ISOLATION AND IDENTIFICATION OF POTENT STIMULATORY ALLELOPATHIC SUBSTANCES EXUDED FROM GERMINATING BURDOCK (Arctium lappa) SEEDS

摘要

Two stimulatory allelopathic substances,which have a significant promotive activity for the shoot growth of cockscomb (Celosia cristata),were isolated from the exudates of germinating burdock (Arctium lappa) seeds.They were identified to be arctigenic acid and arctigenin by ~1H and ~(13)C NMR and EIMS spectra of them,respectively.Both substances showed growth-promoting activity at the concentrations higher than 10 mg/L for the cockscomb growth test.The contents of arctigenic acid and arctigenin were 58.5 and 39.0 mg/L in the exudates of germinating burdock seeds,respectively.These results suggest that arctigenic acid and arctigenin play important roles in the stimulatory allelopathy of burdock seeds during seed germination stage.