Cholinesterase, protease inhibitory and antioxidant capacities of Sri Lankan medicinal plants

Abstract Plant sources contain numerous natural compounds, which could act as lead compounds for drug scaffolds. These lead compounds have beneficial therapeutic roles, some of which are used for the treatment of Alzheimer’s disease and cancer. Total ethanolic extracts of seventeen selected medicinal plants from Sri Lanka were evaluated for Acetylcholinesterase (AChE), Butyrylcholinesterase (BChE), and protease enzyme inhibitory and antioxidant activities. Of these, the bark extract of Toona ciliata showed marked AChE, BChE, protease enzyme inhibitory activities. Extracts of T. ciliata, Osbeckia octandra, Fleuggea leucopyrus and Evolvulus alsinoides showed both high antioxidant capacities and high phenolic contents. Extracts of these plants could be used for pharmaceutical as well as for nutraceutical purpose. The strong correlation ( r  = 0.789, p r  = −0.609, p  free radical scavenging IC 50 and ORAC values of the tested plant extracts, suggests that the components capable of reducing oxidants could be similar to those scavenging free radicals in these plants.