Chemical Compositions Of Sorbaria Arborea And Their Bioactivities In Vitro

Sorbaria arborea, a kind of deciduous shrub, belongs to Sorbaria of Rosaceae. It is one of the orginal plants of the Chinese herbal medicine Zhenzhumei which is used for the therapeutic purpose of activating blood, eliminating stasis, decreasing swelling and alleviating pain. The chemical components and pharmacological research of the plants of the Sorbaria genus at home and abroad mainly concentrated in the S. sorbifolia and S. sorbifolia(L.)A.Br.var.stellipila, while the study of Sorbaria arborea is only on the chemical composition of leaves. In order to make up for the lack of the study on the Sorbaria arborea, this topic carries on a systemic research to the chemical constituents and biological activity in vitro of the stems and branchs of Sorbaria arborea in Qinling. We hope to find activity compounds and provide the rationale for the exploitation and utilization of the medicinal plant, so that future generations have a more comprehensive understanding and utilization on it.The stems and branchs of Sorbaria arborea were selected as the research object in this topic. The air-dried stems and branchs of Sorbaria arborea (5.6 kg) were powdered and extracted with 95% ethanol at room temperature for six times. The ethanolic extracts were evaporated to get crude extract. Three kinds of coarse separation materials with different polarity were isolated from crude extract with petroleum ether, ethyl acetate and methanol by silica gel column chromatography. After that we used silica gel column chromatography, Sephadex LH-20 column chromatography and recrystallization repeatedly on these three groups. The purity of compounds were determined by the compound melting point and thin layer chromatography, then the 11 compounds were identified with high resolution mass spectrometry(HRESI-MS), nuclear magnetic resonance (NMR) spectroscopy, etc. They were elucidated as Lupeol(1), Betulin(2), Lup-20(29)-en-3β,30-diol(3), Ursolic acid(4), Tormentic acid(5), (-)-Epicatechin(6), Cucurbitacin F(7), Daucosterol(8), Arbutin(9), Tachioside(10), 2,6-dimethoxy-p-hydroquino-ne-4-O-β-D-glucopyranoside(11). All of the compounds were isolated from this plant for the first time, and compounds 1, 3～5,10 and 11 were obtained from Sorbaria genus for the first time.Using 4 strains of bacteria and 8 strains of fungi to carry out the minimum bacteriostasis experiment(MICs). All of the compounds were tested. The results showed that three compounds had good antibacterial activity. Tormentic acid and ursolic acid had broad-spectrum antibacterial activity. Cucurbitacin F had good antifungal inhibitions. The experimental results elucidated the material basis for the antibacterial activity of this plant, and these substances can be used in the development of antibacterial, etc.The DPPH radical-scavenging capacity of compound 4、6、9-11 was measured. Compared with vitamin C, (-)-epicatechin got good antioxidant effects, and arbutin, tachioside and 2,6-dimethoxy-p-hydroquino-ne-4-O-β-D-glucopyranoside also had a certain antioxidant activity. That showed that Sorbaria arborea can produce substances with antioxidant activity.