Acetylcholinesterase/Butyrylcholinesterase inhibition activity of some new carbacylamidophosphate deriviatives

Figures & data

short-legendScheme 1. 

Figure 1.  The plot of v_i/v₀ aganst log ([I] × 10⁷) for inhibitor 1a–4a and 1b–4b: v_i and v₀ are the activity of human erythrocyte AChE in the presence and absence of inhibitor, respectively and [I] is inhibitor concentration (M).

Figure 2.  The plot of v_i/v₀ aganst log ([I] × 10⁷) for inhibitors 1a–4a and log ([I] × 10⁸) for inhibitors 1b–4b: v_i and v₀ are the activity of horse plasma BuChE in the presence and absence of inhibitor, respectively and [I] is inhibitor concentration (M).

Table I.  Kinetics of human erythrocyte AChE inactivation by compounds (1a–4a) and (1b–4b).

Compound	IC50 (μM)	ki (μM^− 1 min^− 1)	kp (min^− 1)	KD (μM)
(p–Cl–C6H4)C(O)NHP(O)(Cl)2,1a	87 ± 3.4*	0.0598 ± 0.0	12.33 ± 1.7	206 ± 6.4
(p–Br–C6H4)C(O)NHP(O)(Cl)2,2a	57 ± 2.7	0.0672 ± 0.0	15.06 ± 1.3	230 ± 7.1
(C6H5)C(O)NHP(O)(Cl)2,3a	385 ± 8.9	0.00956 ± 0.0	11.13 ± 0.9	1100 ± 12.3
(p–Me–C6H4)C(O)NHP(O)(Cl)2,4a	260 ± 7.3	0.0168 ± 0.0	9.31 ± 0.5	554 ± 8.6
(p–Cl–C6H4)C(O)NHP(O)(NC4H8O)2,1b	932 ± 15.2	0.00692 ± 0.0	1.65 ± 0.1	239 ± 7.5
(p–Br–C6H4)C(O)NHP(O)(NC4H8O)2,2b	620 ± 10.5	0.00911 ± 0.0	3.48 ± 0.2	382 ± 8.4
(C6H5)C(O)NHP(O)(NC4H8O)2,3b	4150 ± 64.8	0.000769 ± 0.0	2.27 ± 0.3	2954 ± 10.2
(p–Me–C6H4)C(O)NHP(O)(NC4H8O)2,4b	2890 ± 42.5	0.000956 ± 0.0	4.07 ± 0.2	4260 ± 15.3

* Values represent the means ± SD of three individual parameters determination.

Table II.  Kinetics of BuChE inactivation by compounds (1a–4a) and (1b–4b).

Compound	IC50 (μM)	Ki (μM^− 1 min^− 1)	Kp (min^− 1)	KD (μM)
(p–Cl–C6H4)C(O)NHP(O)(Cl)2,1a	920 ± 13.5*	0.00418 ± 0.0	18.11 ± 2.1	43000 ± 124
(p–Br–C6H4)C(O)NHP(O)(Cl)2,2a	650 ± 11.2	0.00734 ± 0.0	15.13 ± 1.7	2100 ± 14.2
(C6H5)C(O)NHP(O)(Cl)2,3a	4800 ± 75.3	0.000755 ± 0.0	14.02 ± 1.4	18000 ± 75.6
(p–Me–C6H4)C(O)NHP(O)(Cl)2,4a	1200 ± 25.6	0.00192 ± 0.0	17.12 ± 1.8	8900 ± 213
(p–Cl–C6H4)C(O)NHP(O)(NC4H8O)2,1b	9980 ± 130.7	0.000368 ± 0.0	1.86 ± 0.1	5063 ± 17.5
(p–Br–C6H4)C(O)NHP(O)(NC4H8O)2,2b	5240 ± 80.2	0.000453 ± 0.0	1.82 ± 0.1	4370 ± 16.2
(C6H5)C(O)NHP(O)(NC4H8O)2,3b	55620 ± 986	0.0000684 ± 0.0	5.26 ± 0.4	76804 ± 241
(p–Me–C6H4)C(O)NHP(O)(NC4H8O)2,4b	16720 ± 274	0.000140 ± 0.0	4.70 ± 0.6	33557 ± 163

* Values represent the means ± SD of three individual parameters determination.

Figure 3.  A representative set of data for determining –kapp at diffrent concentrations of inhibitors 1a–4a for human erythrocyte AChE. The time of incubation was variable for each inhibitor concentration and the slope of the lines ( − kapp) increased with increasing inhibitor concentration. Inhibitor concentrations (μM) were, 1a: 6, 9, 15, 30, 60; 2a: 5, 10, 20, 30, 100; 3a: 20, 60, 80, 100, 200; 4a: 20, 50, 100, 200.

Figure 4.  A representative set of data for determining –kapp at diffrent concentrations of inhibitors 1b–4b for human erythrocyte AChE. The time of incubation was variable for each inhibitor concentration and the slope of the lines ( − kapp) increased with increasing inhibitor concentration. Inhibitor concentrations (μM) were, 1b: 40, 80, 100, 150; 2b: 70, 100, 150, 250; 3b: 300, 1000, 2000, 3000; 4b: 200, 500, 1000, 1500, 3000.

Figure 5.  A representative set of data for determining –kapp at diffrent concentrations of inhibitors 1a–4a for horse plasma BuChE. The time of incubation was variable for each inhibitor concentration and the slope of the lines ( − kapp) increased with increasing inhibitor concentration. Inhibitor concentrations (μM) were, 1a: 80, 100, 180, 200, 500; 2a: 30, 80, 150, 250, 500; 3a: 600, 1500, 2500, 5000; 4a: 300, 600, 1000, 1500.

Figure 6.  A representative set of data for determining –kapp at diffrent concentrations of inhibitors 1b–4b for horse plasma BuChE. The time of incubation was variable for each inhibitor concentration and the slope of the lines ( − kapp) increased with increasing inhibitor concentration. Inhibitor concentrations (μM) were, 1b: 600, 900, 1500, 2500, 5000; 2b: 600, 1000, 1500, 1700, 2500; 3b: 3000, 10000, 20000, 35000; 4b: 1500, 5000, 10000, 20000, 50000.

Figure 7.  A representative double reciprocal plot of different concentrations of inhibitors (1a–4a and 1b–4b) versus K_app from Figures 3 and 4. Linear regression of representing kapp at different concentrations of inhibitor concentrations for each inhibitor resulted a line with slope = 1/K_i, y-intercept = 1/kp, and x-intercept = − 1/K_D = − K_A.

Figure 8.  A representative double reciprocal plot of different concentrations of inhibitors (1a–4a and 1b–4b) versus K_app from Figures 5 and 6. Linear regression of representing kapp at different concentrations of inhibitor concentrations for each inhibitor resulted a line with slope = 1/K_i, y-intercept = 1/kp, and x-intercept = − 1/K_D = − K_A.

Table III.  log P of selected inhibitors.

Compound	log P (Theoretical)	*log P (Experimental)
1a	3.25	5.21 ± 0.6
2a	2.97	6.55 ± 0.7
3a	2.45	4.23 ± 0.6
4a	2.99	5.68 ± 0.7
1b	1.54	3.11 ± 0.4
2b	1.26	3.54 ± 0.5
3b	0.74	1.32 ± 0.1
4b	1.21	2.99 ± 0.2

*Values represent the means ± SD of three individual parameters determination.

Table IV.  In vivo experiments^‡.

Compound	LD50 (mg/kg)	IC50^* (μM)	IC50^† (μM)
(p–Br–C6H4)C(O)NHP(O)(Cl)2,2a	150 ± 10.5*	130 ± 9.2	1600 ± 18.3
(C6H5)C(O)NHP(O)(Cl)2,3a	600 ± 15.3	820 ± 14.1	9900 ± 22.6
(p–Br–C6H4)C(O)NHP(O)(NC4H8O)2,2b	240 ± 13.8	970 ± 13.7	12000 ± 142

* AChE

^† BuChE

^‡ Values represent the means ± SD of three individual parameter determination.

Table V.  Some spectroscopic data for compounds (1a–4a) and (1b–4b).

Compound	1a	2a	3a	4a	1b	2b	3b	4b
MW(g/mol)	272.45	316.6	238.01	252.00	373.5	418.00	339.35	353.35
^31δP(ppm)	11.41	11.47	11.52	11.29	10.87	10.81	10.83	10.81
^2JPNH(amide) (Hz)	12.03	12.01	12.00	11.9	5.5	5.2	5.3	5.9
δNH(amide) (ppm)	9.91	9.89	9.77	9.88	8.05	8.82	8.41	8.18
ν P = O(cm^− 1)	1226	1232	1221	1230	1193	1191	1194	1195
υ(C = O) (cm^− 1)	1683	1684	1682	1680	1666	1667	1661	1662