Two new diarylheptanoids from the green walnut husks of Juglans mandshurica Maxim.

Chemical investigation on the 95% ethanol extract of green walnut husks of Juglans mandshurica Maxim. led to the isolation of two new diarylheptanoid compounds, including Juglanin K (1) and Myricananin I (2), together with ten known compounds (3–13). Their structures were elucidated by extensive analyses of comprehensive spectroscopic methods. The isolated compounds were evaluated for their antibacterial activities against Escherichia coli and Staphylococcus aureus. The results showed that compound 2 had moderate antibacterial activity with the MIC values of 0.313 and 0.156 mg/mL, respectively. compounds 1, 3–7 and 13 showed weakly antibacterial activities against Escherichia coli and Staphylococcus aureus with the MIC values of 0.625–2.5 mg/mL.