Lycibarbarspermidines A–O, New Dicaffeoylspermidine Derivatives from Wolfberry, with Activities against Alzheimer’s Disease and Oxidation

Fifteen new dicaffeoylspermidine derivatives, lycibarbarspermidines A–O (1–15), were isolated from the fruit of Lycium barbarum (wolfberry). The structures were unambiguously determined by spectroscopic analyses and chemical methods. Dicaffeoylspermidine derivatives, a rare kind of plant secondary metabolites, are primarily distributed in the family of Solanaceae. Only six compounds were structurally identified, and all of them are acyclic aglycones. Compounds 1–15 are the first glycosidic products of dicaffeoylspermidine derivatives, and compounds 14–15 are the first cyclization products of dicaffeoylspermidine derivatives. Moreover, dicaffeoylspermidine derivatives were first isolated and identified from wolfberry. The short-term memory assay on a transgenic fly Alzheimer’s disease (AD) model showed that 1–15 exhibited different levels of anti-AD activity. The oxygen radical absorbance capacity assay revealed that 1–15 all displayed antioxidant capacity. Both anti-AD and antioxidant functions are related to the effects of wolfberry. Therefore, dicaffeoylspermidine derivatives are considered beneficial constituents responsible for the antiaging, neuroprotective, anti-AD, and antioxidant effects of wolfberry.