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Optimized on-line HPLC-DPPH method for evaluation and identification of the antioxidants in <b>Limonium aureum</b> (Linn.)<br><br>Display Omitted<br>• On-line HPLC-DPPH method was used for evaluate and identify of the antioxidants in <b>Limonium aureum</b> (Linn.) extract. • The optimum conditions of the method were obtained by response surface methodology. • Antioxidants were identified by MS.<br><b>Limonium aureum</b> (Linn.) is a traditional Chinese medicine with strong antioxidant activity. To search for antioxidants in <b>L. aureum</b>, an optimized, on-line high performance liquid chromatography (HPLC) method with DPPH (1,1-diphenyl-2-picrylhydrazyl) for the detection of radical scavenging ability was developed. Response surface methodology (RSM) was used to determine the best combination of experimental conditions, such as DPPH concentration, DPPH velocity and the reaction tank length. The optimized method uses a DPPH concentration of 25.0 μg/mL, DPPH velocity of 0.45 mL/min and a 15.0 m long reaction tank. The highly sensitive, optimized method can not only be used for the detection of antioxidants in plants, but can also be coupled with mass spectrometry (MS) to obtain the mass-to-charge ratios of chemical species corresponding to the different peaks in the HPLC profiles. Seven antioxidants were identified in <b>L. aureum</b> using the optimized method, including myricetin-3-<b>O</b>-β-d-(6”-<b>O</b>-galloyl)-glucopyranoside, myricetin-3-<b>O</b>-glucoside, myricitrin, eriodictyol-7-<b>O</b>-glucoside, myricetin, eriodictyol and homoeridictyol.

Three compounds were isolated from alcoholic extracts of Gentiana tizuensis Franch.. On the basis of spectroscopic methods. Their structures were identified as ursolic acid (1), isooreintin (2), swertiajaponin (3). Among them,compound 2 was isolated from the plant for the first time,compound 3 was isolated from Gentiana for the first time.

The contents of four iridoids ( loganic acid, swertiamarin, gentiopicroside, sweroside) in Gentiana tizuensis Franch. and Gentiana farreri were analyzed by HPLC. The analysis was performed on Econosphere C18 (250 x 4.6 mm, 5 µm) column, with the solution of 0.5 % acetic acid and methanol as mobile phase, at a flow rate of 1.0 mL/min. The detection wavelength was 254 nm. The results indicated that swertiamarin was not detected in Gentiana tizuensis Franch., and the contents of four iridoids in these two plants were different.

<br>Display Omitted<br>• Response surface methodology was applied to optimize supercritical fluid extraction conditions of alantolactone and isoalantolactone. • The optimized extraction conditions were pressure 20 MPa, extraction temperature 50 °C, carbon dioxide flow rate of 17 × 10−5 kg/s and extraction time of 40 min. • Freezing purification greatly improve the content of the target compounds by 30.7 wt.%.<br><b>Inula racemose</b> Hook.f. (<b>I</b>. <b>racemosa</b>) is a traditional herbal medicine with strong anti-fungal and anti-inflammation activity while alantolactone (AL) and isoalantolactone (IAL) are the major active compounds of this plant. The aim of this paper was obtaining AL and IAL from the radix of <b>I</b>. <b>racemosa</b> by supercritical fluid extraction (SFE) which was optimized by response surface methodology (RSM). Our results showed that, the optimal conditions for maximum extraction efficiency were as follows: pressure 20 MPa, extraction temperature 50 °C, carbon dioxide (CO2) flow rate of 17.0 × 10−5 kg/s and extraction time of 40 min. Subsequently, an efficient freezing method was developed for purification of AL and IAL in the crude extract obtained from SFE. After purification by freezing, the total content of the target compounds was greatly improved by 30.7%. The results demonstrate that SFE coupled with freezing would be a powerful technique for extraction and purification of AL and IAL from the radix of <b>I</b>. <b>racemosa</b>.

<i>Gentiana straminea</i> is the famous Tibetan folk medicine thought to cure various diseases. Historically, the Qinghai-Tibetan region has been considered as the geo-authentic production area of “Mahua Jiao,” where large quantities of the medicine are grown. However, there is still little known about the phytochemical constituent spatial variation of this species. In order to find the differences between the main phytochemical constituents of <i>G. straminea</i> and to provide comprehensive information for quality evaluation, four main bioactive compounds (loganic acid, swertiamarin, gentiopicroside and sweroside) were analysed in 26 populations grown in areas with elevations ranging from 2320 to 4720 m across the Qinghai-Tibetan Plateau. The results showed that the four phytochemical constitutes’ concentrations varied greatly in the spatial profiling of the Qinghai-Tibetan region. Throughout the range of distribution of this species, no altitudinal, latitudinal or longitudinal trends have proven to be significant in any of the four constitutes’ concentrations or their summation. Furthermore, hierarchical clustering analysis and statistical tests showed that four populations (Liu0609-18, Liu0609-15, Liu2006-13-9 and Liu0609-22) had total constitute contents that were higher than other populations. The spatial profiling of the four phytochemical constituents suggests that the geo-authentic producing area of this species exists at a few regions within the Qinghai province, which could be attributed to specific environmental or genetic factors.