A new bischromanone from the stems of <i>Semecarpus caudata</i>

<p>From an CHCl₃-soluble fraction of the stems of <i>Semecarpus caudata</i>, one new bischromanone named semecarpanone (<b>1</b>), together with 5 known flavonoids (<b>2</b>–<b>6</b>) were isolated. Their structures were elucidated based on interpretation of spectroscopic data. The stereo-configuration of <b>1</b> was identified based on the calculated and experimental coupling constants. Compounds <b>4</b>–<b>6</b> showed potent tyrosinase inhibitory activity with the IC₅₀ values ranging from 15.0 to 76.3 μM.