Comparative analysis of chemical composition and antioxidant activity of essential oil and hydrolate from black pepper fruit (Piper nigrum L.)

The objective of this study was to analyze the chemical composition of the essential oil (EO) and hydrolate of black pepper fruit, as well as their antioxidant activity. The EO was obtained by Clevenger-type hydrodistillation with hydromodule 1:10 m/v for 240 minutes, and the hydrolate was collected after the hydrodistillation process. The qualitative composition of EO was determined by GC/MS and quantitative by GC/FID method, while the qualitative composition of a hydrolate was determined by HS-SPME-GC/MS and quantitative composition by HS-SPME-GC/FID method. The antioxidant activity was investigated by DPPH assay. Fifty-five compounds were identified from black pepper EO, where the most abundant compounds were (E)-caryophyllene (41.6 %), limonene (9.7 %), and sabinene (8.6 %). Twelve compounds were identified from black pepper hydrolate, where the most abundant compounds were α-terpineol (34.7 %), borneol (17.3 %), and terpinen-4-ol (13.9 %). The hydrolate showed higher antioxidant activity after 20 minutes of incubation with an EC50 value of 0.993 ± 0.011 mg/cm3 compared to the EO with an EC50 value of 67.72 ± 1.871 mg/cm3. According to the results obtained in this study, both the EO and hydrolate are good sources of natural antioxidants with potential uses in the food, organic agriculture, pharmaceutical, and cosmetic industries as a safer alternative to synthetic additives. Furthermore, the possibility of wider uses of the hydrolate should be investigated in more detail. Although researchers interested in hydrolate investigation focus mostly on their antioxidant activity, these "aromatic wastes" could also present promising cosmetic activities.