Abstract
Accumulation of advanced glycation endproducts (AGEs) due to glycative stress in the body leads to tissue stiffening and physiological dysfunction due to protein cross-link formation, and is one of the factors contributing to aging and lifestyle-related diseases. Suppression of glycative stress includes suppression of postprandial hyperglycemia, suppression of glycation reaction, and degradation and excretion of AGEs. Fluorescent AGEs include both cross-linked and non-cross-linked AGEs. Inhibition of fluorescent AGE formation has been reported in various plant materials, one of which is the ginger plant black galingal (Kaempferia parviflora Wall. Ex. Baker; KP), with hydrophilic components and polymethoxy flavonoids (PMF) involved in this effect. On the other hand, there are several types of cross-linked structures of glycated proteins, α-diketone being one of them. The cleavage action of α-diketones is called AGE cross-link cleavage, and phenylpropanedione (1-phenyl-1,2-propanedione; PPD) has been used as a cross-linking model substance. The rate of AGE cross-link cleavage has been evaluated from the rate of free benzoic acid formation. KP rhizome has also been reported to have AGE cross-link-cleaving activity. There have been only a few reports on the effect of AGE formation inhibition and AGE cross-link cleavage on protein cross-linking by glycation. In this study, we examined the inhibition of glycated-protein cross-linking (IGPC) and cleavage of glycated-protein cross-linking (CGPC) of KP extract, which previously has been shown to have effects of fluorescent AGE formation inhibition and AGE cross-linking cleavage.
