Methods for Determining Cell Wall-Bound Phenolics in Maize Stem Tissues.

We compared two methods with different sample pretreatment, hydrolysis, and separation procedures to extract cell wall-bound phenolics. The samples were pith and rind tissues from six maize inbred lines reportedly containing different levels of cell wall-bound phenolics. In method 1, pretreated samples were extracted with a C18 solid-phase extraction cartridge, and it took 6 days to complete. In method 2, phenolics were extracted from crude samples with ethyl acetate, it took 2 days to complete, and the cost per sample was reduced more than 60%. Both methods extracted more 4-coumarate than ferulate. Overall, method 1 yielded more 4-coumarate, while method 2 yielded more ferulate. The lack of a genotype × method interaction and significant correlations between the results obtained using the two methods indicate that both methods are reliable for use in large-scale plant breeding programs. Method 2, scaled, is proposed for general plant biology research.