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Recent Trends in the Separation of Natural Products and Pharmaceuticals
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Recent Trends in the Separation of Natural Products and Pharmaceuticals

A topical collection in Separations (ISSN 2297-8739). This collection belongs to the section "Analysis of Natural Products and Pharmaceuticals".

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Editors

Dr. Paraskevas D. Tzanavaras

E-Mail Website
Collection Editor
Laboratory of Analytical Chemistry, School of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
Interests: automation; sequential injection analysis; separation techniques (HPLC, CE); post-column derivatization; microextraction
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Susanne K. Wiedmer

E-Mail Website
Collection Editor
Department of Chemistry, University of Helsinki (UH), Helsinki, Finland
Interests: capillary electrophoresis; capillary liquid chromatography; physico-chemical characterization; cytotoxicity; liposomes; ionic liquids
Special Issues, Collections and Topics in MDPI journals

Topical Collection Information

Dear Colleagues,

In general terms, “natural products” can be defined as compounds that are synthesized/produced by living organisms (plants, animals, etc.). The importance of natural products has been recognized for thousands of years, and a considerable proportion of new drugs are still based on the discovery of natural biogenic molecules.

In the Topical Collection on “Recent Trends in the Separation of Natural Products and Pharmaceuticals”, we welcome original research and review articles on the development and application of analytical separation technologies to both natural product and pharmaceutical sciences.

Research on the analysis and separation of natural products should ideally increase the current knowledge on the extraction, separation, isolation, identification, structure elucidation, and quantification of bioactive compounds. All aspects of instrumental analytical separation and analysis methodologies that can be used as a tool to achieve these tasks are welcome. Reports on the quality control and standardization of natural products will also be considered on the basis of their significance in the field.

Analysis of pharmaceuticals, on the other hand, is an extremely broad topic ranging from quality control or raw materials to the impurity profiling of active ingredients and to bioanalytical applications. Original work on all aspects of related research is welcome. Impurity profiling and especially the identification/quantification of genotoxic impurities are of particular interest, while simple assays using HPLC should provide clear advantages from an analytical point of view to be processed further. Research work from industries reporting results from real-world analytical problems is also warmly welcome. All pharmaceutical-related analytical methods should be fully validated.

Bioanalytical methods including pharmacokinetic, bioequivalence, protein, and DNA-binding studies are welcome on the basis of analytical novelty, including sample preparation. Real-world applications (endogenous analytes or sampling from patients) are highly recommended versus demonstration through the spiking of blank biological matrices.

In all cases, novelty will be the major suitability criterion of submitted articles. Authors must therefore always address the question of how their proposed methodology compares with previously reported methods. We look forward many interesting submissions!

Dr. Paraskevas D. Tzanavaras
Prof. Dr. Susanne K. Wiedmer
Collection Editors

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Keywords

  • natural products
  • pharmaceuticals
  • automation
  • sequential injection analysis
  • separation techniques (HPLC, CE)
  • post-column derivatization
  • microextraction

Published Papers (8 papers)

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2023

Jump to: 2022, 2021

13 pages, 1495 KiB  
Article
Programmable Low-Pressure Chromatographic Sub-90 s Assay of Parabens in Cosmetics with Post-Column Chemiluminescence Detection
by Margarita Barbatsi and Anastasios Economou
Separations 2023, 10(6), 350; https://doi.org/10.3390/separations10060350 - 11 Jun 2023
Viewed by 1039
Abstract
This work describes a new programmable low-pressure chromatography method with post-column chemiluminescence (CL) detection for the rapid and cost-effective determination of four parabens in cosmetic products. Elution of the target analytes was achieved using a programmable mobile phase prepared by implementing a linear [...] Read more.
This work describes a new programmable low-pressure chromatography method with post-column chemiluminescence (CL) detection for the rapid and cost-effective determination of four parabens in cosmetic products. Elution of the target analytes was achieved using a programmable mobile phase prepared by implementing a linear solvent gradient protocol based on appropriate flow rate modulation of 2 MilliGAT pumps. A 5 mm monolithic C18 column was used to separate the parabens. Post-column reaction of the eluted parabens with an acidic Ce(IV)-rhodamine 6G (Rho 6G) medium was carried out by introducing a flow stream of the reactants into the column eluate. The light generated from the CL reaction was detected with a flow-through CL detector fabricated in-house. The whole sequence of operations (including sample injection, generation of the mobile phase, addition of the post-column reaction reagents and signal acquisition) was under full computer control. Various operational parameters (the mobile phase composition and gradient conditions, the CL reagents’ concentrations and flow rates and the length of the reaction coil) were studied. The method was validated and applied to the analysis of various cosmetic products. The proposed approach allows sub-90 s separation of the four parabens and their determination with a limit of quantification of 0.2 μg L−1 with a sample throughput of 24 samples h−1. In addition, the method is economical, makes use of low-cost low-pressure components, is fully automated and produces a low amount of waste. Full article
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14 pages, 1761 KiB  
Article
Quantification of Health Claim-Relevant Tyrosol and Hydroxytyrosol after Direct Hydrolysis Improves Customer Understanding and Mitigates Market Distortion
by Alex Mair, Martin Fischnaller, Oliver M. D. Lutz, Danilo Corradini, Alexios-Leandros Skaltsounis, Panagiotis Stathopoulos, Thomas A. E. Jakschitz, Matthias Rainer and Günther K. Bonn
Separations 2023, 10(4), 268; https://doi.org/10.3390/separations10040268 - 21 Apr 2023
Viewed by 1462
Abstract
The EFSA-approved claim that olive oil is beneficial for cardiovascular health suffers from ambiguities that lead to a vague and potentially subjective interpretation of the underlying analytical data. Misunderstandings among customers, but also market distortions are possible consequences. In this study, a rapid [...] Read more.
The EFSA-approved claim that olive oil is beneficial for cardiovascular health suffers from ambiguities that lead to a vague and potentially subjective interpretation of the underlying analytical data. Misunderstandings among customers, but also market distortions are possible consequences. In this study, a rapid and simple analytical technique is presented that circumvents the ambiguity by measuring levels of putative health-promoting compounds as the equivalent of tyrosol and hydroxytyrosol, cleaving such moieties from more complex constituents such as oleuropein and oleocanthal. Since the direct hydrolysis of the olive oil is the central element of the process, the reaction temperature, time, reagent concentration and reagent type were optimized. In addition, the influence of co-solvents, which might support the intermittent miscibility of the two phases during hydrolysis, was investigated. The analytical and economic implications are discussed particularly in the context of a commonly used technique. Full article
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2022

Jump to: 2023, 2021

23 pages, 1592 KiB  
Review
Extraction, Separation, Antitumor Effect, and Mechanism of Alkaloids in Sophora alopecuroides: A Review
by Ruixia Zhang, Ruizhou Wang, Shipeng Zhao, Dan Chen, Fusheng Hao, Bo Wang, Jin Zhang, Yingying Ma, Xingyi Chen, Xiaojuan Gao, Lu Han and Changcai Bai
Separations 2022, 9(11), 380; https://doi.org/10.3390/separations9110380 - 20 Nov 2022
Cited by 3 | Viewed by 1599
Abstract
Malignant tumors pose a serious threat to human health, reducing quality of life. Natural antitumor drugs play a vital role in the treatment of cancer. Sophora alopecuroides, a traditional Chinese medicine not a part of the Chinese Pharmacopoeia, grows in the arid [...] Read more.
Malignant tumors pose a serious threat to human health, reducing quality of life. Natural antitumor drugs play a vital role in the treatment of cancer. Sophora alopecuroides, a traditional Chinese medicine not a part of the Chinese Pharmacopoeia, grows in the arid desert and edge zone of grassland. Previous studies have extensively investigated the antitumor effects of S. alopecuroides and its major alkaloids. Of these, aloperine, matrine, oxymatrine, sophoridine, and sophocarpine have received the most attention. In recent years, a variety of extraction and separation methods have been applied to the study of the alkaloids of Sophora alopecuroides, which has greatly promoted the study of the chemical constituents and pharmacological activities of the plant. S. alopecuroides has been shown to impede cancer cell growth, induce cell cycle arrest, enhance apoptosis and cellular differentiation, and impede cancer metastasis and invasion. Several mechanisms have been proposed for modulating cancer signaling and molecular pathways or targets based on multitudinous studies in various types of cancerous cells. This review provides an in-depth overview of the antitumor effects of S. alopecuroides and the potential targets of 12 alkaloids in S. alopecuroides via a pharmacophore mapping approach and offers a scientific basis for the further exploration of the mechanism related to the antitumor effects of this plant. Full article
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17 pages, 3129 KiB  
Article
Separation and Purification of Taxanes from Crude Taxus cuspidata Extract by Antisolvent Recrystallization Method
by Yajing Zhang, Zirui Zhao, Wenlong Li, Yuanhu Tang, Huiwen Meng and Shujie Wang
Separations 2022, 9(10), 304; https://doi.org/10.3390/separations9100304 - 11 Oct 2022
Cited by 4 | Viewed by 2133
Abstract
Taxanes are natural compounds with strong antitumor activity. In this study, we first enriched taxanes by ultrasonic extraction and liquid–liquid extraction from Taxus cuspidata, then purified these taxanes by the antisolvent recrystallization method, and discussed the effects of four recrystallization conditions on [...] Read more.
Taxanes are natural compounds with strong antitumor activity. In this study, we first enriched taxanes by ultrasonic extraction and liquid–liquid extraction from Taxus cuspidata, then purified these taxanes by the antisolvent recrystallization method, and discussed the effects of four recrystallization conditions on the purity of eight target compounds. The most promising purification results were obtained using methanol as a solvent and water as an antisolvent. Response surface methodology (RSM) was used to further optimize the optimal purification conditions: when the crude extraction concentration was 555.28 mg/mL, an antisolvent to solvent volume ratio was 28.16 times, the deposition temperature was 22.91 °C, and the deposition time was 1.76 min, the purity of the taxanes reached its maximum. The scanning electron microscopy (SEM) results showed that recrystallization could effectively reduce the particle size of crude Taxus cuspidata and control the particle morphology. X-ray diffraction (XRD) and Raman spectrum experiments demonstrated that the amorphous state of the crude Taxus cuspidata did not change during the recrystallization process, and always remained amorphous. This recrystallization method can effectively improve the purity of taxanes in Taxus cuspidata, and is suitable for the preliminary purification of taxanes. Full article
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41 pages, 4964 KiB  
Review
Lycium Genus Polysaccharide: An Overview of its Extraction, Structures, Pharmacological Activities and Biological Applications
by Bo Wang, Lu Han, Jun-Mei Liu, Jin Zhang, Wen Wang, Bing-Ge Li, Cai-Xia Dong and Chang-Cai Bai
Separations 2022, 9(8), 197; https://doi.org/10.3390/separations9080197 - 30 Jul 2022
Cited by 6 | Viewed by 2701
Abstract
Polysaccharide is considered to be the main active ingredient of the genus Lycium L., which is taken from the dried fruit of the famous Chinese herbal medicine and precious tonic known as wolfberry. Traditional uses include nourishing the liver and kidney and improving [...] Read more.
Polysaccharide is considered to be the main active ingredient of the genus Lycium L., which is taken from the dried fruit of the famous Chinese herbal medicine and precious tonic known as wolfberry. Traditional uses include nourishing the liver and kidney and improving eyesight, with widespread use in the clinical practice of traditional Chinese medicine. Many studies have focused on the isolation and identification of the genus Lycium L. polysaccharide and its biological activities. However, the variety of raw materials and the mechanisms of polysaccharides differ. After extraction, the structure and biological activity of the obtained polysaccharides also differ. To date, approximately 58 kinds of polysaccharides have been isolated and purified from the Lycium genus, including water-soluble polysaccharides; homogeneous polysaccharides; pectin polysaccharides; acidic heteropolysaccharides; and arabinogalactans, which are composed of arabinose, glucosamine, galactose, glucose, xylose, mannose, fructose, ribose, galacturonic acid, and glucuronic acid. Pharmacological studies have shown that LBPs exhibit a variety of important biological activities, such as protection of nerves; promotion of reproduction; and anti-inflammatory, hepatoprotective, hypoglycemic, and eyesight-improving activities. The aim this paper is to summarize previous and current references to the isolation process, structural characteristics, and biological activities of the genus Lycium L. polysaccharide. This review will provide a useful reference for further research and application of the genus Lycium L. polysaccharide in the field of functional food and medicine. Full article
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9 pages, 1607 KiB  
Article
Optimized Isolation of Safranal from Saffron by Solid-Phase Microextraction (SPME) and Rotatable Central Composite Design-Response Surface Methodology (RCCD-RSM)
by Panagiota-Kyriaki Revelou, Spyridoula Mouzoula, Marinos Xagoraris, Haralambos Evangelaras, George K. Papadopoulos, Christos S. Pappas and Petros A. Tarantilis
Separations 2022, 9(2), 48; https://doi.org/10.3390/separations9020048 - 10 Feb 2022
Viewed by 2896
Abstract
Safranal is the main aroma component of saffron stigmas. It is also a great antioxidant with known pharmacological properties and is a potent indicator for the grading and authentication of saffron. In this study, the optimum extraction conditions of safranal from saffron stigmas [...] Read more.
Safranal is the main aroma component of saffron stigmas. It is also a great antioxidant with known pharmacological properties and is a potent indicator for the grading and authentication of saffron. In this study, the optimum extraction conditions of safranal from saffron stigmas were investigated using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and response surface methodology (RSM). A rotatable-central composite design was applied, and a linear regression model has been used for the model building. The optimized factors were as follows: sample weight (15 mg), water volume (4 mL), exposure time in the headspace (20 min), and extraction temperature (45 °C). All factors were found significant; however, extraction temperature and exposure time were the most important for the isolation of safranal. The obtained model was successfully validated with a test set of saffron samples analyzed under the optimum extraction conditions. The optimized SPME extraction conditions of safranal found in this study contribute to the efforts towards the detection of saffron authentication and adulteration. Full article
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2021

Jump to: 2023, 2022

9 pages, 2347 KiB  
Article
Improvement of Cucurbitacin B Content in Cucumis melo Pedicel Extracts by Biotransformation Using Recombinant β-Glucosidase
by Jianfeng Mei, Xia Wu, Sujing Zheng, Xiang Chen, Zhuliang Huang and Yichun Wu
Separations 2021, 8(9), 138; https://doi.org/10.3390/separations8090138 - 01 Sep 2021
Cited by 1 | Viewed by 1919
Abstract
For the efficient biotransformation of cucurbitacin B 2-o-β-d-glucoside (CuBg) to cucurbitacin B (CuB) in Cucumis melo pedicel extracts, the β-glucosidase gene bglS—consisting of 1344 bp (447 amino acids) from Streptomyces sp. RW-2—was cloned and expressed in Escherichia coli [...] Read more.
For the efficient biotransformation of cucurbitacin B 2-o-β-d-glucoside (CuBg) to cucurbitacin B (CuB) in Cucumis melo pedicel extracts, the β-glucosidase gene bglS—consisting of 1344 bp (447 amino acids) from Streptomyces sp. RW-2—was cloned and expressed in Escherichia coli BL21(DE3). The activity of recombinant β-glucosidase with p-nitrophenyl-β-d-glucoside (pNPG) as a substrate was 3.48 U/mL in a culture. Using the recombinant β-glucosidase for the biotransformation of C. melo pedicel extracts, CuBg was converted into CuB with a conversion rate of 87.6% when the concentration of CuBg was 0.973 g/L in a reaction mixtures. The concentration of CuB in C. melo pedicel extracts was improved from 13.6 to 20.2 g/L after biotransformation. The present study provides high-efficiency technology for the production of CuB from its glycoside by biotransformation. Full article
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17 pages, 3218 KiB  
Article
Optimum Parameters for Extracting Three Kinds of Carotenoids from Pepper Leaves by Response Surface Methodology
by Nenghui Li, Jing Li, Dongxia Ding, Jianming Xie, Jing Zhang, Wangxiong Li, Yufeng Ma, Feng Gao, Tianhang Niu, Cheng Wang and Emily Patience Bakpa
Separations 2021, 8(9), 134; https://doi.org/10.3390/separations8090134 - 26 Aug 2021
Cited by 5 | Viewed by 2124
Abstract
To determine the optimum parameters for extracting three carotenoids including zeaxanthin, lutein epoxide, and violaxanthin from pepper leaves by response surface methodology (RSM), a solvent of acetone and ethyl acetate (1:2) was used to extract carotenoids with four independent factors: ultrasound time (20–60 [...] Read more.
To determine the optimum parameters for extracting three carotenoids including zeaxanthin, lutein epoxide, and violaxanthin from pepper leaves by response surface methodology (RSM), a solvent of acetone and ethyl acetate (1:2) was used to extract carotenoids with four independent factors: ultrasound time (20–60 min); ratio of sample to solvent (1:12–1:4); saponification time (10–50 min); and concentration of saponification solution (KOH–methanol) (10–30%). A second-order polynomial model produced a satisfactory fitting of the experimental data with regard to zeaxanthin (R2 = 75.95%, p < 0.0197), lutein epoxide (R2 = 90.24%, p < 0.0001), and violaxanthin (R2 = 73.84%, p < 0.0809) content. The optimum joint extraction conditions of zeaxanthin, lutein epoxide, and violaxanthin were 40 min, 1:8, 32 min, and 20%, respectively. The optimal predicted contents for zeaxanthin (0.823022 µg/g DW), lutein epoxide (4.03684 µg/g dry; DW—dry weight), and violaxanthin (16.1972 µg/g DW) in extraction had little difference with the actual experimental values obtained under the optimum extraction conditions for each response: zeaxanthin (0.8118 µg/g DW), lutein epoxide (3.9497 µg/g DW), and violaxanthin (16.1590 µg/g DW), which provides a theoretical basis and method for cultivating new varieties at low temperatures and weak light resistance. Full article
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