Dispersive liquid-liquid microextraction for the determination of flavonoid aglycone compounds in honey using liquid chromatography with diode array detection and time-of-flight mass spectrometry

Phenolic compounds determination in stingless bee by dispersive liquid-liquid microextraction coupled with capillary electrophoresis - diode array detection

A dispersive liquid-liquid microextraction (DLLME) coupled to capillary electrophoresis with diode array detection (CE-DAD) for determination of sixteen phenolic compounds (PCs) is described. DLLME conditions that affect extraction performance were investigated using single-factor variable experiments. The PCs were extracted using ethyl acetate as extraction solvent and acetonitrile as dispersive solvent. The separation was achieved using fused-silica capillary with buffer constituted of 40 mmol L-1 borax (pH 9.3) and 10 % (v/v) ethanol. Voltage of 20 kV, cassette temperature of 25 °C, hydrodynamic injection (30 mbar for 6 s) and variable UV detection wavelengths were applied. The PCs were separated in < 32 min. Calibration curves were linear (r2 > 0.998) within 1-20 mg L-1 for naringin and catechin hydrate, and 0.3-20 mg L-1 for other PCs. Detection limits were 0.01-0.52 mg L-1, relative standard deviations of ≤ 2.39 % (migration times) and ≤ 5.66 % (peak areas) were obtained. The method exhibited good recoveries (85.2-110.7 %), with enrichment factors of 1.79-13.94 and greenness score of 0.35 (AGREEprep) and 0.54 (AGREE). The validated method was applied for determination of PCs in Tualang and stingless bee honey. These results demonstrated the potential of DLLME-CE-DAD as a simple, and environmentally friendly method to quantify PCs in SBH.

Anti-bacterial, anti-biofilm and anti-quorum sensing activities of honey: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Man has used honey to treat diseases since ancient times, perhaps even before the history of medicine itself. Several civilizations have utilized natural honey as a functional and therapeutic food to ward off infections. Recently, researchers worldwide have been focusing on the antibacterial effects of natural honey against antibiotic-resistant bacteria.

AIM OF THE STUDY

This review aims to summarize research on the use of honey properties and constituents with their anti-bacterial, anti-biofilm, and anti-quorum sensing mechanisms of action. Further, honey's bacterial products, including probiotic organisms and antibacterial agents which are produced to curb the growth of other competitor microorganisms is addressed.

MATERIALS AND METHODS

In this review, we have provided a comprehensive overview of the antibacterial, anti-biofilm, and anti-quorum sensing activities of honey and their mechanisms of action. Furthermore, the review addressed the effects of antibacterial agents of honey from bacterial origin. Relevant information on the antibacterial activity of honey was obtained from scientific online databases such as Web of Science, Google Scholar, ScienceDirect, and PubMed.

RESULTS

Honey's antibacterial, anti-biofilm, and anti-quorum sensing activities are mostly attributed to four key components: hydrogen peroxide, methylglyoxal, bee defensin-1, and phenolic compounds. The performance of bacteria can be altered by honey components, which impact their cell cycle and cell morphology. To the best of our knowledge, this is the first review that specifically summarizes every phenolic compound identified in honey along with their potential antibacterial mechanisms of action. Furthermore, certain strains of beneficial lactic acid bacteria such as Bifidobacterium, Fructobacillus, and Lactobacillaceae, as well as Bacillus species can survive and even grow in honey, making it a potential delivery system for these agents.

CONCLUSION

Honey could be regarded as one of the best complementary and alternative medicines. The data presented in this review will enhance our knowledge of some of honey's therapeutic properties as well as its antibacterial activities.

Simple and selective extraction of quercetin with microextraction in packed syringe method using modified glass powder by a molecularly imprinted polymer followed by spectrophotometric determination

A new sample preparation method based on microextraction in packed syringe was developed for preconcentration of quercetin prior to its spectrophotometric determination. Molecularly imprinted polymers as packing material was used for higher extraction efficiency. First, glass powder as support material because of low cost and available substrate was modified, and then molecularly imprinted polymers were synthesized by the sol-gel method using 3-aminopropyltriethoxysilane as a functional monomer and tetraethyl orthosilicate as cross-linker agent. The combination of a molecularly imprinted polymers and microextraction in packed syringe increased the selectivity and sensitivity. The surface morphology and functionality of the prepared molecularly imprinted polymers was characterized using Fourier-transform infrared spectroscopy, Field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermogravimetric analysis. Different influencing parameters on extraction efficiency such as effect of the number of sample sorption/desorption cycles, type and volume of desorption solvent, pH of the sample solution, and molecularly imprinted polymers amounts were optimized. Under the optimum condition, the proposed method displayed a linear range from 0.01 to 5 µg mL-1 and limit of detection 3.68 ng mL-1 . Relative standard deviation for three replicate determination of 1 µg mL-1 quercetin was 2.1 %. The proposed method was applied successfully for the selective extraction of quercetin from tea and coffee samples.

Determination of Flavonoid Compounds in Shanxi Aged Vinegars Based on Hydrophobic Deep Eutectic Solvent VALLME-HPLC Method: Assessment of the Environmental Impact of the Developed Method

This research presents a novel, eco-friendly, vortex-assisted liquid-liquid microextraction (VALLME) approach, integrating hydrophobic deep eutectic solvents (DESs) with HPLC for the identification and quantification of nine specific flavonoids in Shanxi aged vinegar (SAV). The parameters of DES-VALLME, including the ratio of trioctylmethylammonium chloride to 1,4-butanediol (1:6), DES volume (150 μL), vortex duration (5 min), the concentration of NaCl (0.40 g), and centrifugation time (10 min), were optimized to achieve the maximum extraction efficiency of target substances. Under these optimal conditions, quantitative analyses performed via HPLC demonstrated a broad linear range of 0.20-50.00 μg/mL and correlation coefficients (r²) greater than 0.9944 for all nine calibration curves. The limits of detection (LOD) and limits of quantitation (LOQ) were 0.09-0.18 μg/mL and 0.30-0.60 μg/mL, respectively, ensuring high sensitivity. The relative standard deviations for intra-day and inter-day variability were within the acceptable range, 2.34-3.77% and 3.04-4.96%, respectively, demonstrating the method's reliability. The recovery rates ranged from 85.97% to 108.11%, underscoring the method's precision. This technique exhibited a significant enrichment effect (enrichment factor: 43 to 296) on SAV flavonoids. Notably, the eco-friendliness of this procedure was evaluated using the Analytical Eco-Scale, Green Analytical Procedure Index, and Analytical Greenness Metric. The results suggested that this technique is a viable green alternative to traditional flavonoid determination methods in SAV. In summary, this novel method provides a theoretical basis for assessing flavonoid content in SAV samples and tracing SAV products. This contribution has significant implications for enhancing analytical techniques in food chemistry and environmental science and the sustainable development of the food industry.

Updating the status quo on the extraction of bioactive compounds in agro-products using a two-pot multivariate design. A comprehensive review

Extraction is regarded as the most crucial stage in analyzing bioactive compounds. Nonetheless, due to the intricacy of the matrix, numerous aspects must be optimized during the extraction of bioactive components. Although one variable at a time (OVAT) is mainly used, this is time-consuming and laborious. As a result, using an experimental design in the optimization process is beneficial with few experiments and low costs. This article critically reviewed two-pot multivariate techniques employed in extracting bioactive compounds in food in the last decade. First, a comparison of the parametric screening methods (factorial design, Taguchi, and Plackett-Burman design) was delved into, and its advantages and limitations in helping to select the critical extraction parameters were discussed. This was followed by a discussion of the response surface methodologies (central composite (CCD), Doehlert (DD), orthogonal array (OAD), mixture, D-optimal, and Box-Behnken designs (BBD), etc.), which are used to optimize the most critical variables in the extraction of bioactive compounds in food, providing a sequential comprehension of the linear and complex interactions and multiple responses and robustness tests. Next, the benefits, drawbacks, and possibilities of various response surface methodologies (RSM) and some of their usages were discussed, with food chemistry, analysis, and processing from the literature. Finally, extraction of food bioactive compounds using RSM was compared to artificial neural network modeling with their drawbacks discussed. We recommended that future experiments could compare these designs (BBD vs. CCD vs. DD, etc.) in the extraction of food-bioactive compounds. Besides, more research should be done comparing response surface methodologies and artificial neural networks regarding their practicality and limitations in extracting food-bioactive compounds.

Characterization, Classification and Authentication of Spanish Blossom and Honeydew Honeys by Non-Targeted HPLC-UV and Off-Line SPE HPLC-UV Polyphenolic Fingerprinting Strategies

Honey is a highly consumed natural product produced by bees which is susceptible to fraudulent practices, some of them regarding its botanical origin. Two HPLC-UV non-targeted fingerprinting approaches were evaluated in this work to address honey characterization, classification, and authentication based on honey botanical variety. The first method used no sample treatment and a universal reversed-phase chromatographic separation. On the contrary, the second method was based on an off-line SPE preconcentration method, optimized for the isolation and extraction of polyphenolic compounds, and a reversed-phase chromatographic separation optimized for polyphenols as well. For the off-line SPE method, the use of HLB (3 mL, 60 mg) cartridges, and 6 mL of methanol as eluent, allowed to achieve acceptable recoveries for the selected polyphenols. The obtained HPLC-UV fingerprints were subjected to an exploratory principal component analysis (PCA) and a classificatory partial least squares-discriminant analysis (PLS-DA) to evaluate their viability as sample chemical descriptors for authentication purposes. Both HPLC-UV fingerprints resulted to be appropriate to discriminate between blossom honeys and honeydew honeys. However, a superior performance was accomplished with off-line SPE HPLC-UV polyphenolic fingerprints, being able to differentiate among the different blossom honey samples under the study (orange/lemon blossom, rosemary, thyme, eucalyptus, and heather). In general, this work demonstrated the feasibility of HPLC-UV fingerprints, especially those obtained after off-line SPE polyphenolic isolation and extraction, to be employed as honey chemical descriptors to address the characterization and classification of honey samples according to their botanical origin.

Thorough Investigation of the Phenolic Profile of Reputable Greek Honey Varieties: Varietal Discrimination and Floral Markers Identification Using Liquid Chromatography–High-Resolution Mass Spectrometry

Honey is a highly consumed commodity due to its potential health benefits upon certain consumption, resulting in a high market price. This fact indicates the need to protect honey from fraudulent acts by delivering comprehensive analytical methodologies. In this study, targeted, suspect and non-targeted metabolomic workflows were applied to identify botanical origin markers of Greek honey. Blossom honey samples (n = 62) and the unifloral fir (n = 10), oak (n = 24), pine (n = 39) and thyme (n = 34) honeys were analyzed using an ultra-high-performance liquid chromatography hybrid quadrupole time-of-flight mass spectrometry (UHPLC-q-TOF-MS) system. Several potential authenticity markers were revealed from the application of different metabolomic workflows. In detail, based on quantitative targeted analysis, three blossom honey markers were found, namely, galangin, pinocembrin and chrysin, while gallic acid concentration was found to be significantly higher in oak honey. Using suspect screening workflow, 12 additional bioactive compounds were identified and semi-quantified, achieving comprehensive metabolomic honey characterization. Lastly, by combining non-targeted screening with advanced chemometrics, it was possible to discriminate thyme from blossom honey and develop binary discriminatory models with high predictive power. In conclusion, a holistic approach to assessing the botanical origin of Greek honey is presented, highlighting the complementarity of the three applied metabolomic approaches.

A Three-Reagent “Green” Paper-Based Analytical Device for Solid-Phase Spectrometric and Colorimetric Determination of Dihydroquercetin

Microfluidic paper-based analytical devices (µPADs) represent one of the promising green analytical strategies for low-cost and simple determination of various analytes. The actual task is the development of such devices for quantitation of antioxidants, e.g., flavonoids. In this paper, possibilities of a novel three-reagent µPAD including silver nitrate, 4-nitrophenyldiazonium tetrafluoroborate, and iron(III) chloride as reagents are assessed with respect to the determination of dihydroquercetin. It is shown that all the three reagents produce different colorimetric responses that can be detected by a mini-spectrophotometer–monitor calibrator or by a smartphone. The method is applicable to direct measuring high contents of dihydroquercetin (the linearity range is 0.026–1 mg mL⁻¹, and the limit of detection is 7.7 µg mL⁻¹), which is favorable for many dietary supplements. The analysis of a food supplement was possible with the relative standard deviations of 9–26%, which is satisfactory for quantitative and semiquantitative determinations. It was found that plotting a calibration graph in 3D space of the three reagents’ responses allows us to distinguish dihydroquercetin from its close structural analogue, quercetin.

Monofloral Honeys as a Potential Source of Natural Antioxidants, Minerals and Medicine

Background: vegetative diversity is based on different climate and geographical origins. In terms of beekeeping, herbal diversity is strongly correlated to the production of a wide variety of honey. Therefore, based on the existing plant diversity in each country, multiple honey varieties are produced with different health characteristics. While beekeeping potential and consumption preferences are reflected in products’ variety, this leads to an increase in the region’s economy and extensive export. In the last years, monofloral honey has gained interest from consumers and especially in the medicinal field due to the presence of phytochemicals which are directly linked to health benefits, wound healing, antioxidant, anticancer and anti-inflammatory activities. Scope and approach: this review aims to highlight the physicochemical properties, mineral profiles and antioxidant activities of selected monofloral honeys based on their botanical and geographical origin. Moreover, this review focuses on the intercorrelation between monofloral honey’s antioxidant compounds and in vitro and in vivo activities, focusing on the apoptosis and cell proliferation inhibition in various cell lines, with a final usage of honey as a potential therapeutic product in the fight towards reducing tumor growth. Key findings and conclusions: multiple studies have demonstrated that monofloral honeys have different physicochemical structures and bioactive compounds. Useful chemical markers to distinguish between monofloral honeys were evidenced, such as: 2-methoxybenzoic acid and trimethoxybenzoic acid are distinctive to Manuka honey while 4-methoxyphenylacetic acid is characteristic to Kanuka honey. Furthermore, resveratrol, epigallocatechin and pinostrobin are markers distinct to Sage honey, whereas carvacrol and thymol are found in Ziziphus honey. Due to their polyphenolic profile, monofloral honeys have significant antioxidant activity, as well as antidiabetic, antimicrobial and anticancer activities. It was demonstrated that Pine honey decreased the MDA and TBARS levels in liver, kidney, heart and brain tissues, whereas Malicia honey reduced the low-density lipoprotein level. Consumption of Clover, Acacia and Gelam honeys reduced the weight and adiposity, as well as trygliceride levels. Furthermore, the antiproliferative effect of chrysin, a natural flavone in Acacia honey, was demonstrated in human (A375) and murine (B16-F1) melanoma cell lines, whereas caffeic acid, a phenolic compound found in Kelulut honey, proves to be significant candidate in the chemoprevention of colon cancer. Based on these features, the use of hiney in the medicinal field (apitherapy), and the widespread usage of natural product consumption, is gaining interest by each year.

Honey Phenolic Compound Profiling and Authenticity Assessment Using HRMS Targeted and Untargeted Metabolomics

Honey consumption is attributed to potentially advantageous effects on human health due to its antioxidant capacity as well as anti-inflammatory and antimicrobial activity, which are mainly related to phenolic compound content. Phenolic compounds are secondary metabolites of plants, and their content in honey is primarily affected by the botanical and geographical origin. In this study, a high-resolution mass spectrometry (HRMS) method was applied to determine the phenolic profile of various honey matrices and investigate authenticity markers. A fruitful sample set was collected, including honey from 10 different botanical sources (n = 51) originating from Greece and Poland. Generic liquid-liquid extraction using ethyl acetate as the extractant was used to apply targeted and non-targeted workflows simultaneously. The method was fully validated according to the Eurachem guidelines, and it demonstrated high accuracy, precision, and sensitivity resulting in the detection of 11 target analytes in the samples. Suspect screening identified 16 bioactive compounds in at least one sample, with abscisic acid isomers being the most abundant in arbutus honey. Importantly, 10 markers related to honey geographical origin were revealed through non-targeted screening and the application of advanced chemometric tools. In conclusion, authenticity markers and discrimination patterns were emerged using targeted and non-targeted workflows, indicating the impact of this study on food authenticity and metabolomic fields.

The Immunomodulatory Effects of Honey and Associated Flavonoids in Cancer

Honey has exerted a high impact in the field of alternative medicine over many centuries. In addition to its wound healing, anti-microbial and antioxidant properties, several lines of evidence have highlighted the efficiency of honey and associated bioactive constituents as anti-tumor agents against a range of cancer types. Mechanistically, honey was shown to inhibit cancer cell growth through its pro-apoptotic, anti-proliferative and anti-metastatic effects. However, the potential of honey to regulate anti-tumor immune responses is relatively unexplored. A small number of in vitro and in vivo studies have demonstrated the ability of honey to modulate the immune system by inducing immunostimulatory as well as anti-inflammatory effects. In the present review, we summarize the findings from different studies that aimed to investigate the immunomodulatory properties of honey and its flavonoid components in relation to cancer. While these studies provide promising data, additional research is needed to further elucidate the immunomodulatory properties of honey, and to enable its utilization as an adjuvant therapy in cancer.

Increase in longevity and amelioration of pesticide toxicity by natural levels of dietary phytochemicals in the honey bee, Apis mellifera

For the past decade, migratory beekeepers who provide honey bees for pollination services have experienced substantial colony losses on a recurring basis that have been attributed in part to exposure to insecticides, fungicides, or their combinations applied to crops. The phytochemicals p-coumaric acid and quercetin, which occur naturally in a wide variety of bee foods, including beebread and many types of honey, can enhance adult bee longevity and reduce the toxicity of certain pesticides. How variation in concentrations of natural dietary constituents affects interactions with xenobiotics, including synthetic pesticides, encountered in agroecosystems remains an open question. We tested the effects of these two phytochemicals at a range of natural concentrations on impacts of consuming propiconazole and chlorantraniliprole, a triazole fungicide and an insecticide frequently applied as a tank mix to almond trees during bloom in California's Central Valley. Propiconazole, even at low field concentrations, significantly reduced survival and longevity when consumed by adult bees in a sugar-based diet. The effects of propiconazole in combination with chlorantraniliprole enhanced mortality risk. The detrimental effects of the two pesticides were for the most part reduced when either or both of the phytochemicals were present in the diet. These findings suggest that honey bees may depend on non-nutritive but physiologically active phytochemical components of their natural foods for ameliorating xenobiotic stress, although only over a certain range of concentrations; particularly at the high end of the natural range, certain combinations can incur additive toxicity. Thus, efforts to develop nectar or pollen substitutes with phytochemicals to boost insecticide tolerance or immunity or to evaluate toxicity of pesticides to pollinators should take concentration-dependent effects of phytochemicals into consideration.

Analytical Quality by Design (AQbD) Approach Based HPTLC Method for Quantification of Fisetin with Superior Recovery in Formulations

Background:

A stability indicating high-performance thin layer chromatography (HPTLC) method was developed for the evaluation of fisetin (FIS) in active pharmaceutical ingredient (API) and marketed capsule formulation in accordance with the ICH guidelines.

Methods:

The mobile phase combination toluene: ethyl acetate: formic acid: methanol (3: 5.5: 1: 0.5 v/v/v/v) was optimized with the aid of AQbD approach. The absorbance mode at 254 nm was chosen for densitometric analysis as it gives a compact spot of FIS at Rf value of 0.74.

Results:

The R2 value obtained from the linear regression equation of calibration plots made by taking the spot in the concentration range of 100-1400 ng/spot was found to be 0.9993. The observed LOD and LOQ value was found to be 29.8 ng/spot and 98.5 ng/spot, respectively. The exposure of FIS to various stress conditions revealed the fact that the drug is stable in photochemical and dry heat stress conditions without any degradation. The drug-exposed to acidic, alkaline and oxidative stress was found to be degraded into different degradation products with the highest degradation was found in alkaline stress. All degradation products were observed to be fairly separated from well-resolved parent peak of FIS.

Conclusion:

The developed HPTLC method have shown well-resolved peaks and also shown good recovery in the compound FIS as well as FIS formulation.

Dispersive liquid-liquid microextraction with high-performance liquid chromatography for the analysis of 1,4-benzodioxane-6-aldehyde in eliglustat tartrate active pharmaceutical ingredient

Potential genotoxic impurities (PGIs) are a series of compounds that could potentially damage DNA. Therefore, a sensitive method is needed for detection and quantification. The present work described and validated a method for the quantification of one PGI (namely 1,4-benzodioxane-6-aldehyde) in Eliglustat tartrate (EGT) active pharmaceutical ingredient (API) substances using dispersive liquid-liquid microextraction (DLLME) as sample preparation to remove matrix effect and detected by HPLC-UV. Parameters influencing the microextraction efficiency were systematically investigated. The combined application of DLLME and HPLC-UV provided the sensitivity of the method. The achieved limit of detection (LOD) and the limit of quantification (LOQ) were adequate for the specific purpose and found to be 1.29 μg g^-1 and 2.58 μg g^-1, respectively. This simple and effective methodology offers a key advantage in the ease of removing matrix effect and improves sensitivity obviously. In addition, no costly instrumentation and skilled personnel are needed when using this method, which is available and can be successfully implemented in routine factory drug quality control analysis.

Honey and Its Phenolic Compounds as an Effective Natural Medicine for Cardiovascular Diseases in Humans?

Honey is a sweet, viscous syrup produced by the honey bee (Apis mellifera). It is probably the first natural sweetener ever discovered, and is currently used as a nutritious food supplement and medicinal agent. The aim of the present mini-review is to summarize and update the current knowledge regarding the role of honey in CVDs based on various experimental models. It also describes the role of its phenolic compounds in treating CVDs. Many such phenolic and flavonoid compounds, including quercetin, kaempferol, apigenin, and caffeic acid, have antioxidant and anti-platelet potential, and hence may ameliorate cardiovascular diseases (CVDs) through various mechanisms, such as by decreasing oxidative stress and inhibiting blood platelet activation. However, as the phenolic content of a particular type of honey is not always known, it can be difficult to determine whether any observed effects on the human cardiovascular system may be associated with the consumption of honey or its constituents. Therefore, further experiments in this area are needed.

Fungicide suppression of flight performance in the honeybee (Apis mellifera) and its amelioration by quercetin

As a managed agricultural pollinator, the western honeybee Apis mellifera frequently encounters agrochemicals as contaminants of nectar and pollen. One such contaminant, the fungicide boscalid, is applied at bloom in orchards for fungal floral pathogen control. As an inhibitor of complex II in the mitochondrial electron transport chain of fungi, boscalid can potentially interfere with high energy-demanding activities of bees, including flight. We designed an indoor flight treadmill to evaluate impacts of ingesting boscalid and/or quercetin, a ubiquitous phytochemical in bee food that also affects mitochondrial respiration. Boscalid reduced the wingbeat frequencies of foragers during flight but did not alter the duration of flight. At the colony level, boscalid ingestion may thereby affect overall health by reducing forager efficiency. The consumption of quercetin, by contrast, led to higher adenosine triphosphate levels in flight muscles and a higher wingbeat frequency. Consuming the two compounds together increased wingbeat frequency, demonstrating a hitherto unrecognized mechanism by which dietary phytochemicals may act to ameliorate toxic effects of pesticides to promote honeybee health. In carrying out this work, we also introduce two methodological improvements for use in testing for pesticide effects on flight capacity-a 'force-feeding' to standardize flight fuel supply and a novel indoor flight treadmill.

Phenolic Compounds in Honey and Their Associated Health Benefits: A Review

Honey is a natural substance appreciated for its therapeutic abilities since ancient times. Its content in flavonoids and phenolic acids plays a key role on human health, thanks to the high antioxidant and anti-inflammatory properties that they exert. Honey possesses antimicrobial capacity and anticancer activity against different types of tumors, acting on different molecular pathways that are involved on cellular proliferation. In addition, an antidiabetic activity has also been highlighted, with the reduction of glucose, fructosamine, and glycosylated hemoglobin serum concentration. Honey exerts also a protective effect in the cardiovascular system, where it mainly prevents the oxidation of low-density lipoproteins, in the nervous system, in the respiratory system against asthma and bacterial infections, and in the gastrointestinal system. A beneficial effect of honey can also be demonstrated in athletes. The purpose of this review is to summarize and update the current information regarding the role of honey in health and diseases.

Honey flavonoids inhibit hOATP2B1 and hOATP1A2 transporters and hOATP-mediated rosuvastatin cell uptake in vitro

1. Some flavonoids contained in the common diet have been shown to interact with important membrane uptake transporters, including organic anion transporting polypeptides (OATPs). OATP2B1 and OATP1A2 expressed in the apical membrane of human enterocytes may significantly contribute to the intestinal absorption of drugs, e.g. statins. This study is aimed at an evaluation of the inhibitory potency of selected food honey flavonoids (namely galangin, myricetin, pinocembrin, pinobanksin, chrysin and fisetin) toward hOATP2B1 and hOATP1A2 as well as at examining their effect on the cellular uptake of the known OATP substrate rosuvastatin. 2. Cell lines overexpressing the hOATP2B1 or hOATP1A2 transporter were employed as in vitro model to determine the inhibitory potency of the flavonoids toward the OATPs. 3. Chrysin, galangin and pinocembrin were found to inhibit both hOATP2B1 and hOATP1A2 in lower or comparable concentrations as the known flavonoid OATP inhibitor quercetin. Galangin, chrysin and pinocembrin effectively inhibited rosuvastatin uptake by hOATP2B1 with IC₅₀ ∼1-10 μM. The inhibition of the hOATP1A2-mediated transport of rosuvastatin by these flavonoids was weaker. 4. The found data indicate that several of the tested natural compounds could potentially affect drug cellular uptake by hOATP2B1 and/or hOATP1A2 at relative low concentrations, a finding which suggests their potential for food-drug interactions.

A novel multi-purpose enzymatic system and procedures for the rapid fluorescent determination of flavonoids in herbal pharmaceuticals and plant materials

The paper presents a novel multi-purpose enzymatic system and procedures for fluorescent determination of several flavonoids in herbal pharmaceuticals and plant materials after their enzyme-catalyzed oxidation by hydrogen peroxide and further derivatization with meso-1,2-diphenylethylenediamine. This system may be used for rapid (15-30min/20 samples) simultaneous screening of samples containing a certain flavonoid in a standard microplate, or as a HPLC detection system for analyzing plant extracts with uncertain composition. In the first case, this indicator system provides sensitive and reproducible microplate determination of quercetin, epicatechin, caffeic acid, and taxifolin in the ranges 0.1-5, 1-10, 0.1-10, 0.5-5μM, respectively. In the second case, quercetin, epicatechin, and caffeic acid can be determined in the ranges 0.05-0.75, 0.05-0.75, and 0.01-0.75µg/ml (0.16-2.5, 0.17-2.6, 0.06-4.2μM), respectively. We have demonstrated the application of the system for the analysis of 3 pharmaceuticals and 3 types of plants.

Optimizing Mass Spectrometry Analyses: A Tailored Review on the Utility of Design of Experiments

Mass spectrometry (MS) has emerged as a tool that can analyze nearly all classes of molecules, with its scope rapidly expanding in the areas of post-translational modifications, MS instrumentation, and many others. Yet integration of novel analyte preparatory and purification methods with existing or novel mass spectrometers can introduce new challenges for MS sensitivity. The mechanisms that govern detection by MS are particularly complex and interdependent, including ionization efficiency, ion suppression, and transmission. Performance of both off-line and MS methods can be optimized separately or, when appropriate, simultaneously through statistical designs, broadly referred to as "design of experiments" (DOE). The following review provides a tutorial-like guide into the selection of DOE for MS experiments, the practices for modeling and optimization of response variables, and the available software tools that support DOE implementation in any laboratory. This review comes 3 years after the latest DOE review (Hibbert DB, 2012), which provided a comprehensive overview on the types of designs available and their statistical construction. Since that time, new classes of DOE, such as the definitive screening design, have emerged and new calls have been made for mass spectrometrists to adopt the practice. Rather than exhaustively cover all possible designs, we have highlighted the three most practical DOE classes available to mass spectrometrists. This review further differentiates itself by providing expert recommendations for experimental setup and defining DOE entirely in the context of three case-studies that highlight the utility of different designs to achieve different goals. A step-by-step tutorial is also provided.

Recent Advances in the Analysis of Phenolic Compounds in Unifloral Honeys

Honey is one of the most renowned natural foods. Its composition is extremely variable, depending on its botanical and geographical origins, and the abundant presence of functional compounds has contributed to the increased worldwide interest is this foodstuff. In particular, great attention has been paid by the scientific community towards classes of compounds like phenolic compounds, due to their capability to act as markers of unifloral honey origin. In this contribution the most recent progress in the assessment of new analytical procedures aimed at the definition of the qualitative and quantitative profile of phenolic compounds of honey have been highlighted. A special emphasis has been placed on the innovative aspects concerning the extraction procedures, along with the most recent strategies proposed for the analysis of phenolic compounds. Moreover, the centrality of validation procedures has been claimed and extensively discussed in order to ensure the fitness-for-purpose of the proposed analytical methods. In addition, the exploitation of the phenolic profile as a tool for the classification of the botanical and geographical origin has been described, pointing out the usefulness of chemometrics in the interpretation of data sets originating from the analysis of polyphenols. Finally, recent results in concerning the evaluation of the antioxidant properties of unifloral honeys and the development of new analytical approaches aimed at measuring this parameter have been reviewed.

Injection-port derivatization coupled to GC-MS/MS for the analysis of glycosylated and non-glycosylated polyphenols in fruit samples

Polyphenols, including glycosylated polyphenols, were analyzed via a procedure based on injection-port derivatization coupled to gas chromatography-tandem mass spectrometry (GC-MS/MS). The polyphenols in lyophilized fruit samples were extracted with an acidified MeOH mixture assisted by ultrasound. Samples were dried under vacuum, and carbonyl groups were protected with methoxylamine. Free hydroxyl groups were subsequently silylated in-port. Mass fragmentations of 17 polyphenol and glycosylated polyphenol standards were examined using Multiple Reaction Monitoring (MRM) as the acquisition mode. Furthermore, in-port derivatization was optimized in terms of optimal injection port temperature, derivatization time and sample: N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) volume ratio. A C18 solid-phase-extraction clean-up method was used to reduce matrix effects and injection liner degradation. Using this clean-up method, recoveries for samples spiked at 1 and 10μg/g ranged from 52% to 98%, depending on the chemical compound. Finally, the method was applied to real fruit samples containing the target compounds. The complete chromatographic runtime was 15min, which is faster than reported for recent HPLC methods able to analyze similar compounds.