Phenolics profile evolution from Pieris brassicae larvae fasted for distinct periods (1, 2, 4, 6, and 8 h), their excrements and of Brassica oleracea L. var. costata DC leaves were determined by HPLC/UV-PAD/MSn-ESI. This is the first report on the monitorization of phenolics’ metabolism by P. brassicae through time. The results evidence that P. brassicae sequesters and metabolizes the phenolic compounds from the host plant. In a general way, deacylation was the main metabolic reaction that took place, but deglycosylation and sulphate conjugation reactions also occur.

Attending to the bioactivities recognized for the type of identified compounds, the different materials may constitute an interesting source of bioactive compounds, namely of highly glycosilated and acylated kaempferol and quercetin derivatives.