title: Cytotoxic (9βH)-pimarane and (9βH)-17-norpimarane diterpenes from the tuber of Icacina trichantha.
abstract: Three (9βH)-pimaranes, 1, 2, and 3, and two (9βH)-17-norpimaranes, 4 and 5, belonging to a rare compound class in nature, were obtained from the tubers of Icacina trichantha for the first time. Compound 1 is a new natural product, and 2-5 have been previously reported. The structures were elucidated based on NMR and MS data, and optical rotation values. The absolute configurations of (9βH)-pimaranes were unambiguously established based on X-ray crystallographic analysis. Full NMR signal assignments for the known compounds 2, 4, and 5, which were not available in previous publications, are also reported. All five isolates displayed cytotoxic activities on MDA-MB-435 cells (IC50 0.66-6.44 μM), while 2, 3, and 4 also exhibited cytotoxicities on HT-29 cells (IC50 3.00-4.94 μM).
authors.affiliation: Department of Medicinal Chemistry and Pharmacognosy, WHO Collaborating Center for Traditional Medicine, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA, (phone: +1-312-996-1557; fax: +1-312-996-7107); Department of Veterinary Physiology and Pharmacology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Nigeria; Department of Physiology and Biochemistry, Faculty of Veterinary Medicine, University of Abuja, PMB 117, Abuja, Nigeria.
authors.forename: Michael
authors.initials: M
authors.lastname: Monday Onakpa
authors.forename: Ming
authors.initials: M
authors.lastname: Zhao
authors.forename: Tanja
authors.initials: T
authors.lastname: Gödecke
authors.forename: Wei-Lun
authors.initials: WL
authors.lastname: Chen
authors.forename: Chun-Tao
authors.initials: CT
authors.lastname: Che
authors.forename: Bernard D
authors.initials: BD
authors.lastname: Santarsiero
authors.forename: Steven M
authors.initials: SM
authors.lastname: Swanson
authors.forename: Isaac
authors.initials: I
authors.lastname: Uzoma Asuzu
mesh_terms: D045784:Abietanes / Q000302:isolation & purification* / Q000494:pharmacology; D045744:Cell Line, Tumor; D004224:Diterpenes / Q000302:isolation & purification* / Q000494:pharmacology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D019684:Magnoliopsida / Q000737:chemistry*; D008958:Models, Molecular; D014961:X-Ray Diffraction
chemical_list: D045784:Abietanes; D004224:Diterpenes; C433018:pimarane
keywords: (9βH)-17-Norpimarane diterpenes; (9βH)-Pimarane diterpenes; Cytotoxic activity; Diterpenes; Icacina trichantha