Distribution of photoactive -carboline alkaloids across Passiflora caerulea floral organs

This study reports valuable information regarding the presence and concentration of a series of photoactive beta-carboline (beta Cs) alkaloids (norharmane, harmane, harmine, harmol, harmaline, and harmalol) and their distribution across the floral age and organs of Passiflora caerulea. UHPLC-MS/ MS data reported herein reveal that the beta Cs' content ranged from 1 to 110 mu g kg(-1), depending on the floral organ and age. In certain physiologically relevant organs, such as anthers, beta Cs' content was one order of magnitude higher than in other organs, suggesting a special role for beta Cs in this specific organ. beta Cs' content also varied in a structure-dependent manner. Alkaloids bearing a hydroxyl group at position C(7) of the main beta C ring were present at concentrations one order of magnitude higher than other beta C derivatives investigated. UV-visible and fluorescence spectroscopy of the flower extracts provided complementary information regarding other biologically relevant groups of chromophores (phenolic/indolic derivatives, flavonoids/carotenes, and chlorophylls). Since flowers are constantly exposed to solar radiation, the presence of photoactive beta Cs in floral organs may have several (photo) biological implications that are further discussed.