Pan Yuanjiang

Study on the chemical constituents of Euonymus alatus (Thunb.) Sleb.

This phytochemical study onEuonymus alatus (Thunb.) Sleb. (Celestrceae) yielded two compounds: a new compound, 2,3-dihydroxypropanyl hentetracosanate and a known compound: neozeaxanthin A. Their structures were elucidated by spectral evidences.

A new germacranolide fromCarpesium cernuum

As a part of our interest in biologically active germacranolides from the genusCarpesium (Compositae), we have investigated the constituents ofCarpesium cernuum. This paper reports the isolation and structural elucidation of a new germacranolide, cernolide A (Compound 1), from the herb. The structure of Compound 1 was determined as 2α,3β-dihydroxy-9-angeloxygermacra-4-en-6,12-olide on the basis of spectral evidence. The skeleton of Compound 1 was elucidation by IR, MS,1H and13CNMR, COSY, HMQC and HMBC experiments. The stereochemistry of Compound 1 was deduced by ROESY spectral data. Finally, the procedures of extraction and isolation were described in detail.

Affinity ultrafiltration of DNA topoisomerases-targeted compounds determined with HPLC/ESI-MS for drug candidate screening

A method of screening assay is demonstrated. The approach is based on the affinity of antitumor candidates for topoisomerases. In this method, antitumor candidates are fished out using topoisomerases as targets. Traditional analysis of complex compounds typically encounters signal suppression due to the relatively low concentrations, but enzyme-affinity screening for the active compounds can effectively concentrate the desired analysts into a small volume of high concentration. Active compounds are separated from non-affinity compounds by ultrafiltration. The molecules-enzymes complexes that are retained on the filter are subsequently separated by acidification to obtain the topoisomerases-affinity compounds for analysis on High Performance Liquid Chromatography coupled with electrospray ionization mass spectrometric detection (ESI-MS). This enzyme-affinity based screening assay provides a highly specific and efficient method that can directly screen, identify, and acquire drug candidates thus improving the accuracy and speed of high-throughput screening activities.

Rapid synthesis of phosphenium cations and detection of organic molecules in the gas phase

The article provides a method to synthesize phosphonium cations in the gas phase, and detect organic molecules by ion-molecule reactions. The active diphenylphosphonium cations were generated from the collision induced dissociation of methyltriphenylphosphonium cations by tandem mass spectrometry. There were 10 different kinds of molecules selected to make ion-molecule reaction with diphenylphosphonium cations, including acetonitrile, formic acid, acrylonitrile, dichloromethane, ethyl acetate, n -butanol, t -butanol, triethylamine, benzene, and styrene. The detection of these 10 kinds of molecules and the resolution of a pair of isomeric compounds n -butanol and t -butanol were both achieved. By adjusting the flow rate of molecules in a certain reaction time, different abundance of product peaks will be obtained. The quantitative analysis of molecules can be completed by making standard curves. This method is simple and convenient. It also offers an approach to make research of the gas phase reactivity of phosphonium cations.

A novel lactam from Delphinium caeruleum

The structure of a novel lactam(I) isolated fromDelphinium caeuleum Jacq. ex Camb was determined by spectral data.