Table 1.

Antimicrobial (MICs, µM) and Cancer Cell Growth Inhibitory (GI₅₀, µM) Activities of the Synthesized Indole Derivatives^a

Compound	Gram-(+) bacterial strains			Gram-(−) bacterial strains		Fungus	Cancer cell line
	S. aureusb BAA-44	S. aureusc 29213	E. faecalisd 51299	P. aeruginosa 27853	A. baumannii 15151	C. albicans 26555	HeLa
1a	12.5	12.5	25	>100	>100	12.5	23 ± 3e
1b	6.3	6.3	12.5	>100	>100	25	49 ± 5
2a	1.6	0.6	8	>100	>100	>100	26 ± 0
2b	12.5	6.3	6.3	>100	>100	>100	9 ± 1
2c	1.6	1.3	3.1	>100	>100	>100	12 ± 1
2d	50	3.1	> 100	>100	>100	>100	23 ± 1
2e	6.3	6.3	6.3	>100	>100	>100	13 ± 0
3	>100	>100	>100	>100	>100	>100	>100
4	>100	25	>100	>100	>100	>100	64 ± 5
5	>100	>100	> 100	> 100	> 100	> 100	69 ± 5
6	>100	>100	>100	> 100	> 100	> 100	16 ± 1
7a	3.1	1.6	3.1	>100	>100	>100	6 ± 1
7b	3.1	1.6	3.1	>100	>100	>100	12 ± 2
7c	1.3	1.6	6.3	>100	>100	>100	8 ± 1
8a	3.1	1.6	12.5	>100	>100	>100	9 ± 0
8b	0.6	1.6	12.5	>100	>100	>100	8 ± 2
8c	3.1	3.1	12.5	>100	>100	>100	3 ± 0
8d	1.6	1.6	6.3	>100	>100	>100	13 ± 3
8e	6.3	12.5	25	>100	>100	>100	24 ± 2
8f	1.3	1.6	3.1	>100	>100	>100	13 ± 4
8g	6.3	12.5	50	>100	>100	>100	19 ± 1
9	>100	>100	>100	>100	>100	>100	14 ± 1
10	>100	>100	>100	>100	>100	>100	19 ± 1
Vancomycin	2.8	2.8	86.3	NDf	ND	ND	ND
Penicillin G	>100	23.9	11.9	ND	ND	ND	ND

^aBacterial suspensions were adjusted to ~5×10⁵ CFU/mL.^20,21 The suspensions were treated with compounds, serially diluted 2-fold and were incubated according to ATCC recommendations for 18 hours. Fungal testing was accomplished according to a previously published method.²² Bacterial and fungal viability was determined using the MTT method due to coloring of compounds.²³ HeLa testing was also accomplished according to a previously published method.²⁴

^bMethicillin-resistant S. aureus

^cSusceptible S. aureus strain

^dLow-level vancomycin-resistant Enterococcus

^eThe data are presented as GI₅₀ ± SD from four experiments.

^fND = not determined