THE ISOLATION AND STRUCTURAL ELUCIDATION OF 4 NOVEL TRITERPENE LACTONES, PSEUDOLAROLIDE-A, PSEUDOLAROLIDE-B, PSEUDOLAROLIDE-C, AND PSEUDOLAROLIDE-D, FROM PSEUDOLARIX-KAEMPFERI

Four novel triterpene lactones, pseudolarolides A 1!, B 2!, C 3!, a nd D 4!, were isolated from the seeds of Pseudolarix kaempferi. Their structures and stereochemistry were elucidated from spectral data. Co mpound 2 shows potent cytotoxicity against three human cancer cell lin es, KB (nasopharyngeal), A-549 (lung), and HCT-8 (colon), and against a murine leukemia cell line (P-388) with ED50 values of 0.49, 0.67, 0. 73, and 0.79 mug/ml, respectively.