Table 2.

Cytotoxicity, Antiviral, Anti-IN, and Anti-RNase H Activities of Compounds 10x–aa and 11x–aa

			Activity in enzyme assays
			IN IC50 (μM)a		RNaseH		Antiviral activity and cytotoxicity
R		X	3’-P	ST	% in. at 10 μMb	IC50 (μM)x	EC50(μM)c	CC50 (μM)d	SIe
10x		Et	>333	120	19.4	nd	>50	ndf
10y		Et	>333	32	29.7	nd	>50	nd
10z		Et	>333	14	−5.6	nd	>50	nd
10aa		Et	>1000	3.5	4.4	nd	>50	nd
11x		H	>333	<0.45	33.0	nd	>50	nd
11y		H	18	<0.45	40.7	nd	4.8	>50	>10.4
11z		H	>1000	16	−2.6	nd	>50	nd
11aa		H	70	0.40	16.4	nd	>50	nd

^aInhibitory concentration 50% (μM) determined from dose response curves.

^bPercentage of inhibition determined at compound concentration of 10 μM.

^cEffective concentration 50% (μM).

^dCytotoxic concentration 50% (μM).

^eSI = CC₅₀/EC₅₀.

^fnd: not determined.