Diarylheptanoid from Pleuranthodium racemigerum with in vitro prostaglandin E2 inhibitory and cytotoxic activity

Bioactivity-guided fractionation of an ethanolic extract of the rhizome of Pleuranthodium racemigerum, a tropical Zingiberaceae species from Northeastern Australia, resulted in the isolation and structural elucidation of 1-(4''-methoxyphenyl)-7-(4'-hydroxyphenyl)-(E)-hept-2-ene (1), a new diarylheptanoid related to curcumin. Compound 1 was a fairly potent inhibitor of prostaglandin E2 production in 3T3 murine fibroblasts (IC50 ≈ 34 μM) and also displayed moderate cytotoxicity against this cell line (IC50 = 52.8 μM). The compound also demonstrated cytotoxic activity against the P388D1 murine lymphoblast cell line (IC50 = 117.0 μM) and four human cell lines: Caco-2 colonic adenocarcinoma (IC50 = 44.8 μM), PC3 prostate adenocarcinoma (IC50 = 23.6 μM), HepG2 hepatocyte carcinoma (IC50 = 40.6 μM), and MCF7 mammary adenocarcinoma (IC50 = 56.9 μM). The cytotoxicity of compound 1 closely resembled that of curcumin, in terms of both IC50 values and dose-response curves.