title: Immunomodulatory and anticancer potential of Gan cao (Glycyrrhiza uralensis Fisch.) polysaccharides by CT-26 colon carcinoma cell growth inhibition and cytokine IL-7 upregulation in vitro.
abstract: BACKGROUND
  Chinese licorice, (Glycyrrhiza uralensis Fisch.) is one of the commonly prescribed herbs in Traditional Chinese Medicine (TCM). Gancao, as commonly known in China, is associated with immune-modulating and anti-tumor potential though the mechanism of action is not well known. In this study, we investigated the in vitro immunomodulatory and antitumor potential of Glycyrrhiza uralensis polysaccharides fractions of high molecular weight (fraction A), low molecular weight (fraction B) and crude extract (fraction C).
  
  
  METHODS
  Cell proliferation and cytotoxicity was investigated using Cell Counting kit 8 (CCK-8) on Intestinal epithelial cell line (IEC-6) and Colon carcinoma cell line (CT-26). IL-7 gene expression relative to GAPDH was analysed using Real time PCR. The stimulation and viability of T lymphocytes was determined by Trypan blue exclusion assay.
  
  
  RESULTS
  G.uralensis polysaccharides did not inhibit proliferation of IEC-6 cells even at high concentration. The ED50 was found to be 100 μg/ml. On the other hand, the polysaccharides inhibited the proliferation of cancer cells (CT-26) at a concentration of ≤50 μg/ml. Within 72 h of treatment with the polysaccharides, expression of IL-7 gene was up-regulated over 2 times. It was also noted that, IEC-6 cells secrete IL-7 cytokine into media when treated with G.uralensis polysaccharides. The secreted IL-7 stimulated proliferation of freshly isolated T lymphocytes within 6 h. The effect of the polysaccharides were found to be molecular weight depended, with low molecular weight having a profound effect compared to high molecular weight and total crude extract.
  
  
  CONCLUSIONS
  Our findings indicate that G.uralensis polysaccharides especially those of low molecular weight have a potential as anticancer agents. Of great importance, is the ability of the polysaccharides to up-regulate anticancer cytokine IL-7, which is important in proliferation and maturation of immune cells and it is associated with better prognosis in cancer. Therefore, immunomodulation is a possible mode of action of the polysaccharides in cancer therapy.
authors.affiliation: Tianjin University of Traditional Chinese Medicine, 312 Anshan Western Road, Nankai District, Tianjin, 300193, People's Republic of China.|Department of Biological Sciences, Faculty of Science, Egerton University, PO BOX 536-20115, Egerton, Kenya.
authors.forename: Peter Amwoga
authors.initials: PA
authors.lastname: Ayeka
authors.affiliation: Tianjin University of Traditional Chinese Medicine, 312 Anshan Western Road, Nankai District, Tianjin, 300193, People's Republic of China. bianyuhong_2012@163.com.|Tianjin University of Traditional Chinese Medicine, 312 Anshan Western Road, Nankai District, Tianjin, 300193, People's Republic of China. bianyuhong_2012@163.com.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Bian
authors.affiliation: Tianjin University of Traditional Chinese Medicine, 312 Anshan Western Road, Nankai District, Tianjin, 300193, People's Republic of China.|Center for Traditional Medicine and Drug Research, Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya.
authors.forename: Peter Githaiga
authors.initials: PG
authors.lastname: Mwitari
authors.affiliation: Tianjin University of Traditional Chinese Medicine, 312 Anshan Western Road, Nankai District, Tianjin, 300193, People's Republic of China.
authors.forename: Xiaoqian
authors.initials: X
authors.lastname: Chu
authors.affiliation: Tianjin University of Traditional Chinese Medicine, 312 Anshan Western Road, Nankai District, Tianjin, 300193, People's Republic of China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Tianjin University of Traditional Chinese Medicine, 312 Anshan Western Road, Nankai District, Tianjin, 300193, People's Republic of China.|School of Pharmacy, Mount Kenya University/Kigali campus, P.O BOX 5826, Kigali, Rwanda.
authors.forename: Rosette
authors.initials: R
authors.lastname: Uzayisenga
authors.affiliation: Department of Biological Sciences, Faculty of Science, Egerton University, PO BOX 536-20115, Egerton, Kenya.
authors.forename: Elick Onyango
authors.initials: EO
authors.lastname: Otachi
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D003110:Colonic Neoplasms; D029882:Glycyrrhiza uralensis / Q000737:chemistry*; D015851:Interleukin-7 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D011134:Polysaccharides / Q000737:chemistry / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D015851:Interleukin-7; D010936:Plant Extracts; D011134:Polysaccharides
keywords: Anti-cancer; Glycyrrhiza uralensis; IL-7; Immunomodulatory; Polysaccharides; TCM