Identification of Brassinolide, Castasterone and Norcastasterone (Brassinone) in Sunflower (Helianthus annum L.) Pollen

From the pollen of sunflower (Helianthus annuus L.), the biologically active substances in the rice lamina inclination test were extracted and partially purified. They were converted to bis-9- phenanthreneboronates and bismethaneboronates, and analyzed by fluorescence HPLC and GC/MS analytical methods, respectively. The active principles were identified as brassinolide, castasterone and norcastasterone (brassinone).