Eight cyclic peroxide norterpenoids, compounds 1-8, have been isolated and characterized from the Red Sea sponge Diacarnus erythraeanus, including two new norsesterterpene derivatives (3, 4). Among these metabolites, (-)-muqubilin A (5) (nine cell lines analyzed) and the new compounds 3 and 4 (seven cell lines analyzed) displayed mean IC₅₀ growth inhibitory concentrations in vitro of <10 μM, while the remaining compounds (1, 6-8) were inactive in these cancer cell lines. Compound 5 displayed no selectivity between normal and cancer cells in terms of in vitro growth inhibition. Quantitative video microscopy analysis carried out on (-)-muqubilin A-treated cells validated the data obtained by means of the MTT colorimetric assay, while flow cytometry analysis revealed ROS production but no induction of apoptosis in cancer cells.
We developed synthetic chemistry to access the marine alkaloid rigidins and over forty synthetic analogues based on the 7-deazaxanthine, 7-deazaadenine, 7-deazapurine and 7-deazahypoxanthine skeletons. Analogues based on the 7-deazahypoxanthine skeleton exhibited nanomolar potencies against cell lines representing cancers with dismal prognoses, tumor metastases and multidrug resistant cells. Studies aimed at elucidating the mode(s) of action of the 7-deazahypoxanthines in cancer cells revealed that they inhibited in vitro tubulin polymerization and disorganized microtubules in live HeLa cells. Experiments evaluating the effects of the 7-deazahypoxanthines on the binding of [3H]colchicine to tubulin identified the colchicine site on tubulin as the most likely target for these compounds in cancer cells. Because many microtubule-targeting compounds are successfully used to fight cancer in the clinic, we believe the new chemical class of antitubulin agents represented by the 7-deazahypoxanthine rigidin analogues have significant potential as new anticancer agents.
Toad venom, namely, "Chansu" in China, has been widely used for the treatment of heart failure, sores, pains, and various cancers. Upon LC-MS analysis of the venom from Bufo melanosticus collected in Indonesia, new bufadienolide sulfates were identified. For a complete characterization, the MeOH extract of the toad venom from B. melanosticus was fractionated by preparative HPLC, and the structures of five new buadienolide sulfates (1-5) along with one new bufogenin (6) were rapidly elucidated on the basis of LC-DAD-MS(n) and LC-SPE-NMR data. The in vitro growth inhibitory activity of these six compounds along with hellebrin (positive control) has been assayed by means of the MTT colorimetric assay in four human and two mouse cancer cell lines. Compound 3 and hellebrin displayed similar and marked in vitro cytotoxicity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.