Cyclodextrins are well-known macrocyclic oligosaccharides that consist of α-(1,4) linked glucose units and have been widely used as artificial enzymes, chiral separators, chemical sensors, and drug excipients, owing to their hydrophobic and chiral interiors. Due to their remarkable inclusion capabilities with small organic molecules, more recent interests focus on organic reactions catalyzed by cyclodextrins. This contribution outlines the current progress in cyclodextrin-catalyzed organic reactions. Particular emphases are given to the organic reaction mechanisms and their applications. In the end, the future directions of research in this field are proposed.
Context: Alzheimer's disease (AD) is a chronic neurodegenerative disease that originates from central nervous system lesions or recessions. Current estimates suggest that this disease affects over 35 million people worldwide. However, lacking effective drugs is the biggest handicap in treating AD. In traditional Chinese medicine (TCM), Polygala tenuifolia Willd. (Polygalaceae) is generally used to treat insomnia, memory dysfunction and neurasthenia. Objective: This review article explores the role of P. tenuifolia and its active components in anti-Alzheimer's disease. Methods: Literature for the last ten years was obtained through a search on PubMed, SciFinder, CNKI, Google Scholar, Web of Science, Science Direct and China Knowledge Resource Integrated with the following keywords: Polygala tenuifolia, polygalasaponin XXXII (PGS 32), tenuifolin, polygalacic acid, senegenin, tenuigenin, Alzheimer's disease. Results: Polygala tenuifolia and its active components have multiplex neuroprotective potential associated with AD, such as anti-Ab aggregation, anti-Tau protein, anti-inflammation, antioxidant, anti-neuronal apoptosis, enhancing central cholinergic system and promote neuronal proliferation. Conclusions: Polygala tenuifolia and its active components exhibit multiple neuroprotective effects. Hence, P. tenuifolia is a potential drug against Alzheimer's disease, especially in terms of prevention.
With continuous development in analytical instruments over recent years, high performance liquid chromatography (HPLC) with various detectors has become very important tools for routine analysis and quality control of TCMs and botanical medicines. As a new ''mass'' detector, charged aerosol detector (CAD) provides an alternative detection method, which ultraviolet (UV) is unable to achieve for components owning almost no chromophore in its chemical structures with the lower sensitivity. With the purpose of evaluating the applicability of CAD for the analysis of TCMs, an HPLC-CAD method for simultaneous determination of saponins in Radix et Rhizoma Notoginseng (''Sanqi'' in chinese) was established in this contribution, which was successfully applied for quantitation of seven saponins, notoginsenoside R 1 , ginsenosides Rg 1 , Re, Rb 1 , Rg 2 , Rh 1 , and Rd, in thirty batches of Sanqi samples. Meanwhile, the LODs and LOQs of UV, ELSD and CAD were compared and the results showed that the CAD method exhibited a lower LOD (0.01 $ 0.15 mg) and LOQ (0.04 $ 0.41 mg) than UV and ELSD. Furthermore, the CAD exhibited a steadier baseline in gradient elution compared with UV at 203 nm. Also, the HPLC-CAD method presents many apparent advantages of high sensitivity, steady baseline in gradient elution, easy operating, and it was expected to be a sensitive and universal method for analysis of TCMs containing weak UV absorption compounds. It was demonstrated that the content of seven saponins in Radix et Rhizoma Notoginseng did not significantly correlate with the original work nor with the conventional quality standard.
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