title: A simple and rapid method for calixarene-based selective extraction of bioactive molecules from natural products.
abstract: Natural products derived from medicinal plants have gained an important role in drug discovery due to their complex and abundant composition of secondary metabolites, with their structurally unique molecular components bearing a significant number of stereo-centers exhibiting high specificity linked to biological activity. Usually, the extraction process of natural products involves various techniques targeting separation of a specific class of compounds from a highly complex matrix. Aiding the process entails the use of well-defined and selective molecular extractants with distinctly configured structural attributes. Calixarenes conceivably belong to that class of molecules. They have been studied intensely over the years in an effort to develop new and highly selective receptors for biomolecules. These macrocycles, which display remarkable structural architectures and properties, could help usher a new approach in the efficient separation of specific classes of compounds from complex matrices in natural products. A simple and rapid such extraction method is presented herein, based on host-guest interaction(s) between a calixarene synthetic receptor, 4-tert-butyl-calix[6]arene, and natural biomolecular targets (amino acids and peptides) from Helleborus purpurascens and Viscum album. Advanced physicochemical methods (including GC-MS and chip-based nanoESI-MS analysis) suggest that the molecular structure and specifically the calixarene cavity size are closely linked to the nature of compounds separated. Incorporation of biomolecules and modification of the macrocyclic architecture during separation were probed and confirmed by scanning electronic microscopy and atomic force microscopy. The collective results project calixarene as a promising molecular extractant candidate, facilitating the selective separation of amino acids and peptides from natural products.
authors.affiliation: National Institute of Research and Development for Electrochemistry and Condensed Matter INCEMC Timisoara, 1 Plautius Andronescu, 300224, Timisoara, Romania.
authors.forename: Adina-Elena
authors.initials: AE
authors.lastname: Segneanu
authors.affiliation: National Institute of Research and Development for Electrochemistry and Condensed Matter INCEMC Timisoara, 1 Plautius Andronescu, 300224, Timisoara, Romania.|University Politehnica Timisoara, 2 Piata Victorie, 30006, Timisoara, Romania.
authors.forename: Daniel
authors.initials: D
authors.lastname: Damian
authors.affiliation: University Politehnica Timisoara, 2 Piata Victorie, 30006, Timisoara, Romania.
authors.forename: Iosif
authors.initials: I
authors.lastname: Hulka
authors.affiliation: National Institute of Research and Development for Electrochemistry and Condensed Matter INCEMC Timisoara, 1 Plautius Andronescu, 300224, Timisoara, Romania.|University Politehnica Timisoara, 2 Piata Victorie, 30006, Timisoara, Romania.
authors.forename: Ioan
authors.initials: I
authors.lastname: Grozescu
authors.affiliation: National Institute of Research and Development for Electrochemistry and Condensed Matter INCEMC Timisoara, 1 Plautius Andronescu, 300224, Timisoara, Romania. salif@auth.gr.|Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124, Thessaloníki, Greece. salif@auth.gr.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Salifoglou
mesh_terms: D001688:Biological Products / Q000737:chemistry / Q000302:isolation & purification*; D047250:Calixarenes / Q000737:chemistry; D005591:Chemical Fractionation / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification*; D010946:Plants, Medicinal / Q000737:chemistry*
chemical_list: D001688:Biological Products; D010936:Plant Extracts; D047250:Calixarenes
keywords: Atomic force microscopy; Calixarene; Chip-based nanoESI-MS analysis; Host–guest interaction; Scanning electronic microscopy; Selective extraction