title: A new phenolic enamide and a new meroterpenoid from marine alga-derived endophytic fungus Penicillium oxalicum EN-290.
abstract: Ten secondary metabolites (1-10) including a new phenolic enamide, methyl (Z)-3-(3,4-dihydroxyphenyl)-2-formamidoacrylate (1), and a new meroterpenoid, 15-hydroxydecaturin A (2), were characterized from the EtOAc extracts of the marine alga-derived endophytic fungus Penicillium oxalicum EN-290. The structures of these compounds were elucidated on the basis of 1D and 2D NMR experiments and the absolute configuration of compound 2 was confirmed by electronic circular dichroism quantum calculations. Compound 1 showed potent activity against Staphylococcus aureus with an MIC value of 2.0 μg/ml, which is stronger than that of the positive control (chloromycetin, with an MIC 4.0 μg/ml). This compound also showed activity against harmful algal bloom causative species Nitzschia closterium with inhibition zones of 20, 16, and 10 mm at 20, 10, and 5 mg/ml, respectively. Interestingly, so far, this type of anti-HAB metabolites has only been found in the algal-derived isolate of P. oxalicum. It could probably be a defense of this fungus against environmental stress and threat of survival.
authors.affiliation: a Key Laboratory of Experimental Marine Biology , Institute of Oceanology, Chinese Academy of Sciences , Qingdao 266071 , China.|b College of Earth Science, University of Chinese Academy of Sciences , Beijing 100049 , China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: a Key Laboratory of Experimental Marine Biology , Institute of Oceanology, Chinese Academy of Sciences , Qingdao 266071 , China.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Li
authors.affiliation: a Key Laboratory of Experimental Marine Biology , Institute of Oceanology, Chinese Academy of Sciences , Qingdao 266071 , China.|b College of Earth Science, University of Chinese Academy of Sciences , Beijing 100049 , China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: a Key Laboratory of Experimental Marine Biology , Institute of Oceanology, Chinese Academy of Sciences , Qingdao 266071 , China.
authors.forename: Bin-Gui
authors.initials: BG
authors.lastname: Wang
mesh_terms: D000179:Acrylates / Q000737:chemistry / Q000302:isolation & purification*; D000577:Amides / Q000737:chemistry / Q000302:isolation & purification*; D044722:Laurencia / Q000382:microbiology; D008386:Marine Biology; D015394:Molecular Structure; D010407:Penicillium / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification*; D013211:Staphylococcus aureus; D013729:Terpenes / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: C000607676:15-hydroxydecaturin A; D000179:Acrylates; D000577:Amides; D010636:Phenols; D013729:Terpenes; C000607674:methyl (Z)-3-(3,4-dihydroxyphenyl)-2-formamidoacrylate
keywords: Marine alga-derived fungus; Penicillium oxalicum; anti-HAB activity; antibacterial activity; secondary metabolites