Common name: Gibberellic acid
Chemical Abstracts name:
(1a,2b,4aa,4bb,10b)-2,4a,7-trihydroxy-1-methyl-8-methylenegibb-3-ene-1,10-dicarboxylic acid 1,4a-lactone
Mol. wt.: 346.4
M.p.: 223-225 ºC (decomp.)
Solubility In water 5 g/l (room temperature). Soluble in methanol, ethanol, acetone, and aqueous alkalis; slightly soluble in diethyl ether and ethyl acetate. Insoluble in chloroform. Potassium, sodium, and ammonium salts: Readily soluble in water (potassium salt 50 g/l).
Stability Dry gibberellic acid is stable at room temperature, but slowly undergoes hydrolysis in aqueous or aqueous-alcoholic solutions, DT50 (20 ºC) c. 14 d (pH 3-4), 14 d (pH 7). In alkalis, undergoes a rearrangement to less biologically-active compounds. Decomposed by heat.
Oral Acute oral LD50 for rats and mice >15 000 mg/kg.
Skin and eye Acute percutaneous LD50 for rats >2000 mg/kg. Non-irritating to skin and eyes.
Inhalation No ill-effect on rats subjected to 400 mg/l for 2 h/d for 21 d.
NOEL (90 d) for rats and dogs >1000 mg/kg diet (6 d/w).
Toxicity class WHO (a.i.) III
EPA (formulation) III
Birds Acute oral LD50 for bobwhite quail >2250 mg/kg. Acute oral LC50 >4640 mg/kg.
Fish LC50 (96 h) for rainbow trout >150 ppm.