Comparison of UPLC and HPLC for Determination of trans-10-Hydroxy-2-Decenoic Acid Content in Royal Jelly by Ultrasound-Assisted Extraction with Internal Standard

Targeted and Suspect Fatty Acid Profiling of Royal Jelly by Liquid Chromatography—High Resolution Mass Spectrometry

Royal jelly (RJ) is a bee product produced by the mandibular and hypopharyngeal glands of worker honeybees which has attracted special attention because of its numerous pharmacological activities and its applications to dermatology and cosmetics. In 2020, we demonstrated a liquid chromatography–high resolution mass spectrometry (LC–HRMS) method for the determination of seven medium-chain FFAs in RJ samples. The aim of the present work was to extend our studies on FA profiling of RJ, exploring the presence of common long-chain saturated, mono-unsaturated and poly-unsaturated free FAs in RJ samples using this LC–HRMS method. Among twenty common FAs studied by a targeted approach, palmitic acid, stearic acid and oleic acid were found at concentrations higher than the rest of the FAs (the concentrations of these three acids ranged from 37.4 to 48.0, from 17.7 to 24.0 and from 9.4 to 11.1 mg/100 g of fresh RJ, respectively). The high mass accuracy of LC–HRMS allowed the application of a suspect approach, which enabled the exploration of various C9 and C11 FAs, as well as hydroxylated C12 FAs. Nonenoic acid was indicated as the most abundant among these acids. In addition, for the first time, the presence of a variety of regio-isomers of hydroxymyristic, hydroxypalmitic and hydroxystearic acids was demonstrated in RJ samples.

Carbon quantum dots as a sensitive fluorescent probe for quantitation of pregabalin; application to real samples and content uniformity test

A novel optical nano-sensor for the detection of pregabalin (PG) in its pharmaceutical (Lyrica®) capsules and biological samples was reported. For the fabrication of highly fluorescent carbon quantum dots (CQDts), a simple green hydrothermal approach was described, and ascorbic acid (AA) was used as a carbon source. The obtained CQDts were confirmed by spectroscopic characterization such as transmission electron microscopy (TEM) and Fourier-transform infrared (FTIR) spectra. The synthesized CQDts were capped by alcohol to form yellow emitters, showing strong fluorescent emission at 524 nm, and excitation at 356 nm. The method is based on fluorescence quenching of CQDts in the presence of PG. The proposed analytical method was validated according to ICH guidelines. PG was successively assayed in the concentration range of 4.0 to 100 μg/ml). The detection and quantitation limits were 1.12 and 3.39 μg/ml, respectively. The proposed method could be used in both quality control and pharmacokinetic research for the studied drug.

Royal jelly fatty acids bioprofiling using TLC-MS and digital image analysis coupled with chemometrics and non-parametric regression for discovering efficient biomarkers against melanoma

A comprehensive approach of untargeted and targeted fatty acid bioprofiling of different royal jelly commercial and pharmaceutical products based on HPTLC-image analysis and melanoma cytotoxic activity together with chemometric analysis was applied in this study for discovering efficient biomarkers. Principal component analysis based on HPTLC-image analysis fingerprints of fatty acid loading plots were used to determine the chemical markers responsible for classification of royal jelly samples into fresh and lyophilized ones. These markers were identified using the HPTLC-MS technique as 8-hydroxyoctanoic acid, 3,10-dihydroxydecanoic acid, 10-hydroxy-2-decenoic acid, decanedioic acid and 10-hydroxydecanoic acid. These discriminating markers were quantified via the HPTLC-imaging technique for targeted profiling using two different methods: parametric and non-parametric regression. The non-parametric regression method exhibited superiority in terms of linearity, accuracy and precision. Biomarkers were determined from the 3D-loading plot of orthogonal projection to latent structures model based on the fatty acid quantitative data together with the melanoma cytotoxic activity data. 10-Hydroxy-2-decenoic acid showed the greatest reduction in melanoma cell viability followed by decanedioic acid then 8-hydroxyoctanoic acid. The present study is considered the first attempt to discriminate fresh and lyophilized royal jelly samples based on their holistic lipidomic profile to discover efficient fatty acid reducing melanoma cell viability.

Transcriptional regulator SpxA1a controls the resistance of the honey bee pathogen Melissococcus plutonius to the antimicrobial activity of royal jelly

Royal jelly (RJ), a brood food of honey bees, has strong antimicrobial activity. Melissococcus plutonius, the causative agent of European foulbrood of honey bees, exhibits resistance to this antimicrobial activity and infects larvae orally. Among three genetically distinct groups (CC3, CC12 and CC13) of M. plutonius, CC3 strains exhibit the strongest RJ resistance. In this study, to identify genes involved in RJ resistance, we generated an RJ-susceptible derivative from a highly RJ-resistant CC3 strain by UV mutagenesis. Genome sequence analysis of the derivative revealed the presence of a frameshift mutation in the putative regulator gene spxA1a. The deletion of spxA1a from a CC3 strain resulted in increased susceptibility to RJ and its antimicrobial component 10-hydroxy-2-decenoic acid. Moreover, the mutant became susceptible to low-pH and oxidative stress, which may be encountered in brood foods. Differentially expressed gene analysis using wild-type and spxA1a mutants revealed that 45 protein-coding genes were commonly upregulated in spxA1a-positive strains. Many upregulated genes were located in a prophage region, and some highly upregulated genes were annotated as universal/general stress proteins, oxidoreductase/reductase, chaperons and superoxide dismutase. These results suggest that SpxA1a is a key regulator to control the tolerance status of M. plutonius against stress in honey bee colonies.

A Validated Stability-Indicating HPTLC Assay for Determination of 10-Hydroxy-2-Decenoic Acid Content in Royal Jelly Products Using Robust Regression Methods

A new, simple, stability-indicating high-performance thin-layer chromatography method was developed for the quantification of 10-hydroxy-2-decenoic acid (10-HDA) in some royal jelly products marketed in Egypt. The used solvent system was chloroform:acetic acid (10:1, v/v) and the bands were measured densitometrically at 210 nm. First- and second-derivative treatments of the data were performed. The present study shows a comparison between three statistical regression methods for handling data: parametric, nonparametric and weighted regression (WR) methods. The developed methods were validated as per International Conference on Harmonization guidelines. To validate the stability-indicating power of the developed analytical method, the royal jelly standard was subjected to forced degradation studies including the effect of hydrolysis, oxidation, photolysis and dry heat. It was found that derivative treatment of the chromatographic response data gives improved quantitation and sensitivity of the chromatographic signals. Weighted regression of the response data is found to be advantageous over the use of both parametric and nonparametric regression models. This was shown by a great enhancement in the accuracy and precision in the analysis of 10-HDA in royal jelly products. The % recovery in case of WR was 99.92 ± 0.16, while % recovery in case of nonparametric and parametric regressions were 99.56 ± 0.25 and 98.63 ± 0.65, respectively.

Study of the Royal Jelly Free Fatty Acids by Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS)

The lipidome of royal jelly (RJ) consists of medium-chained (8-12 carbon atoms) free fatty acids. We present herein a liquid chromatography-high resolution mass spectrometry (HRMS) method that permits the determination of RJ fatty acids and at the same time the detection of suspect fatty acids. The method allows for the direct quantification of seven free fatty acids of RJ, avoiding any derivatization step. It was validated and applied in seven RJ samples, where the major RJ fatty acid trans-10-hydroxy-2-decenoic acid (10-HDA) was found to vary from 0.771 ± 0.08 to 0.928 ± 0.04 g/100 g fresh RJ. Four additional suspect fatty acids were simultaneously detected taking advantage of the HRMS detection.

Comparison of salting-out and sugaring-out liquid-liquid extraction methods for the partition of 10-hydroxy-2-decenoic acid in royal jelly and their co-extracted protein content

Homogeneous liquid-liquid extraction (h-LLE) has been receiving considerable attention as a sample preparation method due to its simple and fast partition of compounds with a wide range of polarities. To better understand the differences between the two h-LLE extraction approaches, salting-out assisted liquid-liquid extraction (SALLE) and sugaring-out assisted liquid-liquid extraction (SULLE), have been compared for the partition of 10-hydroxy-2-decenoic acid (10-HDA) from royal jelly, and for the co-extraction of proteins. Effects of the amount of phase partition agents and the concentration of acetonitrile (ACN) on the h-LLE were discussed. Results showed that partition efficiency of 10-HDA depends on the phase ratio in both SALLE and SULLE. Though the partition triggered by NaCl and glucose is less efficient than MgSO₄ in the 50% (v/v) ACN-water mixture, their extraction yields can be improved to be similar with that in MgSO₄ SALLE by increasing the initial concentration of ACN in the ACN-water mixture. The content of co-extracted protein was correlated with water concentration in the obtained upper phase. MgSO₄ showed the largest protein co-extraction at the low concentration of salt. Glucose exhibited a large protein co-extraction in the high phase ratio condition. Furthermore, NaCl with high initial ACN concentration is recommended because it produced high extraction yield for 10-HDA and the lowest amount of co-extracted protein. These observations would be valuable for the sample preparation of royal jelly.

High-level resistance of Melissococcus plutonius clonal complex 3 strains to antimicrobial activity of royal jelly

Melissococcus plutonius is the causative agent of European foulbrood of honey bee larvae. Among its three genetically distinct groups (CC3, CC12 and CC13), CC3 strains have been suggested to be more virulent at the colony level. Honey bee larvae are fed royal or worker jellies by adult bees, and these jellies exhibit antimicrobial activity. Since M. plutonius orally infects larvae via brood food, we herein investigated the resistance of M. plutonius to the antimicrobial activity of royal jelly (RJ). The results obtained revealed that M. plutonius strains were more resistant to RJ and its component, 10-hydroxy-2-decenoic acid, than the other species tested. Moreover, among the M. plutonius strains examined, CC3 strains exhibited the strongest resistance to antimicrobial activity; they temporarily proliferated and survived for a long period in 50% RJ-containing broth. However, resistance was not observed when freshly cultured bacteria were used, it was only detected after a preculture on agar media for five or more days, suggesting that, under certain conditions, CC3 strains change their physiological state to that which is advantageous for survival in brood food. This high-level RJ resistance of CC3 strains may contribute to their virulence in the field.

In Vitro Anti-Inflammatory Effects of Three Fatty Acids from Royal Jelly

Trans-10-hydroxy-2-decenoic acid (10-H2DA), 10-hydroxydecanoic acid (10-HDAA), and sebacic acid (SEA) are the three major fatty acids in royal jelly (RJ). Previous studies have revealed several pharmacological activities of 10-H2DA and 10-HDAA, although the anti-inflammatory effects and underlying mechanisms by which SEA acts are poorly understood. In the present study, we evaluated and compared the in vitro anti-inflammatory effects of these RJ fatty acids in lipopolysaccharide-stimulated RAW 264.7 macrophages. The results showed that 10-H2DA, 10-HDAA, and SEA had potent, dose-dependent inhibitory effects on the release of the major inflammatory-mediators, nitric oxide, and interleukin-10, and only SEA decreased TNF-α production. Several key inflammatory genes have also been modulated by these RJ fatty acids, with 10-H2DA showing distinct modulating effects as compared to the other two FAs. Furthermore, we found that these three FAs regulated several proteins involved in MAPK and NF-κB signaling pathways. Taken together, these findings provide additional references for using RJ against inflammatory diseases.

Rapid separation of seed gliadins by reversed-phase ultra performance liquid chromatography (RP-UPLC) and its application in wheat cultivar and germplasm identification

To separate gliadin from wheat flour, a novel and stability-indicating reversed-phase ultra performance liquid chromatography (RP-UPLC) method is established and optimized. A comparative analysis of routine capillary electrophoresis (CE), reversed-phase high-performance liquid chromatography (RP-HPLC), and RP-UPLC was performed and the results showed that the resolution and efficiency of RP-UPLC were significantly higher than those of CE and RP-HPLC. Characteristic RP-UPLC patterns of different bread wheat variety and related species were readily identified. These results demonstrated that our RP-UPLC procedure resulted in significant improvements in sensitivity, speed, and resolution, and thus is highly useful in wheat cultivar and germplasm identification.

The Lyophilization Process Maintains the Chemical and Biological Characteristics of Royal Jelly

The alternative use of natural products, like royal jelly (RJ), may be an important tool for the treatment of infections caused by antibiotic-resistant bacteria. RJ presents a large number of bioactive substances, including antimicrobial compounds. In this study, we carried out the chemical characterization of fresh and lyophilized RJ and investigated their antibacterial effects with the purpose of evaluating if the lyophilization process maintains the chemical and antibacterial properties of RJ. Furthermore, we evaluated the antibacterial efficacy of the main fatty acid found in RJ, the 10-hydroxy-2-decenoic acid (10H2DA). Chromatographic profile of the RJ samples showed similar fingerprints and the presence of 10H2DA in both samples. Furthermore, fresh and lyophilized RJ were effective against all bacteria evaluated; that is, the lyophilization process maintains the antibacterial activity of RJ and the chemical field of 10H2DA. The fatty acid 10H2DA exhibited a good antibacterial activity against Streptococcus pneumoniae. Therefore, it may be used as an alternative and complementary treatment for infections caused by antibiotic-resistant S. pneumoniae.

Identification of the distribution of adenosine phosphates, nucleosides and nucleobases in royal jelly

Nucleotides, nucleosides and nucleobases play a greater role in the physiological activity of organisms which are highly present in royal jelly (RJ). The objective of the present study is to develop a HPLC method to simultaneous determine nucleotides, nucleosides and nucleobases in RJ and access them in fresh and commercial RJ samples. The LOD and LOQ were 12.2-99.6 μg/L and 40.8-289.4 μg/L, respectively with nearly 100.9% recoveries. Except uric acid, all other compounds were found in RJ samples. Significant difference in the average content of compounds in fresh (2682.93 mg/kg) and commercial samples (3152.78 mg/kg) were observed. AMP, adenosine and adenine were found predominant in all the samples. Significant higher levels of ATP, ADP and AMP was seen in fresh RJ samples, and IMP, uridine, guanosine, and thymidine was seen in commercial RJ samples. The investigated compounds can be used as indexes for assessment RJ freshness and quality.

Rapid characterization of wheat low molecular weight glutenin subunits by ultraperformance liquid chromatography (UPLC)

Low molecular weight glutenin subunits (LMW-GS), as important seed storage proteins, together with HMW-GS significantly define unique dough viscoelastic properties. In this study, a rapid ultraperformance liquid chromatography (UPLC) method for the separation and characterization of LMW-GS in wheat was optimized and established. The fast, reproducible, and high-resolution UPLC separation of LMW-GS could be obtained by gradually increasing eluting gradient from 21 to 47% in 30 min at flow rate of 0.55 mL/min and 60 °C for separation temperature. By this method, analysis of one sample could be completed in <20 min, significantly less time than the traditional reversed-phase high-performance liquid chromatography (RP-HPLC) method. Under the optimized conditions, the genetic features of LMW-GS and genotype × environmental interaction were successfully analyzed, leading to a fast identification of 17 main LMW-GS alleles that were related to different quality properties in wheat. The results demonstrated that UPLC could be a powerful and alternative tool for genetic and proteomic studies of wheat grain proteins and fast identification or screening of desirable LMW-GS alleles in wheat quality improvement.

Quality evaluation of snow lotus (Saussurea): quantitative chemical analysis and antioxidant activity assessment

Snow lotus is commonly used as a medicinal plant and has great pharmacological value. To protect these endangered plants, in vitro propagation and cell cultures have been established in order to meet the growing market demand. The phenolic composition, antioxidant activities, total phenolic content (TPC) and total flavonoid content (TFC) from three most commonly used species, in vitro propagated lines and the cell cultures were investigated to qualify their pharmacological value. Quantitative analysis showed that the phenolics varied greatly among different species and the same species at different habitats. From this it can be inferred that the phenolics were influenced by genetic background and the environmental conditions. Significant correlations were observed between the antioxidant activity and several phenolics/TPC/TFC, suggesting that the phenolics are a major contributor of the antioxidant activity and are important for quality evaluation of snow lotus. Based on the abundance of phenolics, TPC, TFC and antioxidant activity, the order of the quality for wild species would be Saussurea involucrata > Saussurea medusa > Saussurea gossypiphora. For S. medusa, its quality judged by origin would be Shigatse > Lhasa > Nagqu. For in vitro propagated plants, the matured plants could be a reliable substitute for wild plants, and the dynamics of phenolics is critical for quality control of this monocarpic species. We provide the first report of quality comparison between the wild plants and the cell cultures. The advantages of developing cell cultures as alternatives for plants collected from the wild are discussed.

Online cleanup of accelerated solvent extractions for determination of adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), and adenosine 5'-monophosphate (AMP) in royal jelly using high-performance liquid chromatography

Determination of the levels of adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), and adenosine 5'-monophosphate (AMP) in royal jelly is important for the study of its pharmacological activities, health benefits, and adenosine phosphate degradation. In this study was developed a novel method to determine ATP, ADP, and AMP levels in royal jelly using accelerated solvent extraction (ASE) followed by online cleanup and high-performance liquid chromatography (HPLC) with diode array detection (DAD). The optimum extraction conditions were obtained using an 11 mL ASE cell, ethanol/water (5:5 v/v) as the extraction solvent, 1500 psi, 80 degrees C, a 5 min static time, and a 60% flush volume. Optimum separation of the three compounds was achieved in <25 min using a Waters XBridge Shield RP18 column with 0.05 mol L(-1) NH(4)H(2)PO(4) (pH 5.70) and acetonitrile as the mobile phase. Detection was performed at 257 nm. The method was sensitive (LOD <or= 0.32 mg L(-1)), repeatable (RSD <or= 4.5%), accurate (recovery rates of 87.6-94.2% with RSD <or= 5.4), and precise (intraday RSD <or= 8.5%, interday RSD <or= 3.4%). The ASE extraction procedures developed here were compared with the classical adenosine phosphate extraction procedures (perchloric acid). The results indicate that the two techniques are similar in terms of recovery and reproducibility, but when other factors such as extraction time, environmental protection, and worker's health are considered, ASE is preferable to the classical extraction method. With this ASE-HPLC method, a minisurvey of ATP, ADP, and AMP levels in 15 samples of royal jelly of different origins was performed. Sample results indicated that the AMP concentration was 24.2-2214.4 mg kg(-1), whereas ATP and ADP were not detectable or present only at low levels.