A series of E and Z-isomers of 3-（4＇-substituted benzylidene）-indolin-2-one derivatives were synthesized and separated. Based on their 1H NMR characterization, an unusual counterintuitive deshielding phenomenon for the protons presenting in the shielding zone of phenyl ring was observed and analyzed for the first time.
Twenty-seven flavonoids, including 10 isoflavones, 9 flavanones, 3 dihydrochalcones, 3 flavonols and 2 flavans, were isolated from the whole plant of Tibetan medicine Oxytropis falcate Bunge. Structure elucidation was conducted by extensive spectroscopic analysis, including MS, NMR and CD spectra. Twelve compounds were obtained from this plant for the first time, among which 10 compounds were obtained from the genus of Oxytropis for the first time.
To facilitate the species identification and quality assessment of Chaihu （Bupleuri Radix）, a simple and valid chromatographic fingerprint method was developed. The method uses high-performance liquid chromatography coupled with evaporative light scattering detector （HPLC-ELSD） and the data analysis is assisted by professional analytical software recommended by the State Food and Drug Administration （SFDA）. The results indicate that Nan Chaihu raw materials and Chaihu decoction pieces vary markedly in chemical quality, while Bei Chaihu raw materials are relatively more stable. Furthermore, it is obvious that Nan Chaihu is chemically very different from Bei Chaihu, suggesting that Nan Chaihu may not be suitable for medicinal use. In addition, the obvious differences between the chromatograms of decoction pieces and raw materials, especially the peaks between 30 and 40 rain and after 45 rain, indicate possible effects of the processing procedures on the chemicals. By analyzing the fingerprints of all samples, 12 main saponin-like fingerprint peaks, of which at least three are characteristic peaks of saikosaponins a, c, and d, are proposed to be considered for further characterization and quality evaluation of Chaihu.
