Evaluation of Scopadulciol-Related Molecules for Their Stimulatory Effect on the Cytotoxicity of Acyclovir and Ganciclovir against Herpes Simplex Virus Type 1 Thymidine Kinase Gene-Transfected HeLa Cells

Herpes simplex virus type 1 thymidine kinase (HSV TK) is involved in both antiherpetic therapy and cancer gene therapy with acyclovir (ACV) and ganciclovir (GCV). Enhanced sensitivity to these drugs is advantageous in their clinical use. In the present study, scopadulciol (SDC) and its related compounds were evaluated for their stimulatory effect on the cytotoxicity of ACV and GCV by determination of selective toxicities against HSV TK-expressing HeLa cells. Although SDC remarkably potenciated the cytotoxicity of ACV and GCV, the other tested compounds showed only weak selectivity, except for compound 34.