Use of UHPLC-TripleQ with synthetic standards to profile anti-inflammatory hydroxycinnamic acid amides in root barks and leaves of Lycium barbarum

Hydroxycinnamic acid amides (HCAA) are the secondary metabolites ubiquitously exist in flowering plants, formed by condensation between hydroxycinnamates and mono or polyamines. HCAA species not only serve multiple functions in plant growth and development, but also exert significant positive effects on human health. In this study, we combined organic synthesis and UPHLC-TripleQ-MS/MS specifically targeting at HCAA species. The method was fully validated with respect to specificity, linearity, intra- and inter-day precision and accuracy, limit of detection (LOD), limit of quantification (LOQ), recovery, and reproducibility. We applied this method to identify and quantify HCAAs from the root barks and leaves of Lycium barbarum. HCAA species were reported in leaves for the first time, and 10 new HCAA species were further identified in root barks in addition to the ones reported in the literature. We also examine anti-inflammatory properties of identified HCAAs species. Seven HCAA compounds had a potent NO inhibitory effect with IC₅₀ as low as 2.381 μM (trans-N-caffeoyl phenethylamine). Our developed method largely improved analytical sensitivity of HCAAs species that potentially contributes to plant metabolomics studies.