CHARACTERIZATION AND DETERMINATION OF PREHELMINTHOSPOROL, A TOXIN FROM THE PLANT PATHOGENIC FUNGUS BIPOLARIS-SOROKINIANA, USING LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY

The most active and abundant phytotoxin formed by the plant parasitic fungus Bipolaris sorokiniana was prehelminthosporol (C15H22O2). The toxin is a hydrophobic sesquiterpene with restricted thermal stability and low water solubility (0.15-mu-g.mu-l-1). Prehelminthosporol was detected in conidia, hyphae and surrounding culture medium at 1.2-2.1-mu-g.mg-1 fungal tissue (dry wt). Preparation of the toxin was performed using "flash" -chromatography on silica gel and preparative HPLC. Purity controls were carried out on both straight-and reverse phase HPLC columns using RI detection. For quantification we used reverse phase on-line high performance liquid chromatography/mass spectrometry and plasma spray ionization. Using selected ion monitoring measuring at m/z 219 a detection limit of almost-equal-to 5 ng toxin was obtained.