Deacetylation Affects the Physical Properties and Bioactivity of Acemannan, an Extracted Polysaccharide From Aloe Vera

Carbohydr Polym. 2015 Nov 20;133:556-66. doi: 10.1016/j.carbpol.2015.07.039. Epub 2015 Jul 17.

Abstract

Acemannan, an acetylated polymannose from Aloe vera, induces tissue repair. We investigated the role of acemannan's acetyl-groups on its physical and biological properties. Deacetylated acemannan (DeAcAM) was prepared and characterized. The physical properties and microscopic structure of DeAcAM were evaluated using water solubility, contact angle, X-ray diffraction, and scanning-electron microscopy. The activity of DeAcAM on cell proliferation and gene expression were assessed. Acemannan and DeAcAM structures were simulated and the acemannan tetramer diad and its completely deacetylated structure were also determined. Increased acemannan deacetylation reduced its water solubility and hydrophilicity. Complete deacetylation altered acemannan's conformation to a partial crystal structure. The bioactivity of acemannan was reduced corresponding to its deacetylation. Acemannan induced cell proliferation, and VEGF and Collagen I expression; however, 100% DeAcAM did not. The simulated structures of the acemannan diad and the completely deacetylated diad were different. We conclude acetyl-groups affect acemannan's structure and physical/biological properties.

Keywords: Acemannan; Aloe vera; Bioactivity; Deacetylation; Semi-empirical AM1 method.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Aloe / chemistry*
  • Cell Proliferation / drug effects
  • Collagen Type I / metabolism
  • Gene Expression Regulation / drug effects
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Mannans / chemistry*
  • Mannans / pharmacology*
  • Models, Molecular
  • Molecular Conformation
  • Physical Phenomena*
  • Solubility
  • Structure-Activity Relationship
  • Vascular Endothelial Growth Factor A / metabolism
  • Water / chemistry

Substances

  • Collagen Type I
  • Mannans
  • Vascular Endothelial Growth Factor A
  • Water
  • acemannan