A metabolomic study based on accurate mass and isotopic fine structures by dual mode combined-FT-ICR-MS to explore the effects of Rhodiola crenulata extract on Alzheimer disease in rats

Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Applications for Metabolomics

Metabolomics is an interdisciplinary field that aims to study all metabolites < 1500 Da that are ubiquitously found within all organisms. Metabolomics is experiencing exponential growth and commonly relies on high-resolution mass spectrometry (HRMS). Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is a form of HRMS that is particularly well suited for metabolomics research due to its exceptionally high resolution (105-106) and sensitivity with a mass accuracy in parts per billion (ppb). In this regard, FT-ICR-MS can provide valuable insights into the metabolomics analysis of complex biological systems due to unique capabilities such as the easy separation of isobaric and isomeric species, isotopic fine structure analysis, spatial resolution of metabolites in cells and tissues, and a high confidence (<1 ppm mass error) in metabolite identification. Alternatively, the large and complex data sets, long acquisition times, high cost, and limited access mainly through national mass spectrometry facilities may impede the routine adoption of FT-ICR-MS by metabolomics researchers. This review examines recent applications of FT-ICR-MS metabolomics in the search for clinical and non-human biomarkers; for the analysis of food, beverage, and environmental samples; and for the high-resolution imaging of tissues and other biological samples. We provide recent examples of metabolomics studies that highlight the advantages of FT-ICR-MS for the detailed and reliable characterization of the metabolome. Additionally, we offer some practical considerations for implementing FT-ICR-MS into a research program by providing a list of FT-ICR-MS facilities and by identifying different high-throughput interfaces, varieties of sample types, analysis methods (e.g., van Krevelen diagrams, Kendrick mass defect plot, etc.), and sample preparation and handling protocols used in FT-ICR-MS experiments. Overall, FT-ICR-MS holds great promise as a vital research tool for advancing metabolomics investigations.

Anti-senescence effects of Rhodiola crenulate extracts on LO2 cells and bioactive compounds

ETHNOPHARMACOLOGICAL RELEVANCE

Rhodiola crenulata (Rc) is a traditional herb, used in Tibetan medicine, has shown promise efficacy in physical performance improvement, work capacity enhancement, fatigue elimination, and altitude sickness prevention. Also, Rc exhibited therapeutic effects on aging-related diseases. However, relevant researches on Rc and their bioactive components are quite few and needs further investigation.

AIM OF THE STUDY

The objective of this study was to understand the relationship between phytochemical profiles and their activities of Rc extracts.

MATERIALS AND METHODS

Rc extracts prepared by solvents with various hydrophilicity (i.e. aqueous ethanol (70%, v/v), water, and ethyl acetate), and their chemical compositions and specific compounds were analyzed by chemical analysis method and ultra-performance liquid chromatography quadruple time-of-flight mass spectrometry (UPLC-QTOF-MS). The regulate effects of Rc extracts on senescence and antioxidant activity were evaluated using the models of LO₂ cells and Caenorhabditis elegans.

RESULTS

The 70% ethanol extracts exhibited better regulating effects on senescence via the assays of senescence -associated β-galactosidase (SAβG) staining and lifespan, which was consistent with the higher antioxidant activities observed based on the results of antioxidant assays. A total of 14 phytochemicals have been identified in 70% ethanol extracts, whereas the other two extracts contained much fewer compounds in varieties. Phytochemical profile of water extract was similar to the first half (polar compounds, running time: 0-6 min) of 70% ethanol extract profile, while those of ethyl acetate extract was consistent with its second half (more nonpolar compounds, running time: 6-12 min).

CONCLUSIONS

The 14 phytochemicals in Rc might exhibit additive or synergistic effects on senescence regulating and antioxidant activities, providing theoretical basis for daily administration of Rc.

Qualitative and quantitative evaluation of Flos Puerariae by using chemical fingerprint in combination with chemometrics method

In order to better control the quality of Flos Puerariae (FP), qualitative and quantitative analyses were initially performed by using chemical fingerprint and chemometrics methods in this study. First, the fingerprint of FP was developed by HPLC and the chemical markers were screened out by similarity analysis (SA), hierarchical clustering analysis (HCA), principal components analysis (PCA), and orthogonal partial least squares discriminant analysis (OPLS-DA). Next, the chemical constituents in FP were profiled and identified by HPLC coupled to Fourier transform ion cyclotron resonance mass spectrometry (HPLC-FT-ICR MS). Then, the characteristic constituents in FP were quantitatively analyzed by HPLC. As a result, 31 common peaks were assigned in the fingerprint and 6 of them were considered as qualitative markers. A total of 35 chemical constituents were detected by HPLC-FT-ICR MS and 16 of them were unambiguously identified by comparing retention time, UV absorption wavelength, accurate mass, and MS/MS data with those of reference standards. Subsequently, the contents of glycitin, genistin, tectoridin, glycitein, genistein, and tectorigenin in 13 batches of FP were detected, ranging from 0.4438 to 11.06 mg/g, 0.955 to 1.726 mg/g, 9.81 to 57.22 mg/g, 3.349 to 41.60 mg/g, 0.3576 to 0.989 mg/g, and 2.126 to 9.99 mg/g, respectively. In conclusion, fingerprint analysis in combination with chemometrics methods could discover chemical markers for improving the quality control standard of FP. It is expected that the strategy applied in this study will be valuable for further quality control of other traditional Chinese medicines.

•

The qualitative and quantitative analysis were carried out for Flos Puerariae.

•

Fingerprints were combined with different chemometrics to discover the qualitative markers FP.

•

Thirty five constituents of FP were characterized by HPLC-FT-ICR MS.

•

Six chemical constituents were simultaneously determined by HPLC.

Investigation of fennel protein extracts by shot-gun Fourier transform ion cyclotron resonance mass spectrometry

A rapid shot-gun method by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is proposed for the characterization of fennel proteins. After enzymatic digestion with trypsin, few microliters of extract were analyzed by direct infusion in positive ion mode. A custom-made non-redundant fennel-specific proteome database was derived from the well-known NCBI database; additional proteins belonging to recognized allergenic sources (celery, carrot, parsley, birch, and mugwort) were also included in our database, since patients hypersensitive to these plants could also suffer from fennel allergy. The peptide sequence of each protein from that derived list was theoretically sequenced to produce calculated m/z lists of possible m/z ions after tryptic digestions. Then, by using a home-made Matlab algorithm, those lists were matched with the experimental FT-ICR mass spectrum of the fennel peptide mixture. Finally, Peptide Mass Fingerprint searches confirmed the presence of the matched proteins inside the fennel extract with a total of 70 proteins (61 fennel specific and 9 allergenic proteins).

Rhodiola crenulata protects against Alzheimer's disease in rats: A brain lipidomics study by Fourier-transform ion cyclotron resonance mass spectrometry coupled with high-performance reversed-phase liquid chromatography and hydrophilic interaction liquid chromatography

RATIONALE

Alzheimer's disease (AD) is a chronic, severe, progressive neurodegenerative disorder associated with cognitive and memory impairment that ultimately causes death. Most approved drugs can only alleviate some of the symptoms of AD, but no interventions have been found that reverse the underlying disease mechanisms. Rhodiola crenulata extract (RCE) has been reported to alleviate AD symptoms in rats. However, its underlying mechanism of action is still unclear.

METHODS

A brain lipidomics study was conducted to investigate the protective effects of RCE against AD in rats to identify potential biomarkers of AD using Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) coupled with high-performance reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC). Differences in lipid metabolism profiles were evaluated using multivariate statistical analysis. Finally, the possible mechanism of action of RCE on AD was investigated by analysing metabolic pathways.

RESULTS

The RPLCHILIC/FT-ICR MS results showed 20 lipid components with significant differences between the control and model groups. After administration of RCE, the levels of 10 lipids in AD rats tended to shift toward reference levels. The pathway analysis revealed that the protective effect of RCE against AD might be related to regulation of glycerophospholipid metabolism.

CONCLUSIONS

This study provides a novel perspective on the potential intervention mechanism of RCE in the treatment of AD.

Serum lipidomics study reveals protective effects of Rhodiola crenulata extract on Alzheimer's disease rats

Alzheimer's disease (AD) is a chronic and progressive neurodegenerative disorder. Rhodiola crenulata extract (RCE) has shown its protective effects on AD, however, the underlying mechanism is still unclear. In this work, serum lipidomics was conducted to reveal the action mechanism of RCE on AD by HPLC coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The animal model of AD was reproduced by intrahippocampal injection of Aβ_1-42 in rats. The novel object recognition test and passive avoidance test were performed to evaluate the protective effects of RCE on AD rats. The differences of lipid metabolism profiles in rats were evaluated by multivariate statistical analysis. Then, the potential lipid biomarkers were identified and the possible mechanism of RCE on AD was elucidated by metabolic pathways analysis. As a result, twenty-eight lipids with significant differences between the control group and the model group were screened out. With the treatment of RCE, 19 lipids in AD rats showed a trend of callback to the normal levels. The results of pathway analysis indicated that the protective effects of RCE on AD might be closely related to the regulation of linoleic acid metabolism, α-linoleic acid metabolism, sphingolipid metabolism and ether lipid metabolism. In conclusion, this study provides a new perspective on the potential intervention mechanism of RCE for AD treatment.

Explore of the beneficial effects of Huang-Lian-Jie-Du Decoction on diabetic encephalopathy in db/db mice by UPLC-Q-Orbitrap HRMS/MS based untargeted metabolomics analysis

Diabetic encephalopathy (DE) is a severe diabetic complication with cognitive dysfunction. Huang-Lian-Jie-Du Decoction (HLJDD), a famous traditional Chinese formula, is effective for the treatment of diabetes mellitus and Alzheimer's disease in clinical practices, however, the therapeutic effects and the underlying mechanisms of HLJDD on DE is unclear yet. With this purpose, behavior test, brain histological and biochemical analysis were estimated to assess the beneficial effects of HLJDD on DE. Plasma samples were collected for metabolomics analysis based on UPLC-Q-Orbitrap HRMS/MS and chemometric analysis. As a result, morris water maze test revealed that HLJDD could effectively improve the learning and memory abilities in db/db mice. Brain histological and biochemical analysis indicated that HLJDD could protect against neurodegeneration and oxidative stress in db/db mice. Meanwhile, a total of 21 potential biomarkers with significant differences were identified between Model group and Control group using untargeted metabolomics strategy. Among them, 11 metabolites showed a trend towards the normal levels after HLJDD intervention. These metabolites principally involved in glycerophospholipid metabolism, fatty acid β-oxidation, linoleic acid metabolism, glucose metabolism and glutathione metabolism based on the metabolic pathway analysis, which were regulated in DE model mice after HLJDD intervention. Generally, the results demonstrated that HLJDD had beneficial effects on DE, which could be mediated via ameliorating the metabolic disorders.

Regulation by fungal endophyte of Rhodiola crenulata from enzyme genes to metabolites based on combination of transcriptome and metabolome

BACKGROUND

The contents of some its crucial metabolites tend to decrease when Rhodiola crenulata is cultured at low altitude. Interestingly, it was found that an endophyte, Phialocephala fortinii, could alleviate this problem.

RESULTS

There were 16 151 differential genes including 14 706 up-regulated and 1445 down-regulated unigenes with significant differences (P < 0.05), and a total of 1432 metabolites exhibited statistically significant (P < 0.05) metabolic differences comprising 27 different marker metabolites which showed highly significant values of VIP > 5 and P < 0.01. Results highlight differential regulation of 20 enzymatic genes that are involved in the biosynthesis of five different marker metabolites including acetaldehyde, homocysteine, cyclopropylamine, 1-pyrrolinium and halistanol sulfate.

CONCLUSIONS

The positive physiological effect of P. fortinii on R. crenulata encompasses differential regulation in carbohydrate metabolism, lipid metabolism and secondary metabolite synthesis. © 2020 Society of Chemical Industry.

Phytochemical, Antibacterial and Antioxidant Activity Evaluation of Rhodiola crenulata

The chemical components, as well as the antibacterial and antioxidant activities of the essential oil (EO) and crude extracts prepared from Rhodiola crenulata were investigated. The essential oil was separated by hydrodistillation, and gas chromatography-mass spectrometry (GC-MS) was used to identify its constituents. A total of twenty-seven compounds was identified from the EO, and its major components were 1-octanol (42.217%), geraniol (19.914%), and 6-methyl-5-hepten-2-ol (13.151%). Solvent extraction and fractionation were applied for preparing the ethanol extract (crude extract, CE), petroleum ether extract (PE), ethyl acetate extract (EE), n-butanol extract (BE), and water extract (WE). The CE, EE and BE were abundant in phenols and flavonoids, and EE had the highest total phenol and total flavonoid contents. Gallic acid, ethyl gallate, rosavin and herbacetin were identified in the EE. The antibacterial activity results showed that the EO exhibited moderate inhibitory activity to the typical clinic bacteria, and EE exhibited the strongest antibacterial activity among the five extracts. For the compounds, ethyl gallate showed the strongest inhibitory activity to the test bacteria, and its minimum inhibitory concentration (MIC) value and minimum bactericidal concentration (MBC) value for all the tested bacteria was 0.24 mg/mL and 0.48 mg/mL, respectively. The results of antioxidant activity showed that both CE and EE exhibited strong antioxidant activities in the DPPH radical scavenging and Fe2+ reducing power tests, however, EO showed relatively weaker antioxidant ability. Ethyl gallate and rosavin exhibited excellent activity in the DPPH radical scavenging assay, and their IC50 value was 5.3 µg/mL and 5.9 µg/mL, respectively. Rosavin showed better reduction power activity than the other three compounds. These results could provide more evidence for the traditional use of R. crenulata, and would be helpful for improving its application further.

Brain metabolomics study for the protective effects of Rhodiola crenulata extract on Alzheimer's disease by HPLC coupled with Fourier transform-ion cyclotron resonance mass spectrometry

In order to investigate the protective effects of Rhodiola crenulata extract on Alzheimer's disease, a brain metabolomics study in rats was conducted by high performance liquid chromatography coupled with Fourier transform ion cyclotron resonance mass spectrometry. Rat model was constructed by bilateral hippocampal injection of amyloid-β peptide and immunohistochemistry was performed to evaluate the pharmacological effect of Rhodiola crenulata extract. Multivariate statistical analysis was used to discover potential biomarkers in rat brain and related metabolic pathways analysis was conducted to elucidate the action mechanism of Rhodiola crenulata extract. As a result, a total of 19 metabolites contributing to Alzheimer's disease progress were identified and nine of them were restored to the normal levels after drug administration. Pathway analysis revealed that the protective effects of Rhodiola crenulata extract are related to the regulation of glutathione metabolism and arachidonic acid metabolism in rat brain. In conclusion, this work demonstrates that the developed metabolomics method is useful to investigate the protective effects of Rhodiola crenulata extract against Alzheimer's disease. These outcomes may further provide reliable evidence to illuminate the intervention mechanism of other traditional Chinese medicines on Alzheimer's disease.

An algorithm to calibrate ionic isotopes using data mining strategy in hyphenated chromatographic datasets from herbal samples

The bottleneck of analytical instrument itself and non-ideal instrumental performance will produce a certain degree of drifts between the measured isotopes and the true values. An AAID-IC algorithm was thereby proposed to keep the isotopic distributions more accurate in hyphenated instruments, e.g. Gas Chromatography (GC)/ Liquid Chromatography (LC) - Mass Spectrometry (MS). During this data mining process, chemical information will be fully used from dozens of data points in retention time (rt) dimension: the target isotopes were firstly re-constructed in mass charge ratio (m/z) dimension; their re-calculation values were then averaged from an interesting rt zone; the calibration functions were followed established based on a well-defined series of calibration ions. It is worth mentioning that natural metabolites in complex samples can be identified as reference materials to amend the target isotopes. Next, the corrected mass axes (m/z values)/isotope abundances were transformed into an ionic isotopic curve using Gaussian box. Taking herbal sample as an example, AAID-IC can better reduce the systematic and random errors of the m/z ions in one run environment, whether it's profile or bar graph from any type of MS and any ionization method employed. Finally, the calibrated values can be utilized to deduce the elemental compositions of molecular (fragment) ions in GC/LC-MS determination.

Effects of anti-inflammatory and adaptogenic herbal extracts on gene expression of eicosanoids signaling pathways in isolated brain cells

INTRODUCTION

The adaptogens modulate expression of genes playing key roles in development of aging-related disorders, which are considered as low-grade systemic inflammatory conditions characterized by an imbalance between pro-and anti-inflammatory eicosanoids.

AIM OF THE STUDY

We compared the effects of anti-inflammatory and adaptogenic plant extracts on the expression of genes involved in biosynthesis of eicosanoids with the purpose to find those plants, which selectively upregulated the expression of anti-inflammatory lipoxins signaling pathways and inhibited pro-inflammatory signaling pathways associated with biosynthesis of leukotrienes, prostaglandins and thromboxanes.

MATERIALS AND METHODS

We conducted transcriptome-wide RNA sequencing to profile gene expression alterations in T98G neuroglia cells upon treatment of plant extract and analyzed the relevance of deregulated genes to eicosanoids signaling pathways using in silico models.

RESULTS

For the first time, we demonstrated that Rhodiola rosea, Withania somnifera and Eleutherococcus senticosus downregulate the expression of key genes (ALOX5AP, DPEP2, LTC4S) involved biosynthesis of leukotrienes A, B, C, D and E, resulting in inhibition of leukotriene signaling pathway suggesting their potential benefits in Alzheimer disease. The common feature for all tested anti-inflammatory plants extracts was related to downregulation of ALOX12, which was also associated with neuroprotective action of these medicinal plants as well as their potential benefits in neurodegenerative diseases. None of tested anti-inflammatory and adaptogenic plants selectively activated the ALOX15-mediated signaling pathway, which is associated with generation anti-inflammatory lipoxins. Almost all tested plants upregulated the expression of the prostaglandin E receptor 3 gene (PTGER3) suggesting their potential benefits in the treatment of cancer.

CONCLUSION

Every single plant tested in this study revealed a specific "signature" on eicosanoid signaling-related gene expression, regardless of their common features as anti-inflammatory or adaptogenic activity. Further studies of the combination of Rhodiola with Withania (Adaptra) for the treatment of Alzheimer disease are required.