Screening and identification of acetylcholinesterase inhibitors from Terminalia chebula fruits based on ultrafiltration and ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry

Exploring potential inhibitors of acetylcholinesterase, lactate dehydrogenases, and glutathione reductase from Hagenia abyssinica (Bruce) J.F. Gmel. based on multi-target ultrafiltration-liquid chromatography-mass spectrometry and molecular docking

ETHNOPHARMACOLOGICAL RELEVANCE

Parasitic infections impose a significant burden on public health worldwide. European pharmacopoeia records and ethnopharmacological studies indicate that Hagenia abyssinica (Bruce) J.F. Gmel. has traditionally been used to treat a variety of parasitic infections, while the potential antiparasitic compounds remain ambiguous.

AIM OF THE STUDY

Acetylcholinesterase (AChE), lactate dehydrogenases (LDH), and glutathione reductase (GR) are the key target enzymes in the survival of parasites. The aim of our work was to screen antiparasitic compounds targeting AChE, LDH, and GR from H. abyssinica.

MATERIALS AND METHODS

Ultrafiltration-liquid chromatography-mass spectrometry (UF-LC-MS) combined with molecular docking was used in this study. Therein, the alamarBlue® and Ellman's methods were employed to reveal the antitrypanosomal effect and AChE inhibitory activity. Meanwhile, the UF-LC-MS was carried out to screen the potential active compounds from H. abyssinica. Subsequently, molecular docking was performed to evaluate the binding mechanisms of these active compounds with AChE, LDH, and GR. Finally, the AChE inhibitory activity of potential inhibitors was detected in vitro.

RESULTS

H. abyssinica exhibited significant antitrypanosomal and AChE inhibitory activity. Corilagin, brevifolin carboxylic acid, brevifolin, quercetin, and methyl ellagic acid were recognized as potential AChE inhibitors by UF-LC-MS, while methyl brevifolin carboxylate was identified as AChE, LDH, and GR multi-target inhibitor, with binding degree ranged from 20.96% to 49.81%. Molecular docking showed that these potential inhibitors had a strong affinity with AChE, LDH, and GR, with binding energies ranging from -6.98 to -9.67 kcal/mol. These findings were further supported by the observation that corilagin, quercetin, brevifolin carboxylic acid, and methyl brevifolin carboxylate displayed significant AChE inhibitory activity compared with the positive control (gossypol, 0.42 ± 0.04 mM), with IC50 values of 0.15 ± 0.05, 0.56 ± 0.03, 0.99 ± 0.01, and 1.02 ± 0.03 mM, respectively.

CONCLUSIONS

This study confirms the antiparasitic potential of H. abyssinica, supporting the traditional use of H. abyssinica in local ethnopharmacology to treat parasites. At the same time, corilagin, brevifolin carboxylic acid, brevifolin, quercetin, methyl ellagic acid, and methyl brevifolin carboxylate exert their anti-parasitic effects by inhibiting AChE, LDH, and GR, and they are expected to be natural lead compounds for the treatment of parasitic diseases.

Exploring the composition and properties of Centella asiatica metabolites and investigating their impact on BSA glycation, LDL oxidation and α-amylase inhibition

Centella asiatica (L.) Urb. is a small herbaceous plant belonging to the Apiaceae family that is rich in triterpenes, such as asiaticoside and madecassoside. Centella asiatica finds broad application in promoting wound healing, addressing skin disorders, and boosting both memory and cognitive function. Given its extensive therapeutic potential, this study aimed not only to investigate the Centella asiatica ethanolic extract but also to analyze the biological properties of its organic fractions, such as antioxidant antiglycation capacity, which are little explored. We also identified the main bioactive compounds through spectrometry analysis. The ethanolic extract (EE) was obtained through a static maceration for seven days, while organic fractions (HF: hexane fraction; DF: dichloromethane fraction; EAF: ethyl acetate fraction; BF: n-butanol fraction and HMF: hydromethanolic fraction) were obtained via liquid-liquid fractionation. The concentration of phenolic compounds, flavonoids, and tannins in each sample was quantified. Additionally, the antiglycation (BSA/FRU, BSA/MGO, and ARG/MGO models) and antioxidant (FRAP, ORAC, and DPPH) properties, as well as the ability to inhibit LDL oxidation and hepatic tissue peroxidation were evaluated. The inhibition of enzyme activity was also analyzed (α-amylase, α-glycosidase, acetylcholinesterase, and butyrylcholinesterase). We also evaluated the antimicrobial and cytotoxicity against RAW 264.7 macrophages. The main compounds present in the most bioactive fractions were elucidated through ESI FT-ICR MS and HPLC-ESI-MS/MS analysis. In the assessment of antioxidant capacity (FRAP, ORAC, and DPPH), the EAF and BF fractions exhibited notable results, and as they are the phenolic compounds richest fractions, they also inhibited LDL oxidation, protected the hepatic tissue from peroxidation and inhibited α-amylase activity. Regarding glycation models, the EE, EAF, BF, and HMF fractions demonstrated substantial activity in the BSA/FRU model. However, BF was the only fraction that presented non-cytotoxic activity in RAW 264.7 macrophages at all tested concentrations. In conclusion, this study provides valuable insights into the antioxidant, antiglycation, and enzymatic inhibition capacities of the ethanolic extract and organic fractions of Centella asiatica. The findings suggest that further in vivo studies, particularly focusing on the butanol fraction (BF), may be promising routes for future research and potential therapeutic applications.

A comprehensive strategy for quality evaluation of Changan powder by fingerprinting combined with rapid qualitative and quantitative multi-ingredients profiling

INTRODUCTION

Changan powder (CAP) is mainly used to treat various intestinal diseases. Few studies on CAP have been reported; therefore, it is necessary to clarify the material basis of CAP to lay the foundation for further elucidating its functional mechanism and support the rational use of drugs.

OBJECTIVES

In the present study, we aimed to propose a methodology for the quality control of CAP based on qualitative and quantitative analysis of its components.

METHODS

An ultra-performance liquid chromatography coupled with Fourier transform ion cyclotron resonance mass spectrometry (UPLC-FT-ICR-MS) method was developed to identify chemical components in CAP. In addition, fingerprints of 10 different batches of CAP were established, and quantitative analysis based on UPLC was performed to analyze the quality of CAP.

RESULTS

A total of 58 compounds were preliminarily characterized. The similarity of 10 batches of CAP was greater than 0.995, and 23 common peaks were calibrated. Investigation of the quantitative analytical methodology showed that the four components had good linear relationships within their respective concentration ranges (r2 ≥ 0.9992), and the relative standard deviation (RSD) of precision and stability was less than 2%. The RSD of sample recovery ranged from 0.78% to 1.52%.

CONCLUSION

The established method can quickly and effectively identify the chemical components of CAP and accurately quantify the known components in CAP. The established fingerprinting and content determination method is stable, reliable, and easy to operate and can be applied in quality control and in vivo research on CAP.

Rapid screening, isolation, and activity evaluation of potential xanthine oxidase inhibitors in Polyporus umbellatus and mechanism of action in the treatment of gout

INTRODUCTION

Studies show that Polyporus umbellatus has some pharmacological effects in enhancing immunity and against gout.

OBJECTIVES

We aimed to establish new techniques for extraction, biological activity screening, and preparation of xanthine oxidase inhibitors (XODIs) from P. umbellatus.

METHODS

First, the extraction of P. umbellatus was investigated using the back propagation (BP) neural network genetic algorithm mathematical regression model, and the extraction variables were optimised to maximise P. umbellatus yield. Second, XODIs were rapidly screened using ultrafiltration, and the change of XOD activity was tested by enzymatic reaction kinetics experiment to reflect the inhibitory effect of active compounds on XOD. Meanwhile, the potential anti-gout effects of the obtained active substances were verified using molecular docking, molecular dynamics simulations, and network pharmacology analysis. Finally, with activity screening as guide, a high-speed countercurrent chromatography (HSCCC) method combined with consecutive injection and two-phase solvent system preparation using the UNIFAC mathematical model was successfully developed for separation and purification of XODIs, and the XODIs were identified using MS and NMR.

RESULTS

The results verified that polyporusterone A, polyporusterone B, ergosta-4,6,8(14),22-tetraen-3-one, and ergosta-7,22-dien-3-one of P. umbellatus exhibited high biological affinity towards XOD. Their structures have been further identified by NMR, indicating that the method is effective and applicable for rapid screening and identification of XODIs.

CONCLUSION

This study provides new ideas for the search for natural XODIs active ingredients, and the study provide valuable support for the further development of functional foods with potential therapeutic benefits.

Inhibition mechanisms of four ellagitannins from terminalia chebula fruits on acetylcholinesterase by inhibition kinetics, spectroscopy and molecular docking analyses

Acetylcholinesterase (AChE) is an important therapeutic target for the treatment of Alzheimer's disease (AD), and the development of natural AChE inhibitors as candidates has played a significant role in drug discovery. In this study, the inhibition mechanisms of four ellagitannins, punicalagin, chebulinic acid, geraniin and corilagin, from Terminalia chebula fruits on AChE were investigated systematically by a combination of inhibition kinetics, multi-spectroscopic methods and molecular docking. The kinetic results showed that punicalagin, chebulinic acid and geraniin exhibited strong reversible inhibitory effects on AChE in an uncompetitive manner with the IC50 values of 0.43, 0.50, and 0.51 mM, respectively, while corilagin inhibited AChE activity in a mixed type with the IC50 value of 0.72 mM. The results of fluorescence and UV-vis spectra and fluorescence resonance energy transfer (FRET) revealed that four ellagitannins could significantly quenched the intrinsic fluorescence of AChE though a static quenching along with non-radiative energy transfer. Thermodynamic analyses showed that values of ΔG, ΔH and ΔS were negative, indicating that all binding processes were spontaneous, and the hydrogen bonding and Van der Waals forces might make a great contribution to the formation of inhibitor-AChE complexes. The synchronous fluorescence, three-dimensional (3D) fluorescence, UV-vis, and FT-IR spectra studies suggested that four ellagitannins could lead to alterations in the micro-environment and secondary structure of AChE, and thus the conformational change of AChE. Moreover, molecular docking demonstrated that four ellagitannins could interacted with main amino acid residues of AChE with affinity energies ranging from -9.9 to -8.7 kJ/mol, and further confirmed the above experimental results. This study provided valuable findings for the potential application of four ellagitannins as promising candidates in the exploration of natural AChE inhibitors for the treatment of AD.

Structural determination and anticholinesterase assay of C-glycosidic ellagitannins from Lawsonia inermis leaves: A study supported by DFT calculations and molecular docking

An ellagitannin monomer, lythracin M (1), and a dimer, lythracin D (2), along with eight known monomers (3-10) were isolated from Lawsonia inermis (Lythraceae) leaves. Lythracin M (1) is a C-glycosidic ellagitannin with a flavogallonyl dilactone moiety that participates in the creation of a γ-lactone ring with the anomeric carbon of the glucose core. Lythracin D (2) was determined as an atropisomer of the reported lythcarin D. These newly discovered structures (1 and 2) were determined by intensive spectroscopic experiments and by comparing DFT-calculated ¹H¹H coupling, ¹H NMR chemical shifts, and ECD data with experimental values. The anti-acetylcholinesterase assay of the compounds 1-10 revealed that the C-1 ellagitannin epimers [casuarinin (7; IC₅₀ = 34 ± 2 nM) and stachyurin (8; IC₅₀ = 56 ± 3 nM)], and the new dimer (2; IC₅₀ = 61 ± 4 nM) possess enzyme inhibitory effects comparable to the reference drug (donepezil, IC₅₀ = 44 ± 3 nM). Molecular docking of compounds 1-10 with AChE identified the free galloyl moiety as an important pharmacophore in the anticholinesterase activity of tannins.

Screening and identification of anti-acetylcholinesterase ingredients from Tianzhi granule based on ultrafiltration combined with ultra-performance liquid chromatography-mass spectrometry and in silico analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Tianzhi granule (TZG) is a traditional Chinese formula that is widely used for the treatment of vascular dementia (VaD).

AIM OF THE STUDY

To discover the herbs in TZG possessing acetylcholinesterase (AChE) inhibitory activity and to screen the anti-acetylcholinesterase ingredients from active herbs.

MATERIALS AND METHODS

In vitro AChE inhibitory activity assay of eleven herbal extracts was conducted. An ultrafiltration combined with ultra-performance liquid chromatography-mass spectrometry method was established to screen and identify the anti-acetylcholinesterase ingredients from active extracts. In addition, in vitro AChE inhibitory activity assay and molecular docking were adopted for further investigation. Moreover, ultra-performance liquid chromatography-mass spectrometry was performed for the content determination of active compounds in TZG.

RESULTS

Three herbs in TZG showed significant AChE inhibitory activity. A total of thirteen active ingredients were screened out and identified, and all of these compounds were present in TZG. Five available commercial standards presented moderate AChE inhibitory activity, and all of which have a relatively high content in TZG.

CONCLUSION

A number of herbs and compounds with acetylcholinesterase inhibitory activity were found in TZG, which provided a scientific basis for the material basis and quality control research of TZG.

Receptor-ligand affinity-based screening and isolation of water-soluble 5-lipoxygenase inhibitors from Phellinus igniarius

We developed an efficient combination method for extraction, biological activity screening, and preparation of 5-lipoxygenase inhibitors from Phellinus igniarius. 5-Lipoxygenase inhibitors were rapidly screened using ultrafiltration-liquid chromatography based on the receptor-ligand affinity. Parameters such as extraction time, extraction times, and temperature as well as liquid-solid ratio were optimized using response surface methodology to maximize the total yield of the three target compounds. Next, bioactive ingredients were isolated using high-speed countercurrent chromatography and semi-preparative liquid chromatography. Three active ingredients, phellibaumin E, protocatechuic aldehyde, and osmundacetone, were obtained via ultrafiltration-liquid chromatography. Subsequently, the potential anti-dementia effects of the obtained bioactive compounds were verified using molecular docking assays. The above-mentioned target compounds, with purities of 98.82%, 98.89%, and 99.51%, respectively, were separated using a two-phase solvent system consisting of n-hexane-ethyl acetate-ethanol-water (2.5:2:0.75:3, v/v/v/v) coupled with semi-preparative liquid chromatography.

Margaritaria nobilis L.F. (Phyllanthaceae): Ethnopharmacology and Application of Computational Tools in the Annotation of Bioactive Molecules

Margaritaria nobilis is a shrubby species widely distributed in Brazil from the Amazon to the Atlantic Rainforest. Its bark and fruit are used in the Peruvian Amazon for disinfecting abscesses and as a tonic in pregnancy, respectively, and its leaves are used to treat cancer symptoms. From analyses via UHPLC-MS/MS, we sought to determine the chemical profile of the ethanolic extract of M. nobilis leaves by means of putative analyses supported by computational tools and spectral libraries. Thus, it was possible to annotate 44 compounds, of which 12 are phenolic acid derivatives, 16 are O-glycosylated flavonoids and 16 hydrolysable tannins. Among the flavonoids, although they are known, except for kaempferol, which has already been isolated from this species, the other flavonoids (10, 14, 15, 21, 24–26, 28–30, 33–35, 40 and 41) are being reported for the first time in the genus. Among the hydrolysable tannins, six ellagitannins present the HHDP group (6, 19, 22, 31, 38 and 43), one presents the DHHDP group (5), and four contain oxidatively modified congeners (12, 20, 37 and 39). Through the annotation of these compounds, we hope to contribute to the improved chemosystematics knowledge of the genus. Furthermore, supported by a metric review of the literature, we observed that many of the compounds reported here are congeners of authentically bioactive compounds. Thus, we believe that this work may help in understanding future pharmacological activities.

Flowers and Leaves Extracts of Stachys palustris L. Exhibit Stronger Anti-Proliferative, Antioxidant, Anti-Diabetic, and Anti-Obesity Potencies than Stems and Roots Due to More Phenolic Compounds as Revealed by UPLC-PDA-ESI-TQD-MS/MS

The present work aims to assess the biological potential of polyphenolic compounds in different parts (flowers, leaves, stems, and roots) of Stachys palustris L. Towards secondary metabolites profile, 89 polyphenolic compounds (PCs) were identified by UPLC-PDA-ESI-TQD-MS/MS, with a total average content of 6089 mg/100 g of dry matter (d.m.). In terms of biological activity, antioxidant activity (radical activity, reducing power), digestive enzyme inhibitory (α-glucosidase, α-amylase, pancreatic lipase) effect, and antiproliferative activity (inhibition of cell viability and induction of apoptosis in different human cancer cell lines) were explored. Leaves, flowers, stems, and roots of S. palustris L. have not been studied in this regard until now. Vescalagin and cocciferin d2, isoverbascoside (verbascoside), luteolin 6-C-glucoside, luteolin 6-C-galactoside, apigenin 6-C-glucoside, (−)-epicatechin, ellagic acid, and malvidin 3-O-diglucoside were detected as main ingredients in the studied parts. Methanolic extract of S. palustris L. leaves and flowers revealed the highest amount of PCs with the strongest antiradical (18.5 and 15.6 mmol Trolox equivalent (TE)/g d.m., respectively) and reducing power effects (7.3 and 5.6 mmol TE/g d.m.). Leaf extracts exhibited better α-amylase and pancreatic lipase inhibition effects, while flower extracts exhibited better α-glucosidase inhibition effect. Regarding antiproliferative activity, extracts of the leaves and flowers significantly reduced cell viability and induced a high level of apoptosis in human lung, pancreatic, bladder, and colon cancer cell lines, as well as in human acute myeloid leukemia; whereas the extracts from stems and roots revealed the weaker effects. The results of this work showed anti-proliferative and potentially anti-diabetic, anti-obesity properties of S. palustris L., especially for flowers and leaves, which may have wide potential applications in the functional food, special food, pharmaceutical, cosmetics industries, and/or in medicine.

Screening and identification of acetylcholinesterase inhibitors from Terminalia chebula fruits by immobilized enzyme on cellulose filter paper coupled with ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry and molecular docking

With the increasing demand of new drugs for the treatment of Alzheimer's disease (AD), screening acetylcholinesterase (AChE) inhibitors from traditional Chinese medicines (TCMs) has been proved to be an effective strategy for drug discovery. In present study, a novel strategy was developed to fish out AChE inhibitors from Terminalia chebula fruits based on immobilized AChE coupled with ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) and molecular docking. For AChE immobilization, cellulose filter paper (CFP) as the carrier was modified with chitosan to be introduced to amino groups, and then AChE was modified on the amino-modified CFP through a Schiff base reaction with glutaraldehyde as a cross-linking agent. The CPF-immobilized AChE possessed advantages of a wider range for pH and temperature endurance, better storage stability, excellent reproducibility and reusability. The CPF-immobilized AChE was incubated with the extract of T. chebula fruits, and then the active components would form complexes with immobilized AChE. The complexes were further conveniently separated with inactive components by virtue of the instantaneous separation characteristic of CFP. Eventually, 25 (1-11, 13-26) potential AChE inhibitors were fished out and their structures were further identified by UPLC-QTOF-MS. Moreover, molecular docking was performed to discriminate non-specific compounds to AChE and explore binding mechanisms between potential inhibitors and AChE, and 25 compounds could be well embedded into active sites of AChE with affinities ranging from -9.9 to -6.4 kcal/mol. Inhibitory activities of screened active components on AChE were evaluated in vitro, and punicalagin, 1,3,6-tri-O-galloyl-β-D-glucose (1,3,6-TGG), chebulinic acid and geraniin exhibited excellent AChE-inhibitory properties with IC₅₀ values of 0.43 ± 0.03, 0.46 ± 0.02, 0.50 ± 0.03 and 0.51 ± 0.03 mM, respectively. The results indicated that the developed method was simple and efficient, and could be utilized to screen and identify potential AChE inhibitors from TCMs.

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.

LC-ESI-QTOF-MS/MS Analysis, Cytotoxic, Antiviral, Antioxidant, and Enzyme Inhibitory Properties of Four Extracts of Geranium pyrenaicum Burm. f.: A Good Gift from the Natural Treasure

This study focused on the biological evaluation and chemical characterization of Geranium pyrenaicum Burm. f. Different solvent extracts (hexane, ethyl acetate, methanol, and water extracts) were prepared. The phytochemical profile, antioxidant, and enzyme inhibitory activity were investigated. Cytotoxicity was assessed using VERO, FaDu, HeLa and RKO cells. The antiviral activity was carried out against HSV-1 (Herpes simplex virus 1) propagated in VERO cell line. The aqueous extract, possessing high phenolic content (170.50 mg gallic acid equivalent/g extract), showed the highest reducing capacity (613.27 and 364.10 mg Trolox equivalent/g extract, for cupric reducing antioxidant capacity and ferric reducing antioxidant power, respectively), radical scavenging potential (469.82 mg Trolox equivalent/g extract, against 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), metal chelating ability (52.39 mg ethylenediaminetetraacetic acid equivalent/g extract) and total antioxidant capacity (3.15 mmol Trolox equivalent/g extract). Liquid chromatography-electrospray ionization-quadrupole time-of-flight-mass spectrometry (LC-ESI-QTOF-MS/MS) alloved to tentatively identify a total of 56 compounds in the extracts, including ellagitannins, gallic acid and galloyl derivatives amongst others. The ethyl acetate extracts substantially depressed cholinesterase enzymes (4.49 and 12.26 mg galantamine equivalent/g extract against AChE and BChE, respectively) and α-amylase enzyme (1.04 mmol acarbose equivalent/g extract). On the other hand, the methanolic extract inhibited tyrosinase (121.42 mg kojic acid equivalent/g extract) and α-glucosidase (2.39 mmol acarbose equivalent/g extract) activities. The highest selectivity towards all cancer cell lines (SI 4.5-10.8) was observed with aqueous extract with the FaDu cells being the most sensitive (CC50 40.22 µg/mL). It can be concluded that the presence of certain bioactive antiviral molecules may be related to the high anti HSV-1 activity of the methanolic extract. This work has generated vital scientific data on this medicinal plant, which is a prospective candidate for the creation of innovative phyto-pharmaceuticals.