Determination of polyphenol levels variation in Capsicum annuum L. cv. Chelsea (yellow bell pepper) infected by anthracnose (Colletotrichum gloeosporioides) using liquid chromatography–tandem mass spectrometry

Healthy fruits of Capsicum annuum L. cv. Chelsea (yellow bell pepper) and one infected by Colletotrichum gloeosporioides were analysed for polyphenols via high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC–MS/MS). Among seven polyphenols characterized, four components in the C. annuum fruits were identified for the first time. To investigate the characteristics of the polyphenols as defence materials, the content change of the fruit polyphenols inoculated with C. gloeosporioides was monitored by HPLC. It was observed for the first time that de novo induced N-caffeoyl putrescine (1) and caffeoyl O-hexoside (2) appeared to act as a phytoalexin in the defence mechanism of the C. annuum fruits against C. gloeosporioides, and constitutively formed feruloyl O-glucoside (3), kaempferol O-pentosyldihexoside (4) and dihydroxyflavone O-hexoside (7) as a phytoanticipin in the diseased C. annuum fruits.