Antioxidant activity of Caryocar brasiliense (pequi) and characterisation of components by electrospray ionization mass spectrometry

The Caryocar brasiliense known commonly as pequi is a tropical fruit of Brazilian Cerrado and is considered an important option of income and food for the populations living in this biome. Our previous study indicated that C brasiliense had high total phenol content (209 g as gallic acid equivalent kg(-1)) and excellent scavenging activity against 2,2-diphenyl-1-picrylhydrazyl radical (IC50 of 9.44 mu g ml(-1)). In this study, we evaluated the highly efficient antioxidant activity of C brasiliense using the biological relevant method of chemically induced lipid peroxidation. The half inhibition concentration did not exceed 0.8 mu g ml(-1). In addition, polar components of pequi ethanolic extract were investigated by direct infusion electrospray ionization mass spectrometry (ESI-MS). The technique revealed the presence of important bioactive components widely reported as potent antioxidants such as gallic acid, quinic acid, quercetin, and quercetin 3-O-arabinose possibly explaining its higher antioxidant activity. This is the first report on the composition by ESI-MS of pequi extract demonstrating excellent antioxidant activity. (C) 2008 Elsevier Ltd. All rights reserved.