title: Polyhydroxyanthraquinones as quorum sensing inhibitors from the guttates of Penicillium restrictum and their analysis by desorption electrospray ionization mass spectrometry.
abstract: The endophytic fungus Penicillium restrictum was isolated from the stems of a milk thistle (Silybum marianum) plant. In culture, the fungus produced distinct red guttates, which have been virtually uninvestigated, particularly from the standpoint of chemistry. Hence, this study examined the chemical mycology of P. restrictum and, in doing so, uncovered a series of both known and new polyhydroxyanthraquinones (1-9). These compounds were quorum sensing inhibitors in a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA), with IC50 values ranging from 8 to 120 μM, suggesting antivirulence potential for the compounds. Moreover, the spatial and temporal distribution of the polyhydroxyanthraquinones was examined in situ via desorption electrospray ionization-mass spectrometry (DESI-MS) imaging, demonstrating the first application of this technique to a guttate-forming fungus and revealing both the concentration of secondary metabolites at the ventral surface of the fungus and their variance in colonies of differing ages.
authors.affiliation: Department of Chemistry and Biochemistry, University of North Carolina at Greensboro , Greensboro, North Carolina 27402, United States.
authors.forename: Mario
authors.initials: M
authors.lastname: Figueroa
authors.forename: Alan K
authors.initials: AK
authors.lastname: Jarmusch
authors.forename: Huzefa A
authors.initials: HA
authors.lastname: Raja
authors.forename: Tamam
authors.initials: T
authors.lastname: El-Elimat
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Kavanaugh
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Horswill
authors.forename: R Graham
authors.initials: RG
authors.lastname: Cooks
authors.forename: Nadja B
authors.initials: NB
authors.lastname: Cech
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: Oberlies
mesh_terms: D000880:Anthraquinones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D020944:Silybum marianum / Q000382:microbiology; D015394:Molecular Structure; D010407:Penicillium / Q000737:chemistry*; D053038:Quorum Sensing; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000880:Anthraquinones