Liquid chromatography–mass spectrometry combined with xanthine oxidase inhibition profiling for identifying the bioactive constituents from Cistanche deserticola

Xanthine oxidase (XO) inhibitor can block the synthesis of uric acid and is regarded as one of the therapeutic approaches of gout. The anti-XO constituents in the stem of Cistanche deserticola were characterized though LC–MS combined with xanthine oxidase inhibition profiling method. Seven phenylethanoid glycosides (1–7) and two phenylpropanoid glycosides (8–9) were identified from the bioactive extracts. Isoacteoside (1), kankanoside G (4) and cistanoside F (8) displayed crucial activity against XO with the IC50 values of 46.91, 85.31 μM and 36.41 μM respectively. The main mass fragmentation pathways of phenylethanoid glycosides were the losses of glucosyl, rhamanopyranosyl and phenylethoxyl groups in positive ion mode and the elimination of caffeoyl unit in negative ion mode. It shows that the stem of Cistanche deserticola is a functional food which performs potent anti-gout activity.