Study On The Chemical Compositions And Biological Activity From Sargassum Fusiforme

Sargassum fusiforme and its extracts possess many multiple effects, such as antioxidant, lipid-lowering, anti-cancer, lowering blood sugar. The present study include four parts: 1. the extraction of Sargassum fusiforme using different organic solvents and evaluation on their inhibitive activity against protein tyrosine phosphatase 1B(PTP 1B) in vitro. 2. The chemical composition analysis in the extracts of petroleum ether and ethyl acetate by GC-MS. Separation and purification of the ethanol extract by silica gel chromatography and Sephadex LH-20 chromatography. 3. The extraction and analysis of the chemical composition in the essential oil from Sargassum fusiforme, and combination with molecular docking technology to predict PTP 1B inhibitor. 4. Separation of the chemical composition in the ethyl acetate extract by high-speed counte-rcurrent chromatography.Sargassum fusiforme(1300g) as raw material was extracted by different solvents. Eventually, six different extracts, petroleum ether extract(1.4g), ethyl acetate extract(7.9g), anhydrous ethanol extract(31g), 50% ethanol extract(283.6g), 50% ethanol supernatant(33.4g) and precipitation(203.6g) were obtained, and the rate of extraction was 0.11%、0.61%、2.4%、21.8%、2.6%、15.7%, respectively. After the assay of PTP-1B inhibitory activity, the values of IC50 were 2.00±0.34、0.37±0.07、1.96 ±0.26、1.27±0.29 、1.62±0.31 、0.99±0.19 μg/mL, respectively.Sixteen and fourteen compounds were analyzed and identified in the petroleum ether and ethyl acetate extracts by GC-MS. The principal chemical component in the petroleum ether extract was n-hexadecanoic acid, and in the ethyl acetate extract was 1,2-phthalic acid, dibutyl ester. The chemical composition in the ethanol extract was separated by silica gel chromatography. And 45 fractions were obtained, which were further separated by Sephadex LH-20 chromatography. A pure compound was isolated.44.0 mg essential oil were obtain from fresh Sargassum fusiforme(1500g) by the method of hydrodistillation uisng an all-glass Clevenger-type apparatus. And the extraction yield was 0.03%. After GC-MS analysis, ten compounds were identified from this oil. Among them, palmitic acid was 34.61% as the major compound. After pretreatment of alkylation reaction, the chemical composition in this essential oil was further studied by GC-MS. 26 compounds were identified, and palmitic acid was 40.781%. And then the identified compounds as ligands and PTP 1B as the target were used for molecular docking. The results exhibited that compound 9(N- [4-(diethylamino) phenyl] acetamide) with the lowest binding energy(-5.06 k J/mol) has the potential PTP 1B inhibitory activity.High-speed counter-current chromatography was used to study on the chemical composition in the ethyl acetate extract. Ethyl acetate: n-butanol: water(2: 3: 5, v/v) was as the two-phase solvent system. The flow rate of the mobile phase was 2 ml/min and the revolution speed was 800 rpm. 5 peaks, 4.51 mg, 2.12 mg, 4.46 mg, 2.15 mg, 3.12 mg, respectively, were isolated in 220 min. Their purities were 70%、93%、90%、94%、95%, respectively by HPLC. After concentration under reduced pressure at 50℃, however, the purities of these compounds were changed and reduced to 60%、75%、80%、74%、76%.