The isolation of bioactive substance controlling the plant leaf-movement of Albizzia julibrissin Durazz.

Nyctinastic leaf-movement of the plant is controlled by a biological dock. The most difficult problem encountered in the chemical studies of nyctinasty, is the isolation of chemical signals controlling this movement. Now, we have established a good procedure for isolation of the chemicals causing leaf-movement. The separation of two inversely bioactive substances, causing leaf-closing and opening movement, by Amberlite XAD-7 chromatography was very effective. Final separation with HPLC using a combination of plural ODS columns enabled us to isolate the highly polar leaf-closing and -opening substances of Albizzia julibrissin Durazz.