Purification of Flavonoids from Mulberry Leaves via High-Speed Counter-Current Chromatography

High-Speed Countercurrent Chromatography Isolation of Active Components from Evodia Rutaecarpa and Affinity Ultrafiltration Screening for Their Acetylcholinesterase Inhibitor Activity

Acetylcholinesterase inhibitors from Evodia rutaecarpa were screened, prepared, and evaluated. To screen the lipophilic alkaloid active constituents in E. rutaecarpa, we improved and optimized an ultrafiltration system. Three acetylcholinesterase (AChE) inhibitors, dehydroevodiamine, evodiamine, and rutecarpine, were screened. Addressing the limitations of the traditional response surface methodology (RSM) for multiobjective screening, we integrated RSM with the Non-dominated Sorting Genetic Algorithm III to achieve the optimal extraction of these active ingredients. High-speed countercurrent chromatography was used to isolate the active components using a two-phase solvent system: n-hexane/ethyl acetate/methanol/water (3.0:2.5:3.5:2.0, v/v/v/v) and ethyl acetate/methanol/water (3.0:1.0:4.0, v/v/v). The nuclear magnetic resonance spectroscopy confirmed the structures of the compounds, and molecular docking and dynamics simulations assessed the inhibitory effects of the chemical components on AChE, which were consistent with the findings of the ultrafiltration experiments. We also confirmed the neuroprotective properties of these compounds against glutamate-induced apoptosis in PC12 cells. Overall, we achieved the systematic optimization of multitarget compound extraction and lipophilic alkaloid ultrafiltration screening, as well as preparation and activity validation, laying the groundwork for the development of AChE inhibitors from lipophilic alkaloids.

Purification of linarin and hesperidin from Mentha haplocalyx by aqueous two-phase flotation coupled with preparative HPLC and evaluation of the neuroprotective effect of linarin

The volatile oil of Mentha haplocalyx is widely used in medicine, food, and cosmetics. However, a large amount of its residue after steam extraction of volatile oil is abandoned, resulting in a waste of resources. The method of aqueous two-phase flotation coupled with preparative high-performance liquid chromatography was established for the separation and purification of nonvolatile active compounds from Mentha haplocalyx for the first time. The parameters of the two-phase aqueous flotation were optimized. Under the optimal conditions including flotation solvent PEG 1000 aqueous solution (1:1, w/w), pH 5, (NH₄ )₂ SO₄ concentration of 350 g/L in aqueous phase, N₂ flow rate of 20 mL/min, and flotation time of 20 min, the flotation efficiency of linarin, hesperidin, and didymin was 82.24, 76.38, and 89.33%, respectively. The linarin and hesperidin with the high purities of 95.8 and 97.2%, respectively, were obtained by using preparative high performance liquid chromatography. The neuroprotective effect of linarin against H₂ O₂ -induced oxidative stress in rat hippocampal neurons was investigated. The experimental result indicated that linarin could alleviate H₂ O₂ -induced oxidative stress. The work indicated that the combination of aqueous two-phase flotation and preparative high performance liquid chromatography is a feasible and practical method for the purification of nonvolatile active substances from Mentha haplocalyx, which would provide a reference process for the comprehensive utilization of M. haplocalyx. Especially, linarin might be used as a good source of natural neuroprotectants.

Green Separation and Extraction Processes: Part I

Supercritical fluid extraction comprises a known technology applied to obtain volatile compounds from flowers, i [...]

MMHub, a database for the mulberry metabolome

Mulberry is an important economic crop plant and traditional medicine. It contains a huge array of bioactive metabolites such as flavonoids, amino acids, alkaloids and vitamins. Consequently, mulberry has received increasing attention in recent years. MMHub (version 1.0) is the first open public repository of mass spectra of small chemical compounds (<1000 Da) in mulberry leaves. The database contains 936 electrospray ionization tandem mass spectrometry (ESI-MS²) data and lists the specific distribution of compounds in 91 mulberry resources with two biological duplicates. ESI-MS² data were obtained under non-standardized and independent experimental conditions. In total, 124 metabolites were identified or tentatively annotated and details of 90 metabolites with associated chemical structures have been deposited in the database. Supporting information such as PubChem compound information, molecular formula and metabolite classification are also provided in the MS² spectral tag library. The MMHub provides important and comprehensive metabolome data for scientists working with mulberry. This information will be useful for the screening of quality resources and specific metabolites of mulberry.

Database URL: https://biodb.swu.edu.cn/mmdb/

Preparative Separation of Alkaloids from Stem of Euchresta tubulosa Dunn. by High-Speed Counter-Current Chromatography Using Stepwise Elution

Euchresta tubulosa Dunn. is a Chinese herbal medicine with biological activity, but there are few studies on its components at present. Alkaloids in the stem of Euchresta tubulosa Dunn. were isolated and purified by high-speed counter-current chromatography (HSCCC) using stepwise elution. First of all, liquid-liquid extraction (methylene chloride-methanol-water, 5:1:4, v/v) was used for the preliminary enrichment. According to the partition coefficient (K) of a target compound in a series of different two-phase solvents, the final result was that carbon tetrachloride-methylene chloride-methanol-water (2:3:3:2, v/v) (1) and methylene chloride-methanol-water (5:3:2, v/v) (2) were suitable for the HSCCC using stepwise elution. As a result, the purity was all higher than 93% and matrine (1), oxymatrine (2), N-formyl cytisine (3), and N-acetyl cytisine (4) can be eluted at one time by this mode. Cytisine-type alkaloids were isolated for the first time in this plant. Finally, the applicability of the mode was verified.