(−)-5-O-(3-O-β-d-Glucopyranosylcaffeoyl)-quinic acid from the fruits of Lycium barbarum L. var. auranticarpum K. F. Ching: Purification, identification and in vitro bioactivities

Chlorogenic acids are important phenolics in the fruits of wolfberry, but little attention has been paid on their glucosylated forms. In the present study, a glucosylated form of chlorogenic acid was isolated from the fruits of Lycium barbarum L. var. auranticarpum K. F. Ching (also called yellow wolfberry) and identified to be (-)-5-O-(3-O-β-d-glucopyranosylcaffeoyl)-quinic acid (5-CQA-3'βG) by high resolution mass spectrometry and nuclear magnetic resonance spectrometry. The content of 5-CQA-3'βG in the dried fruit was determined as 0.0293 ± 0.0015% by HPLC. In addition, 5-CQA-3'βG showed a good scavenging capacity for 2,2'-azino-bis-(3-ethylben-zothiazoline-6-sulphonate) free radicals but had a relatively low reducing power and scavenging capacity for 2,2-diphenyl-1-picrylhydrazyl free radical. Moreover, the secretion of nitric oxide, tumor necrosis factor-α and interleukin-6 as well as related mRNA expression were reduced in lipopolysaccharide-stimulated RAW264.7 macrophage cells treated with 5-CQA-3'βG. This is the first report describing purification, identification and bioactivity of glucosylated CQA from yellow wolfberry.