Anti-cancer activity of carbamate derivatives of melampomagnolide B

Melampomagnolide B (MMB) is a natural sesquiterpene structurally related to parthenolide (PTL). We have shown that MMB exhibits anti-leukemic properties similar to PTL. Unlike PTL, the presence of a primary hydroxyl group in the MMB molecule allows the opportunity for examining the biological activity of a variety of conjugated analogs of MMB. We have now synthesized a series of carbamate analogs of MMB and evaluated these derivatives for anti-cancer activity against a panel of sixty human cancer cell lines. Analogs 6a and 6e exhibited promising anti-leukemic activity against human leukemia cell line CCRF-CEM with GI₅₀ values of 680 and 620 nM, respectively. Analog 6a also showed GI₅₀ values of 1.98 and 1.38 μM respectively, against RPMI-8226 and SR leukemia cell lines and GI₅₀ values of 460 and 570 nM against MDA-MB-435 melanoma and MDA-MB-468 breast cancer cell lines, respectively. Analog 6e had GI₅₀ values of 650 and 900 nM against HOP-92 non-small cell lung and RXF 393 renal cancer cell lines.