Quantitative determination of latrunculins A and B in the Red Sea sponge Negombata magnifica by high performance liquid chromatography.

An accurate, reproducible and sensitive method for the quantitative determination of latrunculins A and B in the organic extract of the Red Sea sponge Negombata magnifica was developed and validated. Latrunculin A and B concentrations were determined by RP-C18-HPLC and a mobile phase consisting of acetonitrile and water (60:40, v/v). The flow rate utilized was 1 mL min(-1) and the detector was set at 235 nm. The HPLC analysis of several N. magnifica samples collected from different locations in the Red Sea revealed that Ras Mohamed had the highest concentrations of latrunculin A, while Safaga had the highest levels of latrunculin B. Also, a comparison between latrunculin concentrations in the summer and winter revealed that the yield of latrunculins were generally higher in the winter.