Two new diterpenes from the seeds of Caesalpinia minax Hance

Molecules with diterpene skeletons often possess valuable medicinal properties. Two new diterpenes 1α,6α,7β-triacetoxy-5α-hydroxy-14β-ethyl-O-vouacapane (1) and 2α-acetoxy-14,15-cyclopimara-7β,16-diol (2) were isolated from the seeds of Caesalpinia minax Hance. Their structures were established on the basis of extensive spectroscopic analyses, including HR-ESI-MS, UV, IR, 1D, and 2D NMR (HSQC, HMBC, NOESY) methods. The stereochemical structure of 1 was confirmed via the circular dichroism spectrum and calculated ECD experiment. The inhibitory activity of nitric oxide production of RAW264.7 macrophages stimulated by lipopolysaccharide of compounds 1 and 2 was evaluated, and compound 1 was found to show significant inhibitory effect.