Algerian wild fennel essential oils: chromatographic profile, acute toxicity, antioxidant, and antimicrobial activities

Abstract

The present study deals with the characterization of essential oils from umbels and seeds of Algerian wild (bitter) fennel (Foeniculum vulgare Mill. Var vulgare) by determining the chromatographic profile, lethal dose (LD50), antioxidant and antimicrobial activities, as well as a kinetic modeling study of the extraction of the seed-based essential oils. The extrac- tion of essential oils (EOs) was performed by hydrodistillation using Clevenger for 3.5 and 6 h for the umbels and seeds, respectively. The two mathematical models from the experimental data show a good fit with an R2 of 99.99 and 98.94%. GC/ MS analyses of fennel EOs showed that fennel was rich in different oxygenated monoterpenes compounds. However, while fenchone was the main compound in fennel seeds (FSEO), fennel umbel EO (FUEO) mainly contained α-pinene, o-cymene, sylvestrene, fenchone, Endo-fenchyl acetate, and carvacrol. The acute toxicity study of FSEO showed a lethal dose (LD50) of 4.9085 ± 0.1213 g/kg body weight in mice. Based on the free radical scavenging method using BHT as a positive control, the IC50 values were 9.9658 ± 0.057 mg/mL and 0.4570 ± 0.0456 mg/mL for FSEO and BHT, respectively. The study of antimicrobial activity in two gram-negative bacteria: Echerichi coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 9027), and one gram-positive bacterium: Bacilus subtilis (ATCC 6633), as well as two fungal strains: Candida albicans (ATCC 10,231), Saccaromyces cerevisiaes (ATCC 9763), revealed that the fungal strains were more susceptible to FSEO and showed a significant fungicidal effect. The results of this study highlight the high quality of Algerian wild fennel, and the possibility of recovering it for use in the pharmaceutical, cosmetic, and food industries