Five novel diarylheptanoids from green walnut husks (Juglans regia L.).

A ethanol extract of green walnut husks (Juglans regia L.) was isolated by various chromatographic techniques yielding 5 previously unknown diarylheptanoids, namely Juglanin F (1), Juglanin G (2), Juglanin H (3), Juglanin I (4) and Juglanin J (5), respectively, together with 12 known diarylheptanoids. The structures of these 17 compounds were elucidation on the basis of spectroscopic analysis. Upon evaluation of compounds 1-5 on the human hepatoma cells HepG2, compound 3 exhibited moderate inhibitory activity with IC50 27.72 μM.