Lumpidin, a novel biomarker of some ochratoxin a producing penicillia.

The novel compound lumpidin (1) has been isolated as a major compound from an isolate of Penicillium nordicum. Compound 1 is a diketopiperazine with a unique ring system likely to be a condensate of one mole each of L-tryptophan, L-phenylalanine, and L-homo-proline. The fact that 1 has been detected from only three out of sixteen isolates of P. nordicum indicates that lumpidin-producing isolates might represent a separate and third ochratoxin A producing Penicillium species.