Chemical characterization, antioxidant, antimicrobial, enzyme inhibitory and cytotoxic activities of Illicium lanceolatum essential oils

Illicium lanceolatum is a medicinal and aromatic plant widely distributed in the south of China. The reports on chemical composition and biological activities of its essential oils (EOs) were very limited. In this study, Illicium lanceolatum EOs were extracted by hydro distillation, and analyzed by GC-MS and GC-FID. DPPH radical scavenging assay, ABTS cation radical scavenging assay and ferric reducing/antioxidant power (FRAP) assay were used for antioxidant activity evaluation. Minimum inhibitory concentrations (MICs) and minimum microbiocidal concentrations (MMCs) against 9 microorganisms were determined. The inhibitory effects on tyrosinase, alpha-glucosidase and cholinesterases were evaluated and cytotoxic activities were evaluated using MTT assay. The results revealed 110 identified compounds, with asaricin, eucalyptol, linalool and caryophyllene oxide as major compounds. Eucalyptol was the most abundant compound in the stem, leaf and fruit EOs while asaricin accounted for 50.52 +/- 0.33 % in the root EO. Very weak radical scavenging capacities were noticed for all EOs, but the root EO showed moderate antioxidant activity (176.33 +/- 4.52 mg TE/g of EO) in the FRAP assay, which could be attributed to asaricin. The root EO displayed better antimicrobial activities than other three EOs, with MIC values as 3.13 mg/mL against three bacteria including Staphylococcus aureus BNCC 186335, Bacillus cereus BNCC 103930 and Listeria monocytogenes BNCC 336877. Camphor and borneol were found to be important antimicrobial compounds. No inhibitory effect on alpha-glucosidase was found. The leaf EO displayed better acetylcholinesterase inhibitory activity (17.79 +/- 0.32 mg GE/g of EO) while the root EO showed better tyrosinase (30.34 +/- 0.40 mg KAE/g of EO) and butyrylcholinesterase (43.25 +/- 1.50 mg GE/g of EO) inhibitory activities. Molecular docking between active compounds and enzymes revealed the main interactions as hydrophobic interaction, hydrogen bond and pi-stacking. All EOs displayed weak cytotoxicity to HK-2 cells of normal kidney at six tested concentrations. The leaf EO showed strong anticancer activities to HepG2 cells at the concentration of 500 mu g/mL. I. lanceolatum EOs showed promising prospects with possible applications in pharmaceutical and cosmetic industries.