Neuroprotective Iridoids and Lignans from Valeriana amurensis

Valeriana amurensis (V. amurensis) is widely distributed in Northeast China. In addition to medicines, it has also been used to prepare food, wine, tobacco, cosmetics, perfume, and functional foods. Other studies have investigated the neuroprotective effects of V. amurensis extract. As the therapeutic basis, the active constituents should be further evaluated. In this paper, six new compounds (1–6) were isolated, including five iridoids (Xiecaoiridoidside A–E) and one bisepoxylignan (Xiecaolignanside A), as well as six known compounds (7–12). The neuroprotective effects of 1–12 were also investigated with amyloid β protein 1−42 (Aβ(1-42))-induced injury to rat pheochromocytoma (PC12) cells. As a result, iridoids 1 and 2 and lignans 6, 8, and 9 could markedly maintain the cells’ viability by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) and lactate dehydrogenase (LDH) release assay.