Studies On Chemical Constituents And Pharmacological Activities Of The Roots Of Polyalthia Obliqua

Polyalthia obliqua which belongs to the genus of Polyalthia of Annonaceae is the endemic plant of China only distributed in Hainan. Scholars at home and abroad had extracted many types of chemical constituents from the genus of Polyalthia, such as alkaloids, terpenes, and some other types of compounds. But as the endemic plant of hainan, there are no reports on chemical constituents and pharmacological activity of To determine the chemical constituents and their pharmacological activity, we have extracted and separated the ethanol extracts from the roots of P. obliqua, and then characterized structures of chemical compounds and investgated pharmacological activity. This work will provide a theoretical basis for developing and utilizing P. obliqua.The air-dried and powdered roots of P. obliqua were extracted by75%ethanol solution(in volume fraction). Ethanol extracts was obtained after evaporation ethanol solution under reduced pressure. The extracts were mixed with water, and then extracted by petroleum ether, chloroform and ethyl acetate, respectively. The fractions were respectively subjected to silica gel column chromatography, sephadex LH-20, preparation thin-layer chromatography and recrystallization repeatedly, and then obtained pure compounds. The structures of the isolated compounds were identified by spectrum technology and their physicochemical properties. And the tests on antioxidation, antimicrobial and cytotoxic activities of different fractions had taken.Bioassay-guided isolation study on the root extract of P. obliqua led to the isolation of fourteen compounds:5,7-dihydroxy-8-formyl-6-methylflavanone(1),5,7-dihydroxy-6-formyl-8-methylflavone(6), demethoxymatteucinol(7),5,7-dihydroxy-6-methyl-8-formylflavone(8), marcanine A(9), isoursuline(12), nicotinic acid(13), suberosol(3), β-Sitosterol(2), β-daucoster ol(14), vanillin(4), succinic acid(5), bis(2-ethylhexyl)phthalate(10), cinnamic acid(11). Compounds (1),(6),(7),(8) were reported from this genus for the first time, and all the compounds were isolated from this plant for the first time.The petroleum ether fraction and chloroform fraction showed cytotoxic activities against human lung cancer(SPC-A-1) and human gastric cancer(SGC-7901) cell lines by In vitro cytotoxic test, and compound3showed cytotoxic activity against SPC-A-1and SGC-7901, the IC50values were34.3μmol/mL and15.02μmol/mL, respectively. The four fractions extracted by different solutions showed antioxidant activity, and the ethyl acetate fraction exhibited better effects than other fractions in antioxidant test. From In vitro antibacterial test, the chloroform fraction showed the highest antibacterial effect among the four extrats, the MIC values against Escherichia coli and Bacillus subtilis were20mg/mL, and the MIC value against Staphyloccocus aureus was40mg/mL.