Inhibitory Effects of Essential Oil Extracts From Panax Plants Against β-Secretase, Cholinesterase, and Amyloid Aggregation

Numerous pharmacological studies on Panax plants have been performed. However, these studies were limited to ginsenosides, which are typical constituents in Panax plants. In our research program to discover novel agents to prevent dementia and improve dementia symptoms, especially Alzheimer’s disease (AD), we investigated the inhibitory activities of essential oil (EO) extracts from 4 Panax plants against β-secretase, amyloid β (Aβ) aggregation, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE). An EO extract of Panax japonicus showed the most potent activity with 51.3% inhibition at 500 μg/mL against β-secretase. Panax ginseng showed the most potent inhibitory activity against AChE and BChE with 70.4% and 84.4% inhibition at 50 μg/mL, respectively. Panax notoginseng extract showed the most potent activity with 57.3% inhibition at 500 μg/mL against Aβ aggregation. From these results, an EO extract of P. ginseng could be an effective agent to improve AD symptoms, while EO extracts of P. japonicus and P. notoginseng could be suitable for AD prevention.