More Possible Uses:
ANTI-CANCER: Over 30 years ago, there were many studies of polysaccharide antitumor properties. Amongst the sugar polymers investigated was levan. Based on the fact that levan had already been shown to be an immunological modulator, Leibovici et al reasoned that levan had the potential to direct the immune response to the advantage of the host (Leibovici). Indeed, studies in that laboratory showed that levan did inhibit various malignancies (Leibovici). Despite the laboratory success, a combination of the inability to obtain a reliable supply of levan and redirection of funding, resulted in abandonment of this line of research (personal communication).
In recent years, there has been a renewed interest in the antineoplastic activity of levan. In Brazil, Calazans et al have used levan produced by the bacterium Zymomonas mobilis in antitumor studies. For one week, Swiss albino mice with subcutaneously implanted tumor cells were treated daily with levan at a rate of 200 mg/kg. The four microbial strains showed a range of inhibitory effects. The highest activity against Ehrlich carcinoma was 74% inhibition. It was theorized that differences in the molecular weights of the various levans was potentially responsible for the varying results (Calazans).
A Korean group looked at levan produced by four different microorganisms. An MTT assay was performed using doses of levan in the range of 200-1000 µg/ml. The highest activity observed was 69% using the levan from Rahnella aquatilis. Higher doses of levan from a particular microorganism did not always result in higher inhibition. Rather, the organism producing the levan appeared to be more significant, suggesting that the size of the levan could be the deciding factor (Yoo).
Calazans G, Lopes C, Lima R, de Franca F. Antitumour activities of levans produced by Zymomonas mobilis strains. Biotechnology Letters 19:19-21 (1997).
Leibovici J, Stark Y, Eldar T, Brudner G, Wolman M. Mechanism of the inhibitory effect of levan on experimental tumors. Recent Results in Cancer Research 75:173-179 (1980).
Roberfroid M, Frippiat A, Van Loo J, Taper H. Synergistic composition of a non-digestible carbohydrate and an anti-cancer drug for use in the treatment of cancer. Patent number EP0958825 (1999).
Yoo S-H, Yoon E, Cha J, Lee H. Antitumor activity of levan polysaccharides from selected microorganisms. International Journal of Biological Macromolecules 34: 37-41 (2004).