Essential Oils From Different Parts of Piper nigrum L.: Chemical Composition, Antibacterial, and Antioxidant Activities

TL;DR

This study analyzed essential oils from black pepper seeds, stems, and leaves, finding differences in their chemical makeup and antibacterial and antioxidant properties.

Contribution

The study provides a comparative analysis of essential oil composition and bioactivity across different parts of Piper nigrum.

Findings

Pepper seed, leaf, and stem essential oils showed distinct chemical compositions with β-caryophyllene as a major component in all.

Stem essential oil had the strongest antioxidant activity, while stem and leaf oils showed higher antibacterial activity against S. aureus.

PCA analysis confirmed significant compositional differences among the essential oils from different plant parts.

Abstract

Pepper (
Piper nigrum
L.) is a spice plant that contains bioactive compounds, including essential oils, with antioxidant and antimicrobial activity. The study intended to determine the composition of essential oil in the pepper plant's seeds, stems, as well as leaves and whether these materials had any potential antioxidant activity, and antibacterial activity against
Escherichia coli
and
Staphylococcus aureus
. GC–MS (Gas Chromatography–Mass Spectrometry) was utilized to investigate the components of pepper oil, and the inhibition diameter was used to determine the antibacterial activity. The findings revealed that 19, 19, and 29 compounds were found in pepper seed, leaf and stem essential oils, respectively. The three most important contents of seed essential oil were δ‐3‐carene (11.49%), limonene (13.35%), and β‐caryophyllene (37.42%). Leaf essential oil contained δ‐elemene (3.73%), δ‐3‐carene (19.03%), and β‐caryophyllene (50.50%), while stem essential oil was dominated by α‐selinene (11.93%), β‐caryophyllene (12.83%), and δ‐elemene (19.73%). Principal Component Analysis (PCA) revealed clear compositional differences among the three essential oils. Antibacterial assays showed variable activity, with inhibition zones against
E. coli
measuring 1.5 mm, 6.83 mm, and 4.83 mm, for seed, leaf, and stem oils, respectively, and against
S. aureus
measuring 8.89 mm, 8.06 mm, and 13.00 mm. Antioxidant activity, evaluated by the DPPH assay demonstrated that stem essential oil exhibited the strongest radical scavenging effect (IC50 255.10 ppm; TEAC 8.39 μmol TE/g), followed by leaf oil (IC50 358.62 ppm; TEAC 5.98 μmol TE/g) and seed oil (IC50 485.98 ppm; TEAC 4.41 μmol TE/g), though all were considered weak antioxidants. These results indicate that
P. nigrum
essential oils vary significantly in chemical composition and bioactivity across plant parts. The findings confirm their antibacterial and antioxidant potential and underscore the value of seeds, leaves, and stems as alternative sources of bioactive essential oils for prospective applications in food preservation, pharmaceuticals, and natural health products.

This study investigates the essential oil composition from the seeds, stems, and leaves of Piper nigrum L. and evaluates their antibacterial activity against Escherichia coli and Staphylococcus aureus. GC‐MS analysis identified key compounds such as β‐caryophyllene, δ‐3‐carene, and limonene, while antibacterial testing showed promising inhibition zones, particularly against S. aureus. The results suggest that black pepper essential oil holds potential as a natural antibacterial agent.

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