Studies On Active Constituents Of Hypericum Ascyron, Haloxylon Ammodendron, Sophora Japonia L. And Quercus Aliena Blume

This dissertation is composed of three chapters. The first chapter showed the isolation and identification of all kinds of compounds from Hypericum ascyron, Haloxylon ammodendron, Sophora japonica L. and Quercus aliena Blume by bioassay guide. Thirty-one compounds were isolated and twenty-one compounds were identified. The second chapter reported antioxidant andα-glucosidase inhibitory activity in vitro of extracts and compounds from H. ascyron, H. ammodendron, S. japonica L., Q. aliena Blume, and hypoglycemic effect in vivo of extracts from H. ascyron. In last chapter, the study progress of chemical constituent, pharmaceutical and utility value of the genus Haloxylon were summarized.Chapter 1. The chemical constituents of Hypericum ascyron, Haloxylon ammodendron, Sophora japonica L. and Quercus aliena Blumei. Recently, H. perforatum is used as a herbal medicine for the treatment of moderate depression, and this effect has inspired further investigations on secondary metabolites from Hypericum species. Bioassay guided fractionation of antioxidant and antihyperglycemic EtOAC and MeOH extract of H. ascyron in our study led to the isolation of nine known compounds. Compounds 4 and 8 were isolated from H. ascyron firstly.ii. The genus Haloxylon as a typical desert plants is traditionally used as an external application to treat insect stings. The ash of the plant is used to treat internal ulcers. No phytochemical work has so far been reported on H. ammodendron collected from inner Mongolia. From EtOAC and MeOH extract of H. ammodendron, ten compounds were isolated, six compounds were identified. Compounds SS-4 and SS-6 were firstly obtained from the genus Haloxylon. iii. Bioassay guided fractionation of a-glucosidase inhibitory activity EtOAC and MeOH extract of S. japonica L. in our study led to the isolation of eleven compounds, and six compounds were identified.iv. The genus quercus distribute widely in Henan province, and have a wide range of pharmacological effects. In order to develop the plant, we investigated the old leaves of Q. aliena Blume collected from Luanchuan of Henan province. But only one compound was isolated and identified asα-Glutenol for the first time from this plant, because the leaves of this plant contain large phenolic contents and xanthophylls interfered the separation.Chapter 2. Bioassay of Hypericum ascyron, Haloxylon ammodendron, Sophorajaponica L. and Quercus aliena Blumei. The antioxidant activities of different solvent extracts of H. ascyron, H. ammodendron and Q. aliena Blume were evaluated by the DPPH, ABTS and FRAP assay comprehensively.The antioxidant capacity of extracts from leaves of Q. aliena Blume was strongest, H. ascyron was second, and H. ammodendron also showed certain antioxidant activities. The activity of compounds from H. ascyron was screened by scavenging activity against DPPH radical with microplate assay. Quercetin, quercetin-3-O-β-D-galactoside, quercetin-3-O-β-D-glucoside and kaempferol exhibited strong activity against DPPH radical with IC50 value 6.94,24.02,24.02 and 14.78μg/mL respectively.ii. For the first time, we assayed the inhibitory effect againstα-glucosidase of different solvent extracts and several compounds from H. ascyron, H. ammodendron, S. japonica L. and Q. aliena Blume in a 96-well plate. Petroleum ether, EtOAC, MeOH, and water soluble extracts from S. japonica L.showed stronger inhibitory effect against a-glucosidase, and all of them showed noncompetitive type model on a-glucosidase. The inhibitory effect of H. ascyron and Q. aliena Blume was slightly secondary to S. japonica L., and four extracts from H. ammodendron also showed certain inhibitory activities. In eight compounds assayed, quercetin, kaempferol and ursolic acid showed stronger inhibiting activity compared with acarbose as positive control.iii. Based on the above study on H. ascyron, the inhibitory effect against rat intestinal a-glucosidase was evaluated furtherly. EtOAC and MeOH extracts and compounds quercetin and kaempferol from H. ascyron showed good inhibitory activity, which provided a new experimental and theoretical evidence for hypoglycemic effect and mechanism. iv. Based on the antioxidant and a-glucosidase inhibitory activities of H. ascyron in vitro, hypoglycemic and antioxidant activities of EtOAC and MeOH extracts were investigated on normal and alloxan-induced diabetic mice in vivo for the first time. The results showed that EtOAC and MeOH extracts had hypoglycemic effect on alloxan-induced diabetic mice, lowered the blood lipid level, and inhibited the oxidant stress and oxidative damage to tissues.Chapter 3. The study progress of chemical constituent, pharmaceutical and utility value of the genus HaloxylonThe study progress of chemical constituent, pharmaceutical and utility value of the genus Haloxylon were summarized.