Neuroprotective Effects of 2,5-Diaryl-3,4-dimethyltetrahydrofuran Neolignans

We previously reported the neurotrophic effects of talaumidin (1) from Aristolochia arcuata MASTERS. In the present study, we compared the neurotrophic and neuroprotective effects of six other 2,5-diaryl-3,4-dimethyltetrahydrofuran neolignans isolated from the same plant, veraguensin (2), galgravin (3), aristolignin (4), nectandrin A (5), isonectandrin B (6), and nectandrin B (7), with compound 1 in primary cultured rat neurons. Compounds 3—7 promoted neuronal survival and neurite outgrowth, among which compounds 6 and 7 showed neurotrophic activity comparable with that of 1. Furthermore, compounds 1—7 protected hippocampal neurons against amyloid β peptide (Aβ25—35)-induced cytotoxicity, while compounds 1 and 4—7 protected against neuronal death from 1-methyl-4-phenylpyridinium ion (MPP+)-induced toxicity in cultured rat hippocampal neurons.