Isolation of three new meroterpenoids and seven known compounds from Albatrellus yasudae and their Aβ-aggregation inhibitory activity.

Alzheimer's disease is a serious neurologic disorder that cannot be cured completely. In this study, we targeted compounds that inhibit amyloid-beta (Aβ) aggregation, based on the amyloid cascade hypothesis. Ten compounds (1-10) were isolated from CHCl extracts of the mushroom Albatrellus yasudae using Aβ-aggregation inhibitory activity-guided separation. The structures of these compounds were elucidated from 1D and 2D NMR and MS spectral data. Compounds 1-3 were novel, whereas 4-10 were identified as the known compounds grifolin, grifolic acid, neogrifolin, confluentin, 2-hydroxyneogrifolin, daurichromenic acid, and a cerebroside derivative. Compounds 1-10 were tested for Aβ-aggregation inhibitory activity. Compounds 1, 3, 5, 6, 8, and 9 have potential as Aβ-aggregation inhibitory activity.