Cytotoxic Constituents of the Roots of Exostema acuminatum

✍ Scribed by Aiko Ito; Hee-Byung Chai; Young Geun Shin; Ricardo Garcı́a; Miliciades Mejı́a; Qi Gao; Craig R Fairchild; Kate E Lane; Ana T Menendez; Norman R Farnsworth; Geoffrey A Cordell; John M Pezzuto; A Douglas Kinghorn

• Book ID: 104202885
• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 108 KB
• Volume: 56
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(00)00584-6

✦ Synopsis

AbstractÐBioassay-guided phytochemical investigation of the roots of Exostema acuminatum (Rubiaceae) using human oral epidermoid carcinoma (KB) cells as a monitor, led to the isolation of two norditerpenoids, namely, (16R)-ent-16,17-dihydroxy-19-nor-kaur-4-en-3-one ( ) and (16S)-ent-16,17-dihydroxy-19-nor-kaur-4-en-3-one (2), and six previously known 4-phenylcoumarins (3±8). The structure and relative stereochemistry of the novel compound 1 were determined by X-ray crystallography. All isolates were tested against a panel of human tumor cell lines, and the 4-phenylcoumarins showed signi®cant cytotoxicity, with 3 H -hydroxy-5,7,4 H -trimethoxy-4-phenylcoumarin (5) and 8-hydroxy-5,7,4 H -trimethoxy-4-phenylcoumarin (6) exhibiting the most potent activity. Two of the 4-phenylcoumarins, 5,7,4 Htrimethoxy-4-phenylcoumarin (3) and 6, were evaluated in an in vivo P388 murine leukemia model.