title: Cytotoxic principles from the formosan milkweed, Asclepias curassavica.
abstract: A series of cardenolides and related compounds have been isolated from the aerial parts and roots of the ornamental milkweed, Asclepias curassavica. Their structures were determined by spectroscopic and chemical methods. Among them, three derivatives of calactinic acid methyl ester (13-15), 19-nor-16 alpha-acetoxy-10 beta-hydroxyasclepin (16), 20 beta,21-dihydroxypregna-4,6-dien-3-one (19), and 3,4-seco-urs-20(30)-en-3-oic acid (22) are new compounds. The relative configuration of calactinic acid methyl ester (12) has been confirmed by X-ray diffraction analysis on its derivative 13. Most of the cardenolides obtained showed pronounced cytotoxicity against four cancer cell lines (IC(50) 0.01 to 2.0 microg/mL).
authors.affiliation: Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung 807, Taiwan, Republic of China.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Roy
authors.forename: Fang-Rong
authors.initials: FR
authors.lastname: Chang
authors.forename: Hsiao-Chu
authors.initials: HC
authors.lastname: Huang
authors.forename: Michael Y-N
authors.initials: MY
authors.lastname: Chiang
authors.forename: Yang-Chang
authors.initials: YC
authors.lastname: Wu
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D031108:Asclepias / Q000737:chemistry*; D002298:Cardenolides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018517:Plant Roots / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D013624:Taiwan; D014407:Tumor Cells, Cultured; D014961:X-Ray Diffraction
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D002298:Cardenolides