Inhibitory effect of some tropical green leafy vegetables on key enzymes linked to Alzheimer's disease and some pro-oxidant induced lipid peroxidation in rats' brain

This study sought to investigate the inhibitory effect of some commonly consumed Nigerian green leafy vegetables (raw and blanched) on acetylcholinesterase and butyrylcholinesterase (key enzyme linked to Alzheimer's disease) activities and some pro-oxidants (FeSO4, Sodium nitroprusside and Quinolinic acid) induced lipid peroxidation in rat brain in vitro. Three commonly consumed green leafy vegetables in Nigeria [Amarantus cruentus (Arowojeja), Struchium sparganophora (Ewuro-odo) and Telfairia occidentalis (Ugwu] were blanched in hot water for 10 min, and the extracts of the raw and blanched vegetables were prepared and used for subsequent analysis. The result revealed that all the vegetables inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity as well as the pro-oxidants induced lipid peroxidation in rat brain in a dose dependent manner; however, Amarantus cruentus extract (EC50 = 97.9 mu g/ml) had the highest inhibitory effect on acetylcholinesterase activity while Telfairia occidentalis extract (EC50 = 52.7 mu g/ml) had the highest inhibitory effect on butyrylcholinesterase activity. However, blanching of the vegetables caused a significant (P < 0.05) decrease in the inhibitory effect of the vegetables on AChE activities while it enhanced the inhibition of the pro-oxidants induced lipid peroxidation in rat brain in vitro. Therefore, some of the possible mechanism by which green leafy vegetables exert their neuroprotective activities could be through the inhibition of acetylcholinesterase and butyrylcholinesterase activities and prevention of lipid peroxidation in the brain. However, blanching of the vegetables could reduce their ability to inhibit acetylcholinesterase and butyrylcholinesterase activity.