Antitumor effect of humus extract on murine transplantable L1210 leukemia

Humic substances are formed during the decomposition of organic matter in humus that found in many natural environments in which organic materials and microorganisms have been present. In the present study, humus extract exhibited antitumor effect on L1210 tumor development in isogeneic DBA/2 mice with the delay of tumor formation and a significant smaller tumor mass that infer a significant increase of life span of mice. The antitumor effect was not due to direct killing of L1210 or induction of apoptosis in tumor cells by humus extract.