Simple screening method for staurosporine in bacterial cultures using liquid chromatography-tandem mass spectrometry

Staurosporine has been shown to possess an array of important biological properties such as anti-fungal, anti-bacterial, antihypertensive and anti-cancer. Methods available to screen any plant or bacterial extract for this compound are lengthy and laborious. We present here a simple HPLC-MS-MS method for the highly selective identification of Staurosporine in various strains of the marine sponge-derived bacterium Salinispora. Gradient elution using acetonitrile/water/ammonium acetate was used to separate Staurosporine from the matrix and positive ionelectrospray mass spectrometry was used for detection and confirmation. Presence of Staurosporine in bacterial extracts was confirmed by matching retention times and parent-daughter ion mass spectra (using Multiple Reaction Monitoring, MRM mode) of the standard Staurosporine with those of the bacterial extracts. Detection of Staurosporine was achieved down to 11 ng/mL bacterial extract. This method can be easily adapted to screen any plant extract for Staurosporine. The simplicity and the speed of this method make it possible for the analyst to screen a large number of extracts before embarking on lengthy and costly isolation and purification of Staurosporine in a selected few