p-Coumaric acid, a novel and effective biomarker for quantifying hypoxic stress by HILIC-ESI-MS

Identification of chemical constituents in pomegranate seeds based on ultra-high-performance supercritical fluid chromatography coupled with quadrupole time-of-flight mass spectrometry

Pomegranate seeds are a potential source of bioactive compounds. Nonetheless, most pomegranate seeds are discarded in the food processing industry, likely due to the lack of convincing data on their component analysis.

METHODS

To reveal the main chemical constituents of pomegranate seeds, a reliable and sensitive method based on ultra-high-performance supercritical fluid chromatography coupled with electrospray ionization and quadrupole time-of-flight mass spectrometry (MS) was developed. A time-dependent MSE data acquisition mode was applied to acquire the mass spectrometric data. The chemical constituents were identified by an automatic retrieval of a traditional Chinese medicine library and relevant literature.

RESULTS

A total number of 59 compounds, including fatty acids, sterols, vitamins, cerebrosides, phospholipids, flavonoids, phenylpropanoids, and others, were tentatively identified. Their possible fragmentation pathways and characteristic ions were proposed and elucidated.

CONCLUSIONS

The findings of this study, along with the developed methodology, could provide a reference for basic research on the pharmacodynamic substances of pomegranate seeds and shed light on their potential nutritional and therapeutic applications in the future.

Hydrophilic Interaction Liquid Chromatography (HILIC): Latest Applications in the Pharmaceutical Researches

Background:

Significant advances have been occurred in analytical research since the 1970s by Liquid Chromatography (LC) as the separation method. Reverse Phase Liquid Chromatography (RPLC) method, using hydrophobic stationary phases and polar mobile phases, is the most commonly used chromatographic method. However, it is difficult to analyze some polar compounds with this method. Another separation method is the Normal Phase Liquid Chromatography (NPLC), which involves polar stationary phases with organic eluents. NPLC presents low-efficiency separations and asymmetric chromatographic peak shapes when analyzing polar compounds. Hydrophilic Interaction Liquid Chromatography (HILIC) is an interesting and promising alternative method for the analysis of polar compounds. HILIC is defined as a separation method that combines stationary phases used in the NPLC method and mobile phases used in the RPLC method. HILIC can be successfully applied to all types of liquid chromatographic separations such as pharmaceutical compounds, small molecules, metabolites, drugs of abuse, carbohydrates, toxins, oligosaccharides, peptides, amino acids and proteins.

Objective:

This paper provides a general overview of the recent application of HILIC in the pharmaceutical research in the different sample matrices such as pharmaceutical dosage form, plasma, serum, environmental samples, animal origin samples, plant origin samples, etc. Also, this review focuses on the most recent and selected papers in the drug research from 2009 to the submission date in 2020, dealing with the analysis of different components using HILIC.

Results and Conclusion:

The literature survey showed that HILIC applications are increasing every year in pharmaceutical research. It was found that HILIC allows simultaneous analysis of many compounds using different detectors.

Comprehensive analysis of the compound profiles of Folium Camelliae Nitidissimae extract by ultrafast liquid chromatography with quadrupole-time-of-flight mass spectrometry and hepatoprotective effect against CCl4 -induced liver injury in mice

Folium Camelliae Nitidissimae (jinhuacha in Chinese, JHC) is a kind of caffeine-less tea with antioxidant, antitumor and antibacterial effects. Studies on the chemical profiles and hepatoprotective effects of JHC extracts have not been systematically conducted so far. This study comprehensively investigated the compound profiles of JHC extract by ultrafast liquid chromatography with quadrupole time-of-flight tandem mass spectrometry. We also determined JHC's hepatoprotective effects against CCl₄ -induced liver injury in mice. A JHC extract was administered orally to mice at 1.95 and 7.80 g/kg body weight once daily for 14 consecutive days prior to CCl₄ treatment. Eighty-four compounds including flavonoids, organic acids, catechins, coumarins, phenylpropanol, amino acids, anthraquinones, saponins and nucleosides in JHC extract were authentically identified or tentatively identified by comparing MS information and retention times with those of authentic standards or available references. JHC administration significantly decreased elevated levels of aspartate aminotransferase and alanine aminotransferase in mouse serum, inhibited hepatic malondialdehyde formation and enhanced glutathione and superoxide dismutase activities in the liver of CCl₄ -treated mice. The histological observations also further supported the results. These results demonstrate that JHC contains various chemical compounds and its hepatoprotective effects against CCl₄ -induced liver injury correlated with decreasing lipid oxidation are significant.

Phytochemical species intercalated into layered double hydroxides: structural investigation and biocompatibility assays

The compound p-coumaric acid (HCou) is found in many foods and presents action in the suppression of chronic diseases and protective effects on neurodegenerative disorders.

A Single Standard to Determine Multi-Components Method Coupled with Chemometric Methods for the Quantification, Evaluation and Classification of Notopterygii Rhizoma et Radix from Different Regions

An ultra-high-performance liquid chromatography-quadrupole/time of flight mass spectrometry is used to identify 33 compounds in Notopterygii rhizoma and radix, after which a single standard to determine multi-components method is established for the simultaneous determination of 19 compounds in Notopterygii rhizoma and radix using chlorogenic acid and notopterol as the internal standard. To screen the potential chemical markers among Notopterygii rhizoma and radix planted in its natural germination area and in others, the quantitative data of 19 compounds are analyzed via partial least-squares discriminant analysis (PLS-DA). Depending on the variable importance parameters (VIP) value of PLS-DA, six compounds are selected to be the potential chemical markers for the discrimination of Notopterygii rhizoma and radix planted in the different regions. Furthermore, the Fisher's discriminant analysis is used to build the models that are used to classify Notopterygii rhizoma and radix from the different regions based on the six chemical markers. Experimental results indicate that Notopterygii rhizoma and radix planted in the Sichuan province are distinguished successfully from those in other regions, reaching a 96.0% accuracy rating. Therefore, a single standard to determine multi-components method combined with a chemometrics method, which contains the advantages such as simple, rapid, economical and accurate identification, offers a new perspective for the quantification, evaluation and classification of Notopterygii rhizoma and radix from the different regions.

ERO1α is a novel endogenous marker of hypoxia in human cancer cell lines

Background

Hypoxia is an important factor that contributes to tumour aggressiveness and correlates with poor prognosis and resistance to conventional therapy. Therefore, identifying hypoxic environments within tumours is extremely useful for understanding cancer biology and developing novel therapeutic strategies. Several studies have suggested that carbonic anhydrase 9 (CA9) is a reliable biomarker of hypoxia and a potential therapeutic target, while pimonidazole has been identified as an exogenous hypoxia marker. However, other studies have suggested that CA9 expression is not directly induced by hypoxia and it is not expressed in all types of tumours. Thus, in this study, we focused on endoplasmic reticulum disulphide oxidase 1α (ERO1α), a protein that localises in the endoplasmic reticulum and is involved in the formation of disulphide bonds in proteins, to determine whether it could serve as a potential tumour-hypoxia biomarker.

Methods

Using quantitative real-time polymerase chain reaction, we analysed the mRNA expression of ERO1α and CA9 in different normal and cancer cell lines. We also determined the protein expression levels of ERO1α and CA9 in these cell lines by western blotting. We then investigated the hypoxia-inducible ERO1α and CA9 expression and localisation in HCT116 and HeLa cells, which express low (CA9-low) and high (CA9-high) levels of CA9, respectively. A comparative analysis was performed using pimonidazole, an exogenous hypoxic marker, as a positive control. The expression and localisation of ERO1α and CA9 in tumour spheres during hypoxia were analysed by a tumour sphere formation assay. Finally, we used a mouse model to investigate the localisation of ERO1α and CA9 in tumour xenografts using several cell lines.

Results

We found that ERO1α expression increased under chronic hypoxia. Our results show that ERO1α was hypoxia-induced in all the tested cancer cell lines. Furthermore, in the comparative analysis using CA9 and pimonidazole, ERO1α had a similar localisation to pimonidazole in both CA9-low and CA9-high cell lines.

Conclusion

ERO1α can serve as a novel endogenous chronic hypoxia marker that is more reliable than CA9 and can be used as a diagnostic biomarker and therapeutic target for cancer.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5727-9) contains supplementary material, which is available to authorized users.

Stability Study and Identification of Degradation Products of Caffeoylgluconic Acid Derivatives from Fructus Euodiae

Caffeoylgluconic acid derivatives are characteristic constituents isolated from the aqueous extract of Fructus Euodiae. In this research focusing on caffeoylgluconic acid derivatives, trans-caffeoyl-6-O-d-gluconic acid (CGA), trans-caffeoyl-6-O-d-gluconic acid methyl ester (CGA-ME), and trans-caffeoyl-6-O-d-glucono-γ-lactone (CGA-LT), a systematic study of stability was performed under different temperatures and pH levels by ultra performance liquid chromatography-diode array detector (UPLC-DAD) and ultra performance liquid chromatography-diode array detector/electrospray ionization-quadrupole-time of flight mass spectrometry (UPLC-DAD/ESI-Q-TOF MS). From the concentration–time curves and sensitivity index (SeI), it was found that compared to CGA, which is inert to the variation of temperature and pH in the tested range, CGA-ME and CGA-LT were more sensitive, with stabilities more likely to be influenced by temperature. Considering the stability index (StI), the integrated stability of CGA was the best, and that of CGA-ME was the worst. In terms of the quasi-molecular and fragment ions of the tested compounds, the degradation products were identified or tentatively characterized, which could shed light on the degradation pathways. CGA-ME and CGA-LT were easily converted to CGA by hydrolytic reaction, all of which were susceptible to the formation of isomers. This study elucidated the degradation mechanism of caffeoylgluconic acid derivatives, contributing to better guidance on manufacturing and controlling the quality of drugs.

A Review of Analytical Methods for p-Coumaric Acid in Plant-Based Products, Beverages, and Biological Matrices

p-Coumaric acid (p-CA), also known as 4-hydroxycinnamic acid, is a phenolic acid, which has been widely studied due to its beneficial effects against several diseases and its wide distribution in the plant kingdom. This phenolic compound can be found in the free form or conjugated with other molecules; therefore, its bioavailability and the pathways via which it is metabolized change according to its chemical structure. p-CA has potential pharmacological effects because it has high free radical scavenging, anti-inflammatory, antineoplastic, and antimicrobial activities, among other biological properties. It is therefore essential to choose the most appropriate and effective analytical method for qualitative and quantitative determination of p-CA in different matrices, such as plasma, urine, plant extracts, and drug delivery systems. The most-reported analytical method for this purpose is high-performance liquid chromatography, which is mostly coupled with some type of detectors, such as UV/Vis detector. However, other analytical techniques are also used to evaluate this compound. This review presents a summary of p-CA in terms of its chemical and pharmacokinetic properties, pharmacological effects, drug delivery systems, and the analytical methods described in the literature that are suitable for its quantification.