Two new cassane diterpenoids from the seed kernels of <i>Caesalpinia sinensis</i>

Two new cassane diterpenoids, sucupiranin MN (<b>1</b>) and sucupiranin ML (<b>2</b>), together with two known compounds sucutinirane C (<b>3</b>) and deacetylsucutinirane C (<b>4</b>) were isolated from the seed kernels of <i>Caesalpinia sinensis</i>. Their structures were elucidated by means of analysis of comprehensive spectroscopic data, especially HRESIMS and 1D/2D NMR spectroscopy. Compounds <b>1–4</b> are typical furan-type cassane derivatives with an aromatized C ring. Biological evaluation revealed that compounds <b>1–4</b> at the concentration of 10 μM could inhibit the overproduction of NO in LPS-stimulated RAW 264.7 macrophages.