Detection of griseofulvin in a marine strain of Penicillium waksmanii by ion trap mass spectrometry.

A marine strain of Penicillium waksmanii Zaleski was isolated from a sample of seawater from shellfish-farming area in the Loire estuary (France). The in vitro marine culture showed an important antifungal activity. Bioassay-guided fractionation was used to purify the crude extract. Dereplication by electrospray-ion trap/mass spectrometry (ESI-IT/MS) afforded the identification of the antifungal compound, after a semi-purification consisting of two stages. A comparison of the ionic composition between the active and the non-active fractions allowed the detection of a monocharged ion at m/z 353 containing a chlorine atom, which could be attributed to the antifungal griseofulvin [C17H17ClO6+H]+. Multi-stage fragmentation (MSn) confirmed the identity of the m/z 353 ion of the antifungal fraction as griseofulvin. It is the first description of griseofulvin production by a strain of P. waksmanii and the first chemical study of a strain of this species isolated from marine temperate cold water.

Combined use of analytical high-performance liquid chromatography and cell morphology transformation assay to detect new protein phosphatase inhibitors of okadaic acid type.

The search for new protein phosphatase inhibitors in shellfish contaminated by toxin-producing dinoflagellates generally relies on preliminary separation techniques followed by biological tests. To detect such substances without purifying them initially, we developed an approach based on a correlation of the results of two different analytical techniques applied to toxic extracts: high-performance liquid chromatography after derivation of the toxins and the cell morphology transformation assay on KB cells. Application of this protocol to stored frozen mussels showed a decrease in okadaic acid concentration during storage, with formation of degradation derivatives, some of which possessed notable protein phosphatase inhibition activity.