The essential oils from leaves, stems and roots of Piper caldense were analyzed by GC-MS. The antibacterial potential of the oils was evaluated against gram-negative bacteria and gram-positive bacteria. The major chemical constituents that were identified from various parts of this plant were α-cardinal, α-muurolol, tujopsan-2-β-ol and δ-cadiene in the leaves, valencene, pentadecane, elina-3,7-11-dieno α-terpineol in the roots and terpine-4-ol, α-terpineol, α-cadinol 2-β-ol in the stems. Tissue oils showed antibacterial activity against the bacteria tested except for Enterococcus faecalis. This is the first report of the biological activity and chemical composition essential oil of P. caldense.

This is the first report of the antimicrobial and antioxidant potential of extract from Piper marginatum roots. The extract showed highest antioxidant activity with an EC50 of 47.3 ± 0.80 µg/mL and a total phenolic content of 42.7 ± 1.10 mg GAE/g. The extract exhibited strong antimicrobial activity with minimum inhibitory concentrations of 250, 250 and 125 µg/mL for the bacteria Bacillus subtilis, Staphylococcus aureus and fungus Mycobacterium smegmatis. Antimicrobial activity was attributed to (E,E)-N-Isobutyl -2,4-octadienamide and (E,E)-N-Isobutyl-2,4-decadienamide amides isolated as major compounds of the roots. Structural elucidation of the two amides was determined based on the interpretation of their IR, UV, MS, 1H and 13C NMR spectra. The results contribute significantly to the development of a herbal remedies based on P. marginatum roots.