Three lignans isolated from the roots of A. koreanum (Araliaceae), namely eleutheroside E (1), tortoside A (2), and hemiariensin (4), were evaluated for their ability to inhibit NFAT transcription factor. Of these compounds, compound 4, possessing a diarylbutane skeleton, exhibited potent inhibitory activity against NFAT transcription factor (IC50: 36.3 +/- 2.5 microM). However, the activities of 1 (IC50: > 500 microM) and 2 (IC50: 136.1 +/- 9.4 microM), which possess bisaryldioxabicyclooctane skeletons, were lower. As the lignan derivatives of the same skeletons, hinokinin (5) and (-)-yatein (6) with diarylbutane skeletons and (+)-syringaresinol (3) with a bisaryldioxabicyclooctane skeleton were also studied for their inhibitory effects on NFAT transcription factor.