Synthesis, cytotoxicity, and structure–activity relationship (SAR) studies of andrographolide analogues as anti-cancer agent

A series of analogues of andrographolide, prepared through chemo-selective functionalization at C14 hydroxy, have been evaluated for in vitro cytotoxicities against human leukemic cell lines. Two of the analogues ( 6a, 9b) exhibited significant potency. Preliminary studies on structure–activity relationship (SAR) revealed that the α-alkylidene-γ-butyrolactone moiety of andrographolide played a major role in the activity profile. The structures of the analogues were established through spectroscopic and analytical data. A series of analogues of andrographolide, prepared through chemo-selective functionalization at C14 hydroxy, have been evaluated for in vitro cytotoxicities against human leukemic cell lines. Two of the analogues ( 6a, 9b) exhibited significant potency. Preliminary studies on structure–activity relationship (SAR) revealed that the α-alkylidene-γ-butyrolactone moiety of andrographolide played a major role in the activity profile. The structures of the analogues were established through spectroscopic and analytical data