Two new steroids with NO inhibitory effects from lansium domesticum

Chemical investigation of Lansium domesticum has led to the isolation of two undescribed compounds, namely 17(20)E-dyscusin B (1) and 17(20)Z-dyscusin B (2), as well as three known ones (3 – 5). Structural elucidation was accomplished by the analysis of NMR, MS and IR data. Compounds 1 and 2 were a pair of Δ17(20) geometric isomers of pregnane steroids and showed the significant nitric oxide (NO) inhibitory activities.