| Citrus aurantium L. var. amara Engl (C. aurantium L. var amara), a member of genus Citrus (Rutaceae), is the variant of Citrus aurantium L, which contains the similar chemical composition and pharmacological role with dry unripe (or) ripe fruit of Citrus aurantium L. Fruit of C. aurantium L. var amara have been used in traditional medicines with the effectiveness of digestant and expectorant. Its flower is rich in volatile oil, which have been applied in perfumes and cosmetics. At present, there are few studies on the flower of C. aurantium L. var amara, especially on its chemical composition and pharmacological effects. Reseach on its chemical components provides theoretical references for the application of flower of C. aurantium L. var amara in more areas.Firstly, the extraction of flower power was undertaken three times with 95% ethanol. After suspension procedure by adding water, different polar solvents were used for the diffusion of flower and four fractions of petroleum ether, chloroform, ethyl acetate and n-butanol phase were gotten. Meanwhile, the effect of anti-inflammatory was carried out for the total ethanol extracts and four fraction extracts of flower. The results obtained were that petroleum ether fraction had the strongest anti-inflammatory activity, and then chloroform fraction. Eethyl acetate and n-butanol fraction were almost of no anti-inflammatory activity.The petroleum ether and chloroform fraction were subjected to separation and purification using sephadex, TLC and silica gel column chromatography. Three compounds were gotten from flower. Using mass spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopy and comparison with literatures, the three monomeric compounds was identified to be:β- Sitosterol, 5-Hydroxy-6,7,3',4'-tetramethoxyflavone and Limonexic acid.Volatile oil from the flower was extracted by steam distillation, ultrasontic assisted and reflux method. Its compositions were identified by gas chromatography-mass spectrometry (GC-MS) and the relative contents were calculated by area normalization method. 54 species, extracted by steam distillation method, were identified. The highest content of species was (-)-Terpinen-4-ol (20.98%), and then (+)-Dipentene (11.67%). 30 species, extracted by ultrasontic assisted method, were identified. The highest content of species was Heneicosane (11.06%), and then Tetracosane (9.78%). 35 species, extracted by reflux method, were identified. The highest content of species was Hexadecanoic acid (20.61%), and then 9,12-Octadecadienoic acid (9Z,12Z)-, 2-chloroethyl ester (14.54%). There were great differences on the composition and content of volatile oil from flower extracted by three different methods. The right extraction method would be chosen for the target product.Ultrasonic-assisted extraction process for maximum flavonoids from the flower was investigated by response surface methodology. Though single factor experiment, ranges of the main variables affecting the extraction yield of flavonoids were confirmed. DPS (Design Expert 7.0) software was applied to analyze the experimental date. A rotatable central composite design was then applied and a regress model was obtained to predict the optimal extraction yiled. The optimal conditions (extraction temperature 72.11℃, time 51.min, ethanol concentration 51.19% and liquid/solid radio 40.11) were obtained from the regress equation. Under the optimal conditions, the maximum response value of yield (1.88%) was predicted by the model. To further test the reliability of the model equations, a verification experiment was carried out under adjusted conditions (extraction temperature 70.00℃, time 50.00min, ethanol concentration 50.00% and liquid/solid radio 40.00) on the basis of the optimal conditions. The result showed that the experimental value (the yield 1.87%) was consistent with the predictive value. The good correlation between these results demonstrated the validation of the RSM model and it was accurate and reliable to reflect the expected optimization.
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