Identification and quantification of phenolic compounds in diverse cultivars of eggplant grown in different seasons by high-performance liquid chromatography coupled to diode array detector and electrospray-quadrupole-time of flight-mass spectrometry

Eggplant (Solarium melongena L.) is an important vegetable for its richness in healthy components such as phenolic compounds. As environmental conditions and growing techniques may influence the phenolic content in plants, this study was focused on characterizing and quantifying of phenolic compounds, by high-performance liquid chromatography coupled to diode array detector and electrospray-quadrupole-time of flight-mass spectrometry (HPLC-DAD-ESI-TOF-MS), in three eggplant cultivars grown in different seasons. A total of 25 compounds were identified and quantified by the optimized methodology. To our knowledge, of these compounds, 14 have been reported for the first time in eggplant, 9 of which have been found for the first time in Solanaceae family. Two of the major compounds were chlorogenic acid and delphinidin rutinoside in all eggplant cultivars studied; furthermore, most of the phenolic compounds showed significant differences according to the cultivar and the harvest season. Besides, phenolic compounds of two of the cultivars sharply decreased from spring to summer. These results showed that phenolic compounds concentration depends on the cultivar adaptation to abiotic variation. Indeed, it was seen that cultivar and harvest season have a marked influence on polyphenols in eggplant which could be due mainly to climatic factors such as the high increase of temperatures in the summer season, in the region of Andalusia. This information may be important for the agricultural sector because it can help to know the suitable period for harvesting eggplants with high content in phenolic compounds. (C) 2014 Elsevier Ltd. All rights reserved.