Chemical constituents and antibacterial activity from the stems and leaves of <i>Piper wallichii</i>

Abstract

A phytochemical investigation of the stems and leaves of <i>Piper wallichii</i> led to the isolation of two new compounds, an aryl alkanone, piwalkanone (<b>1</b>) and a dioxoaporphine alkaloid, piwallidione (<b>2</b>), together with nine known compounds, a dioxoaporphine alkaloid, cepharadione A (<b>3</b>); two aristolactams, piperolactam A (<b>4</b>) and stigmalactam (<b>5</b>); a piperidine, piperine (<b>6</b>); four isobutylamides, piperlonguminine (<b>7</b>), pellitorine (<b>8</b>), <i>N</i>-isobutyl-<i>2E,4E</i>-octadecadienamide (<b>9</b>), and guineensine (<b>10</b>); and a tyramine, <i>N</i>-<i>trans</i>-feruloyltyramine (<b>11</b>). Their structures were elucidated on the basis of spectroscopic evidence (IR, ¹H NMR, ¹³C NMR and 2 D NMR) and MS. Compounds <b>2</b> and <b>3</b> showed inhibitory activities against pathogenic bacteria, <i>Bacillus cereus</i>, <i>Bacillus subtilis</i> and <i>Staphylococcus aureus.</i>