Natural variation of hydroxycinnamic acid amides in maize landraces

Maize is a highly relevant source of diverse phytochemicals. While these active compounds with nutraceutical and defensive properties, and their germplasm sources have been elucidated for maize, especially those related to phenolic compounds, some compounds such as hydroxycinnamic acid amides (HCAAs) are poorly studied. In this investigation, the distribution of HCAAs was investigated in 32 Mexican landraces to provide an estimation of the range of variability of HCAA content in maize kernel. Kernel tissues were analysed to localize and quantify these compounds. The variation in HCAAs was also analysed in relation of its eco-geographical origin, distribution and as taxonomic marker. The major compounds determined were diferuloyl putrescine, feruloyl putrescine and cinnamoyl putrescine. Ranges of concentration were detected from 428 to 2336 mu g/g for diferuloyl putrescine meanwhile feruloyl putrescine and cinnamoyl putrescine were quantified from 6 to 85 mu g/g. A significant correlation (r(2) = 0.603, p = 0.018) was found between the maximum altitude of origin of the landrace and the concentration of diferuloyl putrescine in the external grain tissues. This relationship suggests that the maize with high HCAAs content were selected in low altitudes environments under natural selection pressure. Maize landraces are proposed as sources of HCAAs for diverse purposes.