Phenolic constituents from the fresh pericarps of Juglans sigillata.

Three new phenolic compounds, 2,3,4-trihydroxy-1-(4'-hydroxybenzyl)benzoic acid (1), 2,3,4-trihydroxy-1-(4'-hydroxy-3'-methoxybenzyl)benzoic acid (2), and 2-(4'-hydroxy-3'-methoxybenzyl)-3,5-dimethoxy-1,4-benzoquinone (3), were isolated from the fresh pericarps of Juglans sigillata Dode. Their structures were elucidated by integrated spectroscopic techniques. Bioactivity screening results showed that compounds 1-3 exhibited moderate neuroprotective effects against H2O2-induced or CoCl2-induced cellular damage in human neuroblastoma SH-SY5Y cell line.