干旱区生态环境知识资源中心

Medemia argun is an ancient endemic palm growing in Nubian Desert of Egypt and Sudan. Liquid chromatography coupled with mass spectrometry in negative ion mode (LC/ESI-MS) has proved to be a potent tool for rapid identification and characterization of complex phytochemicals in male racemes of M. argun. A total of seven compounds were tentatively identified comprising of two C-glycoside acetophenones, along with the known compounds one stilbene derivative and four known flavonol derivatives from 40% methanolic portion. The product ions of acetophenone derivatives [M-H](-) were shown to be cross-ring cleavages of the hexoside moiety [M-(90/120)-H](-) characteristic for C-glycoside linkage. The position of C-C-linkage was elucidated by DFF study using the Fukui functions and descriptors. The results revealed that hexose was conjugated with aglycones at 0 or C5. In addition, the theoretical antioxidant activity of compounds 6 and 7 was evaluated by using Bond Dissociation Enthalpy (BDE). (C) 2017 Elsevier B.V. All rights reserved.