Neuroprotective, neurite enhancing, and cholinesterase inhibitory effects of Lamiaceae family essential oils in Alzheimer’s disease model

Abstract

IntroductionThe present study investigates the cholinesterase inhibitory and neuritogenic activities of selected essential oils from the Lamiaceae family, as well as their neuroprotective and antioxidant potential against scopolamine-induced cytotoxicity in SH-SY5Y cells. MethodsThe anticholinesterase activity was analysed using a modified Ellman’s assay. The neuroprotective potential was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Intracellular reactive oxygen species (ROS) levels were quantified using 2',7’- dichlorofluorescin diacetate assay. A neurite outgrowth assay was employed to evaluate the neuritogenic activity. ResultsOregano leaf (terpineol-type), peppermint leaf, rosemary, and sage essential oils have antibutyrylcholinesterase activity, while oregano leaf (phenol-type) essential oil has both acetylcholinesterase and butyrylcholinesterase inhibitory activities. Pretreatment with lavender flower essential oil (30 µg/mL), linalool, and linalyl acetate for 24 hours protects against scopolamine-induced toxicity. Linalool also displayed a significant decrease in intracellular ROS. The oregano leaf (terpineol-type), peppermint, rosemary, and sage essential oils at 100 µg/mL exhibited neuritogenic activity, with the highest activity being observed with oregano leaf (terpineol-type) essential oil. Discussion/ConclusionsEssential oils from plants of Lamiaceae family displayed anticholinesterase, neuroprotective, antioxidant, and neuritogenic activities. These properties demonstrate their potential as complementary treatments to prevent and/or delay dementia-related diseases such as Alzheimer’s disease.