Table 4.

Antibacterial activity of 3-phenylaminopyridinium Analogs, 12a-s

Compound		IC50 /MIC/MBC (μg/mL)
Entry	R	Sa	MRSA	E. Coli	M. int.
12a	H	0.7/1.3/10	3.4/10/20	7.6>20/>20	2.1/25/2.5
12b	o-Cl	0.3/0.6/10	1.1/2.5/10	7.6/>20/>20	2.1/2.5/5.0
12c	m-Cl	0.34/0.63/5.0	1.3/2.5/5.0	6.5/>20/>20	2.1/2.5/5.0
12d	p-Cl	1.5/3.1/NT	NT	NT	1.0/1.6/NT
12e	o-CF3	0.3/0.3/10	0.6/1.3/5.0	9.1/>20/>20	1.2/3.5/2.5
12f	m-CF3	NT	1.5/2.5/5.0	4.5/>20/>20	2.0/2.5/2.5
12g	p-CF3	NT	0.9/2.5/2.5	3.5/20/20	1.0/1.3/1.3
12h	p-F	0.7/1.3/10	3.0/5.0/20	18/>20/>20	3.2/5.0/10.0
12i	o-CH3	0.3/0.6/10	1.0/2.5/10	9.4/>20/>20	1.6/2.5/2.5
12j	m-CH3	0.7/1.3/5.0	1.2/2.5/5.0	7.7/>20/>20	1.1/1.3/5.0
12k	p-CH3	NT	1.0/2.5/2.5	4.5/20/>20	1.5/2.5/2.5
12l	p-C2H5	0.2/3.0/5.0	0.7/1.3/2.5	4.0/20/20	0.6/1.3/5.0
12m	p-SCH3	0.3/0.6/5.0	1.0/2.5/2.5	5.2/20/20	1.0/1.3/5.0
12n	o-OCH3	0.4/0.6/20	1.2/5.0/20	14/>20/>20	1.9/2.5/2.5
12o	m-OCH3	0.8/1.3/20.0	4.8/10/20	NA	3.3/5.0/10
12p	p-OCH3	0.3/0.6/10.0	1.9/5.0/10	5.4/>20/>20	1.0/1.3/5.0
12q	o-CN	1.3/2.5/10.0	6.4/20/20	NA	3.5/5.0/20
12r	m-CN	0.8/1.3/20	3.9/10/10	NA	2.0/2.5/10
12s	p-CN	2.5/5.0/20	6.2/10/20	NA	2.8/5.0/5.0
Cryptolepine a		10 ( IC50)	20 ( IC50)	NT	15 ( IC50)
Ciprofloxacin		0.07/0.3/0.5	0.07/0.3/0.5	0.005/0.3/0.6	0.3/0.5/>20

Abbreviations: Sa = Staphylococcus aureus, MRSA = Methicillin-resistant Staphylococcus aureus, M. Int. = Mycobacterium intracellulare. NT = Not tested. NA = not active at 20 μg/mL· IC₅₀ = The concentration that affords 50% inhibition of growth, MIC = Minimum inhibitory concentration and is the lowest test concentration that allows no detectable growth; MFC = Minimum bactericidal concentration and is the lowest test concentration that kills the microorganism; TC₅₀ = The concentration that is toxic to 50% of cells. The syntheses and characterization of all compounds in this Table were previously reported [3].

^aData previously reported [10].