Antitumor agents 57. The isolation and structural elucidation of microhelenin-E, a new antileukemic nor-pseudoguaianolide, and microhelenin-F from Helenium microcephalum.
Two new nor-pseudoguaianolides, microhelenin-E (1) and -F (2), were isolated from Texas Helenium microcephalum and their structures elucidated on the basis of physicochemical data and spectral evidence. Microhelenin-E demonstrated significant in vitro and in vivo cytotoxic and antileukemic activities against KB tissue cell culture (ED50 = 1.38 microgram/ml) P-388 lymphocytic leukemia growth in BDF1 male mice (T/C-166% at 8 mg/kg/day), respectively.
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification*; D055598:Chemical Phenomena; D002621:Chemistry; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051379:Mice; D009374:Neoplasms, Experimental / Q000188:drug therapy; D012717:Sesquiterpenes / Q000302:isolation & purification*
D000972:Antineoplastic Agents, Phytogenic; D012717:Sesquiterpenes; C013137:microhelenins