Chemical constituents from Neo-Taraxacum siphonathum / 中国中药杂志

<p><b>OBJECTIVE</b>To study the chemical constituents from the antioxidant fraction of Neo-Taraxacum siphonathum.</p><p><b>METHOD</b>Various chromatographic techniques were used to isolate and purify the constituents. The structures were elucidated on the basis of chemical evidence and spectral analysis.</p><p><b>RESULT</b>Ten compounds were isolated and identified from Neo-T. siphonathum, caffeic acid (1), chlorogenic acid (2), quercetin (3), luteolin (4), quercetin-3-O-beta-D-glucopyranoside (5), quercetin-3-O-alpha-D-arabinofuranoside (6), quercetin-3-O-alpha-D-arabinopyranoside (7), luteolin-7-O-beta-D-glucopyranoside (8), beta-sitosterol (9) and daucosterol (10).</p><p><b>CONCLUSION</b>Compounds 1-10 were isolated from this plant for the first time.</p>

Quantitative Relationship Between ~(13)C Nuclear Magnelic Resonance Chemical Shift and Structural Parameters of Acyclic Alcohol / 分析化学

A newly developed topological vector of atom Y_C, equilibrium electro-negativity of atom q_e, molecular structural information parameter[N_H~i(i=α, β)] and γ calibration parameter were used to describe the local chemical microenvironment of 63 acyclic alcoholic compounds. Quantitative structural spectrum relationships (QSSR) was systematically made on relationship between ~(13)C NMR chemical shifts of 353 carbon atoms and their molecular structure descriptors. By partial least square regression(PLS), the statistical results indicated that the model correlation coefficient and standard error were 0.9915 and 2.4827, respectively. And the average absolute error was only 2.01×10~(-6) between the calculated and experimental chemical shifts for 353 carbon atoms. To validate the estimation stability for internal samples and the predictive capability for external samples of resulting models, leave-molecule-out(LMO) cross validation(CV) and external validation were performed. Compared with the reported result, not only the number of descriptors employed in this study was much fewer, but also the calculation was much easier.

To Stress Innovation and Improve the Quality and Effect of Medical Chemistry Experiment Teaching / 中华医学教育探索杂志

Medical chemistry is one of the important basic medicines.Faced with the rapid development of education,Medical chemical education reform or innovation should also keep vigorous.In this paper,we discuss how to innovate and improve the quality and effect of experiment in the process of medical chemistry experiment and lay a solid foundation for continued study.