Abstract:

Objective　To study glycyrrhizin′s anticancer effect and its mechanism.Methods　3-methylcholanthrene were in- jected into mice′s submandibular glands to induce tumor, then transplanted the tumor pieces(1 mm3) to mice. The transplanted tumors were measured, and flow cytometry analysis and cytomorphology observation were conducted.Results　Glycyrrhizin (GL) inhibited the transplanted mandibular gland fibro-sarcoma of mice and the suitable GL dose for inhibiting fibrosarcoma of mice was 1.61 mg per20 gweight. The GLdose below3.22 mg per20 gweight didn′t produce remarkable toxicity and side effects. GL in- duced cytomorphological changes of tumor cells and enhanced immunosuppression of macrophage on fibrosarcoma. The result of flow cytometry showed that tumor cell counts of GL1 and GL2 groups increased remarkably in DNA synthetic prophase, and de- creased in DNA synthetic phase.Conclusion　GL can inhibit transplanted mandibular gland fibro-sarcoma of mice. The antican- cer mechanism of GLmay be acting on related enzymes with phagocytosis. The result of flow cytometry showed that the shift of fi- brosarcoma cells fromG1 phase to S phase was blocked. This suggests that the anticancer action of GL is related to its inhibition of ribonucleotide reductase, a rate-limiting enzyme in DNA synthesis.

Key words: glycyrrhizin, fibrosarcoma, transplanted-tumor, phagocytosis, flow cytometry