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In vivo metabolism of aloemannan
1Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Japan. yagi@fupharm.fukuyama-u.ac.jp
Abstract:
The metabolism of fluoresceinyl isothiocyanate labeled aloemannan (FITC-AM) was examined by p.o. and i.v. administration in mice at a dose of 120 mg/kg. Analysis of FITC-AM in urine and feces showed that FITC-AM (MW 500 KD) was metabolized into smaller molecules that mainly accumulated in the kidneys. AM was catabolized by the human intestinal microflora to catabolites 1 and 2 with molecular weights of 30 and 10 KD, respectively. Hydrolysis of AM showed hexosamine peaks on HPAE. The findings suggest that the immunomodulation of AM may come from not only neutral polysaccharides but also contaminated hexosamine in AM.
Insights
Fluoresceinyl isothiocyanate labeled aloemannan (FITC-AM) is metabolized into smaller compounds that accumulate in the kidneys. Its immunomodulatory effects may stem from both polysaccharides and hexosamine components.
Area of Science:
- Biochemistry
- Pharmacology
- Immunology
Background:
- Aloemannan (AM) is known for its immunomodulatory properties.
- The metabolic pathways and active components of AM require further elucidation.
Purpose of the Study:
- To investigate the metabolism and catabolism of fluoresceinyl isothiocyanate labeled aloemannan (FITC-AM) in vivo.
- To identify potential sources of AM's immunomodulatory activity.
Main Methods:
- Administration of FITC-AM (120 mg/kg) via oral and intravenous routes in mice.
- Analysis of FITC-AM and its metabolites in urine and feces.
- Characterization of AM catabolites produced by human intestinal microflora.
- Hydrolysis of AM and detection of hexosamine using High-Performance Anion-Exchange Chromatography (HPAE).
Main Results:
- FITC-AM (500 KD) was metabolized into smaller molecules, primarily accumulating in the kidneys.
- Human intestinal microflora catabolized AM into two main components (Catabolites 1 and 2, MW 30 KD and 10 KD).
- Hydrolysis revealed hexosamine peaks, indicating their presence in the AM preparation.
Conclusions:
- The metabolism of FITC-AM involves breakdown into smaller, kidney-accumulating compounds.
- Aloemannan catabolism by gut microflora produces distinct molecular weight fragments.
- Immunomodulation by AM may be attributed to both its neutral polysaccharide structure and contaminating hexosamines.