Chemical constituents and antibacterial activity from the stems and leaves of Piper wallichii

Abstract

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

Graphical abstract

Keywords:

• Piperaceae
• Piper wallichii
• piwalkanone
• piwallidione
• piperine
• antibacterial activity

Acknowledgments

We acknowledge the Center of Excellence for Innovation in Chemistry (PERCH-CIC) and the Natural Products Research Unit, Khon Kaen University for partial support. We thank Assoc. Prof. Sophon Boonlue, Department of Microbiology, Faculty of Science, Khon Kaen University for antibacterial testing facility. We thank Mr. Ian Thomas for linguistic corrections.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the Thailand Research Fund via Direct Basic Research Grant (Grant no. DBG6180092).