Quercetin inhibits Toxoplasma gondii tachyzoite proliferation and acts synergically with azithromycin

Parasites & Vectors

Table 1 Comparison of the in vitro inhibitory activity of azithromycin and quercetin against Toxoplasma gondii growth

Compounds (µM)	IC₅₀	CC_{50 Vero cells}	SI_{Vero cells}	FIC	Designation
QUE Alone	0.50	14.98	29.96
AZ Alone	0.66	2575.00	3901.5
QUE + AZ (2:1)	0.08	60.82	760.25	0.28	Synergy
QUE + AZ (1:2)	1.50	47.17	31.45	5.27	Antagonistic
QUE + AZ (1:1)	0.89	37.22	41.82	3.13	Antagonistic

Data in table are the means IC_50s of Toxoplasma gondii strain RH-(YFP)₂ tachyzoites from at least 3 experiments
IC₅₀ 50% inhibitory concentration, CC₅₀ 50% cytotoxicity concentrations, SI selectivity index (CC_{50 Vero cells}/IC₅₀ T. gondii), FIC fractional inhibitory concentration: IC₅₀ of QUE in combination (QUE-AZ (1:1, 1:2 and 2:1)/IC₅₀ QUE alone + IC₅₀ of AZ in combination (QUE-AZ (1:1) or (1:2) or (2:1)/IC₅₀ of AZ alone, QUE quercetin, AZ azithromycin

ISSN: 1756-3305