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Authors = Ana Mornar

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18 pages, 3812 KiB  
Article
The Stability-Indicating Ultra High-Performance Liquid Chromatography with Diode Array Detector and Tandem Mass Spectrometry Method Applied for the Forced Degradation Study of Ritlecitinib: An Appraisal of Green and Blue Metrics
by Jelena Kovačić, Daniela Amidžić Klarić, Nikša Turk, Željko Krznarić, Emma Riordan and Ana Mornar
Pharmaceuticals 2025, 18(1), 124; https://doi.org/10.3390/ph18010124 - 17 Jan 2025
Cited by 1 | Viewed by 1786
Abstract
Background/Objectives: Janus kinase inhibitors open new horizons for small-molecule drugs in treating inflammatory bowel disease, with ritlecitinib demonstrating significant efficacy in clinical trials for ulcerative colitis and Crohn’s disease. Ritlecitinib, a second-generation JAK3 inhibitor, is a novel therapeutic agent for alopecia areata and [...] Read more.
Background/Objectives: Janus kinase inhibitors open new horizons for small-molecule drugs in treating inflammatory bowel disease, with ritlecitinib demonstrating significant efficacy in clinical trials for ulcerative colitis and Crohn’s disease. Ritlecitinib, a second-generation JAK3 inhibitor, is a novel therapeutic agent for alopecia areata and other autoimmune conditions. Methods: A new stability-indicating UHPLC-DAD-MS/MS method was developed, validated, and applied for a forced degradation study of ritlecitinib under ICH guidelines. Results: The method demonstrated high specificity, sensitivity (LOD: 0.04 µg/mL; LOQ: 0.14 µg/mL), precision (RSD ≤ 0.15%), and accuracy (99.9–100.3%). Forced degradation studies under acidic, basic, oxidative, thermal, and photolytic conditions revealed four novel degradation products. Basic degradation followed second-order kinetics, while oxidative degradation followed zero-order kinetics. Conclusions: The validated method reliably characterized ritlecitinib’s stability and degradation products, providing essential data for optimizing formulation, determining proper storage conditions, anticipating drug–excipient interactions, and ensuring quality control. The eco-friendliness and applicability of the developed forced degradation procedure were evaluated using various green and blue metric tools. Incorporating green analytical principles underscores its potential for sustainable pharmaceutical analysis. Full article
(This article belongs to the Special Issue Advances in Drug Analysis and Drug Development)
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18 pages, 717 KiB  
Article
Assessment of Physicochemical Parameters and Contaminants in Herbal Dietary Supplements Used in the Treatment of Inflammatory Bowel Disease
by Daniela Amidžić Klarić, Jelena Kovačić, Mario-Livio Jeličić, Snježana Zubčić, Vladimir Stankov, Marija Gulan Čičak, Boris Bučar, Ilija Klarić and Ana Mornar
Pharmaceuticals 2023, 16(6), 893; https://doi.org/10.3390/ph16060893 - 18 Jun 2023
Cited by 2 | Viewed by 2861
Abstract
Inflammatory bowel disease is a complex disorder characterized by chronic gastrointestinal inflammation. Thus, patients prefer to use herbal dietary supplements containing turmeric, Indian frankincense, green chiretta, and black pepper in an attempt to cope better with their chronic condition. The dietary supplements’ dosage [...] Read more.
Inflammatory bowel disease is a complex disorder characterized by chronic gastrointestinal inflammation. Thus, patients prefer to use herbal dietary supplements containing turmeric, Indian frankincense, green chiretta, and black pepper in an attempt to cope better with their chronic condition. The dietary supplements’ dosage forms and herbal ingredients were assessed in terms of the products’ physicochemical parameters (weight uniformity, friability, disintegration, rupture test, tablet’s breaking force, and powder flowability) in view of the USP-NF requirements. In addition, contaminants such as organic solvents and ethylene oxide were evaluated using gas chromatography. Assessment of gluten via an Enzyme-Linked Immunosorbent Assay was also performed. Most of the products met USP requirements. The high average weight of one multicomponent tablet sample with a high breaking force value can explain the observed negative results of the disintegration test. A total of 26% of samples tested positive for gluten, but the most alarming fact is that the ethylene oxide levels found in two samples were up to 30 times higher than the EU limit. Accordingly, dietary supplement quality control is of fundamental importance. Full article
(This article belongs to the Section Natural Products)
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18 pages, 2850 KiB  
Article
Green Solid-Phase (Micro)Extraction of Andrographolides’ from Human Plasma Samples Followed by UHPLC-DAD-QqQ-MS/MS Analysis
by Jelena Kovačić, Mario-Livio Jeličić, Daniela Amidžić Klarić and Ana Mornar
Separations 2023, 10(2), 69; https://doi.org/10.3390/separations10020069 - 18 Jan 2023
Cited by 4 | Viewed by 2477
Abstract
Since inflammatory bowel disease is a progressive disease, optimal treatment early in the disease course is paramount. Still, the use of conventional drugs is accompanied by side effects. The herbal therapies for gastrointestinal disorders are traditionally widespread in Asia, while in Western countries [...] Read more.
Since inflammatory bowel disease is a progressive disease, optimal treatment early in the disease course is paramount. Still, the use of conventional drugs is accompanied by side effects. The herbal therapies for gastrointestinal disorders are traditionally widespread in Asia, while in Western countries have been adopted in recent years. Andrographis paniculata is a herbaceous plant used in anti-inflammatory treatment. To improve its clinical application, an analytical method with the potential to define a relationship between dose and plasma concentration of active ingredients is prerequisite. Considering the increasing demand for eco-friendly bioanalytical methods, our research aimed to implement new sample preparation technique microextraction by packed sorbent for extraction of marker compounds of A. paniculata from plasma. This green procedure using polymeric sorbent based on the poly (styrene-divinylbenzene) allowed miniaturization of sample volume (100 µL), decrease in consumption of solvents, and high recovery (92–98%). A highly selective and sensitive reversed-phase ultrahigh-performance liquid chromatography method has been developed and validated. The newest greenness assessment software AGREE calculator was used for evaluation of the method’s environmental performance. It suggests that our method conforms to the eco-friendly conditions (score 0.8). The sample preparation was identified as weak point of the bioanalytical methods which highlights the importance of microextraction. Full article
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17 pages, 1314 KiB  
Article
Accessing Lipophilicity and Biomimetic Chromatography Profile of Biologically Active Ingredients of Botanicals Used in the Treatment of Inflammatory Bowel Disease
by Mario-Livio Jeličić, Daniela Amidžić Klarić, Jelena Kovačić, Donatella Verbanac and Ana Mornar
Pharmaceuticals 2022, 15(8), 965; https://doi.org/10.3390/ph15080965 - 4 Aug 2022
Cited by 5 | Viewed by 3269
Abstract
In the present study, various procedures have been compared for the determination of lipophilicity, hydrophobicity, and plasma protein binding of curcuminoids, boswellic acids, andrographolides, and piperine as biologically active ingredients of botanicals used in IBD treatment. Our results have shown that IAM-HPLC assay [...] Read more.
In the present study, various procedures have been compared for the determination of lipophilicity, hydrophobicity, and plasma protein binding of curcuminoids, boswellic acids, andrographolides, and piperine as biologically active ingredients of botanicals used in IBD treatment. Our results have shown that IAM-HPLC assay is the most suitable one for lipophilicity determination of all analytes regardless of their class and botanical source. HSA-HPAC and AGP-HPAC assays revealed that all investigated compounds have a higher affinity for HSA which is the most abundant protein in human plasma. The high affinity of biologically active compounds to all biological structures (phospholipids and proteins) admonishes that their small portion is available for therapeutic effects in IBD patients. Our experimental research is complemented by various theoretical approaches based on different algorithms for pharmacokinetic properties prediction. The similarities between experimental and calculated values were evaluated using PCA and CA as a statistical tool. The statistical analysis implies that plasma protein binding is a complex process, and theoretical approaches still cannot fully replace experimental ones. Full article
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13 pages, 942 KiB  
Article
Antioxidant Activity of Pharmaceuticals: Predictive QSAR Modeling for Potential Therapeutic Strategy
by Mario-Livio Jeličić, Jelena Kovačić, Matija Cvetnić, Ana Mornar and Daniela Amidžić Klarić
Pharmaceuticals 2022, 15(7), 791; https://doi.org/10.3390/ph15070791 - 24 Jun 2022
Cited by 6 | Viewed by 2513
Abstract
Since oxidative stress has been linked to several pathological conditions and diseases, drugs with additional antioxidant activity can be beneficial in the treatment of these diseases. Therefore, this study takes a new look at the antioxidant activity of frequently prescribed drugs using the [...] Read more.
Since oxidative stress has been linked to several pathological conditions and diseases, drugs with additional antioxidant activity can be beneficial in the treatment of these diseases. Therefore, this study takes a new look at the antioxidant activity of frequently prescribed drugs using the HPLC-DPPH method. The antioxidative activity expressed as the TEAC value of 82 drugs was successfully determined and is discussed in this work. Using the obtained values, the QSAR model was developed to predict the TEAC based on the selected molecular descriptors. The results of QSAR modeling showed that four- and seven-variable models had the best potential for TEAC prediction. Looking at the statistical parameters of each model, the four-variable model was superior to seven-variable. The final model showed good predicting power (r = 0.927) considering the selected descriptors, implying that it can be used as a fast and economically acceptable evaluation of antioxidative activity. The advantage of such model is its ability to predict the antioxidative activity of a drug regardless of its structural diversity or therapeutic classification. Full article
(This article belongs to the Special Issue Small Molecules Regulating the Redox Landscape for Therapy)
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15 pages, 1763 KiB  
Article
Drug–Drug Compatibility Evaluation of Sulfasalazine and Folic Acid for Fixed-Dose Combination Development Using Various Analytical Tools
by Mario-Livio Jeličić, Edvin Brusač, Stanislav Kurajica, Matija Cvetnić, Daniela Amidžić Klarić, Biljana Nigović and Ana Mornar
Pharmaceutics 2021, 13(3), 400; https://doi.org/10.3390/pharmaceutics13030400 - 17 Mar 2021
Cited by 8 | Viewed by 3700
Abstract
The simultaneous administration of sulfasalazine and folic acid is regular practice in the therapy of inflammatory bowel diseases in order to maintain sufficient folate concentration in patients. Having multiple drugs in the therapy increases the possibility of patients failing adherence, thus unintentionally endangering [...] Read more.
The simultaneous administration of sulfasalazine and folic acid is regular practice in the therapy of inflammatory bowel diseases in order to maintain sufficient folate concentration in patients. Having multiple drugs in the therapy increases the possibility of patients failing adherence, thus unintentionally endangering their health. A fixed-dose combination of sulfasalazine and folic would simplify the classical polytherapeutic approach; however, the physicochemical compatibility investigation of two active pharmaceutical ingredients plays an important role in the development of such a product. In this work, various analytical tools were used to determine the physicochemical compatibility of sulfasalazine and folic acid. For the evaluation of chemical compatibility, infrared spectroscopy in combination with advanced statistical methods, such as the principal component analysis and cluster analysis, were used, whilst a simultaneous thermogravimetry/differential thermal analysis gave us an insight into the physical compatibility of two drugs. Isothermal stress testing, forced degradation and dissolution studies, followed by the analysis with a developed chromatographic method for the monitoring of folic acid, sulfasalazine and two of its related impurities, sulfapyridine and salicylic acid, gave us an insight into its chemical compatibility. The combination of the results obtained from the used techniques implies a satisfactory physicochemical compatibility between sulfasalazine and folic acid, which opens the path to the development of the proposed fixed-dose combination. Full article
(This article belongs to the Special Issue Drug Stability and Stabilization Techniques Volume II)
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16 pages, 2794 KiB  
Article
A Comprehensive Approach to Compatibility Testing Using Chromatographic, Thermal and Spectroscopic Techniques: Evaluation of Potential for a Monolayer Fixed-Dose Combination of 6-Mercaptopurine and Folic Acid
by Edvin Brusač, Mario-Livio Jeličić, Matija Cvetnić, Daniela Amidžić Klarić, Biljana Nigović and Ana Mornar
Pharmaceuticals 2021, 14(3), 274; https://doi.org/10.3390/ph14030274 - 17 Mar 2021
Cited by 5 | Viewed by 3336
Abstract
In this work, a systematical compatibility investigation of 6-mercaptopurine and folic acid, two commonly used medications in the treatment of inflammatory bowel disease, for the needs of a fixed-dose combination development strategy is shown. Various techniques and approaches, such as differential scanning calorimetry, [...] Read more.
In this work, a systematical compatibility investigation of 6-mercaptopurine and folic acid, two commonly used medications in the treatment of inflammatory bowel disease, for the needs of a fixed-dose combination development strategy is shown. Various techniques and approaches, such as differential scanning calorimetry, isothermal stress testing, attenuated total reflectance–Fourier-transform infrared spectroscopy, dissolution medium stability and forced degradation studies, were used to elucidate the possible interactions from different aspects. The results predominantly point to the absence of physicochemical interactions between the examined substances in a variety of possible conditions. However, the forced degradation of the blend of substances and excipients in basic conditions showed a drastic degradation of 6-mercaptopurine, signifying that attention needs to be directed to the careful selection of the excipients for the formulation. To sum up, our findings indicate that a fixed-dose combination of 6-mercaptopurine and folic acid could be produced using one formulation blend, immensely simplifying its manufacture. Full article
(This article belongs to the Special Issue Analytical Techniques in the Pharmaceutical Sciences)
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18 pages, 1138 KiB  
Article
Post-Flood Impacts on Occurrence and Distribution of Mycotoxin-Producing Aspergilli from the Sections Circumdati, Flavi, and Nigri in Indoor Environment
by Daniela Jakšić, Miranda Sertić, Sándor Kocsubé, Ivana Kovačević, Domagoj Kifer, Ana Mornar, Biljana Nigović and Maja Šegvić Klarić
J. Fungi 2020, 6(4), 282; https://doi.org/10.3390/jof6040282 - 12 Nov 2020
Cited by 14 | Viewed by 3123
Abstract
Mycotoxin-producing Aspergilli (Circumdati, Flavi, and Nigri), usually associated with contaminated food, may also cause respiratory disorders and are insufficiently studied in water-damaged indoor environments. Airborne (N = 71) and dust borne (N = 76) Aspergilli collected at post-flood [...] Read more.
Mycotoxin-producing Aspergilli (Circumdati, Flavi, and Nigri), usually associated with contaminated food, may also cause respiratory disorders and are insufficiently studied in water-damaged indoor environments. Airborne (N = 71) and dust borne (N = 76) Aspergilli collected at post-flood and control locations in Croatia resulted in eleven different species based on their calmodulin marker: A. ochraceus, A. ostianus, A. pallidofulvus, A. sclerotiorum, and A. westerdijkiae (Circumdati); A. flavus (Flavi); and A. tubingensis, A. welwitschiae, A. niger, A. piperis, and A. uvarum (Nigri). Most of the airborne (73%) and dust borne (54%) isolates were found at post-flood locations, and the highest concentrations measured in indoor air (5720 colony-forming units (CFU)/m3) and dust (2.5 × 105 CFU/g) were up to twenty times higher than in the control locations. A. flavus dominated among airborne isolates (25%) at the unrepaired locations, while 56% of the dust borne Aspergilli were identified as A. tubingensis and A. welwitschiae. The ability of identified isolates to produce mycotoxins aflatoxin B1 (AFB1), fumonisin B2 (FB2), and ochratoxin A were assessed by LC-MS analysis. All ochratoxin A (OTA)-producing Circumdati belonged to A. westerdijkiae (13.7 ± 15.81 µg/mL); in the section, FlaviA. flavus produced AFB1 (2.51 ± 5.31 µg/mL), while A. welwitschiae and A. niger (section Nigri) produced FB2 (6.76 ± 13.51 µg/mL and 11.24 ± 18.30 µg/mL, respectively). Water damage dominantly supported the occurrence of aflatoxigenic A. flavus in indoor environments. Yet unresolved, the causal relationship of exposure to indoor Aspergilli and adverse health effects may support the significance of this research. Full article
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17 pages, 1119 KiB  
Article
Assessment of Bioactive Phenolic Compounds and Antioxidant Activity of Blackberry Wines
by Daniela Amidžić Klarić, Ilija Klarić, Ana Mornar, Natalija Velić and Darko Velić
Foods 2020, 9(11), 1623; https://doi.org/10.3390/foods9111623 - 7 Nov 2020
Cited by 19 | Viewed by 3982
Abstract
Blackberry wine is a natural source of bioactive phenolic compounds that have profound antioxidant potential. The objectives of the present research were to assess the phenolic compounds and antioxidant activity of blackberry wines (BW), and to use the chemometric analysis to differentiate among [...] Read more.
Blackberry wine is a natural source of bioactive phenolic compounds that have profound antioxidant potential. The objectives of the present research were to assess the phenolic compounds and antioxidant activity of blackberry wines (BW), and to use the chemometric analysis to differentiate among the two groups of samples, i.e., conventional and organic. Fifteen BW samples were analyzed for their total polyphenol index, total polyphenols, total flavonoids, total tannins, total monomeric anthocyanins and antioxidant activity by the appropriate spectrophotometric methods. The concentrations of individual phenolic acids (gallic acid, chlorogenic acid, caffeic acid, p-coumaric acid and cinnamic acid) and trans-resveratrol were determined by high-performance liquid chromatography. A comparison between the two groups of investigated BW samples revealed a statistically significant difference in the concentration of caffeic acid and p-coumaric acid, both being higher in the organic BW samples. Furthermore, the results showed a series of statistically highly significant relationships between the analyzed constituents (caffeic acid and p-coumaric acid). The antioxidant activity of the investigated wines was proportional to the concentrations of bioactive phytochemicals. Full article
(This article belongs to the Special Issue Antioxidant Natural Products in Foods)
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15 pages, 1398 KiB  
Article
Physicochemical Compatibility Investigation of Mesalazine and Folic Acid Using Chromatographic and Thermoanalytical Techniques
by Mario-Livio Jeličić, Edvin Brusač, Daniela Amidžić Klarić, Biljana Nigović, Sabina Keser and Ana Mornar
Pharmaceuticals 2020, 13(8), 187; https://doi.org/10.3390/ph13080187 - 8 Aug 2020
Cited by 9 | Viewed by 4917
Abstract
Inflammatory bowel disease is a common name for Crohn’s disease and ulcerative colitis. These inflammatory states cause damage in the sidewalls of the gastrointestinal tract, resulting in malabsorption of food and vitamins. Folic acid (Vitamin B9) is often associated with inflammatory bowel diseases [...] Read more.
Inflammatory bowel disease is a common name for Crohn’s disease and ulcerative colitis. These inflammatory states cause damage in the sidewalls of the gastrointestinal tract, resulting in malabsorption of food and vitamins. Folic acid (Vitamin B9) is often associated with inflammatory bowel diseases since reduced overall folate concentration in the human body may lead to the development of colorectal cancer and megaloblastic anaemia. However, its deficiency is easily compensated by taking an additional folic acid pill during regular therapy. At the moment, there are no studies that have examined the compatibility of folic acid with 5-aminosalicylate drugs used in the treatment of inflammatory bowel diseases. In this work, differential scanning calorimetry, forced degradation studies, isothermal stress testing and dissolution stability testing were used to determine the stability of folic acid and one of the most commonly used 5-aminosalicylates, mesalazine, when present in the same solution or blend. To monitor the assay of folic acid, mesalazine and nine of its related impurities, a single HPLC method was developed. Results of compatibility studies showed that no physicochemical interaction between mesalazine and folic acid occurs when combined, opening the path to the development of new formulations, such as a mesalazine/folic acid fixed-dose combination. Full article
(This article belongs to the Section Pharmaceutical Technology)
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18 pages, 820 KiB  
Article
Pharmacokinetic Profiling and Simultaneous Determination of Thiopurine Immunosuppressants and Folic Acid by Chromatographic Methods
by Edvin Brusač, Mario-Livio Jeličić, Daniela Amidžić Klarić, Biljana Nigović, Nikša Turk, Ilija Klarić and Ana Mornar
Molecules 2019, 24(19), 3469; https://doi.org/10.3390/molecules24193469 - 24 Sep 2019
Cited by 11 | Viewed by 3762
Abstract
With the increase in the number of medicines patients have to take, there has been a rapid rise of fixed-dose combinations (FDCs) in the last two decades. Prior to FDC development, pharmacokinetic properties of active pharmaceutical ingredients (APIs) have to be evaluated, as [...] Read more.
With the increase in the number of medicines patients have to take, there has been a rapid rise of fixed-dose combinations (FDCs) in the last two decades. Prior to FDC development, pharmacokinetic properties of active pharmaceutical ingredients (APIs) have to be evaluated, as well as methods for their determination developed. So as to increase patient compliance in inflammatory bowel disease, three novel FDCs of thiopurine immunosuppressants and folic acid are proposed; physico-chemical and pharmacokinetic properties such as hydrophobicity, lipophilicity and plasma protein binding of all APIs are evaluated. Moreover, experimental results of different properties are compared to those computed by various on-line prediction platforms so as to evaluate the viability of the in silico approach. A simultaneous method for their determination is developed, optimized, validated and applied to commercial tablet formulations. The method has shown to be fast, selective, accurate and precise, showing potential for reliable determination of API content in proposed FDCs during its development. Full article
(This article belongs to the Special Issue Recent Trends in Pharmaceutical Analytical Chemistry)
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16 pages, 704 KiB  
Article
Phenolic Content and Antioxidant Activities of Burr Parsley (Caucalis platycarpos L.)
by Ana Plazonić, Ana Mornar, Željan Maleš and Nikola Kujundžić
Molecules 2013, 18(7), 8666-8681; https://doi.org/10.3390/molecules18078666 - 22 Jul 2013
Cited by 7 | Viewed by 7845
Abstract
Since C. platycarpos contains a wide variety of antioxidants, in the present study total flavonoid and phenolic acid content as well as antioxidative activity of various C. platycarpos extracts were investigated. The results obtained show a significant polyphenol content and antioxidant activity of [...] Read more.
Since C. platycarpos contains a wide variety of antioxidants, in the present study total flavonoid and phenolic acid content as well as antioxidative activity of various C. platycarpos extracts were investigated. The results obtained show a significant polyphenol content and antioxidant activity of the investigated plant. Moreover, a positive correlation between antioxidant activity and content of flavonoids and phenolic acids was found, indicating the responsibility of these compounds for the antioxidant effectiveness of C. platycarpos extracts and making C. platycarpos a good potential source of natural antioxidants. Full article
(This article belongs to the Section Natural Products Chemistry)
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25 pages, 839 KiB  
Article
Identification and Quantification of Flavonoids and Phenolic Acids in Burr Parsley (Caucalis platycarpos L.), Using High-Performance Liquid Chromatography with Diode Array Detection and Electrospray Ionization Mass Spectrometry
by Ana Plazonić, Franz Bucar, Željan Maleš, Ana Mornar, Biljana Nigović and Nikola Kujundžić
Molecules 2009, 14(7), 2466-2490; https://doi.org/10.3390/molecules14072466 - 9 Jul 2009
Cited by 226 | Viewed by 21919
Abstract
A sensitive method coupling high-performance liquid chromatography (HPLC) with diode-array detector (DAD) and electrospray ionization mass spectrometry (MS) was optimized for the separation and identification of phenolic acids, flavonoid glycosides and flavonoid aglycones in the extract of burr parsley (Caucalis platycarpos L.). [...] Read more.
A sensitive method coupling high-performance liquid chromatography (HPLC) with diode-array detector (DAD) and electrospray ionization mass spectrometry (MS) was optimized for the separation and identification of phenolic acids, flavonoid glycosides and flavonoid aglycones in the extract of burr parsley (Caucalis platycarpos L.). Fragmentation behavior of flavonoid glycosides and phenolic acids were investigated using ion trap mass spectrometry in negative electrospray ionization. The MS, MSn and UV data together with HPLC retention time (TR) of phenolic acids and flavonoids allowed structural characterization of these compounds. Caffeoylquinic acid (CQA) isomers, p-coumaroyl-quinic acids (p-CoQA), feruloylquinic acids (FQA), dicaffeoylquinic acids (diCQA), luteolin-7-O-rutinoside, apigenin-7-O-rutinoside as well as isolated chrysoeriol-7-O-rutinoside have been identified as constituents of C. platycarpos for the first time. An accurate, precise and sensitive LC-DAD method for quantification of four phenolic acids (3-O-caffeoylquinic, caffeic, p-coumaric, o-coumaric acid), four flavonoid glycosides (luteolin-7-O-glucoside, apigenin-7-O-glucoside, quercetin-3-O-galactoside, quercetin-3-O-rhamnoside), and three flavonoid aglycones (luteolin, apigenin, chrysoeriol) in C. platycarpos extract was validated in terms of linearity, limit of detection, limit of quantification, precision and accuracy. 3-O-caffeoylquinic acid was the predominant phenolic acid and luteolin-7-O-glucoside was the predominant flavonoid glycoside. Full article
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16 pages, 199 KiB  
Article
Evaluation of Antioxidative Activity of Croatian Propolis Samples Using DPPH· and ABTS·+ Stable Free Radical Assays
by Ivona Jasprica, Mirza Bojic, Ana Mornar, Erim Besic, Kajo Bucan and Marica Medic-Saric
Molecules 2007, 12(5), 1006-1021; https://doi.org/10.3390/12051006 - 15 May 2007
Cited by 51 | Viewed by 17325
Abstract
Propolis is one of the richest sources of plant phenolics (flavonoids and phenolic acids), which are widely recognized as rather strong antioxidants. The aim of our work was to use colored stable free radical (DPPH· and ABTS·+) spectrophotometric and thin-layer chromatographic [...] Read more.
Propolis is one of the richest sources of plant phenolics (flavonoids and phenolic acids), which are widely recognized as rather strong antioxidants. The aim of our work was to use colored stable free radical (DPPH· and ABTS·+) spectrophotometric and thin-layer chromatographic (TLC) assays to study the antioxidative behavior of the phenolics (caffeic acid, galangin and pinocembrin) most commonly present in Croatian propolis samples obtained from different Croatian regions. We propose a mathematical model providing a more sophisticated interpretation of the obtained results and a new parameter named antioxidative efficiency (AOE) is introduced. The kinetic behaviour of chosen standards determined by spectrophotometric assays follows the exponential decrease of the absorption curve. Explained numerically, AOE represents the absolute value of the first derivative of an absorbance curve in the point A0/e (where A0 is the absorbance measured at t = 0 and e is the natural logarithm base). The advantage of this newly introduced parameter is that it provides an easy and accurate mutual comparison between the rates of antioxidative efficiency of different propolis samples. A TLC assay was only applicable in the case of the DPPH· radical. Dose-response curves were described using a linear function with AOE expressed as a coefficient of the slope. The chromatographic method was shown to be very rapid, reliable and easy-to-perform. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
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