Anti-neuroinflammatory oleanane-type triterpenoids from the seeds of Quercus serrata Thunb.

Abstract Chinese oak (Quercus serrata Thunb.) is widely distributed throughout China and plays an important role as a building material. Its seeds (acorns) have served as a traditional herbal medicine in East Asia. Eighteen oleanane-type triterpenoids, including seven previously undescribed (1, 2, and 4–8) and eleven known triterpenoids, were isolated and identified from acorns. Their structures were elucidated using various spectroscopic and chemical methods. All isolated triterpenoids were screened for anti-neuroinflammatory effects by measuring their abilities to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglial cells, and most of the triterpenoids exhibited obvious anti-neuroinflammatory activity. Among them, Compounds 1 and 5 exhibited the strongest NO inhibitory activity, reduced the expression of inflammatory cytokines (iNOS, COX-2, and TNF-α), and blocked the nuclear translocation of NF-κB.