gamma-Propoxy-sulfo-lichenin, an antitumor polysaccharide derived from lichenin.
A water-soluble semisynthetic polysaccharide, gamma-propoxy-sulfo-lichenin (PSL), was prepared by reaction of propansultone with lichenin, a natural occurring beta-1.3/1.4-linked glucan originating from Cetraria sp. PSL represents a class of mixed-linked beta-glucans with long and hydrophilic side chains in position C-6 of the glucan backbone. PSL with a degree of substitution of 0.8 and an average molecular weight of 250 kDa exhibited a strong antitumor activity in doses of 25 and 5 mg/kg against solid sarcoma 180 (100% resp. 82% tumor inhibition). The antitumor activity of PSL was shown to be dependent on the dimension of the molecule: the higher the average molecular weight, the higher was the inhibition rate obtained in the antitumor assay. No antitumor effect was observed by using a pretreatment of animals prior to transplantation of sarcoma 180. On syngenic DBA/2-MC.SC1 fibrosarcoma PSL inhibited tumor growth by about 88% at a concentration of 25 mg/kg. PSL failed to exhibit any direct cytotoxic effects on hormone-independent MDA-MB 231 mammacarcinoma. For PSL an indirect antitumor effect via modulation of the host mediate immune defence is postulated.
Hensel
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University of Regensburg, Faculty of Chemistry and Pharmacy, Germany.
D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D005260:Female; D005936:Glucans / Q000138:chemical synthesis / Q000494:pharmacology*; D066298:In Vitro Techniques; D051379:Mice; D013329:Structure-Activity Relationship; D013451:Sulfonic Acids / Q000138:chemical synthesis / Q000494:pharmacology*
D000970:Antineoplastic Agents; D005936:Glucans; D013451:Sulfonic Acids; C093813:gamma-propoxy-sulfo-lichenin