Extraction And Modification Of The α-glucosidase Inhibitor From Anemarrhena Asphodeloides And Inhibitory Activity Of Derivates Of ACE

The rhizome of Anemarrhena asphodeloides has been used as a traditional Chinese medicine for thousands of years.It has been demonstrated to have various pharmacological effects, such as anti-diabetic, antioxidant, hepatoprotective.Our study used a-glucosidase as the target, extraction and purification the a-glucosidase inhibitor from Anemarrhena asphodeloides Bge. And we get the antidiabetic active compound, it was mangifein. The molecule structures of mangiferin were modified by introducing alkyl groups in C-3 of mangiferin and evaluated for their angiotensin-Ⅰ-converting enzyme (ACE) inhibitory activity. The methods and results are as follows:1.Extraction and purification ofa-glucosidase inhibitor from Anemarrhena asphodeloidesUsing a-glucosidase as the target, macroporous resin and recrystallisation were used to isolate and purify the a-glucosidase inhibitor.The results demonstrated that the fraction of 30% methanol had the best inhibitory activity. After further isolated and purified, the monomers of a-glucosidase inhibitor were obtained and identified as mangifein by 1H-NMR IR and UV2. Modification of mangifein at C-3The effects of reaction solvents, time, and ratio on the yield of 3-alkoxy mangiferin derivatives were studied. The synthesis approaches were as follows:The reactants of mangiferin, corresponding alkyl bromates(1:1.1) in DMF were refluxed at 45-55℃for 5 hours.The structure analysis including UV, IR,,13C-NMR,'H-NMR were used to identify the structures of 3-alkoxymangifein dervatives.3. The inhibitory activity of mangifein and its dervatives to ACEIn this study mangiferin derivates were synthized and evaluated for inhibition against angiotensin-I-converting enzyme (ACE). The results indicated that all the derivatives displayed an inhibitory activity better than mangiferin. Especially compounds 3 showed the best inhibitory activity among the synthesized compounds, which was 3-fold higher than that of mangiferin. Relationship between ACE inhibitory activity and molecular structure of compounds synthesized was a para-curve, in which the inhibitory activity of compounds 1-6 was increased monotonically as the increase of its alkyl chain length, and then decreased gradually when the number of alkyl carbon atoms exceeded eight.