Purification And Characterization Of Hypoglycemic Factors From Momordica Charantia L. Powder With A Study Of Their Hypoglycemic Actions

Diabetes mellitus has become one of the main diseases threatening an health. Bitter melon (Momordica charantia L.) as a Traditional Chinese Medicine has provided a novel and safe method for preventing and treating diabetes. The aims of this study were to identify the specific factors from bitter melon powder that effectively prevent and treat diabetes, to analyze their molecular composition, and to further investigate their molecular structure. The hypoglycemic mechanism of the factors was also analyzed in this thesis.The results of biochemical analysis showed that the content of protein and sugar in the bitter melon powder was 11.48% and 8.03% respectively. Glutamic acid, aspartic acid and arginine were the most abundant amino acids. The basic constituents of sugars were glucose, fructose and rhamnose. UV scan results showed that the powder did not have typical adsorption peak for protein, but had a special adsorption peak at 290nm. The molecular weight, as measured by SDS-PAGE and High Performance Liquid Chromatography (HPLC), ranged from 128KDa to 300Da.By means of dialysis tubing (8000Da), the bitter melon powder could preliminarily be separated into two groups. The MCE-L fraction, which came from the outside tubing, had a strong ability to repair those β?cells damaged by Alloxan. The MCE-H fraction, which was from the inside tubing had the ability to stimulate insulin secretion in both normal and damaged βcells.Further separation of the MCE-L fraction was carried out using Ion Exchange Chromatography (IEC) in a packed SP-650M column. Among the eight components from the SP-650M column, the 7th peak had the strongest activity to repair damaged βcells; it could increase the proliferation of beta cell 115%. Another separation of the 7th peak was carried out using RPLC in packed C18 column. The results showed that the 2nd peak of five components from the C18 column demonstrate the best activity with damaged βcells.After investigating the superoxide dismutase (SOD) activity in the samples, we found that the repair activity of damaged βcells had accose relationship with superoxide radical scavenge activity. The molecular weight of the 2nd peak from C18 column was investigated by Size Exclusion Chromatography (SEC) in a Superdex Peptide 10/300GL column. The results showed that their molecular weight were approximate 1153.55Da and 761.74 Da. The exact molecular weight of the latter one was 777.87Da as identified by MALDI-TOF-MS. It contains β-D-glucopyranoside and α-D-frucofuranoside as detected by Infrared spectrum.In conclusion, all the above experiments provide elementary material for the further studying the hypoglycemic factors in bitter melon.