Semi-synthesis and cytotoxicity evaluation of pyrimidine, thiazole, and indole analogues of argentatins A–C from guayule (Parthenium argentatum) resin

Argentatins A–C (1–3), the major cycloartane-type triterpenoids of guayule resin, a byproduct commercial rubber production, were converted into their pyrimidine (7–12), thiazole (13–15), and indole (16–18) analogues by molecular hybridization approach. The cytotoxic activities these fused heterocyclic 7–18 compared with those argentatins (1–3) against panel three sentinel human cancer cell lines [NCI-H460 (non-small lung), MCF-7 (breast adenocarcinoma), SF-268 (central nervous system glioma)], normal fibroblast (WI-38) cells. cytotoxicity data suggest that 7 8 (derived from 1), 9 10 2), 12 3) had significantly enhanced activity to parent compounds or (13–15) analogues. These findings indicate triterpenoid constituents resin may be exploited obtain value-added products potential applications in anticancer drug discovery.