Lethal effect of neutral mannan fraction of bakers' yeast in mice.
A simple polysaccharide, the neutral mannan from Saccharomyces cerevisiae wild type strain (WNM) was found to kill ddY strain mice by intravenous administration, showing a LD50 value of 12.2 mg/kg. On the other hand, the acidic mannan fraction from the same yeast containing phosphate (WAM025), and chemically phosphorylated WNM (WNM-P) were practically non-toxic. Concerning the relationship between chemical structure and lethal effect of these mannans, it was demonstrated that a mannan possessing a highly branched structure exhibited stronger lethality than those with less branched structures. Against C3H/HeJ strain mice with no responsiveness to lipopolysaccharide, the LD50 value of WNM was as high as 75 mg/kg. Pretreatment with 500 mg/kg of D-mannose, N-acetyl-D-glucosamine, D-galactose, and L-fucose prevented mice from the lethal effects of WNM. However, WNM (LD100) did not show any lethal effect in mice for 2 to 12 hr after treatment with dexamethasone, an anti-inflammatory steroid.
D000707:Anaphylaxis / Q000209:etiology; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D003167:Complement Activation / Q000187:drug effects; D007928:Lethal Dose 50; D008351:Mannans / Q000037:antagonists & inhibitors / Q000633:toxicity*; D051379:Mice; D008809:Mice, Inbred C3H; D010974:Platelet Aggregation / Q000187:drug effects; D011134:Polysaccharides / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000032:analysis*
D000893:Anti-Inflammatory Agents; D008351:Mannans; D011134:Polysaccharides