Evaluation of ethanol concentration, temperature and shaking time of extracted Thai Jasmine rice on cholinesterase enzyme activity

The objective of this study was to investigate the effect of ethanol concentration, temperature and shaking time of extracted Thai Jasmine rice on cholinesterases, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzyme activities. These enzymes were believed to have activities in termination of neurotransmitters in Alzheimer's disease occurrence. The rice samples used in this experiment included parboiled germinated brown rice (PGBR), germinated brown rice (GBR), brown rice (BR), and white rice (WR). The enzyme assays were performed as a colorimetric reaction between a sulfhydryl product from cholinesterase reaction and 5,5'-dithiobis(2-nitro benzoic acid), and were analyzed using a 96-well plate reader. Results found that the best extraction conditions for the highest activity of AChE and BChE inhibitory activities were found at 40% v/v ethanol concentration, shaked for 2 hours at 50°C. The inhibitory activity of both enzymes showed significantly highest by PGBR compared with other types of rice with the values of 6% AChE inhibition and 39% BChE inhibition. These data suggested that PGBR could be used as a natural prevention of Alzheimer's disease.