Antiproliferative activity and its underlying mechanisms of methanol extract from leaves of Saururus chinensis (Lour.) Baill. on mouse Colon-26 carcinoma cells

Summary. Saururus chinensis is an herbaceous perennial found in East Asia including Korea, China, and Japan and has been used for the folk medicine to relieve edema.  We herein assessed antiproliferative activity of the methanol extract from leaves of S. chinensis (SCE) on several carcinoma and normal cells by the WST-8 assay and trypan blue exclusion.  SCE strongly inhibited growth of Colon-26 cells and HL60 cells, but not induced cell death.  Cell growth of mouse embryonic fibroblasts used as a model of normal cells was not affected by SCE.  Effects of SCE on gene expression and intracellular signal transduction related to cell proliferation were evaluated by quantitative RT-PCR and immunoblotting.  SCE activated a tumor suppressor protein p53 by increased phosphorylation of p38 and ERK, and then expression of p21 gene was enhanced to elongate cell cycle at S phase of Colon-26 cells.  In addition, sauchinone, a lignan contained in S. chinensis , was identified as one of the active substances possessing antiproliferative activity in SCE. Industrial relevance. S. chinensis is known as a medicinal plant.  We herein found that the methanol extract from leaves of S. chinensis exerts antiproliferative activity on several carcinoma, but not on normal cells.  In addition, a lignan sauchinone contained in S. chinensis was identified as one of the active substances.  The data obtained in this study present the mechanism of action of S. chinensis leaves used for the folk medicine, and might be related to treatment of colorectal malignancy.  Limitations in the present study include the experiments performed on a cell line, and therefore, the effect would need to be confirmed in further investigation of the relevance of S. chinensis in colorectal malignancy. Keywords . Saururus chinensis ; Antiproliferative activity; p21; Sauchinone; p38; ERK.