Table 1.

The effect of selected therapeutic agents on T. gondii viability and the oxidant–antioxidant balance in the parasite and in the host in in vitro studies.

Models	Compound	IC50 /EC50	Results/Oxidant–Antioxidant Effect	References
Human foreskin fibroblasts	tert-butyl hydroperoxide	IC50 = 100 ± 8 nM	• ↑ T. gondii parasites death • stable viability of the host cells • ↓ peroxiredoxin activity • changes in redox status of the parasites and destruction of their oxidant homeostasis
	5-hydroxy-1,4-naphtoquinone (Juglon)	IC50 = 148 ± 6 nM
	Phenazine methyl sulfate	IC50 = 406 ± 134 nM		[57]
Vero cell line from kidney of African green monkey	Extract of Azadirachta indica leaves	Toxoplasma elimination at concentrations higher than 2 mg/mL	• ↑ disorganization and elimination of intracellular tachyzoites • antioxidant effect on host cells	[114]
	Extract of Melia azedarach leaves	Toxoplasma elimination at concentrations higher than 0.5 mg/mL	• ↑ disorganization and elimination of intracellular tachyzoites • antioxidant effect on host cells	[113]
Human foreskin fibroblasts	6-oximes of the tryptanthrin (6,12-dihydro-6,12-dioxoindolo-(2,1-b)-quinazoline) and its 8-bromoderivative	ID50 range (0.003 ÷ 1.3) µM	• anti-T. gondii activity • no host cell cytotoxicity • hepatoprotection of host cells • activation of the ERK-Nrf2 pathway • ↓ oxidative damage	[101,102,105]
	6-hydrazones of the tryptanthrin and its 8-bromoderivative	ID50 range (0.31 ÷ 12) µM
	6-hydroxy derivatives of the tryptanthrin and 8-bromotryptanthrin	ID50 range (0.002 ÷ 8.7) µM
Vero cell line from kidney of African green monkey entry 4	Extract of Psidium guajava (guava)	EC50 = 4.94 ± 0.039 µg/mL	• inhibition of T. gondii growth • no host toxicity • moderate antioxidant—inhibition of free radicals action in host cells	[110]
Human foreskin fibroblasts	1-thio-β-D-glucopyranosatotriethylphosphine gold-2,3,4,6-tetraacetate (Auranofin)	IC50 = 0.28 nM	• ↓ viability of T. gondii parasites • inhibition of thioredoxin reductase activity • ↓ resistance to oxidative damage	[55,93,94]
LLC-MK2 host cells—kidney epithelial cells of rhesus monkey	[Fe(1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol)(SO4)]2 µ-oxo	IC50 = 3.6 µM nontoxic up to 200 µM	• inhibition of parasites growth at concentration for 2.5–25 µM • no effect on host cell viability • ↑ oxidative stress • ↓ metalloenzymes activity	[92]
Human foreskin fibroblasts	Gold nanoparticles (AuNPs)	EC50 ≤ 7 µg/mL	• ↓ viability of the parasites • no host toxicity • alteration in redox status by ROS production and reduction in mitochondrial membrane potential	[97]
	Silver nanoparticles (AgNPs)	EC50 ≤ 1 µg/mL
	Platinum nanoparticles (PtNPs)	EC50 ≤ 100 µg/mL
Vero cell line from kidney of African green monkey	Extract of Aloe vera	IC50 = 13.2 µg/mL	• anti-T. gondii activity in infected cells • ↓ MDA levels in host cells • potent antioxidant effect	[111]
	Extract of Eucalyptus globulus	IC50 = 24.7 µg/mL
Human foreskin fibroblasts	Seed oil of the fruit of Cola gigantea	EC50 ≤ 15 µg/mL	• ↓ viability of T. gondii parasites • ↑ toxicity for parasites by ROS production • mild antioxidant potential in host cells	[112]
GES-1 cells	Amide of 10-oxo derivative of ursolic acid and 1-H-tetrazol-5-amine	IC50 = 218.6 µM	• reduction of number of T. gondii invading of host cells • antioxidant effect on host cells	[115]

EC₅₀, half maximal effective concentration.; ERK-Nrf2, extracellular signal-regulated kinase-Nuclear factor-E2 p45-related factor; GES-1 cells, human gastric epithelial cell line; IC₅₀, half maximal inhibitory concentration; ID₅₀, infective dose; MDA, malondialdehyde; ROS, reactive oxygen species. In column 4, the anti-T. gondii activities of the therapeutic agents are marked in blue, and their specific oxidant-antioxidant effects in black.