The aroma intensities of rice depend on the variety and the volatile compound content. Many volatile compounds in rice have been identified for their biological activity. In this study, we investigated the biological activity and the volatile compounds content of pigmented rice and non-pigmented rice extracts. We also investigated the inhibition potential of volatile compounds including methyl vanillate, vanillin, 2-pentyl furan and guaiacol against acetylcholinesterase through in vitro and in silico studies. The results reveal that the total phenolic and total flavonoid content was closely related to the antioxidant potential of pigmented rice and non-pigmented rice extracts. The strongest inhibition potential of volatile compounds against acetylcholinesterase was obtained from methyl vanillate followed by 2-pentyl furan and vanillin. Guaiacol had the lowest inhibition potential. Docking studies also indicated that strong binding affinity was obtained from methyl vanillate followed by 2-pentyl furan, vanillin and guaiacol, respectively. The highest methyl vanillate and vanillin contents were obtained from Khao Leum Pua. The highest content of 2-pentyl furan was obtained from Khao Leum Klaeng. Interestingly, the highest inhibition potential against acetylcholinesterase was also investigated from Khao Leum Klaeng and followed by Khao Leum Pua, respectively. The results indicated that the volatile compounds including methyl vanillate, 2-pentyl furan and vanillin seem to be the key compounds for acetylcholinesterase inhibitory activity in these rice extracts.

Practical applications

Methyl vanillate, 2-pentyl furan and vanillin are the key compounds for acetylcholinesterase inhibitory activity of rice extracts. Our findings provided candidate compounds for application in the treatment of Alzheimer's disease (AD) and also benefit on human health.