--Elizabeth E. 0. Caldwell and Peter A. Peterson
High performance liquid chromatography was used to analyze the flavonol-glycoside content of pooled aleurone and starchy endosperm. Tissue was collected from mature, fully-colored, red, C-(lineC) sh Bz wx kernels.
Individual kernels were prepared for analysis as follows:
1. pericarp and embryo tissues removed
2. remaining endosperm (including aleurone) ground to a slurry with water
3. supernatant lyophilized
4. pigments redissolved in methanol
Flavonol-glycosides were separated using a C18 reverse phase column
(Lichrosorb 1ORP18, 25 x 0.5cm) and detected at 340nm. The aqueous eluent
(Eluent 1) was 1% triethylamine in water, adjusted to pH 3.0 with phosphoric
acid. The second eluent was acetonitrile. The following gradient was a
modification of one published by Asen and Griesbach (J. Amer. Soc. Hort.
Sci. 108:845-850, 1983):
|Time||Eluent 1||Eluent 2|
|0 to 20 min||100% to 80%||0% to 20%|
|21 to 40 min||80%||20%|
Individual flavonol-glycosides were identified by comparing the unknown retention times with results from extracts of lyophilized Blue Magic petunia petals. The Blue Magic standard was provided by Dr. Robert Griesbach along with the identification of its flavonol-glycoside content.
By comparing the maize and Blue Magic extracts, six flavonol-glycosides
were identified in the C-(lineC) sh Bz wx mature endosperm tissue.
These include: quercetin-3-glucoside, quercetin-3,7-diglucoside, quercetin-7-glucoside,
quercetin-3-sophoroside, quercetin-3-sophoroside-7-glucoside, and quercetin-3-(caffeoylsophoroside)-7-glucoside.
Of these, quercetin-3-sophoroside, quercetin-3-sophoroside-7-glucoside,
and quercetin-3-(caffeoylsophoroside)-7-glucoside are identified for the
first time in maize tissue.
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