Study On Active Components Of Malus

This thesis mainly included two aspects. Firstly, chemical constituents and biological activities of Malus were sumarrized. Secondly, chemical constituents in leaves of Malus halliana Koehne were isolated and identified. At the same time, α-glucosidase inhibitory activity of extracts and compounds was evaluated. The main contents of present study are as follows:The fat-soluble components about leaves of M. halliana were analyzed by GC-MS for the first time. 85 compounds were identified from the extract of petroleum ether, accounting for 80.73 % of the total constituents. Esters(25.66 %), acids(19.01 %), alkanes(14.68 %) and alcohols(11.33 %) were the main compound types. Its main components were palmitic acid(14.49 %), phytol(10.72 %), ethyl palmitate(5.32 %), ethyl linoleate(4.65 %), 2-methyl tetrahydrofuran(4.22 %), methyl palmitate(4.07 %) and hexane(4.03%).Thirty three compounds had been isolated from ethyl acetate and n-butanol extract by various chromatography methods including silica gel, PTLC, Sephadex LH-20, MCI, D-101 macroporous resin and recrystallization. Structures were elucidated using physical and chemical methods and spectral analysis technology. Thirty one compounds were identified as phloridzin(MH-1), juglanin(MH-2), bis(2-ethylhexyl) phthalate(MH-3), syringaresinol-4′-O-β-D-glucoside(MH-4), β-sitosterol(MH-5), daucosterol(MH-6), friedelin(MH-7),α-tocopherol(MH-8), lupeol(MH-9), alphitolic acid(MH-10), phytyl acetate(MH-11),palmitic acid(MH-12), avicularin(MH-13), quercitrin(MH-14), 3-hydroxyphloridzin(MH-15), afzelin(MH-16), ursolic acid(MH-17), oleanic acid(MH-18), tormentic acid(MH-19), euscaphic acid(MH-20), 2α,3β-dihydroxyolean-13(18)-en-28-oic acid(MH-21),drybonioside(MH-22), protocatechuic acid(MH-23), heneicosanoic acid methyl ester(MH-24), p-hydroxybenzoic acid(MH-25), stearic acid(MH-26), citrusin C(MH-27),(6S,9R)-roseoside(MH-28), 5,7-dihydroxychromone(MH-29),(-)-α-tocospirone(MH-30) and(Z)-11-docosenoic acid(MH-31). All compounds were obtained from this plant for the first time, compounds MH-2~4, MH-7, MH-9~11, MH-16, MH-19, MH-21~22 and MH-27~30were obtained from Malus genus for the first time.The petroleum ether, ethyl acetate and n-butanol extract and eleven compounds wereevaluated by α-glucosidase inhibitory activity models in vitro. The results showed that ethyl acetate and n-butanol extract had better α-glucosidase inhibitory activity than that of acarbose as positive control. However, petroleum ether extract had weaker activity than that of acarbose. The active order was n-butanol extract(IC50=168.92 μg/mL) > ethyl acetate extract(IC50=332.24 μg/mL) > acarbose(IC50=1173.72 μg/mL) > petroleum ether extract(IC50=1283.50 μg/mL). Eleven compounds(MH-1~11) were screened α-glucosidase inhibitory activity. Compound types including flavones, triterpenes, steroids, phenolic acids and esters. The results showed that MH-3, MH-6, MH-8, MH-9 and MH-10 from ethyl acetate extract and n-butanol extract had better α-glucosidase inhibitory activity than that of acarbose(IC50=1173.72 μg/mL). Among these compounds, MH-3 had the best inhibitory activity(IC50=92.58 μg/mL). At the same time, in addition to MH-3 and MH-8, other compounds presented a significant dose-dependence relationship. However, the inhibition rate of MH-3 and MH-8 had reached the maximum at 750 μg/mL mass concentration. Results showed compounds in leaves of M. halliana had better α-glucosidase inhibitory activity than that of acarbose.