Abstract: The objective of this study was to investigate the protective effect of tannins from Sanguisorba officinalis (Great Burnet) on myelosuppression in mice.The myelosuppression model was induced by peritoneal injection of cyclophosphamide (CTX).Then the myelosuppression mice were randomly divided into:model group,colony-stimulating factor group,three Great Burnet tannins treatment groups of different dosage (20,10,5 mg/kg),and normal group.The drugs were chronically administrated to myelosuppression mice once a day for 21 days.The counts of peripheral blood leukocytes,DNA contents and CD34⁺ expression of bone marrow cells and the O⁶-methyl guanine-DNA methyltransferase (MGMT) protein expression were used as main indexes and were determined.The results showed that Great Burnet tannins significantly increased peripheral WBC (P<0.05);significantly elevated bone marrow DNA content (P<0.05);significantly promoted the expression of CD34⁺ (P<0.05);also significantly promoted MGMT protein expression (P<0.05).Based on these results,it was concluded that Great Burnet tannins can significantly antagonize CTX induced myelosuppression in mice.

Key words: Great Burnet tannins, cyclophosphamide, myelosuppression, antagonism