New Cytotoxic Laurene‐, Cuparene‐, and Laurokamurene‐Type Sesquiterpenes from the Red Alga Laurencia obtusa

Abstract Three new sesquiterpene alcohols, laur-2-ene-3, 12-diol (1), cuparene-3, 12-diol 
(2), and 8, 11-dihydro-1-methoxylaurokamuren-12-ol (3), along with one known diterpene, 
kahukuen-10-ol (4) have been isolated from the organic extract of the red alga Laurencia 
obtusa. The chemical structures were elucidated on the basis of spectroscopic analysis. The 
cytotoxicity of the isolated compounds were evaluated against three cancer cell lines, ie, KB, 
HepG2, and MCF-7. Compound 4 exhibited a wide range of cytotoxic activity against KB, ...