Design, synthesis, and evaluation of novel 2-phenylpropionic acid derivatives as dual COX inhibitory-antibacterial agents

Figures & data

Scheme 1. Synthesis way for target compounds (6a–6m).

Table 1. IC₅₀ (μM) values of the compounds 4, 6a–6m and reference drugs against COX-1 and COX-2 enzymes.

Compound	IC50 (μM) COX-1	IC50 (μM) COX-2	^aSI	Selectivity
4	38.23	64.30	0.59	COX-1
6a	22.16	37.79	0.59	COX-1
6b	28.61	47.42	0.60	COX-1
6c	19.47	36.68	0.53	COX-1
6d	24.65	39.95	0.62	COX-1
6e	21.77	36.29	0.60	COX-1
6f	2.36	4.41	0.54	COX-1
6g	2.46	4.25	0.58	COX-1
6h	1.76	2.96	0.59	COX-1
6i	5.90	9.56	0.62	COX-1
6j	4.40	7.53	0.58	COX-1
6k	3.71	5.91	0.63	COX-1
6l	1.40	2.34	0.60	COX-1
6m	4.48	8.66	0.52	COX-1
Ibuprofen	2.98	3.15	0.95	Nonselective
Nimesulide	4.28	1.35	3.17	COX-2

^a The selectivity index (SI) was calculated as IC₅₀ (COX-1)/IC₅₀ (COX-2).

Figure 1. (a) Lineweaver–Burk plots for the inhibition of COX-1 enzyme by compound 6h. [S], substrate concentration (mM); V, reaction velocity (nmol/min/mg protein). Inhibitor concentrations are shown at the left. K_m values from 4 × IC₅₀ to Control_; 0.070, 0.048, 0.036, 0.029, 0.021 and 0.014 (mM). V_max value of the competitive inhibition; 0.830 ± 0.011 (nmol/min/mg protein). (b) Secondary plot for calculation of steady-state inhibition constant (K_i) of compound 6h. K_i was calculated as 2.07 μM.

Figure 2. (a) Lineweaver–Burk plots for the inhibition of COX-1 enzyme by compound 6l. [S], substrate concentration (mM); V, reaction velocity (nmol/min/mg protein). Inhibitor concentrations are shown at the left. K_m values from 4 × IC₅₀ to Control_; 0.064, 0.043, 0.030, 0.025, 0.017 and 0.013 (mM). V_max value of the competitive inhibition; 0.669 ± 0.003 (nmol/min/mg protein). (b) Secondary plot for calculation of steady-state inhibition constant (K_i) of compound 6l. K_i was calculated as 1.70 μM.

Table 2. Antimicrobial activity (MIC μg/mL) of compounds 4, 6a–6m and reference drugs against pathogenic microorganisms.

Compound	Sa	Ef	Lm	Kp	Ec-1	Ec-2	Ca	Ck	Cp
4	50	50	50	50	25	50	100	50	50
6a	12.5	12.5	12.5	6.25	6.25	12.5	100	100	100
6b	12.5	12.5	12.5	6.25	6.25	12.5	100	100	50
6c	12.5	12.5	12.5	12.5	6.25	12.5	100	50	50
6d	12.5	6.25	12.5	6.25	6.25	12.5	50	50	50
6e	12.5	12.5	12.5	6.25	6.25	12.5	50	50	50
6f	12.5	12.5	12.5	12.5	6.25	12.5	100	100	50
6g	12.5	12.5	12.5	12.5	6.25	12.5	100	100	50
6h	12.5	12.5	6.25	6.25	6.25	12.5	50	100	50
6i	12.5	12.5	12.5	6.25	6.25	12.5	100	100	50
6j	12.5	12.5	12.5	6.25	6.25	12.5	100	100	50
6k	12.5	12.5	12.5	6.25	6.25	12.5	50	50	50
6l	12.5	12.5	6.25	6.25	6.25	12.5	50	50	50
6m	6.25	6.25	12.5	6.25	6.25	6.25	50	50	50
Chloramphenicol	6.25	6.25	12.5	12.5	6.25	6.25	–	–	–
Ketoconazole	–	–	–	–	–	–	0.78	0.78	0.78

Sa: Staphylococcus aureus (ATCC 25923); Ef: Enterococcus faecalis (ATCC 29212); Lm: Listeria monocytogenes (ATCC 1911); Kp: Klebsiella pneumoniae (NCTC 9633); Ec-1: Escherichia coli (ATCC 35218); Ec-2: Escherichia coli (ATCC 25922); Ca: Candida albicans (ATCC 24433); Ck: Candida krusei (ATCC 6258); Cp: Candida parapsilosis (ATCC 22019)

Table 3. IC₅₀ (μM) values of the ibuprofen. nimesulide and the compounds 6h and 6l against NIH/3T3 cell line.

Compound	6h	6l	Ibuprofen	Nimesulide
IC50 (μM)	≥1000	≥1000	≥1000	≥1000

Table 4. The AMES^MPF results of the compounds.

		Revertants fold increase (over baseline)
		TA 98		TA 100
Compound	Concentration (mg/mL)	S9+	S9−	S9+		S9−
6h	0.156	0.87	0.56	0.60		0.87
	0.3125	0.52	0.56	0.50		0.52
	0.625	0.70	0.60	0.20		0.70
	1.25	0.17	0.73	0.25		0.17
	2.5	1.05	0.22^a	0.25		1.05
	5	0.87	0.17^a	0.20		0.87
6l	0.156	0.17^a	0.57	0.74		0.53a
	0.3125	0.50	0.31^a	0.52		0.27^a
	0.625	0.75	0.61	0.52		0.13^a
	1.25	0.08^a	0.04a	0.00^a		0.13^a
	2.5	0.00^a	0.00^a	0.00^a		0.20^a
	5	0.00^a	0.04^a	0.00^a		0.00^a

^a t Test p values (unpaired 1-sided) <.05.

Figure 3. Dose-response curve of compound 6h against TA98 and TA100 in the presence and absence of S9 according to AMES^MPF test.

Figure 4. Dose–response curve of compound 6l against TA98 and TA100 in the presence and absence of S9 according to AMES^MPF test.

Table 5. In silico physicochemical parameters of the compounds 6a–6m.

Comp	Log P	tPSA	MW	n ON	nOHNH	nrotb	MV	Vio
6a	2.95	49.66	281.40	3	1	5	243.51	0
6b	2.73	55.12	276.36	4	1	5	248.54	0
6c	2.13	78.87	263.32	5	2	5	227.44	0
6d	2.20	68.02	277.35	5	1	5	244.39	0
6e	2.06	80.91	278.34	6	1	5	240.23	0
6f	4.91	50.19	329.45	3	1	5	281.32	0
6g	5.56	50.19	363.89	3	1	5	294.86	1
6h	4.94	59.42	359.47	4	1	6	306.87	0
6i	4.17	65.98	312.39	4	2	5	275.59	0
6j	4.59	65.98	326.42	4	2	5	292.15	0
6k	4.82	65.98	346.84	4	2	5	289.13	0
6l	4.20	75.22	342.42	5	2	6	301.14	0
6m	4.10	111.81	357.39	7	2	6	298.93	0
Ibuprofen	3.46	37.30	206.28	2	1	4	211.19	0
Nimesulide	2.81	101.23	308.31	7	1	5	248.17	0

log P: log octanol/water partition coefficient; tPSA: total polar surface area; MW: molecular weight; nON: number hydrogen acceptors; nOHNH: number of hydrogen donors; nrotb: number of rotatable bonds; MV: moleculer volume; Vio: violation were predicted using molinspiration calculation of molecular properties toolkit.

Figure 5. The binding site of COX-1 containing compound 6h (a) and 6l (b). The interacting side chain amino acid residues are shown in sticks style.