Anti-hyperglycemia activity of Galla chinensis based on the inhibition of α- glucosidase activity
Date Issued
2010
Date
2010
Author(s)
Lin, Jia-Wen
Abstract
Diabetes mellitus (DM) is a common metabolism disease worldwide. DM is also on the top five list of the ten major causes of death in Taiwan for many years. Hyperglycemia is the main symptom to the DM patients. It obten inducesvarious complications, and postprandial hyperglycemia is the principal factor of DM complications. Among many kinds of diabetic medicines, only α-glucosidase inhibitors can significantly lower postprandial blood glucose. This research used α-glucosidase inhibition assay to find the plant materials which has ability to inhibit α-glucosidase. It was found that among the eleven plant materials tested, Galla chinensis has the most potent inhibition activity. Therefor, we futher investigated the active component in Galla chinensis usingα-glucosidase inhibition assay.
Various solvents were used to prepare Galla chinensis extracts, and ethyl acetate extract (EA) of Galla chinensis was found to have the highest ability to inhibit α-glucosidase, and it’s also had the highest activity in the DPP-4 inhibition assay, advanced glycation end products inhibition assay and α-amylase inhibition assay. We futher used Sephadex LH-20 gel to separate that EA-A ~ EA-I fractions from the Galla chinensis ethyl acetate extract, and found EA-G had the best ability to inhibit α-glucosidase among the nine fractions, the inhibition ratio of yeast α-glucosidase and rat α-glucosidase were 93.59 % and 42.91 %, respectively. The EA-G fraction also had well activity in the DPP-4 inhibition assay, DPPH free radical scavenge assay, advanced glycation end products inhibition assay and α-amylase inhibition assay, and it also increased glucose uptake of insulin resistant cells.
According to the above experimental result, the EA-G fraction was futher purified using High Performance Liquid Chromatography and G1~ G7 fractions were obtained. The G4 and G5 fractions were found to have highest α-glucosidase inhibition activity among the seven fractions. These two fractions were futher analyzed by Mass Spectrometry, and found that they are 1, 2, 3, 6-tetra-O-galloyl-β-d-glucose and 1, 2, 3, 4, 6-penta-O-galloyl-β-d-glucose.
This research has proved that Galla chinensis not only has high α-glucosidase inhibition activity, but also can inhibit DPP-4, scavenge free radicals, inhibit advanced glycation end products formation, inhibit α-amylase activity, and increase glucose uptake of insulin resistant cells. So, Galla chinensis can modulate blood sugar through various ways and has potential to be developed as an anti-diabetes product.
Subjects
diabetes mellitus
Galla chinensis
α-glucosidase inhibitor
1 ,2,3,6-tetra- O-galloyl-β-d-glucose
1,2,3,4,6-penta-O-galloyl-β-d-glucose
SDGs
Type
thesis
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