Phenolic and organic acid profiles of aqueous extracts from Pieris brassicae material and the host kale
(Brassica oleracea L. var. acephala) leaves were determined by HPLC/UV–DAD/MSn-ESI and HPLC–UV,
respectively. The identified phenolics included acylated and nonacylated flavonoid glycosides, hydroxycinnamic
acyl gentiobiosides, and sulphate phenolics. Kale exhibited the highest content (11 g/kg lyophilized
extract), while no phenolics were identified in the butterflies or exuviae. Nine different organic
acids were characterized in the materials, with kale showing the highest amount (112 g/kg lyophilized
extract). With the exception of the exuviae extract, the rest were screened for bioactivity. Using spectrophotometric
microassays, all exhibited antiradical capacity against DPPH and NO in a concentrationdependent
way, whereas only kale and excrement extracts were active against superoxide. All displayed
activity on intestinal smooth muscle, albeit with distinct relaxation–contraction profiles. Larvae and butterfly
extracts were more efficacious for intestinal relaxation than was kale extract, whereas excrement
extract evoked only contractions, thus evidencing their different compositions. Collectively, these results
show that P. brassicae sequesters and metabolizes kale’s phenolic compounds. Moreover, the extract’s
bioactivities suggest that they may constitute an interesting source of bioactive compounds whose complex
chemical structures preclude either synthesis or isolation.
