Caffeoylquinic acids (CQAs) are main constituents in many herbal medicines with various biological and pharmacological effects. However, CQAs will degrade or isomerize when affected by temperature, pH, light, etc. In this study, high-performance liquid chromatography with photodiode array detection (HPLC-PDA) and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was utilized to study the stability and degradation of CQAs (three mono-acyl CQAs and four di-acyl CQAs) under various ordinary storage conditions (involving different temperatures, solvents, and light irradiation). The results indicated that the stability of CQAs was mainly affected by temperature and light irradiation, while solvents did not affect it in any obvious way under the conditions studied. Mono-acyl CQAs were generally much more stable than di-acyl CQAs under the same conditions. Meanwhile, the chemical structures of 30 degradation products were also characterized by HPLC-MS n , inferring that isomerization, methylation, and hydrolysis were three major degradation pathways. The result provides a meaningful clue for the storage conditions of CQAs standard substances and samples.

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Active learning is an e ective learning approach. In this paper, we present a n i n telligent a g e n t assisted environment for active learning. The system is to better support studentcentered, self-paced, and highly interactive learning approach. Students' learning-related pro les, such as learning styles and background knowledge, are used in selecting, organizing, and presenting learning materials. A new approach t o course content organization and delivery is being developed based on smart instructional components, which c a n b e i ntegrated into a wide range of courses. The system is being implemented using the prevalent I n ternet, Web, digital library, and multi-agent technologies.

Magnesium isoglycyrrhizinate (MgIG), which has been widely employed to treat chronic hepatitis, is synthesized from 18-β glycyrrhizic acid, a main component of traditional Chinese medicine Glycyrrhiza uralensis Fisch. Although the protective effects of MgIG on methotrexate (MTX)-induced liver toxicity have been well-documented, the underlying mechanism remains elusive. MTX was initially used to treat pediatric acute leukemia, and has been widely applied to psoriasis therapy. However, its clinical applications are limited due to hepatotoxicity and intestinal toxicity. Herein, prophylactic administration of MgIG (9 and 18 mg/kg/day) significantly reduced the levels of aspartate aminotransferase and alanine aminotransferase in the serum of rats receiving intravenous injection of MTX (20 mg/kg body weight). MgIG also attenuated MTX-induced hepatic fibrosis. Moreover, it better protected against MTX-induced hepatocyte apoptosis and decreased the serum level of malondialdehyde than reduced glutathione (80 mg/kg/day) did. Interestingly, MTX-induced cyclooxygenase-2 (COX-2) expression, intestinal permeability and inflammation were attenuated after MgIG administration. In addition, MgIG (9 and 18 mg/kg) reduced MTX-induced colocalization of zonula occludens-1 (ZO-1) and connexin 43 (Cx43) in intestinal villi. In conclusion, MgIG exerted beneficial effects on MTX-induced hepatotoxicity and intestinal damage, as a potentially eligible drug for alleviating the hepatic and intestinal side effects of MTX during chemotherapy.