Polysaccharides and their vanadium complexes: New therapeutic perspectives by their ability of modulating macrophages

Certain polysaccharides and their derivatives have been used in different applications including in medicine. As biological response modifiers, activities as immunomodulator, antitumor and antileishmanial are researched. Leishmaniasis is a very epidemiologically important disease and the World Health Organization (WHO) classifies it as a neglected disease. In mammal hosts, the Leishmania parasites live inside mononuclear phagocytes, which impair the action of drugs. The pentavalent antimonials sodium stibogluconate and meglumine antimoniate make up the primary treatment for leishmaniasis, which is associated with serious side effects and resistance to antimony. Since the survival of Leishmania parasites in the host cells is associated with the immune system modulation, compounds able to activate these cells to produce cytotoxic mediators could have great potential of promoting leishmanicidal effects. Therefore, immunomodulation is considered a promising strategy to cure leishmaniasis with fewer side effects. The polysaccharides that activate macrophages for proinflammatory activity have been studied aiming at leishmanicidal effect. When complexed with vanadium, galactomannans, arabinogalactans, and xyloglucans, polysaccharides had greater leishmanicidal effects and were more effective than the antimonials currently used in leishmaniasis treatment.