[Apoptosis-inducing activity of extract from Chinese herb, Albizzia Lucidior I. Nielsen].

Background & Objective: Chinese herb Albizzia Lucidior I. Nielsen (ALN) belongs to Albizzia of Legume. It was reported that the chemical constituents from the bark of Albizza plants possess antitumor activity. So far there was no report about the components of Albizzia Lucidior I. Nielsen and its bioactivities. This study was designed to investigate the apoptosis-inducing activity of ALN extract on human tumor cells and the related mechanism.
Methods: The effect of ALN extract on tumor cells proliferation, cell cycle distribution, and apoptosis inducing were determined by cell molecular biological methods including MTT assay, nucleus morphological characteristics observation, cell size examination, agarose gel electrophoresis, and flow cytometry. Living cells reaction to ALN extract was also detected by cytosensor microphysiometry. Apoptosis related proteins, poly(ADP-ribose) polymersase (PARP), bcl-2 and Bax protein levels were measured by Western blot.
Results: ALN extract showed proliferation inhibition on human tumor cells by inducing apoptosis. The IC50 value to K562 cell line was (29.04 +/- 12.67) micrograms/ml. Western blot analysis showed that PARP was proteolysized and Bax protein level was enhanced, whereas bcl-2 protein level was unchanged.
Conclusions: ALN extract induce human tumor cells apoptosis, probably by increasing Bax protein expression.