20-Hydroxyecdysone from Dacrycarpus imbricatus bark inhibits the proliferation of acute myeloid leukemia cells

Objective:To investigate the anti-proliferative effects of 20-hydroxyecdysone isolated from the bark of Dacrycarpus imbricatus(Blume) de Laub.Methods:Column chromatography was used for isolation of compounds from plant material.The structure of the isolated compound was identified by mass spectrometry and nuclear magnetic resonance techniques,including HSQC,HMBC,NOE-difference experiments.The isolated compound was tested for its anti-proliferative activity in acute myeloid leukemia(AML) and OCI-AML cells.Results:Compound 1 was isolated from the ethyl acetate fraction of Dacrycarpus imbricatus barks by column chromatography.Its chemical structure was identified as 20-hydroxyecdysone(20HE),a cholestane-type ecdysteroid,by a combination of mass spectrometry and nuclear magnetic resonance spectrometric analyses.Our goal was to test the anti-proliferative activity of 20 HE using the OCI-AML cell line.20 HE significantly decreased OCI cell number at a concentration of 1 mg/mL,whereas lower concentrations were ineffective.Moreover,this decrease was due to partial blockage of the G_1/S phase of the cell cycle,with a reduction of cells in the G_2M phase,not due to increased apoptosis.Conclusions:This indicates that 20 HE significantly decreases the number of cells in the G_1/S phase of the cell cycle in human AML cells.This is the first time that the anti-proliferative activity of 20 HE against a human tumor cell line has been reported.