Several Qi Type Pier Fruit Alkanes Triterpenoid Saponin Synthesis And Biological Activity Research

Oleanane-type triterpenoid saponins are kind of wide distribution and content rich natural triterpenoid compound, has many pharmacological activities, it is also effective ingredient in many Chinese herbal medicines. Through the chemical synthesis means constructing active natural compound and its derivatives molecular library, it is one of the most effective ways to looking for new the risk-benefit ratio of drug. This paper completed a natural oleanane type triterpenoid saponins and four oleanane type triterpenoid saponins derivatives synthesis research, and analyses the initial in vitro alpha-glucosidase inhibitory activity test, for screening diabetes drugs lead compound laid the foundation.In this report we synthesized in convergent strategy to construct oleanane-type triterpenoid saponins. Based on the different reaction activity of oleanolic acid C-3hydroxyl and C-28carboxyl. With an effective synthetic access to the C-28carboxyl finishing the sequential glycosylation reaction, then we connected glycosyl parts to C-3hydroxyl under the combined use of glycosyl trichloroacetimidates as donor. finally removed acyl protecting group on the sugar moieties in sodium methoxide alkaline conditions. At last we completed five target compound synthesis. Above all the target compounds and the key intermediates were through the nuclear magnetic resonance (NMR), mass spectrometry and physical and chemical properties analysis confirmed the structurae.In this reaserch we has completed five oleanane type triterpenoid saponin synthesis, including compound1(3-O-[β-D-glucopyranosyl-(1→4)-(3-D-glucopyranosyl]-28-O-β-D-glucopyranosyl-oleanolic acid) for natural products, compound2-5for its derivatives, and haven’t reported in the past reports. For the successful synthetic oleanane-type saponins1-5have carried on the preliminary in vitro a-glucosidase inhibitory activity research, they all showed different degrees of inhibitory activity. Among them, the compound1and2showed a-glucosidase inhibitory activity as well as positive control acarbose considerable, while compound3and4were less potent than1and2. compound5has weakest activity in the class. In addition, the compound2with a-glucosidase inhibitory activity was better than1(compound2:IC50=102.35±10.1μg/mL; compound1:IC50=25.27±7.9μg/mL). Preliminary structure-activity relationship analysis shows that, oleanolic acid C-28carboxyl with a glucose connection was more conducive to improving activity relative than a disaccharide (gentian disaccharide); oleanolic acid with a disaccharide at C-3hydroxyl was better than a single sugar on proving activity; oleanolic acid connected lactose conformation at C-3hydroxyl was better than cellobiose in activity enhancement.