title: Polyketides with antimicrobial activity from the solid culture of an endolichenic fungus Ulocladium sp.
abstract: Two new polyketides, 7-hydroxy-3, 5-dimethyl-isochromen-1-one (1) and 6-hydroxy-8-methoxy-3a-methyl-3a,9b-dihydro-3H-furo[3,2-c]isochromene-2,5-dione (2), along with eleven known compounds, 5'-methoxy-6-methyl-biphenyl-3,4,3'-triol (3), 7-hydroxy-3-(2-hydroxy-propyl)-5-methyl-isochromen-1-one (4), rubralactone (5), isoaltenuene (6), altenuene (7), dihydroaltenuenes A (8), altenusin (9), alterlactone (10), 6-O-methylnorlichexanthone (11), norlichexanthone (12), and griseoxanthone C (13) were isolated from the culture of the endolichenic fungus Ulocladium sp. Compound 2 was obtained as a racemate with an unprecedented chemical skeleton. The NMR data assignments for 3 and 4 were achieved for the first time. Compounds 1-13 were screened for their antimicrobial and radical scavenging activities. Compound 1 showed some antifungal activity against Candida albicans SC 5314 with IC(50) of 97.93 ± 1.12 μM. Compounds 11-13 showed strong activity against Bacillus subtilis with IC(50) in the range of 1-5 μM. Compound 12 significantly inhibited the growth of methicillin-resistant Staphylococcus aureus with IC(50) of 20.95 ± 1.56 μM. Compounds 9 and 10 showed strong radical scavenging activity in comparison with vitamin C. The plausible biosynthetic pathways for compounds 1, 2, and 4-8 were discussed.
authors: School of Life Science, University of Science and Technology of China, No. 96 Jinzhai-Road, Hefei 230026, PR China.
authors: Quan-Xin
authors: QX
authors: Wang
authors: Li
authors: L
authors: Bao
authors: Xiao-Li
authors: XL
authors: Yang
authors: Hui
authors: H
authors: Guo
authors: Rui-Nan
authors: RN
authors: Yang
authors: Biao
authors: B
authors: Ren
authors: Li-Xin
authors: LX
authors: Zhang
authors: Huan-Qin
authors: HQ
authors: Dai
authors: Liang-Dong
authors: LD
authors: Guo
authors: Hong-Wei
authors: HW
authors: Liu
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology*; D001203:Ascomycota / Q000737:chemistry*; D001419:Bacteria / Q000187:drug effects; D001713:Biphenyl Compounds / Q000737:chemistry; D002176:Candida albicans / Q000187:drug effects; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology; D015394:Molecular Structure; D010851:Picrates / Q000737:chemistry; D061065:Polyketides / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010851:Picrates; D061065:Polyketides; C004931:1,1-diphenyl-2-picrylhydrazyl