Kinetic analysis on the sensitivity of glucose- or glyoxal-induced LDL glycation to the inhibitory effect of Psidium guajava extract in a physiomimic system

Biosystems. 2007 Mar;88(1-2):92-100. doi: 10.1016/j.biosystems.2006.04.004. Epub 2006 Apr 28.

Abstract

Experimentation with a physiomimic system and kinetic analysis exhibited four distinct reaction phases in LDL glycation despite of the type of inducer: glucose or glyoxal. LDL glycation was more sensitive to a status of hyperglycemia (such as 400 mg glucose/100 mL) as evidenced by the reaction order of 0.53. Glucose reacted intensively in the Initial Phase (reaction period 0-2h) which was identified to result from a parallel mechanism involving both the direct Schiff's product formation and the auto-oxidative cleavages. In contrast, a physiological level of glyoxal revealed merely a reaction order of only 0.09, implicitly indicating a far less sensitive glycation which can be attributed to a mechanism proceeding simply through a molecular Schiff's reaction. On treatment with Psidium guajava L. aqueous extract (PE) (0.01-0.625 mg/mL), a rather unique and significant inhibitory characteristic on LDL glycation was observed with a dose-dependent manner. We attributed such an effect of PE to its distinct abundance of polyphenolic content (165.61+/-10.39 mggallic acid equivalent (GAE)/g). Conclusively, PE is an excellent anti-LDL glycative agent whose potential therapeutic uses can be extended to the prevention of a variety of cardiovascular and neurodegenerative diseases associated with glycations.

MeSH terms

  • Glucose / pharmacology
  • Glycation End Products, Advanced / metabolism
  • Glycosylation / drug effects
  • Glyoxal / pharmacology
  • Humans
  • Hyperglycemia / metabolism
  • In Vitro Techniques
  • Kinetics
  • Lipoproteins, LDL / chemistry
  • Lipoproteins, LDL / drug effects
  • Lipoproteins, LDL / metabolism*
  • Models, Biological
  • Plant Extracts / pharmacology
  • Psidium*
  • Systems Biology

Substances

  • Glycation End Products, Advanced
  • Lipoproteins, LDL
  • Plant Extracts
  • glycated lipoproteins, LDL
  • Glyoxal
  • Glucose