Preparative LC isolation and purification of fumonisin B-1 from rice culture

Procedures are presented for the production and rapid isolation of fumonisin B-1 (FB1) from fumonisin B-2 (FB2) and fumonisin B-3 (FB3), and for the purification of the mycotoxin FB1 from cultures of Fusarium moniliforme MRC 826 grown on rice. The toxin was extracted from rice culture with acetonitrile:water (1:1; 5mL/g of culture material), filtered, and reduced in volume on a rotary evaporator to remove the acetonitrile. A three-step liquid chromatographic (LC) method was developed for the isolation of FB1, FB2, and FB3, and the purification of FB1. Preparative reversed-phase LC was used to isolate and partially purify the FB1. In the first step, the extract was applied to a Waters Bondapak PrepPak 500 C-18 reversed-phase cartridge and eluted with a methanol:water gradient. Fractions containing partially purified FB1 were collected, reduced in volume, and subjected to a second preparative LC procedure. The extract was applied to two Bondapak PrepPak cyano cartridges, and isocratic elution with water:0.5% pyridine was used in the purification step. Recovery of the total FB1 was 97% from the first isolation step and was 93% from the second purification step. Analytical high-performance liquid chromatography and fast-atom bombardment/mass spectrometry were used in determining the purity of the FB1. Recovery of the high purity FB1 (95% or greater) was 77% or 2811 mg/3647 mg of starting material.