ABSTRACT
The crude extracts of some selected Pakistani medicinal plants, namely, Acacia modesta, Buddleja crispa. Carthamus oxycantha, Conyza bonariensis and Tanacetum artemisioides were assessed for their inhibitory activities against acetylcholinesterase [AChE] and butyrylcholinesterase [BChE]. All the tested plant extracts exhibited dose dependent [0.25 - 1.0 mg/ml] inhibitory effects against both these enzymes with more selectivity for BChE. A. modesta and C. bonariensis showed activity against BChE only. The plant extracts of B. crispa C. oxycantha and T. artemisioides caused maximum inhibition of AChE at 1.0 mg/ml with% inhibition of 28, 34 and 48 respectively. In the BChE inhibitory evaluation all the tested plant extracts at 1.0 mg/ml produced marked inhibition [68-80%] of the enzyme activity. The results show the presence of selective BChE inhibitory constituents in the aforementioned plant extracts