Further Diterpenes from the Seeds of Caesalpinia minax Hance

Three new cassane‐type diterpenes, neocaesalpin AF (1), neocaesalpin AG (2), and neocaesalpin AH (3), were isolated from the seeds of Caesalpinia minax Hance. Their structures were elucidated on the basis of extensive spectroscopic analyses. The partially hydrogenated lactone unit in a tetracyclic cassane diterpene in 2 is rarely encountered in the cassane diterpenes isolated from the genus Caesalpinia. All compounds were evaluated for their in vitro cytotoxic activities against HCT‐8 and MCF‐7 human cancer cell lines.