Table 1.

Values of effective dose required to reduce the replication of virus by 50% (ED₅₀) and toxic dose for 50% cell death (TD₅₀) of various natural and synthetic compounds.

Compound	ED50 value in μM	TD50 value in μM	Therapeutic index (TI)
Quercetin (1)	48.2	83.4	1.7
Isoquercetin (2)	1.2	45.1	37.6
EGCG (3)	8.3	45.5	5.5
Quercetin-3-gallate (4)	9.1	90.2	9.9
5	19.4	45.2	2.3
6	22.6	60.1	2.7
7	24.1	54.8	2.3
8	>50	ND*	-
9	>50	ND	-
10	>50	ND	-
29	>50	ND	-

^*ND: not determined due to high ED₅₀ values.

Note: Quercetin, isoquercetin and EGCG were purchased from Sigma-Aldrich (St. Louis, MO).