Isolation and purification of fumonisin B1 and B2 from rice culture

Procedures are presented for growing Fusarium moniliforme MRC 826 on rice, separation of fumonisin B1 (FB1) from fumonisin B2 (FB2), purification of FB1 and preliminary procedures for purification of FB2. The mycotoxins were extracted from rice culture material (RCM) with acetonitrile-water (1:1), filtered, and the acetonitrile removed on a rotary evaporator. Preparative reverse phase liquid chromatography (LC) was used to isolate and partially purify FB1 and FB2 from the extract. The extract was applied to a C18 reverse phase cartridge. FB1 and FB2 were eluted from the cartridge by a gradient of water-acetonitrile at a flow rate of 30 mL/min. A second preparative LC procedure using 0.5% pyridine-water and two CN cartridges was used to purify FB1. The FB2 fraction was concentrated on a rotary evaporator to remove the acetonitrile. Acetonitrile was added back in sufficient quantity to redissolve the crystalline material in the fraction. An aliquot of the FB2 fraction was added to a centrifugal spinning silicic acid TLC plate. The centrifugal TLC plate was washed at 3 mL/min with a linear gradient of (A) chloroform-acetone(4:3) and (B) methanol-acetone (1:1) to elute the FB2. Gradient starting conditions were 10% methanol and ending conditions were 50% methanol. This preliminary study using the centrifugal spinning TLC showed the procedure to have the potential to be useful for purification of FB2.