Project description:Naturally occurring oplopanane sesquiterpenoids are rarely reported. A phytochemical investigation on the rhizomes of Homalomena occulta (Lours) has resulted in the discovery of six oplopanane sesquiterpenoids (1-6), including four new (1-4) and one 3,5-seco-oplopanane (6), together with three previously reported sesquiterpenoids (7-9). In addition three new oplopananes (2a-4a) were also obtained by chemical transformation. All structures of these sesquiterpenoids were established based on the comprehensive spectroscopic analyses, including NMR, MS, and IR, and comparing with the literatures.