title: Cardenolides and bufadienolide glycosides from Kalanchoe tubiflora and evaluation of cytotoxicity.
abstract: Two new cardenolides, kalantubolide A (1) and kalantubolide B (2), and two bufadienolide glycosides, kalantuboside A (3) and kalantuboside B (4), as well as eleven known compounds were isolated and characterized from the EtOH extract of Kalanchoe tubiflora. The structures of compounds were assigned based on 1D and 2D NMR spectroscopic analyses including HMQC, HMBC, and NOESY. Biological evaluation indicated that cardenolides (1-2) and bufadienolide glycosides (3-7) showed strong cytotoxicity against four human tumor cell lines (A549, Cal-27, A2058, and HL-60) with IC50 values ranging from 0.01 µM to 10.66 µM. Cardenolides (1-2) also displayed significant cytotoxicity toward HL-60 tumor cell line. In addition, compounds 3, 4, 5, 6, and 7 blocked the cell cycle in the G2/M-phase and induced apoptosis in HL-60 cells.
authors.affiliation: Department of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University, Taichung, Taiwan.
authors.forename: Hui-Chi
authors.initials: HC
authors.lastname: Huang
authors.forename: Ming-Kuem
authors.initials: MK
authors.lastname: Lin
authors.forename: Hsin-Ling
authors.initials: HL
authors.lastname: Yang
authors.forename: You-Cheng
authors.initials: YC
authors.lastname: Hseu
authors.forename: Chih-Chuang
authors.initials: CC
authors.lastname: Liaw
authors.forename: Yen-Hsueh
authors.initials: YH
authors.lastname: Tseng
authors.forename: Minoru
authors.initials: M
authors.lastname: Tsuzuki
authors.forename: Yueh-Hsiung
authors.initials: YH
authors.lastname: Kuo
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D002298:Cardenolides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D031962:Kalanchoe / Q000737:chemistry*; D009369:Neoplasms / Q000188:drug therapy; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D002298:Cardenolides; D010936:Plant Extracts; C587655:kalantubolide A; C587656:kalantubolide B