Neuroprotective, neurite enhancing, and cholinesterase inhibitory effects of Lamiaceae family essential oils in Alzheimer’s disease model
Win Ning Chen, Kar Wei Chin, Kim San Tang, Snežana Agatonović-Kuštrin, Keng Yoon Yeong
Abstract
The 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. The 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 (MTT) assay. Intracellular reactive oxygen species (ROS) levels were quantified using 2',7’- dichlorofluorescin diacetate (DCFDA) assay. A neurite outgrowth assay was employed to evaluate the neuritogenic activity. Oregano leaf (terpineol-type), peppermint leaf, rosemary, and sage essential oils have anti- butyrylcholinesterase activity, while oregano leaf (phenol-type) essential oil has both acetylcholinesterase and butyrylcholinesterase inhibitory activities. Pre-treatment with lavender flower essential oil (30 µg/mL), linalool, and linalyl acetate for 24 h 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. Essential oils from plants of Lamiaceae family displayed anti-cholinesterase, neuroprotective, antioxidant, and neuritogenic activities. These properties demonstrate their potential as complementary treatments to prevent and/or delay dementia-related diseases such as AD.