title: New cytotoxic cyclic peptides and dianthramide from Dianthus superbus.
abstract: Four new cyclic peptides, dianthins C-F (1-4), and a new dianthramide, 4-methoxydianthramide B (5), were isolated from the MeOH extract of the traditional Chinese medicinal plant Dianthus superbus. The sequences of cyclic peptides 1-4 were elucidated as cyclo(Gly(1)-Pro(2)-Phe(3)-Tyr(4)-Val(5)-Ile(6)-), cyclo(Gly(1)-Ser(2)-Leu(3)-Pro(4)-Pro(5)-Ile(6)-Phe(7)-), cyclo(Gly(1)-Pro(2)-Ile(3)-Ser(4)-Phe(5)-Val(6)-), and cyclo(Gly(1)-Pro(2)-Phe(3)-Val(4)-Phe(5)-) on the basis of ESI tandem mass fragmentation analysis, chemical evidence, and extensive 2D NMR methods. The conformation of compound 1 was established as an alpha-helix by CD analysis. Furthermore, compounds 3 and 5 showed cytotoxicities toward the Hep G2 cancer cell line with IC(50) values of 2.37 and 4.08, respectively.
authors.affiliation: Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
authors.forename: Pei-Wen
authors.initials: PW
authors.lastname: Hsieh
authors.forename: Fang-Rong
authors.initials: FR
authors.lastname: Chang
authors.forename: Ching-Chung
authors.initials: CC
authors.lastname: Wu
authors.forename: Kuen-Yuh
authors.initials: KY
authors.lastname: Wu
authors.forename: Chien-Ming
authors.initials: CM
authors.lastname: Li
authors.forename: Su-Li
authors.initials: SL
authors.lastname: Chen
authors.forename: Yang-Chang
authors.initials: YC
authors.lastname: Wu
mesh_terms: D000595:Amino Acid Sequence; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002942:Circular Dichroism; D029749:Dianthus / Q000737:chemistry*; D004354:Drug Screening Assays, Antitumor; D020128:Inhibitory Concentration 50; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry*; D054789:Ribosome Inactivating Proteins, Type 1; D014407:Tumor Cells, Cultured
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D010456:Peptides, Cyclic; D010940:Plant Proteins; D054789:Ribosome Inactivating Proteins, Type 1