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In this work, eight compounds from Phellodendron chinense were separated and purified by pH-zone refining counter-current chromatography and traditional counter-current chromatography coupled with online-storage inner-recycling counter-current chromatography (IRCCC). The pH-zone-refining mode was adopted for separating 2.0 g of crude extract with the solvent system of chloroform-methanol-water (4:3:3, v/v), in which 10 mM hydrochloric acid and 10 mM triethylamine were added in the stationary and mobile phases, respectively. Meanwhile, traditional counter-current chromatography coupled with online-storage IRCCC separation was performed by the solvent system of n-hexane-ethyl acetate-methanol-water (5:5:2:8, v/v). Finally, eight compounds, including six alkaloids as 6-methylpiperidin-2-one(1), isoplatydesmine(4), berlambine(5), epiberberine(6), palmatine(7), berberine(8) and two phenolic acids as ferulic acid(2), isoferulic acid(3), were successfully obtained using these three different CCC modes with the purities over 95.0%., (© 2023 Wiley-VCH GmbH.)

Toddalia asiatica (Linn.) Lam. is a medical plant traditionally used to treat coughs, fevers, and various diseases. Alkaloids are the main active ingredients in Toddalia asiatica (Linn.) Lam., but traditional methods for screening and separation are complex and labor-intensive. In this work, an efficient strategy was developed to rapidly screen, identify, and separate neuraminidase inhibitors from Toddalia asiatica (Linn.) Lam. Ultrafiltration, high performance liquid chromatography, and time-of-flight mass spectrometry were employed for rapid screening and identification of neuraminidase inhibitors. A two-phase solvent system comprising n-hexane/ethyl acetate/methanol/water (5:5:3:7, v/v) was then selected for separation by high-speed counter-current chromatography. A sample loading of 200 mg and a stepwise flow rate were achieved by increasing the flow rate from 2 to 4 mL/min after 4 h. Three main fluoroquinoline alkaloids (haplopine, skimmianine, and 5-methoxydictamnine) along with two coumarins were obtained via one-step separation and their structures were determined by mass spectrometry and nuclear magnetic resonance. In vitro assays revealed skimmianine with half-maximal inhibitory concentration of 16.2 ± 0.7 µmol/L was selected as the potential highest neuraminidase inhibitor. The results suggest that ultrafiltration high performance liquid chromatography-mass spectrometry combined with high-speed counter-current chromatography is efficient for the screening and isolation of neuraminidase inhibitors from complex natural products., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Development of noble-metal-free photocatalysts for highly efficient sunlight-driven water splitting is of great interest. Nevertheless, for the photocatalytic H 2 evolution reaction (HER), the integrated regulation study on morphology, electronic band structures, and surface active sites of catalyst is still minimal up to now. Herein, well-defined 1D Cd 1- x Zn x S@O-MoS 2 /NiO x hybrid nanostructures with enhanced activity and stability for photocatalytic HER are prepared. Interestingly, the band alignments, exposure of active sites, and interfacial charge separation of Cd 1- x Zn x S@O-MoS 2 /NiO x are optimized by tuning the Zn-doping content as well as the growth of defect-rich O-MoS 2 layer and NiO x nanoparticles, which endow the hybrids with excellent HER performances. Specifically, the visible-light-driven (>420 nm) HER activity of Cd 1- x Zn x S@O-MoS 2 /NiO x with 15% Zn-doping and 0.2 wt% O-MoS 2 (CZ 0.15 S-0.2M-NiO x ) in lactic acid solution (66.08 mmol h -1 g -1 ) is about 25 times that of Pt loaded CZ 0.15 S, which is further increased to 223.17 mmol h -1 g -1 when using Na 2 S/Na 2 SO 3 as the sacrificial agent. Meanwhile, in Na 2 S/Na 2 SO 3 solution, the CZ 0.15 S-0.2M-NiO x sample demonstrates an apparent quantum yield of 64.1% at 420 nm and a good stability for HER under long-time illumination. The results presented in this work can be valuable inspirations for the exploitation of advanced materials for energy-related applications., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An efficient coordination high-speed counter-current chromatography method for the preparative separation of ginkgolic acids from the sarcotesta of Ginkgo biloba L was developed. The type, concentration, and mechanism of the coordination agent were investigated. Following the use of four types of metal salts including silver nitrate, copper chloride, ferric chloride, and aluminium nitrate, n-heptane/ethyl acetate/methanol/acetic acid 5:4:1:1, v/v with 0.20 mol/L silver nitrate as the coordination agent was chosen as the optimum two-phase solvent system. Five main ginkgolic acids including C13:0, C15:0, C15:1, C17:1, and C17:2 were successfully separated with purities greater than 98%. The sample loading was 500 mg, the flow-rate was 2.0 mL/min, rotation speed was 800 rpm and temperature was 20°C. The structures of the separated ginkgolic acids were identified by comparison with standard samples and electrospray ionization mass spectrometry. The introduction of coordination chemistry in high-speed counter-current chromatography is novel and effective for the preparative separation and isolation of ginkgolic acids from the sarcotesta of Ginkgo biloba L and could also be applied to separate compounds which form coordination bonds in other complex natural products., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We put forward an efficient strategy based on bioassay guidance for the rapid screening, identification, and purification of the neuraminidase inhibitors from traditional Chinese medicines, and apply to the discovery of anti-influenza components from Lithospermiun erythrorhizon Sieb.et Zucc. Ultrafiltration with high-performance liquid chromatography and electrospray ionization time-of-flight mass spectrometry was employed for the rapid screening and preliminarily identification of anti-influenza components from Zicao. Semipreparative high-performance liquid chromatography was used for the rapid separation and purification of the target compounds. NMR spectroscopy, mass spectrometry, and UV spectroscopy were used for further structural identification, and the activity of the compounds was verified by in vitro assay. Five compounds were found to have neuraminidase inhibitory activity by this method. Subsequently, the five compounds were separated by semipreparative high-performance liquid chromatography with the purity over 98% for all of them by high-performance liquid chromatography test. Combined with the NMR spectroscopy, mass spectrometry, and UV spectroscopy data, they were identified as alkannin, acetylalkannin, isobutyrylalkannin, β,β-dimethylacryloylalkannin and isovalerylalkannin. The in vitro assay showed that all five compounds had good neuraminidase inhibitory activities. These results suggested that the method is highly efficient, and it can provide platform and methodology supports for the rapid discovery of anti-influenza active ingredients from complex Chinese herbal medicines., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Enzymatic hydrolysis pretreatment combined with high-speed counter-current chromatography for the transformation and isolation of arctigenin from Fructus Arctii was successfully developed. In the first step, the extract solution of Fructus Arctii was enzymatic hydrolyzed by β-glucosidase. The optimal hydrolysis conditions were 40°C, pH 5.0, 24 h of hydrolysis time, and 1.25 mg/mL β-glucosidase concentration. Under these conditions, the content of arctigenin was transformed from 2.60 to 12.59 mg/g. In the second step, arctigenin in the hydrolysis products was separated and purified by high-speed counter-current chromatography with a two-phase solvent system composed of petroleum ether/ethyl acetate/methanol/water (10:25:15:20, v/v), and the fraction was analyzed by HPLC, ESI-MS, and (1)H NMR spectroscopy. Finally, 102 mg of arctigenin with a purity of 98.9% was obtained in a one-step separation from 200 mg of hydrolyzed sample., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this study, supercritical fluid extraction (SFE) was used to extract essential oil from Acorus tatarinowii Schott under the pressure of 25 MPa and temperature of 35°C. Two (E)- and (Z)-diastereomers of α-asarone and β-asarone were separated and purified by high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:0.2:1:0.3, v/v). The separation yielded a total of 39 mg of α-asarone and 463 mg of β-asarone from 1.0 g of essential oil in one-step separation with the purity of 98.9 and 99.1%, respectively, as determined by HPLC. The chemical structures of these compounds were identified by EI-MS, (1)H-, and (13)C-NMR., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Preparative separation of alkaloids from embryo of the seed of Nelumbo nucifera Gaertn has been successfully performed for the first time using pH-zone-refining counter-current chromatography. Two kinds of two-phase solvent systems were applied to preparative CCC isolation. The first was the system composed of MtBE-water (1:1, v/v), 10 mM triethylamine in organic stationary phase and 5 mM HCl in aqueous mobile phase, which could only separate neferine partly from the crude extract. The second was the system composed of n-hexane-ethyl acetate-methanol-water (5:5:2:8, v/v), 10 mM triethylamine in organic stationary phase and 5 mM HCl in aqueous mobile phase, which was the optimum for large-scale CCC isolation. 2.5 g of the crude alkaloid was purified in one-step separation of 7 h, yielding 151 mg of liensinine, 118 mg of isoliensinine and 572 mg of neferine with the purities of 93.0, 95.1 and 97.0%, respectively.

An ionic liquid-based ultrasound-assisted extraction method has been developed for the effective extraction of fangchinoline and tetrandrine from Stephaniae tetrandrae. The effects of some ultrasound-assisted extraction parameters including the concentration of [BMIM][BF(4)], pH, ultrasonic power and time were investigated to optimize the ultrasound-assisted extraction conditions. Compared to the regular ultrasound-assisted extraction and traditional refluent extraction, the proposed [BMIM][BF(4)]-based ultrasound-assisted extraction offered shorter extraction times (from 6 h to 40 min) and remarkable higher efficiencies (approximately 30% improved), which supported the suitability of the proposed approach. In addition, the proposed approach was confirmed by the good correlation coefficient (R(2)), recovery and reproducibility (RSD, n = 5), which were in the range of 0.9992-0.9995, 85.5-101.1%, and 1.87-4.33%, respectively.

pH-zone-refining counter-current chromatography was successfully applied to the separation of alkaloids from a crude extract of Peganum harmala L. using a multilayer coil planet centrifuge. The experiment was performed with a two-phase solvent system composed of methyl tert-butyl ether/THF/water (2:2:3 by volume) where triethylamine (10 mM) was added to the upper organic stationary phase as a retainer and hydrochloric acid (5 mM) to the aqueous mobile phase as an eluter. From 1.2 g of the crude extract, 554 mg harmine and 325 mg harmaline were obtained each with a purity of over 96% as determined by HPLC. The structures of the isolated compounds were identified by electron ionization MS (EI-MS), (1)H NMR, and (13)C NMR.

pH-Zone-refining countercurrent chromatography was successfully applied to the separation of salvianolic acid B from the Chinese medicinal plant, Salvia miltiorrhiza Bunge, using a multilayer coil planet centrifuge. A 2.0 g quantity of sample was separated using the following two-phase solvent system: methyl tert-butyl ether (MtBE)-water, 10 mM TFA in organic stationary phase and 10 mM ammonia in aqueous mobile phase. The obtained fractions were analyzed by HPLC and ESI-MS. The separation yielded 572 mg of the main component of salvianolic acid B with a purity of 94.1%.