Lunasin in wheat: a chemical and molecular study on its presence or absence

Lunasin is a peptide whose anticancer properties are widely reported. Originally isolated from soybean seeds, lunasin was also found in cereal (wheat, rye, barley and Triticale), Solanum and amaranthus seeds. However, it was recently reported that searches of transcript and DNA sequence databases for wheat and other cereals failed to identify sequences with similarity to those encoding the lunasin peptide in soy. In order to clarify the presence or absence of lunasin in wheat varieties, a broad investigation based on chemical (LC-ESI-MS) and molecular (PCR) analyses was conducted. Both approaches pointed out the absence of lunasin in the investigated wheat genotypes; in particular no compounds with a molecular weight similar to that of lunasin standard and no lunasin-related sequences were found in the analysed wheat samples. These findings confirm the hypothesis, reported in recent researches, that lunasin is not a wheat-derived peptide.