This study reports valuable information regarding the presence and concentration of a series of photoactive β-carboline (βCs) 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 βCs' content ranged from 1 to 110 μg kg-1 , depending on the floral organ and age. In certain physiologically relevant organs, such as anthers, βCs' content was one order of magnitude higher than in other organs, suggesting a special role for βCs in this specific organ. βCs' content also varied in a structure-dependent manner. Alkaloids bearing a hydroxyl group at position C(7) of the main βC ring were present at concentrations one order of magnitude higher than other βC 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 βCs in floral organs may have several (photo)biological implications that are further discussed.
Keywords: UHPLC-MS/MS; UV-visible absorption spectroscopy; fluorescence spectroscopy; passionflower; photobiology.
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