Chemical Composition, Antioxidant, Anti-Tyrosinase, Anti-Cholinesterase and Cytotoxic Activities of Essential Oils of Six Algerian Plants

In this study, the essential oils (EOs) of six Algerian plants (Artemisia campestris L., Artemisia herba-alba Asso, Juniperus phoenicea L., Juniperus oxycedrus L., Mentha pulegium L. and Lavandula officinalis Chaix) were obtained by hydrodistillation, and their compositions determined by GC-MS and GC-FID. The antioxidant activity of the EOS was evaluated via 2,2′-diphenyl-1-picrylhydrazyl (DPPH), ferric-reducing/antioxidant power (FRAP) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assays. Moreover, their cytotoxic effect was evaluated—as well as their tyrosinase, acetyl- and butyryl-cholinesterase (AChE and BuChE) inhibitory activities. The chemical analyses detected 44, 45, 51, 53, 26 and 40 compounds in EOs of A. campestris, A. herba-alba, J. phoenicea, J. oxycedrus, M. pulegium and L. officinalis, respectively. A. campestris EO was mainly composed of β-pinene (20.7%), while A. herba-alba EO contained davanone D (49.5%) as the main component. α-Pinene (41.8%) was detected as the major constituent in both J. phoenicea (41.8%) and J. oxycedrus (37.8%) EOs. M. pulegium EO was characterized by pulegone as the most abundant (76.9%) compound, while linalool (35.8%) was detected as a major constituent in L. officinalis EO. The antioxidant power evaluation revealed IC50 values ranging from 2.61 to 91.25 mg/mL for DPPH scavenging activity, while the FRAP values ranged from 0.97–8.17 µmol Trolox equivalents (TX)/g sample. In the ABTS assay, the values ranged from 7.01 to 2.40 µmol TX/g sample. In the presence of 1 mg/mL of the samples, tyrosinase inhibition rates ranged from 11.35% to 39.65%, AChE inhibition rates ranged from 40.57% to 73.60% and BuChE inhibition rates ranged from 6.47% to 72.03%. A significant cytotoxic effect was found for A. herba-alba EO. The obtained results support some of the traditional uses of these species in food preservation and for protection against several diseases.