Table-2.

The cytotoxicity (CC₅₀ and CC₁₀) in CRFK cells, the effective concentration, (EC₅₀ and EC₉₀), and the selective indices of flavonoids against FIPV-infected CRFK cells during post-viral entry.

Compound	Cytotoxicity		Antiviral activity		Selective index
	CC501; µM	CC102; µM	EC503; µM	EC904; µM	CC50/EC505
Luteolin	248.0 ± 3.40	136.80 ± 2.37	36.28 ± 0.03	65.98 ± 1.82	6.83
Isoginkgetin	199.40 ± 0.33	77.43 ± 2.52	4.77 ± 0.09	28.82 ± 1.46	41.80
Epigallocatechin gallate	282.20 ± 0.12	84.98 ± 1.93	79.07 ± 0.01	196.50 ± 1.96	3.57
Amentoflavone	197.10 ± 2.29	155.50 ± 2.19	144.10 ± 0.01	242.90 ± 2.40	1.37

¹CC₅₀: Compound concentration required to reduce cell viability by 50% as determined by MTS assay,

²CC₁₀: Compound concentration required to reduce cell viability by 10% as determined by MTS assay,

³EC₅₀: Compound concentration required to effectively protect 50% of cells from virus infection as determined by IPMA,

⁴EC₉₀: Compound concentration required to effectively protect 90% of cells from virus infection as determined by IPMA,

⁵Selective index: A ratio by CC₅₀/EC₅₀, Data values represent as mean ± SD of three independent experiments, EC₅₀=50% maximal effective concentrations, EC₉₀=90% maximal effective concentrations, CC₅₀=50% cytotoxicity concentrations, CC₁₀=10% cytotoxicity concentrations, FIPV=Feline infectious peritonitis virus, CRFK=Crandell–Rees feline kidney