Table 1. In vitro activity of ZCL039.

	IC50 (μM)						MIC (μg/mL)
	LeuRSs				Human cell lines		Bacteria
	S. pneumoniae	E. coli	Human cytosolic	Human mitochondrial	HEK 293	A549	S. pneumoniae	E. coli
ZCL039a	1.72 ± 0.05	8.25 ± 1.2	>250	>250	>200	>200	5	60
Ampicillin							0.0625	4

^aFor ZCL039 (Mr = 240.1), 1 μM equals to 0.24 μg/mL.

The IC₅₀ values are means from at least two independent experiments; errors show s.d.