Composition of lipids from sun-flower pollen (Helianthus annuus)

The contents of the pollen lipids of the sunflower Helianthus annuus are de scribed. The major component is the seco-triterpene helianyl octanoate, fol lowed by new beta-diketones as second major group of compounds. They exhibi t a shorter chain length and often other positions of the functional group compared to already known beta-diketones. Of particular note are the 1-phen yl-beta-diketones. not previously reported from nature. Further lipid class es present are related hydroxyketones and diols. Interestingly, new beta-di oxoalkanoic acids are present in the extracts. which most likely are biogen etic precursors of the diketones. Additionally, we investigated the composi tion of the pollen coat which resembles the total extract, but lacks the di oxoalkanoic acids and certain estolides. (C) 2000 Elsevier Science Ltd. All rights reserved.