The genus Panax (Araliaceae) plant is one of the most important crude drugs used in ancient Chinese medicines (Kampo in Japan) prescriptions. Triterpenoid saponins were identified as active components of the genus Panax. The previous reports were mainly on pharmacological effects derived from triterpenoid saponins. However, few reports on other compounds were published. In the previous study, we investigated pharmacological effects of aromatic components of P. ginseng (Pg). We reported preventive and mitigation effects against Alzheimer’s disease (AD). The purpose of this study is to perform comparative study on essential oil obtained from various Panax plants for preventive and mitigation effects against AD. Inhibitory activities against β-secretase (BACE), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) of essential oil of Pg, P. japonicus (Pj), P. notoginseng (Pn), and P. quinquefolius (Pq) were evaluated. As results, Pn (50 µg/mL) showed most potent inhibitory activity with 27.7% of inhibition against BACE (Table). In addition, Pg (50 µg/mL) showed most potent activity with 35.3% and 80.2% against AChE and BChE, respectively. We performed GC-MS analysis about essential oil of Pg and determined the main components as β-elemene and α-humulene from database search (Wiley7th and NIST08). These two components showed a significantly inhibitory effect on AChE and BChE, especially β-elemene (250 µM) showed 99.8% and 80.7% inhibition against AChE and BChE, respectively. From these results of this study, the inhibitory effect of essential oil obtained from genus Panax against BACE, AChE and BChE was clarified. Furthermore, essential oil of Pn would be effective for prevention of AD while essential oil of Pg would be effective for mitigation of cognitive dysfunction.
