	<5
Bis(7)tacrine 28	0.81 ± 0.09	5.66 ± 0.15	0.14	53.4 ± 1.4
8 29	0.86 ± 0.05	2.18 ± 0.15	0.4	61.3 ± 4.5
9 30	0.72 ± 0.06	542 ± 16	753	37.5 ± 4.9
10 31	0.78 (Ki)	0.06 (Ki)	13	nd
11 31	0.23 (Ki)	8.26 (Ki)	0.028	nd
(±)-1232	0.42 ± 0.04	139 ± 5.2	331	28.1 ± 6.4
(±)-1332	0.74 ± 0.0	75.2 ± 2.6	102	30.9 ± 2.2
(±)-1432	0.31 ± 0.02	51.3 ± 4.6	165	51.3 ± 4.6
15 33	1.05 ± 0.08	63.7 ± 3.5	60.7	nd
16 34	0.43 ± 0.04	210 ± 20	488	nd
17 35	0.008 ± 0.0004	7.8 ± 0.4	975	nd
18 36	0.012 (Ki)	0.82 (Ki)	0.01	nd

^aEach IC₅₀ value is the mean ± SEM of at least two independent experiments in which each point was determined in duplicate/triplicate.

^bSelectivity for hAChE = IC₅₀ (hBuChE)/IC₅₀ (hAChE).

^cPercent inhibition with inhibitor at 10 μM (5 : 1 [Aβ₄₂] : [I]).