| Limonium bicolor Kunze (Bge.), commonly named as broomy grass and so on similarity the grass drought weeds in China, is a perennial (rare annual) herbaceous that belong to the genus of Limoniums (Plumbaginaceae) and grown in the sandiness or light salt region, such as grassland, meadow, mountainous region, is found in northeast, Yellow River drainage area province, and the north of Jiangsu, Mongolia and otherwise. The full plant is traditional drug, to heal bleeding, cancer nephritis and other weakness symptom. Several polyphenolic constituents Gallic acid, Myricetin-3-O-B-D-(6-galloyl)-galactoside, Quercetin, Eriodictyol, Luteolin, and have been isolated from aerial parts of Limonium bicolor, but till now no report related to the chemical composition and biological activities of it. It is well known that many biologically active polysaccharides have been isolated from vegetable kingdom; some of these polysaccharides are used clinically for cancer therapy. Flavones compounds, which generally exist as their glycosides in plants, are a kind of important secondary metabolites in plants. A lot of flavones showed interesting biological activities such as antioxidant, antibacterial, antivirus, and so on. Otherwise, the plant essential oils are other components, which generally have the biological activity of antibacterial, antioxidant, toxicity to pests. The present work is on the isolation, structural identification, and biological activity study of the polysaccharide, flavones and essential oil of Limonium bicolor. The main contents are summarized as follows:1 The recent progress on polysaccharides, flavones and essential oil, such as theisolation and purification, structural analysis, biological activities and structure-activity relationships of them were reviewed.2 Water-soluble polysaccharide (LP) was isolated from the aerial parts of the plants of Limonium bicolor by extraction with hot water. Purification by gel chromatogram of Sephadex. Analysis by gel penneation chromatography (GPC) showed it to be homogeneous and its molecular weight was about 4.63x103. From the results of acid hydrolysis, by GC-MS, FT-IR, 13C NMR, 1H NMR and element analysis, and so on, the result showed that glucose and glucose acid were the main components of LP, and the bond between GlcA and Glc was a-(1-6), then the disaccharide unit was connected by a-(l-4) linkage. The polysaccharides of LP had the fluorescence, 460nm was the highest emission peak, and the Zn2+ or Ca2+ enhanced the fluorescence intensity of LP. Much more research proved that LP had the activity of antioxidant and the function of inhibited the growth of Hela cells, with the IC50 was 62.2ug/mL.3 Two novel components had been isolated by solvent extraction and chromatography separation. The air-dried powder of the plant of Limonium bicolor were defatted with n-hexane and successively extracted with CHCl3, CHCl3-MeOH (9:1) and MeOH, in soxhlet apparatus, respectively. The methanolic residue was concentrated and chromatographed on Sephadex LH-20, then submitted to semi-preparative HPLC on a Eclipse XDB C18 column monitored by photo-diode-array detector, which led to the isolation of compound of 5,7,4'-trihydroxy-3'-methyl-flavan-4-ol, 5,7,4'-trihydroxy-4-methyl-2-flavene, along with other known polyphenolic compounds apigenin, methylgallate. The structure was identified by UV, FT-IR instrument, EI-MS, 1H NMR, 13C NMR spectrometer. The compound was the cytotoxic component in the extract with an IC50 of 3.9ug/ml against HeLa cells. The results of this investigation give support to the traditional use for treatment of tumor. The fluorescence spectra (Tris-HCl pH=7.4) showed its highest emission peak at 460nm, when exited at 388nm.4 The interaction of gallic acid-Zn (II) complex with DNA in solution was studied. The result showed that DNA could bind to calf thymus DNA in the presence of zinc ions, which have been confirmed by absorption, fluorescence spectra and HPLC. The increase of peak intensity and red...
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