Two New Diarylheptanoids from Juglans mandshurica

The roots of Juglans mandshurica Maximowicz (Juglandaceae) have been used as a folk medicine for the treatment of cancer in Korea. Several naphthoquinones, naphthalenyl glucosides, tetralones, flavonoids, diarylheptanoid and galloyl glycosides have been isolated from Juglans species, and these compounds have been shown cytotoxic activity, topoisomerases I and II inhibitory activity, inhibitory effect on DNA polymerase and on the RNase H activity of HIV-1 reverse transcriptase. In the continuation of our studies on this plant, we isolated two new diarylheptanoids (1 and 2) from the CHCl3 fraction of the MeOH extract. This paper described the structural determination of two new diarylheptanoids (1 and 2) on the basis of spectroscopic studies, and the absolute configuration of 1 was elucidated by Mosher’s ester method. Two diarylheptanoids (1 and 2) were isolated from a CHCl3 fraction of the roots of J. mandshurica by repetitive column chromatography and preparative HPLC using a RP18 column. Compound 1 had the molecular formula C20H26O5 as determined from the HREIMS, C-NMR and DEPT spectral data. In the aromatic region of the H-NMR spectrum, J coupling between H-5 and and J coupling between H-2 and indicated an 1,3,4-trisubstituted benzene ring, and J coupling between two sets of chemically equivalent protons (H-2'/H-6' and H-3'/H-5') suggested an 1,4-disubstituted aromatic ring. The C-NMR spectrum exhibited a total of 20 carbon signals, including characteristic signals due to a methoxyl group (3-OCH3) and two chemically equivalent aromatic carbons (C-2'/C-6' and C-3'/ C-5'). In the aliphatic region of DEPT spectra, two hydroxymethine and five methylene signals were exhibited. The HH COSY spectrum showed connectivities among H-1, H-2, H-3, H-4, H-5, H-6 and H-7, between H-2' (H-6') and H-3' (H-5'), and between H-5and H-6. In the HMBC spectrum, the connectivities of the two aromatic rings with the alkyl chain were indicated by the cross peaks between H-7 and C-