Novel artemisinin derivatives with potential usefulness against liver/colon cancer and viral hepatitis

Antitumor and antiviral properties of the antimalaria drug artemisinin from Artemisia annua have been reported. Novel artemisinin derivatives (AD1-AD8) have been synthesized and evaluated using in vitro models of liver/colon cancer and viral hepatitis B and C. Cell viability assays after treating human cell lines from hepatoblastoma (HepG2), hepatocarcinoma (SK-HEP-1), and colon adenocarcinoma (LS174T) with AD1-AD8 for a short (6 h) and long (72 h) period revealed that AD5 combined low acute toxicity together with high antiproliferative effect (IC50 = 1-5 μM). Since iron-mediated activation of peroxide bond is involved in artemisinin antimalarial activity, the effect of iron(II)-glycine sulfate (ferrosanol) and iron(III)-containing protoporphyrin IX (hemin) was investigated. Ferrosanol, but not hemin, enhanced antiproliferative activity of AD5 if the cells were preloaded with AD5, but not if both compouds were added together. Five derivatives (AD1 > AD2 > AD7 > AD3 > AD8) were able to inhibit the cytopathic effect of bovine viral diarrhoea virus (BVDV), a surrogate in vitro model of hepatitis C virus (HCV), used here to evaluate the anti-Flaviviridae activity. Moreover, AD1 and AD2 inhibited the release of BVDV-RNA to the culture medium. Co-treatment with hemin or ferrosanol resulted in enhanced anti-Flaviviridae activity of AD1. In HepG2 cells permanently infected with hepatitis B virus (HBV), AD1 and AD4, at non-toxic concentrations for the host cells were able to reduce the release of HBV-DNA to the medium. In conclusion, high pharmacological interest deserving further evaluation in animal models has been identified for novel artemisinin-related drugs potentially useful for the treatment of liver cancer and viral hepatitis B and C.