13,13a-seco-protoberberines from the tubers of Corydalis yanhusuo and their anti-inflammatory activity

Six undescribed protoberberine derivatives including two pairs of enantiomers, named yanhusanines G-L, along with fifteen reported protoberberine alkaloids, were isolated from the tubers of Corydalis yanhusuo. Among them, yanhusanines H-L feature a unique 13,13a-seco skeleton which is rare in nature. Their structural elucidations were achieved by extensive spectroscopic analysis and quantum chemistry calculations. A biogenetic route for yanhusanines H-L was proposed. Bioassay results showed that yanhusanine J exhibited potent inhibitory effect against the nitric oxide (NO) production in lipopolysaccharide (LPS) induced RAW 264.7 cells (IC₅₀ = 2.25 ± 1.32 μM). Western blot analysis demonstrated that yanhusanine J exerted its anti-inflammatory effect via suppressing the nuclear factor kappa B (NF-κB) pathway, together with the decrease of the inflammatory factors TNF-α, IL-6 and IL-1β. Furthermore, molecular simulation docking indicated that yanhusanine J had strong interaction with the active site of the inducible nitric oxide synthase (iNOS) protein.

A strategy to discover lead chemome from traditional Chinese medicines based on natural chromatogram-effect correlation (NCEC) and natural structure-effect correlation (NSEC): Mahonia bealei and Mahonia fortunei as a case study

Lead compound is an important concept for modern drug discovery. In this study, a new concept of lead chemome and an efficient strategy to discover lead chemome were proposed. Compared with the concept of lead compound, lead chemome can provide not only the starting point for drug development, but also the direction for structure optimization. Two traditional Chinese medicines of Mahonia bealei and Mahonia fortunei were used as examples to illustrate the strategy. Based on natural chromatogram-effect correlation (NCEC), berberine, palmatine and jatrorrhizine were discovered as acetylcholinesterase (AchE) inhibitors. Taking the three compounds as template molecules, a lead chemome consisting of 10 structurally related natural compounds were generated through natural structure-effect correlation (NSEC). In the lead chemome, the IC₅₀ values of jatrorrhizine, berberine, coptisine, palmatine and epiberberine are at nanomolar level, which are comparable to a widely used drug of galantamine. Pharmacophore modeling shows that the positive ionizable group and aromatic rings are important substructures for AchE inhibition. Molecular docking further shows that pi-cation interaction and pi-pi stacking are critical for compounds to maintain nanomolar IC₅₀ values. The structure-activity information is helpful for drug design and structure optimization. This work also expanded the traditional understanding of "stem is the medicinal part of Mahonia bealei and Mahonia fortunei". Actually, all parts except the leaf of Mahonia bealei exhibited potent AchE-inhibitory activity. This study provides not only a strategy to discover lead chemome for modern drug development, but also a reference for the application of different parts of medicinal plants.

Identification and quantification analysis of the chemical constituents from Mahonia fortune using Q‑Exactive HF Mass Spectrometer and UPLC-ESI-MS/MS

In this research, a comprehensive and innovative method was established for the qualitative and quantitative analysis of the main components in Mahonia fortune (MF). On the one hand, comprehensive insight of the constituents in MF extracts was achieved with a Q‑Exactive HF Mass Spectrometer using data-independent acquisition method. The identification of 17 compounds was based on comparison with authentic reference standards and the deduction of 119 additional compounds both in positive and negative modes was using the MS-dial strategy and comparison with literature data. The proportion of alkaloids and phenols were the most in MF. On the other hand, an ultra-performance liquid chromatographic-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) method for the quantification of 25 components in MF extract were developed and validated. The method established provided satisfactory precision and accuracy; acceptable recovery and stability; a good linearity and a reasonable limit of detection. The MF samples from 11 different sources were detected, and relative principal component analysis were applied to discriminate these samples. The variations of Columbamine, Jatrorrhizine, Palmatine and Berberine were suggested as important indicators of MF quality. This study supplies a novel and comprehensive method for the quality evaluation of MF. This research presents a MS based analytical strategy which shows an application potential in the analysis of the chemical constituents in Traditional Chinese Medicine (TCM).

Isolation of Three Lycorine Type Alkaloids from Rhodolirium speciosum (Herb.) Ravenna Using pH-Zone-Refinement Centrifugal Partition Chromatography and Their Acetylcholinesterase Inhibitory Activities

Preparative separation of three lycorine type alkaloids from Rhodolirum speciosum (Amaryllidaceae) was successfully carried out using pH-zone-refinement centrifugal partition chromatography (CPC) using the solvent system methyl-tert-butyl ether/acetonitrile/water (4:1:5, v/v/v) in descending mode. Using this system, Alkaloid 1 (165.7 mg, 88.2%, purity), 2 (60.1 mg, 97.7% purity) and 3 (12.3 mg, 84.4% purity) were obtained in one step. For structure elucidation, the pure alkaloids were subjected to spectroscopy analysis using nuclear magnetic resonance experiments (¹H-NMR, ¹³C-NMR) and gas chromatography coupled with mass spectrometry (GC-MS). Alkaloids 1, 2, and 3 were identified as 1-O-acetyl-5,6-dehydrolycorine, 1-O-acetyl-lycorine, and 1,2-O-diacetyl-5,6-dehydrolycorine, respectively. The acetylcholinesterase inhibitory activity of these alkaloids was IC₅₀ 151.1 μg/mL, IC₅₀ 203.5 μg/mL, IC₅₀ 470.0 μg/mL, and IC₅₀ 17.1 μg/mL, respectively.

Separation of six compounds from pigeon pea leaves by elution-extrusion counter-current chromatography

A valid and reliable method was established to separate six compounds from pigeon pea leaves via elution-extrusion counter-current chromatography. A solvent system composed of n-hexane/methanol/formic acid aqueous solution with pH = 3 (10:6:4, v/v) was screened to achieve satisfactory isolation from the ethanol extract of pigeon pea leaves. Four compounds, 9.2 mg of compound 1 (96.8%), 3.2 mg of 2 (88.0%), 6.2 mg of 4 (94.2%) and 25.2 mg of 5 (94.2%), were obtained by conventional elution from 100 mg of the precipitation fraction, respectively. Two compounds, 14.4 mg of 3 (96.3%) and 28.1 mg of 6 (96.6%), with high K values were obtained by the subsequent extrusion procedure. The compounds 1-6 were identified as 3-methoxy-5-(2-phenylethenyl)-phenol, pinostrobin chalcone, pinostrobin, 2-hydroxy-4-methoxy-6-(2-phenylvinyl)-benzoic acid, longistylin C and cajaninstilbene acid by quadrupole time-of-flight mass spectrometry, and 1 H and 13 C NMR spectroscopy. The in vitro antiproliferation activities of compounds 1, 5 and 6 against human hepatoma cell were evaluated and the half-maximum inhibitory concentrations were acquired.

Development of online-storage inner-recycling counter-current chromatography for the preparative separation of complex components of alkylphenols from sarcotesta of Ginkgo biloba L

High-speed counter-current chromatography (HSCCC) is becoming an effective and non-absorptive separation method from natural products. Due to the insufficient separation efficiency, it is challenging to separate complex components, especially for compounds with similar K _D values. In this study, a novel and effective online-storage inner-recycling CCC method was used to separate alkylphenols from the sarcotesta of Ginkgo biloba L. A two-phase solvent system of n-heptane/ethyl acetate/methanol/acetic acid (5 : 4 : 1 : 1, v/v) was used for HSCCC separation of 500 mg crude extracts. After the inner-recycling of two fractions coupled with pre-HPLC, five main ginkgolic acids (C13:0, C15:1, C17:2, C15:1, C17:1) coupled with bilobol (C15:1) and a mixture were obtained from a non-stop separation using a storage loop and two six-way valves. This novel method was also evaluated and predicted by formula derivation. This method could be an effective, rapid, and simple approach to separate alkylphenols from the sarcotesta of G. biloba.

Preparative separation of flavone dimers from Dysosma versipellis by counter-current chromatography: Trifluoroacetic acid as a solvent system modifier

The separation of natural products is grueling and time-consuming work with repeated isolations needed to obtain purified compounds. However, using counter-current chromatography, a unique liquid-liquid partition chromatography, constituents can usually be purified efficiently. During the separation of flavone dimers from Dysosma versipellis (Hance) by counter-current chromatography, the separation resolution and sample loading was impeded by the emulsification of the sample. By screening, trifluoroacetic acid was selected as the solvent modifier to eliminate the emulsification. Then, a quaternary solvent system of hexane/ethyl acetate/methanol/water (4:6:5:5 v/v/v/v) with trifluoroacetic acid at a low concentration of 0.5% v/v was used to purify the components from D. versipellis. Compared to that without trifluoroacetic acid, the separation resolution as well as the sample loading both increased greatly. In addition, flavone dimers in low concentrations could be enriched and purified at high sample loading. As a result, five podophyllotoxins and 11 flavonoids were purified and characterized by interpretation of spectroscopic data, in which two of eight flavone dimers were new and a known flavone dimer was first separated from this species.

Application of pH-zone-refining countercurrent chromatography in the chiral separation of two β-adrenergic blocking agents

Two β-adrenergic blocking agents, 1-[(1-methylethyl)amino]-3-phenoxy-2-propanol (1) and 1-[(1-methylethyl)amino]-3-(3-methylphenoxy)-2-propanol (2; Toliprolol), were enantioseparated by pH-zone-refining countercurrent chromatography. A two-phase solvent system composed of chloroform containing 0.10 mol/L of di-n-hexyl l-tartrate/0.10 mol/L of boric acid aqueous solution (1:1, v/v) was selected, in which 20 mmol/L triethylamine was added in the organic phase as a retainer and 2 mmol/L HCl was added in the aqueous phase as an eluter. Fifty milligrams of each racemate was completely enantioseparated by pH-zone-refining countercurrent chromatography to yield each enantiomer with a purity of more than 98%, and the recovery of each separated enantiomer reached around 76-82%.