Chemical constituents and antibacterial activity from the stems and leaves of .

A phytochemical investigation of the stems and leaves of led to the isolation of two new compounds, an aryl alkanone, piwalkanone () and a dioxoaporphine alkaloid, piwallidione (), together with nine known compounds, a dioxoaporphine alkaloid, cepharadione A (); two aristolactams, piperolactam A () and stigmalactam (); a piperidine, piperine (); four isobutylamides, piperlonguminine (), pellitorine (), -isobutyl--octadecadienamide (), and guineensine (); and a tyramine, --feruloyltyramine (). Their structures were elucidated on the basis of spectroscopic evidence (IR, H NMR, C NMR and 2 D NMR) and MS. Compounds and showed inhibitory activities against pathogenic bacteria, , and