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In this paper, liquid–liquid chromatography was introduced for the first time for the separation of fingered citron (Citrus medica L. var. sarcodactylis Swingle). The fingered citron cultivated in Jinhua is of significant industrial and medicinal value, with several major coumarin compounds detected in its extract. Therefore, further separation for higher purity was of necessity. A preparative liquid–liquid chromatographic method was developed by combining two elution modes (isocratic and step-gradient) with selection according to different polarities of the target sample. Five coumarin derivatives—5,7-dimethoxycoumarin (52.6 mg, 99.6%), phellopterin (4.9 mg, 97.1%), 5-prenyloxy-7-methoxycoumarin (6.7 mg, 98.7%), 6-hydroxy-7-methoxycoumarin (7.1 mg, 82.2%), and byakangelicol (10.5 mg, 90.1%)—with similar structures and properties were isolated on a large scale from 100 mg of petroleum ether (PE) extract and 100 mg of ethyl acetate (EA) extract in Jinhua fingered citron. The productivity was much improved. The anti-growth activity of the isolated coumarins was evaluated against three cancer cell lines (HeLa, A549, and MCF7) with an MTT assay. The coumarins demonstrated potential anti-tumor activity on the HeLa cell line, with 5,7-dimethoxycoumarin in particular exhibiting the best anti-growth activity (IC50 = 10.57 ± 0.24 μM) by inhibiting proliferation. It inhibited colony formation and reduced the size of the tumor sphere in a concentration-dependent manner. The main mechanism was confirmed as inducing apoptosis. This work was informative for further studies aimed at exploring new natural-product-based antitumor agents.

Triterpenoids are the major secondary metabolites and active substances in Ganoderma, considered as the “marker compounds” for the chemical evaluation or standardization of Ganoderma. A response surface methodology was used to optimize the ultrasonic-assisted extraction of triterpenoids. The extraction rate was 7.338 ± 0.150 mg/g under the optimum conditions: 87% ethanol, ratio of solid to liquid (w : v) 1 : 28, and ultrasound extraction time 36 min. Based on the high sensitivity and selectivity of HPLC-LTQ-Orbitrap-MSn, 24 components of triterpenoids were tentatively identified in the negative mode. Then, the global chemical profiling consisting of HPLC and TLC fingerprints generated by ChemPattern™ software was developed for evaluation of Ganoderma species. For fingerprint analysis, 11 peaks of triterpenoids were selected as the characteristic peaks to evaluate the similarities of different samples. The correlation coefficients of similarity were greater than 0.830. The cluster analysis showed a clear separation of three groups, and 11 peaks played key roles in differentiating these samples. The developed global chemical profiling method could be applied for rapid evaluation, quality control, and authenticity identification of Ganoderma and other herbal medicines.

Camptothecin-20(s)-O-(2-pyrazolyl-1)acetic ester (CPT6) is a novel semi-synthetic analog of camptothecin. In a previous report, CPT6 possessed higher cytotoxic activity in vitro towards human breast tumor MCF-7 cells than topotecan. In this study, the antitumor activity of CPT6 on the human breast tumor MCF-7 cell line was analyzed using the MTT method. The underlying mechanism of CPT6 action was investigated by analyzing the cell cycle distribution, apoptotic proportion, changes in mitochondrial membrane potential, and intracellular Ca2+ concentration using flow cytometry. Nuclear and mitochondrial morphologies were also observed by laser scanning confocal and transmission electron microscopy. DNA damage was observed in MCF-7 cells treated with CPT6. Low-dose CPT6 had a significant cytotoxic effect and could inhibit proliferation and induce apoptosis in MCF-7 cells, possibly through cell nucleus fragmentation and DNA damage. CPT6 thus appears to display potent antitumor activity against human breast tumor MCF-7 cells via the induction of apoptosis, and may be a useful alternative drug for breast cancer therapy.

In an effort to decrease the toxicity of camptothecin (CPT) and improve selectivity for hepatoma and colon cancer cells, bile acid groups were introduced into the CPT 20 or 10 positions, resulting in the preparation of sixteen novel CPT-bile acid analogues. The compounds in which a bile acid group was introduced at the 20-hydroxyl group of CPT showed better cytotoxic selectivity for human hepatoma and colon cancer cells than for human breast cancer cells. Fluorescence microscopy analysis demonstrated that one compound (E2) entered human hepatoma cells more effectively than it did human breast cancer cells. Compound G4 exhibited the best anti-tumour activity in vivo. These results suggested that introduction of a bile acid group at the 20-position of CPT could decrease toxicity in vivo and improve selectivity for hepatoma cells.

A Ag-doped double-layer composite film with TiO2 nanoparticles (P25) as the underlayer and TiO2 nanotube (TNT) arrays with the Ag-doped nanoparticles as the overlayer was fabricated as the photoanode in dye-sensitized solar cells (DSSCs). Five different concentrations of Ag-doped TNT arrays photoelectrode were compared with the pure TNT arrays composite photoelectrode. It is found that the photoelectric conversion efficiency of the TNT arrays composite photoanode is gradually improved from 3.00% of the pure TNT arrays composite photoanode to 6.12% of the Ag-doped TNT arrays photoanode with the increasing of the doping concentration, reaching up to the maximum in the 0.04 mol/L AgNO3 solution, and then slightly decreased to 5.43% after continuing to increase the doping concentration. The reason is mainly that the cluster structure of the Ag nanoparticles with large surface area contributes to dye adsorption and the Surface Plasmon Resonance Effect of the Ag nanoparticles improved the photocatalytic ability of the TNT arrays film.

Highly ordered TiO2 nanotube arrays (TNT arrays) were fabricated by two-step anodization process. In order to further improve the performance of DSSCs, TNT arrays were optimized by changing the anodization conditions to meet the requirements of high-performance photoanode. The photoelectric conversion properties of DSSCs based on P25/TNT arrays double-layer film with different anodization time were investigated and compared. The results show that the conversion efficiency of 4.20% was achieved in double-layer photoanode at 18 h, with an open-circuit voltage (Voc) of 0.65 V and short-circuit current density (Jsc) of 9.98 mA cm−2.

Analytical enantioseparation of five β-substituted-2-phenylpropionic acids by high-performance liquid chromatography with hydroxypropyl-β-cyclodextrin (HP-β-CD) as chiral mobile phase additive was established in this paper, and chromatographic retention mechanism was studied. The effects of various factors such as the organic modifier, different ODS C18 columns and concentration of HP-β-CD were investigated. The chiral mobile phase was composed of methanol or acetonitrile and 0.5% triethylamine acetate buffer at pH 3.0 added with 25 mmol L-1 of HP-β-CD, and baseline separations could be reached for all racemates. As for chromatographic retention mechanism, it was found that there was a negative correlation between the concentration of HP-β-CD in mobile phase and the retention factor under constant pH value and column temperature. [ABSTRACT FROM AUTHOR]

The bioactive iridoid component catalpol was successfully separated by high-speed countercurrent chromatography with high purity from the partially purified crude extract of Rehmannia glutinosa. A polar two-phase solvent system composed of ethyl acetate-n-butanol-water (2:1:3, v/v/v) was selected by thin-layer chromatography and run on a preparative scale where the lower aqueous phase was used as the mobile phase with a head-to-tail elution mode. A 105 mg quantity of the partially purified sample containing 39.2% catalpol was loaded on a 270-mL capacity high-speed countercurrent separation column, yielding 35 mg of catalpol at 95.6% purity. The chemical structure of catalpol was determined by comparison with the high-performance liquid chromatography retention time of standard substance as well as the ¹H NMR spectrum. [ABSTRACT FROM AUTHOR]