IDENTIFICATION OF EPOXYXYPHYTOENE AND HYDROXYPHYTOENE FROM NORFLURAZON-TREATED SCENEDESMUS

In heterotrophically grown Scenedesmus kept in permanent darkness, treatment with the bleaching herbicide norflurazon resulted in the accumulation of five different compounds with a phytoene-like spectrum which could be separated and detected by HPLC. They were all purified by chromatographic procedures and identified by spectroscopic methods. The major compound detected was phytoene. Another was identified as 1,2-epoxy-1,2-dihydrophytoene by IR, NMR, and mass spectroscopies. Six different derivatives could be separated and identified as positional isomers of monohydroxyphytoene by their molecular ion and their fragmentation pattern in mass spectroscopy. The presence of a single hydroxy group was further substantiated by a positive acetylation and silylation reaction. The positions of the hydroxy groups in the different monohydroxy derivatives have been assigned by cochromatography with phytoene derivatives carrying hydroxy groups in defined positions.