title: Isolation and difference in anti-Staphylococcus aureus bioactivity of curvularin derivates from fungus Eupenicillium sp.
abstract: With the anti-microbial and anti-tumor composite screening model, bioassay-guided fractionation led to the isolation of two structurally related bioactive compounds, curvularin and alphabeta-dehydrocurvularin, from ethyl acetate extract of Eupenicillium sp. associated with marine sponge Axinella sp. Further study on the structure-activity relationship demonstrated that both compounds exhibited differences in bioactive profiles which are highly associated with their minor structural differences. Both curvularin and alphabeta-dehydrocurvularin have similar level of anti-fungal and anti-tumorous activity, while alphabeta-dehydrocurvularin is active against Staphylococcus aureus with a minimal inhibitory concentration of 375 microg/ml but curvularin does not. No detectable activity against Gram-negative bacteria such as Escherichia coli and Pseudomonas aeruginosa exists for both compounds. It is suggested that the partial planar backbone structure, due to the conjugation of pi electrons in the presence of a 3,4-double bond and the carbonyl group at position C-2 in alphabeta-dehydrocurvularin, acts as a key factor for the inhibition of S. aureus, a Gram-positive low G + C bacteria that are often the hospital-acquired and/or community-acquired pathogen.
authors.affiliation: Key Laboratory of Marine Bio-resources Sustainable Utilization (LMB-CAS), Guangdong Key Laboratory of Marine Materia Medica (LMM-GD), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, People's Republic of China.
authors.forename: Lian Wu
authors.initials: LW
authors.lastname: Xie
authors.forename: Yong Chang
authors.initials: YC
authors.lastname: Ouyang
authors.forename: Kun
authors.initials: K
authors.lastname: Zou
authors.forename: Guang Hua
authors.initials: GH
authors.lastname: Wang
authors.forename: Min Jie
authors.initials: MJ
authors.lastname: Chen
authors.forename: Hui Min
authors.initials: HM
authors.lastname: Sun
authors.forename: Shi Kun
authors.initials: SK
authors.lastname: Dai
authors.forename: Xiang
authors.initials: X
authors.lastname: Li