Abstract: Ten compounds were isolated from the stem and leave of Piper retrofractum by using the method of Toyopearl HW-40c,silica gel,ODS,MCI-gel CHP20P and pre-HPLC,including one alkaloid (1),six amides (2-7),two phenols (8 and 9),and one ionone derivative (10).The structure elucidation was based on spectroscopic analysis as 4-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl］butanoic acid (1),3-chloro-4-hydroxy-2-piperidone (2),trans-pellitorin (3),1-cinnamoylpiperidine (4),(2E,4E)-piperine (5),piperanine (6),3-phenylpropanamide (7),(2R/2S)-isookanin-7-O-β-D-glucopyranoside(8a and 8b),vanillic acid (9),and blumenol A (10).Among them,compound 1,7,8 and 10 are reported from Piper plants for the first time.Some isolates were tested for their effect on anti-cholinesterase activity by Ellmans method.Compound 4 showed anti-acetylcholinesterase and anti-butyrocholinesterase activities with IC₅₀ values of 37.44±0.62 μM and 3.03±0.11 μM,respectively.Compounds 5 and 6 showed selectively antibutyrocholinesterase activity with IC₅₀ values of 49.43±2.13 and 24.70±0.90 μM,respectively.

Key words: Piper retrofractum, chemical constituent, anti-cholinesterase activity