Phenolic Amides with Immunomodulatory Activity from the Nonpolysaccharide Fraction of <i>Lycium barbarum</i> Fruits

Abstract

The fruits of <i>Lycium barbarum</i> have a long history as an edible and medicinal food in Asian regions and have multiple consumption methods; the polysaccharides (LBPs) are commonly considered as their major immunological constituents. The current study revealed that the total phenolic amide moieties from <i>L. barbarum</i> fruits showed greater potential immunomodulatory activity in vivo than did LBPs. Through subsequent investigation on the immunological bioactive phenolic amides, three new phenolic amides, lyciumamides L-N (<b>1</b>-<b>3</b>), as well as 12 analogues, were obtained from the total phenolic amide fraction. Extensive spectroscopic methods were used to elucidate the new structures. Compounds <b>4</b>-<b>6</b> and <b>15</b> significantly promoted LPS-stimulated B splenocyte, while compounds <b>4</b>-<b>6</b> displayed accelerative effects on the proliferation of Con A-stimulated T lymphocytes at a concentration of 20.0 μg/mL. These data indicated that extracts from <i>L. barbarum</i> fruits enriched with phenolic amides could be developed as a nutritional dietary supplement for immunocompromised individuals.