title: Neglschisandrins E-F: two new lignans and related cytotoxic lignans from Schisandra neglecta.
abstract: Phytochemical investigation of an ethanolic extract of stems of Schisandra neglecta led to the isolation and identification of two new dibenzocyclooctadiene lignans, designated neglschisandrins E (1) and F (2), and thirteen known lignans. All structures and stereochemistries were determined by spectroscopic methods, including 2D-NMR techniques. The isolates were evaluated for in vitro cytotoxic activity. Among them, compounds 2-6 exhibited moderate to weak cytotoxicity against the human colorectal carcinoma HCT-8 cell line with EC₅₀ values of 7.33~19.8 μg/mL. In addition, compounds 2-4 also exhibited marginal cytotoxicity against the human lung carcinoma A549 cell line with EC₅₀ values of 11.8~15.0 μg/mL.
authors: Key Laboratory on Luminescence and Real-Time Analysis-Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China. mminchen@swu.edu.cn
authors: Min
authors: M
authors: Chen
authors: Xiumei
authors: X
authors: Xu
authors: Bing
authors: B
authors: Xu
authors: Panpan
authors: P
authors: Yang
authors: Zhihua
authors: Z
authors: Liao
authors: Susan L
authors: SL
authors: Morris-Natschke
authors: Kuo-Hsiung
authors: KH
authors: Lee
authors: Daofeng
authors: D
authors: Chen
mesh_terms: D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D034242:Cyclooctanes / Q000737:chemistry / Q000633:toxicity*; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D017705:Lignans / Q000737:chemistry* / Q000633:toxicity*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D011083:Polycyclic Compounds / Q000737:chemistry / Q000633:toxicity*; D032141:Schisandra / Q000737:chemistry*
chemical_list: D034242:Cyclooctanes; D017705:Lignans; D011083:Polycyclic Compounds; C582137:neglschisandrin E; C582138:neglschisandrin F; C011105:schizandrin