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Radix Astragali is one of the most famous and frequently used health food supplements and herbal medicines. Among more than 227 components of Radix Astragali, Astragaloside IV (AG IV) is famous functional compound and is commonly used as a quality marker for Radix Astragali. However, the relatively low content of AG IV in Radix Astragali (< 0.04%, w/w) severely limits its application. The purpose of this study is to improve the biotransformation of AG IV and its bioaccessibility during in vitro digestion by Poria cocos solid fermenting Radix Astragali. The optimum fermentation conditions were as follows: Inoculation amount 8 mL; fermentation time 10 d; fermentation humidity 90%. Through fermentation, the content of AG IV was increased from 384.73 to 1986.49 μg/g by 5.16-fold. After in vitro digestion, the contents of genistin, calycosin, formononetin, AG IV, Astragaloside II (AG II) and total flavonoids in fermented Radix Astragali (FRA) of enteric phase II (ENTII) were 34.52 μg/g, 207.32 μg/g, 56.76 μg/g, 2331.46 μg/g, 788.31 μg/g, 3.37 mg/g, which were 2.08-fold, 2.51-fold, 1.05-fold, 8.62-fold, 3.22-fold and 1.50-fold higher than those of control, respectively. The Scanning electron microscopy (SEM) of FRA showed rough surface and porous structure. The DPPH and ABTS radical scavenging rate of FRA were higher than those of control. These results showed that the Poria cocos solid fermentation could increase the content of the AG IV in Radix Astragali and improve the bioaccessibility and antioxidant activity of Radix Astragali, which is providing new ideas for future development and utilization of Radix Astragali. [ABSTRACT FROM AUTHOR]

Abstract: The optimal conditions for extraction of astragalosides III and IV (AGs III and IV) in Radix Astragali by negative pressure cavitation-accelerated enzyme pretreatment were studied on the basis of a Box–Behnken design and response surface methodology. Experimental results showed that negative pressure, amount of enzyme and incubation temperature were the main factors governing the enzyme pretreatment of Radix Astragali. The optimum parameters were obtained as follows: negative pressure −0.08Mpa, amount of enzyme 1.48% (w/w of materials) and incubation temperature 45°C. Under the optimal conditions, the maximal extraction yields of AGs III and IV were 0.103 and 0.325mg/g, which were 41.67% and 65.31% increased as compared to those without enzyme pretreatment, respectively. The effect of negative pressure cavitation and enzyme pretreatment on the structural changes of plant cells was observed by scanning electron microscopy. In conclusion, negative pressure cavitation-accelerated enzyme pretreatment was proved to be environment-friendly and economical, and could be used in secondary metabolites production. [Copyright &y& Elsevier]

Abstract: An efficient microwave-assisted extraction (MAE) technique was employed in extracting astragalosides I–IV from Radix Astragali. Astragalosides were quantified by liquid chromatography-electrospray ionisation mass spectrometry (LC-ESI/MS). The MAE procedure was optimised, validated and compared with other conventional extraction techniques. MAE gave the best result due to the highest extraction efficiency within the shortest extraction time. The optimal conditions of MAE were: employing 80% ethanol as solvent, ratio of solid/liquid 1:25 (g/ml), temperature 70°C, irradiation power 700W and three extraction cycles, each 5min. Scanning electron microscopy (SEM) images of Radix Astragali materials after different extractions were obtained to provide visual evidence of the disruption effect. This is the first report on combining MAE with LC-ESI/MS for the extraction and quantification of astragalosides I–IV in Radix Astragali. The developed MAE method provided a good alternative for the extraction of triterpenoid saponins in Radix Astragali as well as other herbs. [Copyright &y& Elsevier]