1,4-Benzoxazine Derivatives in Plants. Sephadex Fractionation and Identification of a New Glucoside

Glucosides of 1,4-benzoxazine derivatives have been isolated from corn, rye, wheat and Coix Lachryma Jobi seedlings by gel filtration. 2-(2,4-Dihydroxy-7-methoxy-1,4(2H)-benzoxazin-3(4H)-on)-β-β-d-glucopyranoside (DIMBOA-Glc.) and 2-(2-hydroxy-7-methoxy-1,4(2H)-benzoxazin-3(4H)-on)-β-d-glucopyranoside (HMBOA-Glc.) were demonstrated in all four plants, with 2-(2,4-dihydroxy-1,4(2H)-benzoxazin-3(4H)-on)-β-d-glucopyranoside (DIBOA-Glc.) in rye, wheat and corn and 2-(2-hydroxy-1,4(2H)-benzoxazin-3(4H)-on)-β-d-glucopyranoside (HBOA-Glc.) in rye and corn. The structure of HBOA-Glc. has not been described previously. No free aglucones were found in uninjured plant tissue. DIMBOA-Glc. and HMBOA-Glc.; DIBOA-Glc. and HBOA-Glc. appear to be redox pairs and their mutual relation was found to vary with physiological conditions of the tissue.