Semi-Synthesis and Biological Evaluation of 25(-26-Acetoxy-3,5-Dihydroxycholest-6-One.

Previously, we identified a series of steroids (-) that showed potent anti-virus activities against respiratory syncytial virus (RSV), with IC values ranging from 3.23 to 0.19 µM. In this work, we first semi-synthesized and characterized the single isomer of , 25()-26-acetoxy-3,5-dihydroxycholest-6-one, named as (25)-, in seven steps from a commercially available compound diosgenin (), with a total yield of 2.8%. Unfortunately, compound (25)- and the intermediates only showed slight inhibitions against RSV replication at the concentration of 10 µM, but they possessed potent cytotoxicity activities against human bladder cancer 5637 (HTB-9) and hepatic cancer HepG2, with IC values ranging from 3.0 to 15.5 µM without any impression of normal liver cell proliferation at 20 µM. Among them, the target compound (25)- possessed cytotoxicity activities against 5637 (HTB-9) and HepG2 with IC values of 4.8 µM and 15.5 µM, respectively. Further studies indicated that compound (25)- inhibited cancer cell proliferation through inducing early and late-stage apoptosis. Collectively, we have semi-synthesized, characterized and biologically evaluated the 25-isomer of compound ; the biological results suggested that compound (25)- could be a good lead for further anti-cancer studies, especially for anti-human liver cancer.