title: Chemical studies on Taxus canadensis.
abstract: A series of new taxanes, 1-93, have been isolated, together with 37 known taxoids including Taxol(®) (paclitaxel) and cephalomannine, from the Canadian yew, Taxus canadensis (Taxaceae) in the past 30 years. These new taxoids possess various skeletons containing 5/7/6, 6/10/6, 6/5/5/6, 6/8/6, and 6/12 ring systems and six new taxanes with four novel skeletons, i.e., a taxane with a 6/6/8/6 ring system, a taxane with a [3.3.3] propellane skeleton, three taxanes with [3.3.3] [3.4.5] dipropellane sytems, as well as a novel taxane with a unique 5/5/4/6/6/6 hexacyclic skeleton, containing a unique [3.3.2] propellane, were isolated for the first time from natural sources. It should be emphasized that 13-acetyl-9-dihydrobaccatin III, a very useful starting material for the semisynthesis of Taxol(®) and Taxotere(®) , represents the most abundant taxane in the needles of this yew tree. These findings establish the above mentioned yew tree as significantly different from the remaining species. On the other hand, some chemical modifications on the taxanes isolated from this plant were carried out.
authors.affiliation: Department of Thoracic Surgery and Department of Pharmacy, The Fourth Hospital of Hebei Medical University, 12 Jiankang Lu, Shijiazhuang 050011, P. R. China, (phone: +86-311-66696452).
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.forename: Fang
authors.initials: F
authors.lastname: Qin
authors.forename: Si-Ming
authors.initials: SM
authors.lastname: Wang
authors.forename: Rui-Xia
authors.initials: RX
authors.lastname: Guo
authors.forename: Yue-Feng
authors.initials: YF
authors.lastname: Zhang
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Gu
authors.forename: Qing-Wen
authors.initials: QW
authors.lastname: Shi
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D006801:Humans; D007536:Isomerism; D061986:MCF-7 Cells; D008968:Molecular Conformation; D010936:Plant Extracts / Q000737:chemistry*; D043823:Taxoids / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity; D020946:Taxus / Q000737:chemistry* / Q000378:metabolism
chemical_list: D010936:Plant Extracts; D043823:Taxoids
keywords: Diterpenoids; Microtubule polymerization; Propellanes; Semisynthesis; Taxanes; Taxol; Taxus canadensis; Yew