Abstract

We first reported the content of ethyl α-D-glucopyranoside (α-EG) in rice. The inhibition potential against acetylcholinesterase (AChE) of α-EG was also investigated by in vitro, in silico, and fluorescence analysis. The results reveal that α-EG was the highest amount in R_1 rice (Ayutthaya 1) with a content of 0.32 ± 0.031 μg/mg. The content of α-EG closely related to the inhibition potential of rice extract, in which the highest percentage inhibition against AChE was obtained in R_1 (91.94 ± 5.86 (%)). The IC<inf>50</inf> of α-EG (1.13 × 10³ ± 70.0 μM) has shown lower inhibition potent than tacrine (3.3 × 10^-2 ± 2.0 × 10^-3 μM). However, the inhibition type on AChE of α-EG and tacrine was exhibited as mixed-type inhibition by α > 1 and α < 1 for α-EG and tacrine, respectively. The fluorescence shows that α-EG was located in the active site of AChE by its has affected the decrease in the fluorescence intensity of AChE. The docking study also indicates that α-EG was located at peripheral anionic sites (PAS) of AChE with strong hydrogen bonding with the TYR334 (2.78 Å). The results suggest rice is the source of α-EG, the candidate compound for application in Alzheimer's disease treatment.