Abstract
Five new metabolites related to IAA were isolated from aqueous methanol extract of rice bran and their structures were elucidated by spectroscopic methods to be 5-hydroxydioxindole-3-acetic acid (Ia), methyl ester of la (Ib), methyl dioxindole-3-acetate (IIb), methyl 5-hydroxyoxindole-3-acetate (IIIb) and methyl oxindole-3-acetate (IVb), respectively. The presence of these metabolites which are likely to be intermediates of oxidation of IAA to β-acid suggests such oxidation pathway operating in rice seed.
