title: Ophiobolin O and 6-epi-ophiobolin O, two new cytotoxic sesterterpenes from the marine derived fungus Aspergillus sp.
abstract: Two new sesterterpenes, ophiobolin O (1) and 6-epi-ophiobolin O (2), together with the known ophiobolins G (3), H (4), and K (5), and 6-epi-ophiobolin K (6) were isolated from the marine derived fungus Aspergillus sp. The structures of these compounds were elucidated based on chemical and physicochemical evidence, including MS, UV, IR and NMR spectra. T h e stereochemistry of 1 was further confirmed by catalytic reaction of 5 with p-TsOH as acatalyst. Compounds 1 to 6 showed cytotoxicity against mouse leukemia cell line P388, with IC50 values of 4.7, 9.3, 24.6, 105.7, 13.3 and 24.9 microM, respectively.
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. dahaizhang@ouc.edu.cn
authors.forename: Dahai
authors.initials: D
authors.lastname: Zhang
authors.forename: Seketsu
authors.initials: S
authors.lastname: Fukuzawa
authors.forename: Masayuki
authors.initials: M
authors.lastname: Satake
authors.forename: Xianguo
authors.initials: X
authors.lastname: Li
authors.forename: Takafumi
authors.initials: T
authors.lastname: Kuranaga
authors.forename: Ai
authors.initials: A
authors.lastname: Niitsu
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yoshizawa
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tachibana
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification*; D059001:Aquatic Organisms / Q000737:chemistry; D001230:Aspergillus / Q000737:chemistry*; D045744:Cell Line, Tumor; D004354:Drug Screening Assays, Antitumor; D051379:Mice; D008968:Molecular Conformation; D054830:Sesterterpenes / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: C578156:6-epi-ophiobolin O; D000970:Antineoplastic Agents; D054830:Sesterterpenes; C578155:ophiobolin O; C002884:ophiobolins