Total phenolic acids and hydroxycinnamates in the grain tissues of brown midrib(bm)maize mutants

The brown midrib (bm) maize mutants have a genetic alteration that affects lignin biosynthesis. It is unknown whether the genetic alteration modified the balance of the main phenolic acids in maize grain. The grain of bm2, bm3, and bm4 maize mutants that were designed as well-characterized bm(WCbmm) was used. A set of four not well-characterized bmmutants (NWCbmm) was also incorporated and the wild-type B73 genotype. Free (FP), soluble esterified (EP), insoluble (IP) phenolic acids, and p-coumaric (pCA) and ferulic acid (FA) were quantified in the main grain tissues. No significant differences of the variables analyzed were observed among the genotypes for the endosperm and germ. However, the pericarp of the NWCbmm showed a balance of insoluble/soluble phenolic acids of 47 to 98, while in the WCbmm group was in the range of 202 to 214, and of 194 for B73 genotype, what means an outstanding content of soluble phenolic acids in the first group. In the NWCbmm, the mutant bmH exhibed the highest content of pCA and FA in the FP and EP fractions. Ample opportunity exists for the development of maize varieties with altered composition and distribution of phenolic compounds in grain tissues.