Devil's Club Falcarinol-Type Polyacetylenes Inhibit Pancreatic Cancer Cell Proliferation

Natural falcarinol-type (FC-type) polyacetylenes are known to show anticancer activities. We studied the bioactivity of synthetic FC, 1,2-dihydrofalcarinol (FCH) and 3-acetoxyfalcarinol (FCA) and compared them with the natural bioactive polyacetylene [9,17-octadecadiene-12,14-diyne-1,11,16-triol,1-acetate] (DCA) isolated from Devil's club (DC) Oplopanax horridus. Antiproliferation activity of these polyacetylenes, along with DC inner stem bark 70% ethanol and water extracts, was tested on human pancreatic ductal adenocarcinoma cell lines PANC-1 and BxPC-3. Chemically synthesized FC and FCA showed consistent IC₅₀ (50% inhibition concentration) and higher potency than DCA. FC and DCA's mechanism of action investigated by antibody array on apoptosis-associated genes, and cellular features confirmed by microscopy demonstrated that both compounds modulated genes related to pro-apoptosis, antiapoptosis, apoptosis, cell cycle, stress related, and death receptors. FC-type polyacetylenes with a terminal double bond (FC, FCA, and DCA) are potent inhibitors of pancreatic cancer cell proliferation compared to FCH with a terminal single bond. Liquid chromatography mass spectrometry confirmed the presence of FC and FCH in the inner stem bark of DC. For potential applications of FC-type polyacetylenes as anticancer agents, preparing them by chemical synthesis may provide an advantage over the labor intensive extraction process from raw plant material.