Studies On The Chemical Constituents And Bioactivities Of Viola Tianshanica

The genus Violaceae(Viola) consists of more than 500 species in the world, widely distributed in temperate, tropical and subtropical, mainly in the northern temperate. China has more than 110 species of Violaceae, both North and South provinces, but most species are located in the southwest region, followed in the Northeast, North China. Viola plants mainly grow in mountainous forest, forest edge, hillside grassland, roadsides, shrub. It has been used for heat-clearing, detoxifying, cooling blood swelling for a long history. Besides, it has been widely used to treat ulcer sores, wind-heat cough, tuberculosis, asthma, rhinitis, keratitis, pharyngitis, mastitis, rheumatism.Viola tianshanica Maxim., widely used as a traditional herbal in Xinjiang. The aim of this thesis is to study its chemical compositions, the effect of antibacteria, antioxidation, antitumor activity in vitro, in order to provide a scientific basis for rational use.Steam-distillation of dried flowers of Viola tianshanica yielded 0.6%(v/w) of the yellow oil, about 18 constituents (89.67% of the total oil) and 15 constituents were identified by means of FT-IR and GC-MS analysis of the essential oils from Viola tianshanica. The chemical compositions of the essential oils from Viola tianshanica mainly include ester, aromatic hydrocarbons and organic acids.In vitro anti-bacterial, anti-oxidation tests and in vivo anti-inflammation test were used to study the bioactivity of essential oil and the extract of Viola tianshanica. The investigation on the chemical constituents of ethyl acetate fraction led to the isolation and identification of 6 compounds, including chrysin, aesculetin, umbelliferone, p-hydroxyacetophenone,β-sitosterol and stigmasterol. Their structures were elucidated by NMR sepctroscopic study and chemical analysis.Aesculetin is a coumarin isolated from Viola tianshanica. In the current report, we used aesculetin in the human cervical cancer cell line as a model system with which to investigate the effects of aesculetin induced apoptosis in vitro. HeLa cells treated with aesculetin (50μM) showed cytotoxic effects like rounding of cells with increased intercellular spaces, altered morphology and decrease in viability as seen by Hoechst 33258 staining. The survival of HeLa cells was decreased in a dose-and time-dependent manner (p< 0.05). Kidney is an important organ for excreting various toxic substances and drugs. HeLa cells as well as 293 cells belong to epithelial cellular morphology. It is worth to note that the toxicity did not occur in aesculetin-treated non-cancer cell lines,293 cells.Our observations demonstrated that excessive generation of ROS could lead to opening of the mitochondrial permeability transition pore with decline in△Ψm and consequent release of cytochrome c from the intermembrane space into the cytosol culminating in activation of the caspase cascade and apoptotic cell death. The present study strongly proposed that aesculetin may possess potential anti-cancer effects and supported its use as a treatment modality for cancers.