Chemical constituents from the stem bark of Trewia nudiflora L. and their antioxidant activities.

Three new compounds, namely, (+)-dihydrodehydrodiconiferyl alcohol 4- O- beta-(6''- O-galloyl)-glucopyranoside ( 1), 4,4'- O-dimethylellagic acid 3-(2''- O-acetyl)- alpha-rhamnopyranoside ( 2), and ethyl O- beta-(6'-galloyl)-glucopyranoside ( 3), together with eleven known ones, were isolated from the stem bark of Trewia nudiflora. Their structures were elucidated by means of 1D, 2 D NMR and HR-MS analyses. The antioxidant activities of these compounds were evaluated with the DPPH radical-scavenging assay. Compound 1 showed significant antioxidant activity. In addition, compounds 1, 2 and 3 rescued the H (2)O (2)-induced PC12 cell death at 0.4 microM in the MTT assay.