TITLE:
LC-MS-MS Analysis and the Antioxidant Activity of Flavonoids from Eggplant Skins Grown in Organic and Conventional Environments
AUTHORS:
Ajay P. Singh, Yifei Wang, Rachel M. Olson, Devanand Luthria, Gary S. Banuelos, Sajeemas Pasakdee, Nicholi Vorsa, Ted Wilson
KEYWORDS:
Eggplant Skin, Polyphenols, LDL Antioxidant Activity, Conventional and Organic, HPLC, LC-MS
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.8 No.9,
September
28,
2017
ABSTRACT: Eggplant fruits are known to contain different classes of phenolic phytochemicals (flavonols, phenolic acids, and anthocyanins) that can exert beneficial effects on human health. This study developed methods for the qualitative and quantitative composition analysis of phenolic compounds in the skin of eggplant fruits harvested following conventional and certified organic farming conditions. Eggplant skin was extracted using aqueous methanol prior to phenolic profiling with UHPLC-ESI-MS-MS. Eggplant skin extracts yielded a profile of 16 phenolic acids, 4 anthocyanins, and 11 flavonols, the first report of quercetin-3-diglucoside, myricetin-3-neohesperidoside, myricetin-3-galactoside, kaempferol-3,7-diglucoside, kaempferol-diglucoside and quercetin-3-rhamnoside. Polyphenolic extracts from all sources potently delayed the cupric ion-mediated lag-time for LDL lipid oxidation and protected Apo-B100 proteins against oxidative modification. Organic growing environment positively influences eggplant skin extract phenolic profile but not antioxidant capacity. In conclusion, eggplant skin has a robust profile of phenolic phytochemicals with excellent antioxidant properties.