Modulation by Acanthospermum australe extracts of the tumor induced hematopoietic changes in mice.

Previous studies on the Ehrlich ascites tumor (EAT) model indicate that tumor progression is associated with reduced myelopoiesis and increased extramedullar hematopoiesis. In order to investigate the in vivo antitumor activity of Acanthospermum australe, its hydroalcoholic extract was partitioned with different solvents and the resulting extracts were monitored by their effects on bone marrow and spleen hematopoietic progenitor cell proliferation and differentiation in EAT-bearing mice. Oral treatment of tumor-bearing mice with 3 doses of 100, 500 and 1000 mg/kg of the crude hydroalcoholic extract and its chloroformic, butanolic and aqueous fractions significantly stimulated myelepoiesis and brought extramedullar hematopoiesis back to near control values. In normal mice, stimulation of myelopoiesis was only observed with the crude and the butanolic extracts. All the extracts at 500 mg/kg significantly increased survival of tumor-bearing mice, however a clear survival advantage in the group treated with the butanolic extract was observed. These results suggest that A. australe may exert effects on myelopoiesis that may be implicated in antitumor immune responses.