Structural mechanism of a dual-functional enzyme DgpA/B/C as both a C-glycoside cleaving enzyme and an O- to C-glycoside isomerase

The C-glycosidic bond that connects the sugar moiety with aglycone is difficult to be broken or made due to its inert nature. The knowledge of C-glycoside breakdown and synthesis is very limited. Recently, the enzyme DgpA/B/C cascade from a human intestinal bacterium PUE was identified to specifically cleave the C-glycosidic bond of puerarin (daidzein-8-C-glucoside). Here we investigated how puerarin is recognized and oxidized by DgpA based on crystal structures of DgpA with or without substrate and biochemical characterization. More strikingly, we found that apart from being a C-glycoside cleaving enzyme, DgpA/B/C is capable of efficiently converting O- to C-glycoside showing the activity as a structure isomerase. A possible mechanistic model was proposed dependently of the simulated complex structure of DgpB/C with 3″-oxo-daidzin and structure-based mutagenesis. Our findings not only shed light on understanding the enzyme-mediated C-glycosidic bond breakage and formation, but also may help to facilitate stereospecific C-glycoside synthesis in pharmaceutical industry.

Ginsenosides in

Ginsenosides are a series of glycosylated triterpenoids which belong to protopanaxadiol (PPD)-, protopanaxatriol (PPT)-, ocotillol (OCT)- and oleanane (OA)-type saponins known as active compounds of

Advanced study on microRNAs involved in prevention and treatment of respiratory system diseases / 中国药理学通报

Recently, along with the harmful factors in air in-creasing, the incidence of respiratory system diseases has been gradually rising. Therefore, more studies are focused on impro-ving the prevention and treatment on respiratory system diseases. Current researches have shown that microRNAs ( miRNA ) con-tribute to the prevention and treatment on respiratory system dis-eases, including virus infectious respiratory disease, pulmonary fibrosis, asthma, COPD, pulmonary tuberculosis and lung canc-er. The up-regulation and down-regulation of microRNAs could effectively regulate the biological process of these diseases. The review analyzes the recent years′study results of respiratory sys-tem diseases and microRNAs in depth, and discuss the role of microRNA in the treatment and prevention of respiratory disea-ses. Moreover, in this review we can provide new knowledge a-bout respiratory diseases and development of more potent drug targets for the treatment and prevention of respiratory diseases.

Activity directed investigation on anti-inflammatory fractions and compounds from flowers of Trollius chinensis

The flower of Trollius chinensis Bunge is used as an anti-inflammatory drug to treat upper respiratory tract infection, pharyngitis, tonsillitis, and bronchitis. In order to identify the active components, the activity-screen directed compound isolation was carried out, leading to the identification of the major active fraction and 4 compounds thereof. As a result, flavonoids and phenolics were demonstrated to be the major anti-inflammatory components

Determination of trolline in flowers of Trollius chinensis by HPLC / 中国中药杂志

An HPLC method was developed for determinantion of trolline in the flowers of Trollius chinensis commercially available in China. The HPLC analysis was conducted on an Agilent C18 ODS column (4.6 mm x 250 mm, 5 microm) with acetonitrile-0.5% acetic acid solution (gradient: 0-30 min, 2:98-100:0) as mobile phase at a flow rate of 1.0 mL x min(-1). The detecting wavelength was at 258 nm. Linearity of trolline was good in the range of 0.1380-1.2410 microg and the content of trolline in nine batches of the flowers of T. chinensis commercially available in China was ranged from 0.05% to 0.11%. This method is good in terms of precision, accuracy and repeatability and can be used for the quantitative determination of trolline.

Manufacturing process and quality control of total flavonoid from Chrysanthemum morifolium and Sophora japonica and its quality control / 中国中药杂志

<p><b>OBJECTIVE</b>To optimize the manufacturing process of the total flavonoid from Chrysanthemum morifolium and Sophora japonica, and establish the quality control methods for total flavonoid and its indicative constituents.</p><p><b>METHOD</b>The solvent for extraction was investigated and L9 (3(4)) orthogonal experiment was used to optimize the extraction process of the total flavonoid. Colorimetric method was used to determine the content of total flavonoid, and HPLC was used to determine the content of the indicative constituents.</p><p><b>RESULT</b>The optimized manufacturing process of the total flavonoid was that the prescribed crude drugs were extracted by using 70% ethanol for 3 times, 1 h each time. The extract was concentrated to the final concentration of 0.5 g x mL(-1), and was subjected to HPD-600 macroporous resin column chromatography at the weight ratio 1 : 0. 5 of crude drugs to macroporous resin. The sample was eluted with water in the volume of 10 times of the resin's, and then was desorpted with 85% ethanol in the volume of 5 times of the resin's. The content of total flavonoid was determined as 64.98%-66.79%, and the content of indicative constituents was determined as 5.87% - 6.93% for luteolin-7-O-glucoside and 14.09%-16.62% for rutin.</p><p><b>CONCLUSION</b>Extracting with aqueous alcohol in combination with purifying with macroporous resin column chromatography is an efficient way to prepare the total flavonoid from Ch. morifolium and S. japonica, and the colorimetric and the HPLC methods are useful for its quality control.</p>

Study on preparation and quantity determination of Scrophularia ningpoensis dispensing granules / 中国中药杂志

<p><b>OBJECTIVE</b>To develop the preparation method and to determine the quantity of effective constituents of Scrophularia ningpoensis dispensing granules.</p><p><b>METHOD</b>Nine experiments were carried out through L9 (3(4)) orthogonal design. The contents of harpagoside and cinnamic acid were determined by HPLC method.</p><p><b>RESULT</b>The optimal extraction process was as follows: the slices were soaked in water in the ratio of 1:8 for 0.5 h, then they were decocted for 2 h. For the second time, 6 times of water was added and sustained for 1.5 h. Harpagoside and cinnamic acid were linear within the ranges of 0.0776-1.552 microg (r=0.9999) and 0.01446-0.4339 microg (r=0.9999), respectively. The average recoveries were 100.4% (RSD 1.98%, n=6) and 98.27% (RSD1.35%, n=6), respectively. Ten batches of granules were determined.</p><p><b>CONCLUSION</b>The extraction process is scientific and the determination method is suitable for quality control of Scrophularia ningpoensis dispensing granules.</p>