Alkaloids From Picrasma Quassioides (D. Dom) Benn.and Their Anti-inflammatory And Antibacterial Activities

Picrasma quassioides (D. Dom) Benn. belongs to the genus Picrasma and the family Simarubaceae. It is distributed in China widely. The stems of Picrasma quassioides (D. Dom) Benn. have traditionally been used as a folk medicine to treat bacillary, gastroenteritis, eczema etc. Picrasma quassioides (D. Dom) Benn. is reported in Dictionary of Chinese Material Medica and Ch P (2000). It is reported that the plant contains alkaloids and nigakilactone. Research foundation is provided for clinical application and quality control of praeparatum. Given its curative effect, we study to alkaloid constituent of Picrasma quassioides (D. Dom) Benn. By means of modern chemical theory and isolation technique, we systemically study to the plant mentioned above, and elucidat the structure of the compounds which are isolated and purified from this species. Futhermore, the isolates, which are isolated from the plant, are screened for biological activities against anti-inflammatory and antibacterial activities. Extracting by different solvents, isolating by the column chromatography over reversed phase silica gel, Sephadex LH-20, silica gel as well as by other techniques as preparative TLC, MPLC and HPLC. We have isolated 23 compounds from this plant, and 19 compounds are identified by application of special evidence, such as chemical methods and comparison with some authentic samples, standard spectra, physical-chemical data, and these compounds are established as follows: 5-Methoxycanthin-6-one (1), 11- Hydroxycanthin -6-one (2), Canthin-6-one (3), 4,5-Dimethoxycanthin -6-one (4), 4–Methoxy-5-hydroxycanthin-6-one (5), 3-Methylcanthin-2,6-dione (6), 1-Formyl-4-methoxy-β-carboline(7), 1-Methoxy–β-carboline (8), 1-Ethyl -4,8-dimethoxy-β-carboline (9), 1-Methoxycarbonyl-4-hydroxyl-β-carboline (10), 1-Methyl-4- methoxy -β-carboline (11), 1-Ethoxy carbonyl-β-carboline (12), 1-Formyl-β-carboline (13), 1-Methoxycarbony -β-carboline (14), 1-Ethyl-4- methoxy-β-carboline (15), 1,2,3,4 -Tetrahydro -1,3,4- trioxo -β-carboline (16), 1-Formyloxy-β-carboline (17), Kumujiantine (18) and Neoquassin (19). For the first time, compound 11 is separated from the natural resource. Compounds 2, 7 and 15 are obtained from Picrasma as first time, and compound 17 is firstly separated from Picrasma quassioides (D. Dom) Benn.In the course of structural determination, extensive 2D-NMR techniques, especially HMBC (1H-detected multiple-bond heteronuclear multiple quantum coherence) experiments, are successfully applied to determine the structure of compounds. 1H and 13C-signals of compounds are assigned firstly by means of 2D-NMR spectra. Some mistakes which occurred in the literatures of compounds are properly corrected.With respect to the bioassay, the alkaloids, which are isolated from the EtOH extract of Picrasma quassioides (D. Dom) Benn. display moderate anti-inflammatory and antibacterial activities in vitro. With index of LPS induce macrophage NO depressant effect, preliminara assessment of their antiinflammatory indicate the compounds 7 and 13 activities are better than other compounds. With IC₅₀ being 3.9μmol /ml and 5.0μmol /ml respectively.With index of pneumonococcus, preliminara assessment of antibacterial activities of compound 4, with MIC being 1μg/ml.