title: Indole Alkaloids from Chaetomium globosum.
abstract: Two new indole alkaloids chaetocochin J (1) and chaetoglobinol A (8), along with chetomin (2), chetoseminudin A (3), cochliodinol (9), and semicochliodinol (10), were isolated from the rice culture of the fungus Chaetomium globosum. Their structures were elucidated by spectral analysis. Three new epipolythiodioxopiperazines, chaetocochins G-I (5-7), were identified by the combination of UPLC and mass spectrometric analysis. Chaetocochin I contained two sulfur bridges, one formed by three sulfur atoms between C-3 and C-11a, and the other formed by four sulfur atoms between C-3' and C-6'. Chaetocochin I was readily transformed into chetomin (2), chetoseminudin A (3), chaetocochin D (4), chaetocochin G (5), and chaetocochin H (6) by losing sulfur atoms. Compounds 1-3, and 8 exhibited antibacterial activities against Bacillus subtilis with MICs of 25, 0.78, 0.78, and 50 μg/mL, respectively, but not against Gram-negative bacterium (Escherichia coli). Compounds 2 and 8 were inactive against Candida albicans, Fusarium graminearum, Fusarium vasinfectum, Saccharomyces cerevisiae, and Aspergillus niger even at the high concentrations of 200 and 100 μg/mL, respectively. Compound 8 showed free radical scavenging capacity against the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical (ABTS(+•)), with IC50 values of 143.6 and 45.2 μM, respectively. The free radical scavenging capacity rates of compounds 1-3 on the DPPH and ABTS(+•) were less than 20% at the test concentrations (89.9-108.3 μM). The superoxide anion radical scavenging assay indicated that compounds 1-3, and 8 showed 14.8% (90.9 μM), 18.1% (90.9 μM), 51.5% (88.3 μM), and 30.4% (61.3 μM) superoxide anion radical scavenging capacity, respectively.
authors.affiliation: †Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China.|‡School of Pharmacy, Guiyang Medical College, Guiyang, Guizhou 550004, People's Republic of China.
authors.forename: Guo-Bo
authors.initials: GB
authors.lastname: Xu
authors.affiliation: §State Key Laboratory of Biotherapy/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, People's Republic of China.
authors.forename: Gu
authors.initials: G
authors.lastname: He
authors.affiliation: †Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China.
authors.forename: Huan-Huan
authors.initials: HH
authors.lastname: Bai
authors.affiliation: †Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
authors.affiliation: †Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China.
authors.forename: Guo-Lin
authors.initials: GL
authors.lastname: Zhang
authors.affiliation: †Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China.
authors.forename: Lin-Wei
authors.initials: LW
authors.lastname: Wu
authors.affiliation: †Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China.
authors.forename: Guo-You
authors.initials: GY
authors.lastname: Li
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects; D052160:Benzothiazoles / Q000494:pharmacology; D001713:Biphenyl Compounds / Q000494:pharmacology; D002597:Chaetomium / Q000737:chemistry*; D004926:Escherichia coli / Q000187:drug effects; D026121:Indole Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D012275:Oryza / Q000254:growth & development / Q000382:microbiology; D010851:Picrates / Q000494:pharmacology; D010879:Piperazines; D013451:Sulfonic Acids / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D026121:Indole Alkaloids; D010851:Picrates; D010879:Piperazines; D013451:Sulfonic Acids; C000602067:chaetocochin J; C000602068:chaetoglobinol A; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C004931:1,1-diphenyl-2-picrylhydrazyl