Mechanochemical synthesis of cysteine-gum acacia intermolecular complex for multiple metal(loid) sequestration from herbal extracts.

The ubiquitous heavy metal(loid)s (HMs) contamination has triggered great concern about food safety, while sequestration and separation of trace HMs from herbal extracts still calls for appropriate sorbent materials. In this work, gum acacia was modified by cysteine to form a cysteine-acacia intermolecular complex (Cys-GA complex) via facile mechanochemical synthesis, aiming at capturing multiple HMs simultaneously. Preliminary screening confirms the superiority of Cys-CA complex for both cationic and anionic HMs, and determines an optimum Cys/GA mass ratio of 9:1 to achieve high removal capacities for Pb(II) (938 mg g-1), Cd(II) (834 mg g-1), As(V) (496 mg g-1), and Cr(VI) (647 mg g-1) in simulated aqueous solution. The analysis on HMs-exhausted Cys-GA complex indicates that Pb(II), As(V), and Cr(VI) tend to be removed through chelation, electrostatic attraction, and reduction, while Cd(II) can only be chelated or adsorbed by electrostatic interaction. The batch experiments on commercial herbal (e.g. Panax ginseng, Glycine max, Sophora flavescens, Gardenia jasminoides, Cyclocarya paliurus, and Bamboo leaf) extracts indicate that Cys-GA complex can reduce HMs concentration to attain acceptable level that comply with International Organization for Standardization, with negligible negative effect on its active ingredients. This work provides a practical and convenient strategy to purify HMs-contaminated foods without introducing secondary pollution.

An efficient high-speed countercurrent chromatography method for preparative isolation of highly potent anti-cancer compound antroquinonol from Antrodia camphorata after experimental design optimized extraction.

To avoid irreversible stationary phase adsorption and tedious and time-consuming separation steps, high-speed countercurrent chromatography was employed for the preparative separation of anti-tumor compound antroquinonol from solid fermentation culture of Antrodia camphorata for the first time. A Box-Behnken experimental design, based on three parameters including liquid-to-solid ratio, extraction time, and extraction temperature, was applied to optimize the ultrasonic extraction procedure. The optimal extraction condition was set as follows: liquid-to-solid ratio: 49.57:1; extraction time: 55.76 min; extraction temperature was arranged as 44.21°C. Meanwhile, an optimized solvent system containing petroleum ether, ethyl acetate, methanol, and water (4:1:4:1, v/v/v/v) was selected for the preparative separation of antroquinonol at a flow rate of 2.0 mL/min. The yield of isolated antroquinonol was determined to be 6.0 mg from 0.67 g of ethyl acetate extracts. The isolated antroquinonol was elucidated by ultra-high-performance liquid chromatography-tandem mass spectrometry, and NMR spectroscopy, and by comparison with literature data. The purity of isolated antroquinonol was determined to be 97.12%. This study confirmed that high-speed countercurrent chromatography was powerful and cost-effective for the preparative separation of the high-potently anti-tumor compound antroquinonol from solid fermentation culture of A. camphorata.