Effect Of Koumine On The Growth And Apoptotic Induction Of Human Colonic Adenocarcinoma Cells In Vitro And The Pilot Study Of Its Mechanism

Gelsemium elegans benth (GEB) is a kind of Loganiacease, known as one of the most poisonous plants in the world.lt contains many alkaloids with indole moiety. Koumine (Kou), isolated and purified from the root of GEB,is accounting for 30 percent of the total alkaloids.lts molecular formula is C20H22N20 and molecular weight 306.8.It is a white crystal and water- insoluble. It has been reported that GEB and its extracts have antitumor ,anti- inflammatory,analgesic, i mmunoenhancing and acetylcholine-Iike effects. In the present studies, we made use of morphologic method,cell and molecular biology techniques,flow cytometry and adherent cell analysis system to observe the effects of Kou on the growth and apoptotic induction of human colonic adenocarcinoma cells(Lovo),as well as to preliminarily investigate the physiological mechanisms.The main results are as follows: I .Kou inhibited the growth of Lovo cells in a concentration-depedent and time-dependent manner in vitro. 2. Kou induced apoptosis of Lovo cells in vitro. 3. Kou lowered the membrane potential( MIP) of Lovo cells. 4. Kou lowered the mitochondrial membrane potential (ill m) of Lovo cells. 5.Kou decreased the concentration of free cytosolic calcium [Ca2抝, in Lovo cells,But atler addition of EDTA,the concentration of Wa2], rose to a level higher than the basal one. 6.Kou increased the reactive oxygen species (ROS) in Lovo cells. 7.Kou had no intluence on the intracellular pH( pH,) in Lovo cells. 8.Kou enhanced the effects of gap junctional intercellular communication (GJIC)ofLovo cells. 9.Kou lowered the lipidic fluidity of Lovo cells. in brief ,we demonstrate that Kou can inhibit the growth and -4- induce apoptosis of Lovot cells.The ~mech~anisni might be partly due to its interfering the electricity coupling and the signal transduction by activating or inhibiting some ion-channel proteins,ion-carrier proteins or ion- transporting,impairing the metabolism coupling by lowering the lipidic fluidity,and at the same time,enhacing the GJIC function of cells,which in turn brings the effects of Kou to all the cells.