The Isolation, Structure And Fragmentation Characteristics Of Natural Truxillic And Truxinic Acid Derivatives In Abrus Mollis Leaves

Five undescribed compounds were separated from Abrus monis leaves, including two truxillate forms (abrusamide D, H) and three truxinate forms (abrusamide E, F, G). The absolute configuration of abrusamide D was determined by X-ray crystallography. Abrusamide A was reassessed and corrected to be beta-truxinate configuration rather than alpha-form. LC-MS/MS and CD spectroscopy were applied to determine and analyze ten compounds, including four truxillate forms (abrusamide B similar to D and H), four truxinate forms (abrusamide E similar to G and A), and two precursors [(E)-N-(4- hydroxycinnamoyl) tyrosine, (Z)-N-(4-hydroxycinnamoyl) tyrosine]. It showed that the fragmentation pattern of truxillate was symmetric, while that of truxinate was asymmetric and irregular. The CD Cotton effect was related to cyclobutane configuration. These findings provided strong evidence for the cyclobutane dimers to discriminate their configuration. In addition, the bioactivity assay showed that the compounds had low toxicity and anti-inflammatory effect.