The molecule is a C19-gibberellin, initially identified in Phaseolus coccineus and differing from gibberellin A1 by the conversion of the OH at C-2 (gibbane numbering) into an epoxide across C-2 and C-3. It is a lactone, a C19-gibberellin and a gibberellin monocarboxylic acid.
(1R,2R,5S,8S,9S,10R,11S,12R,14S)-5-hydroxy-11-methyl-6-methylidene-17-oxo-13,16-dioxahexacyclo[9.4.2.15,8.01,10.02,8.012,14]octadecane-9-carboxylic acid