Phenolic Characterization and Antioxidant Activity of Chrysanthemum indicum and Opisthopappus Shih during Different Growth Stages.

Recently, much attention has been devoted to natural phenolics because of their ideal structure and chemistry for free radical scavenging activities, which may play important roles in long-term health and a reduction in the risk of developing chronic degenerative diseases. Chrysanthemum indicum (C. indicum) has been widely used as a health food and as a popular herb in China for many centuries. Opisthopappus Shih (O. shih) often takes the place of its related genera, C. indicum, in functional tea or medicine prescriptions in place of origin. In this article, a comparative study on the phenolics and antioxidant activity of C. indicum and O. shih during different growth stages was investigated. The antioxidant properties of plant extracts were tested using DPPH and ABTS assays. The characterization of potential phytochemicals was carried out using Fourier transform infrared (FT-IR) spectroscopy. Total phenolics (TPC) and total flavonoid content (TFC) were measured using Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. An HPLC method was used to simultaneously quantify five phenolic compounds, including chlorogenic acid, luteolin, rutin, quercetin, and apigenin. Results indicated that the Trolox equivalent antioxidant activity (TEAC) values of C. indicum and O. shih had extremely large variations at different growth stages. The most abundant phenolics and potent antioxidant activity of two related plants appear at the early vegetative and then flowering stages. Antioxidant activities and phenolic content of O. shih were higher than those of corresponding organs of C. indicum at the same collection time. The whole plant of O. shih, especially its leaves and flowers, are good candidates for obtaining nutraceuticals and functional food ingredients.

[Determination of poppy ingredients in chafing dish materials by isotopic internal standard coupled with multiple reaction monitoring and online full scan mass spectrometry].

A confirmative method was developed for determining five poppy alkaloids including morphine, codeine, papaverine, tibane, noscapine in chafing dish ingredients by high performance liquid chromatography coupled with triple quadrupole linear ion trap mass spectrometry (HPLC-Q Trap MS). The sample was extracted with dilute HCl solution under heating condition. The removal of lipid procedure was performed with hexane. The purification was carried out on a mixed-cation solid-phase extraction column (MCX) and ethyl acetate-methanol containing 5% aqueous ammonia was used for elution. A PAK ST column was used to separate the analytes, and 5 mmol/L ammonium acetate methanol and 10 mmol/L ammonium acetate (pH 3. 6) were used as mobile phases. The five alkaloids was detected in the positive mode simultaneously by multiple reaction monitoring (MRM) and online enhanced product ion full scan (EPI). The LODs were 0.05-0.5 µg/kg and the LOQs were 0. 2-2 µg/kg for the five poppy alkaloids. The overall recoveries of the method varied from 64. 2% to 110. 6%, and the RSD were between 4. 2% and 12. 5%. The EPI mass spectra of positive samples were searched through standard library for qualitative confirmation. The detection of real hot pot material samples showed this method can be used for the simple and accurate determination of the five poppy alkaloid residues in chafing dish.

[Rapid determination of total residues of ribavirin and its metabolites in chicken and chicken products by ultra-performance hydrophilic interaction chromatography-tandem mass spectrometry].

An analytical method was developed for the determination of total residues of ribavirin and its phosphorylated metabolites in chicken and its products by hydrophilic interaction chromatography-tandem mass spectrometry. The samples were extracted with acetonitrile containing 1% (v/v) acetic acid under ultrasonic condition and then enzymatically hydrolysed with acid phosphatase at 37 degrees C. After liposoluble substances being removed with hexane, C18 and PSA dispersion solid phase extraction (DSPE) was introduced to cleanup procedures. The separation was performed on an ultra-performance hydrophilic interaction chromatographic (HILIC) amide column under a gradient elution using acetonitrile and 0.1% formic acid. The analytes were detected in the positive electrospray ionization and multi-reaction monitoring (MRM) mode. In the range of 1-200 microg/kg, the correlation coefficient was greater than 0.999. The limit of detection (LOD, S/N > or = 3) was 1 microg/kg and the limit of quantification (LOQ, S/N > or = 10) was 5 microg/kg. The recoveries of ribavirin spiked at three levels ranged from 67.8% to 112.7% with the relative standard deviations (RSDs) of 6.1%-13.6%. The results of the determination of ribavirin in various real samples showed that the method is simple, rapid, accurate and suitable for the determination of total residues of ribavirin and its metabolites in chicken and its products.

[Determination of phenylethanolamine A residue in feeds by ultra performance liquid chromatography-tandem mass spectrometry].

A method was developed for the determination of the residue of phenylethanolamine A in feeds by ultra performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS). The phenylethanolamine A in sample was extracted with phosphoric acid methanol solution. The extract was purified and concentrated by an MCX column. In the positive mode, an ultra-performance BEH C18 column (100 mm x 2.1 mm, 1.7 microm) was used to separate the phenylethanolamine A, and the separation was carried out on a Waters UPLC system by using gradient elution with acetonitrile and 0.1% (v/v) formic acid aqueous solution as the mobile phases at a flow rate of 0.4 mL/min. The qualitative and quantitative analysis was carried out by multi-reaction monitoring (MRM) mode, in which the analyte was ionized by electrospray ionization interface (ESI). The results showed that, the calibration curve was linear in the range of 0.5-100 microg/kg (r > 0.999), the limit of quantification (S/N > 10) was 10 microg/kg, the recoveries ranged from 79.6% to 86.2%, and the relative standard deviations (RSDs) were between 3.1% and 6.7%. The real sample tests showed that the method is convenient and reliable.

The synthesis of chitosan-based silver nanoparticles and their antibacterial activity.

Chitosan-based silver nanoparticles were synthesized by reducing silver nitrate salts with nontoxic and biodegradable chitosan. The silver nanoparticles thus obtained showed highly potent antibacterial activity toward both Gram-positive and Gram-negative bacteria, comparable with the highly active precursor silver salts. Silver-impregnated chitosan films were formed from the starting materials composed of silver nitrate and chitosan via thermal treatment. Compared with pure chitosan films, chitosan films with silver showed both fast and long-lasting antibacterial effectiveness against Escherichia coli. The silver antibacterial materials prepared in our present system are promising candidates for a wide range of biomedical and general applications.