Identifying the geographical origin and processing technology of Moyao(Myrrh)on the basis of near-infrared spectroscopy combined with chemometrics

OBJECTIVE:To evaluate the quality of Moyao(Myrrh)in the identification of the geographical origin and processing of the products.METHODS:Raw Moyao(Myrrh)and two kinds of Moyao(Myrrh)processed with vinegar from three countries were identified using near-infrared(NIR)spectroscopy combined with chemometric techniques.Principal component analysis(PCA)was used to reduce the dimensionality of the data and visualize the clustering of samples from different categories.A classical chemometric algorithm(PLS-DA)and two machine learning algorithms[K-nearest neighbor(KNN)and support vector machine]were used to conduct a classification analysis of the near-infrared spectra of the Moyao(Myrrh)samples,and their discriminative performance was evaluated.RESULTS:Based on the accuracy,precision,recall rate,and F1 value in each model,the results showed that the classical chemometric algorithm and the machine learning algorithm obtained positive results.In all of the chemometric analyses,the NIR spectrum of Moyao(Myrrh)preprocessed by standard normal variation or Multivariate scattering correction combined with KNN achieved the highest accuracy in identifying the geographical origins,and the accuracy of identifying the processing technology established by the KNN method after first-order derivative pretreatment was the best.The best accuracy of geographical origin discrimination and processing technology discrimination were 0.9853 and 0.9706 respectively.CONCLUSIONS:NIR spectroscopy combined with chemometric technology can be an important tool for tracking the origin and processing technology of Moyao(Myrrh)and can also provide a reference for evaluations of its quality and the clinical use.

Design,synthesis and SAR study of 2-aminopyridine derivatives as potent and selective JAK2 inhibitors

The abnormal activation of JAK2 kinase is closely related to the occurrence and progression of myeloproliferative neoplasms(MPNs).At present,there is still an obvious unmet medical need for selective JAK2 inhibitors in clinic.In this paper,a class of 2-aminopyridine derivatives as potent and selective JAK2 inhibitors was obtained by combining drug design,synthesis and structure-activity relationship studies based on the previously identified lead Crizotinib.Among them,21 b exhibited high inhibitory activity against JAK2 with an IC_(50)of 9 nmol/L,moreover,it showed 276-and 184-fold selectivity over JAK1 and JAK3,respectively.Besides,21 b had a significant antiproliferative activity against HEL cells,and also inhibited the phosphorylation of JAK2 and its down-stream signaling pathway.These results indicated that2-aminopyridine compound 21 b had the potential to be developed as a selective JAK2 inhibitor for further study.