A carbohydrate polymer composed of mannose and galactose, with chemotherapeutic enhancing activity. Galactomannan derivative binds to galectins on cell surfaces and may promote the transport of certain chemotherapeutics, such as 5-fluorouracil (5-FU), into tumor cells. This may increase the antineoplastic effect of 5-FU when administered concomitantly. Galectins are carbohydrate-binding proteins, upregulated on the surface of certain types of tumor cells, and may mediate cell association, survival and metastasis.