Table 1.

Anti-HCV activity, inhibition of the SCV NTPase/helicase, and cytotoxicity of the 2-arylmethyloxy-6-(3-chlorobenzyloxy)-5-hydroxychromones (5a–5g) in comparison with those of the ADK (1), 3-O-arylmethylgalangin (3), and 7-O-arylmethylgalangin (4).

Compds	R	Antiviral Activity			Cytotoxicity (μM)d
		HCV (EC50, μM)a	SCV (IC50, μM)
			NTPaseb	Helicasec
5a	H	>50	>50	>50	>50
5b	3-Cl	17	10	40	>50
5c	4-Cl	24	28	53	>50
5d	3,5-di-Cl	1	>50	>50	>50
5e	3-I	4	4	11	>50
5f	4-I	3	23	31	>50
5g	3-CN	17	37	>50	>50
1	3-(4-chlorobenzyl-amino)	0.8 [4]	>50 [7]	11 [5]	>50
3	3-NO2	5 [7]	>50	>50	>50
4	3-CN	3 [8]	>50	>50	>50

^aConcentration required to inhibit HCV RNA replication by 50% in HCV replicon cell.

^bConcentration required to inhibit SCV NTPase activity by 50%.

^cConcentration required to inhibit duplex DNA-unwinding activity of SCV helicase by 50%.

^dConcentration required to reduce proliferation of normal human fibroblast cell HS27 by 50%.