A High Performance Liquid Chromatography Method for Quantification of Diboa, DIMBOA, and MBOA from Aqueous Extracts of Corn and Winter Cereal Plants

Abstract

A new HPLC method is described for the quantification of aglycones derived from cyclic hydroxamic acids: DIMBOA (2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one), its degradation product MBOA (6-methoxybenzoxazolinone) and the demethoxy analogue DIBOA (2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one) in crude aqueous solutions from homogenized cereal tissues. After hydrolysis of ß-glycosides to aglycones, extracts of cereal samples were chromatographed on a PRP-1 column using a gradient of tris/citric acid and methanol/acetonitrile, and monitored at 288 nm. The three compounds were separated within 26 min. The minimum detection limit for all of them was 50 pmol. The recovery percentage was 100% for DIBOA, 87% for DIMBOA and 96% for MBOA. The levels of aglycones were determined in aqueous extracts from corn and winter cereal seedlings (20–100 mg), ranging from 3.80 to 11.50 mg DIBOA/g dry weight and 4.75 to 100.43 mg DIMBOA/g dry weight.