Studies On The ?-amylase Inhibition Activities And Applications Of Proanthocyanidins From Plants

Proanthocyanidins,also known as condensed tannins,are a class of oligomeric and polymeric flavan-3-ols,have gained a lot of attention due to their potential health promoting properties,such as antioxidant,anti-inflammation,cancer prevention activity,especially the inhibition activities on a-amylase.a-Amylase is one of the main factors in the post-prandial increase in blood glucose after a meal by catalyzing the starch hydrolysis,so it's an promising research to investigate the inhibition activity of proanthocyanidins on a-amylase,further more,the proanthocyanidins is potential in the application of Low-glycemic index(Low-GI)food and to make contribution in the treatment of type-2 diabetes.In this article,several proanthocyanidins from plants were extracted and characterized,a-amylase inhibition activities,a-glucose inhibition activities and antioxidant activities were investigated.Finally,three Low-GI foods were created by incorporating the proanthocyandins from grape seeds.The results were showed as below:1.Proanthocyanidins from different plants were extracted and purified by using Sephadex LH-20 column,and then structurally characterized by UV-vis,infrared spectra(IR),nuclear magnetic resonance(NMR)and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry(MALDI-TOF MS)methods.Langsat pericarps proanthocyanidins is oligomeric with the mean degree of 3.3,mainly containing procyanidins but also exists a few prodelphinidin units.MALDI-TOF MS results indicated that proanthocyanidins from langsat pericarps,which were A type oligomers with degree of polymerization from 2 to 8,were predominantly composed of catechin/epicatechin.Proanthocyanidins from longan pericarps is oligomeric which was also composed of catechin/epicatechin.2.a-Amylase inhibition activities,a-glucose inhibition activities and antioxidant activities were evaluated.And the results showed that the proanthoyandins from grape seeds,longan pericarps,craneberry,sorghum and langsat pericarps possessed high inhibition activities while the proanthoyandins from green tea and chiku didn't show significantly inhibition activities.3.The stabilities of the inhibition activities of proanthoyandins on a-amylase were investigated,by treating with heat and incubation with different cereals.The results indicated that the proanthoyandins still have significantly inhibition activities after heat treatment.However,the complexation were diverse depends on the different cereals.4.Low-GI noodle,Low-GI dumplings and Low-GI steamed bread were created by adding grape seeds proanthocyanidins.A dose response for the different concentrations of grape seeds proanthocyanidins in the noodle and steamed bread were evident,noodles and steamed bread with 1%proanthocyanidins significantly reduced the hydrolysis of starch while more proanthocyanidins needed to be added in the dumplings to show the inhibition effects.