Sponge-Derived Fijianolide Polyketide Class:  Further Evaluation of Their Structural and Cytotoxicity Properties

The sponge-derived polyketide macrolides fijianolides A (1) and B (2), isolaulimalide and laulimalide, have taxol-like microtubule-stabilizing activity, and the latter exhibits potent cytotoxicity. Insight on the biogeographical and phenotypic variations of Cacospongia mycofijiensis is presented that will enable a future study of the biosynthetic pathway that produces the fijianolides. In addition to fijianolides A and B, six new fijianolides, D−I (7−12), were isolated, each with modifications to the C-20 side chain of the macrolide ring. Compounds 7−12 exhibited a range of in vitro activities against HCT-116 and MDA-MB-435 cell lines. Fijianolides 8 and 10 were shown to disrupt interphase and mitotic division, but were less potent than 2. An in vivo evaluation of 2 using tumor-bearing severe combined immuno-deficiency mice demonstrated significant inhibition of growth in HCT-116 tumors over 28 days.