<p>Phytochemical investigation of the barks of <i>Juglans mandshurica</i> Maxim led to the isolation, purification, and identification of one new lignan named Juglansol A (<b>1</b>), along with nine known compounds (<b>2–10</b>). Their structures were determined by the results of UV, IR, CD, HRESIMS, 1D, and 2D NMR spectroscopic analysis. Compounds <b>1–10</b> were evaluated for their cytotoxicities against A549, HepG2, Hep3B, Bcap-37, and MCF-7 cell lines. The results showed that compound <b>2</b> possessed stronger cytotoxicities against the tested tumor cell lines compared with positive control 5-fluorouracil.</p
