A new sesquiterpenoid from the rhizomes of Homalomena occulta.

Chemical constituents of EtOAc extract from the rhizomes of traditional Chinese medicine Qian-nian-jian (Homalomena occulta) have been studied, a new sesquiterpenoid, named euadesma-4-ene-1β,15-diol (1), and four related known compounds, polydactin B (2), oplodiol (3), 1β,4β,7α-trihydroxyeudesmane (4), and (-)1β,4β,6α-trihydroxy-eudesmane (5), were isolated. Their structures were elucidated using spectroscopic methods including 1D and 2D NMR techniques and mass spectrometry. All the isolates were tested against the human lung adenocarcinoma A549 using MTT assay method. Oplodiol (3) and (-)1β,4β,6α-trihydroxy-eudesmane (5) were found to show moderate cytotoxic effects on A549 with IC50 values at 25.5 and 15.0 μg/mL, respectively.