Antioxidant activity of two isomeric benzoxepin derivatives from the stem bark of Bauhinia aculeata L.

Mulyadi Tanjung, Ratih Dewi Sa

Abstract

Two benzooxepin types isolated from the stem bark of Bauhinia aculeata L. (Fabaceae) have been identified as bauhiniastin 4 (1) and pacharin (2). The structure of both compounds have been elucidated based on its spectroscopic data, including UV, 1D and 2D NMR, and HREISMS spectra. Compounds 1 – 2 were evaluated for their radical scavenging against 2,2-diphenyl-1-picrylhydrazyl (DPPH), showing their IC50 were 32.7, and 1495.2 μM, respectively. The results indicate that as bauhiniastin 4 (1) slightly more active than ascorbic acid (62.8 μM).