[Absorption enhancing effects and safety of PAMAM dendrimers on liquiritin].

PAMAM dendrimer is one of the most widely studied dendrimers in recent years, which has a large number of functional groups on the surface and cavities inside, specific three-dimensional structure and good biocompatibility, permeability and stability. It has been widely applied in drug and gene carrier fields and may become a new absorption enhancer. In order to study the absorption enhancing effects of PAMAM dendrimers, liquiritin was selected as the model drug, with the protection of spleen and liver, detoxification and other functions, but it had not been widely used in clinical application because of its difficult absorption, first pass effect, and low bioavailability. This topic was based on the two main determinants (solubility and permeability) of intestinal absorption in the body, researched the physicochemical properties of liquiritin, analyzed the transport volume of liquiritin with or without PAMAM dendrimers by using Caco-2 cell model, and analyzed the cytotoxicity of PAMAM dendrimers on Caco-2 cells by MTT experiments. These results showed that 0.1% of the G4 generation PAG can promote the absorption of liquiritin safely and effectively, and it was suitable for further development into a new type of pharmaceutical excipients.

[Biopharmaceutics classification and absorption mechanisms primary study on four kinds of flavonoids].

The solubility and permeability on four kinds of flavonoids (kaempferol, hesperidin, apigenin, genistein) were test according to the theory of biopharmaceutics classification system (BCS), and their absorption mechanism. The solubility was investigated by the method in determination of solubility of "Chinese Pharmacopoeia 2010". To detect appearance permeability of compounds mentioned above, the appropriate concentrations were selected by the MTT method in cell transfer experiments in Caco-2 cell model, which established by in vitro cell culture method. Therefore, these compounds were classified with BCS according to solubility and permeability. In addition, to explore absorption mechanisms, the experiments in three different concentrations of compounds in high, medium and low in bidirectional transformation methods in Caco-2 cell model contacted. The study indicated that all of kaempferol, hesperidin, apigenin, genistein have the characteristics in low solubility and high permeability, which belong to BCSⅡ, and the absorption mechanism of kaempferol was active transportation. Whereas, hesperidin, apigenin, genistein were passive transportation. In this study, it carried out initial explorations on establishment of determination for solubility and permeability in flavonoids, and provided theoretical reference for further research on BCS in traditional Chinese medicine.

Comparison of volatile profiles of nine litchi (Litchi chinensis Sonn.) cultivars from Southern China.

Volatile components of nine litchi cultivars (10 samples) with high commercial value from Southern China were investigated by means of gas chromatography-mass spectrometry combined with headspace solid phase microextraction. A total of 96 volatiles were detected, of which 43 were identified. Seventeen common volatiles in all the samples included linalool, cis-rose oxide, alpha-terpineol, beta-citronellol, geraniol, p-cymene, ethanol, 3-methyl-3-buten-1-ol, 3-methyl-2-buten-1-ol, 1-hexanol, (E)-2-hexen-1-ol, 2-ethyl-1-hexanol, 1-octen-3-ol, 1-octanol, ethyl acetate, p,alpha-dimethylstyrene and 3-tert-butyl-4-hydroxyanisole. Although the volatile composition and concentration varied between these cultivars, the components with the highest OAVs in most cultivars were still cis-rose oxide, trans-rose oxide, 1-octen-3-ol, and geraniol. Two Huaizhi samples from two producing areas exhibited similar volatile profiles, and significantly different from other cultivars according to cluster analysis performed on amounts of major volatile components.