Evaluation of Constituents of <i>Piper retrofractum</i> Fruits on Neurotrophic Activity

Three new compounds, <b>1</b>–<b>3</b>, together with 22 known compounds, were isolated from the fruits of <i>Piper retrofractum</i>. The structures of the new compounds were elucidated on the basis of spectroscopic data analysis and comparison with literature values. Compound <b>1</b> was found to enhance the neurite outgrowth of NGF-mediated PC12 cells at concentrations ranging from 0.1 to 10 μM