Insulin mimetic (nano)biotechnology of flavonoid metal complexes and bioavailable propolis in Diabetes mellitus II

The present doctoral research pursues the development of (nano)biotechnology of metallo-pharmaceuticals as potential hybrid research models in the treatment, prevention, treatment and/or diagnosis of human (patho)physiologies. Based on these grounds, the research project includes the following goals: a) the synthesis of flavonoid derivatives, b) the synthesis of new hybrid metal-organic materials using flavonoid substrates and trivalent metal ions, and c) the encapsulation of new hybrid materials and water-soluble bioavailable propolis (encapsulated in cyclodextrin) into organic and inorganic nanoparticles. In such an endeavor, the selected flavonoids, naringin (Naringin), naringenin (Naringenin), quercetin (QC), and chrysin (Chr) were systematically employed in the present research. More specifically, the development of flavonoid derivatives (Part I) involves their chemical modification through organic synthesis to produce oxime derivatives and/or Schiff bases using linear diamines. All materials were fully characterized by FT-IR, ESI-MS, 1H-, 13C-NMR, UV-Visible, and luminescence. For the metal-organic materials, trivalent metal ions of lanthanides (Sm(III), Dy(III), Er(III), Ce(III)) and chromium (Cr(III)) were used as basic metal ions of biological interest (Part I). The ternary hybrid materials of the metal ions with the flavonoids and the aromatic chelators (1,10-phenanthroline (phen), 2,2'-dipyridine (bipy)) have been fully characterized by FT-IR, ESI-MS, UV-Visible, luminescence, and x-ray crystallography.Organic (liposomes), i.e. polymeric (poly(ε-caprolactone), PCL, chitosan, Ch), and inorganic (silica, SiO2) nanoparticles were systematically investigated to optimally develop their method of synthesis and their isolation in well-defined hybrid materials, accompanied by complete physicochemical profiling, confirming their nature and morphology (Part II). Encapsulation of flavonoids, water-soluble bioavailable propolis, and pharmaceuticals (amikacin (AS), colistin (CS)) in the aforementioned nano- and micro-particles successfully pursued and quantified by UV-Visible spectroscopy and size exclusion chromatography (SEC).Based on their physicochemical property profile, further investigation of the aforementioned materials was pursued in vitro to probe into the biological properties of these new materials in a cellular setting, including: a) biotoxicity in immature C2C12 myoblasts, b) toxicity in mature C2C12 myoblasts, and c) investigation of antioxidant activity in the presence of the well-known oxidizing agent H2O2.The overall approach to developing such new hybrid materials composed, of natural products and inorganic components, aspires to answer basic and fundamental questions regarding the contribution of a) inorganic agents-cofactors, b) specifically modified natural antioxidants, and c) well-defined inorganic-organic complex forms of metal ions and flavonoids, in their antioxidant and potentially protective capacity in complex biological systems, such as those encountered in human (patho)physiology.Η παρούσα διδακτορική έρευνα αποσκοπεί στη συνδυαστική διερεύνηση μεταλλο-φαρμάκων και νανοτεχνολογίας ως εν δυνάμει υβριδικών μοντέλων έρευνας στην αντιμετώπιση, πρόληψη, θεραπεία ή/και διάγνωση ανθρώπινων (παθο)φυσιολογιών. Με βάση το σκοπό αυτό, το παρόν ερευνητικό έργο στοχεύει α) στη σύνθεση παραγώγων φλαβονοειδών, β) στη σύνθεση νέων υβριδικών μεταλλο-οργανικών υλικών με χρήση υποστρωμάτων φλαβονοειδών και τρισθενών μεταλλοϊόντων, και γ) στην ενθυλάκωση νέων υλικών και υδατοδιαλυτής βιοδιαθέσιμης πρόπολης (ενθυλακωμένης σε κυκλοδεξτρίνη) σε οργανικά και ανόργανα νανοσωματίδια. Τα επιλεγμένα φλαβονοειδή, ναριγκίνη (Naringin), ναριγκενίνη (Naringenin), κερσετίνη (QC), και χρυσίνη (Chr) χρησιμοποιήθηκαν επισταμένα στην παρούσα έρευνα.Πιο συγκεκριμένα, η ανάπτυξη παραγώγων φλαβονοειδών (Μέρος Ι) περιλαμβάνει τη χημική τροποποίησή τους με οργανική σύνθεση προς παραγωγή οξιμικών παραγώγων ή/και βάσεων Schiff με χρήση γραμμικών διαμινών. Όλα τα υλικά χαρακτηρίστηκαν πλήρως με FT-IR, ESI-MS, 1H-, 13C-NMR, UV-Visible, και φωταύγεια. Για τα μεταλλο-οργανικά υλικά χρησιμοποιήθηκαν τρισθενή μεταλλοϊόντα λανθανίδων (Sm(III), Dy(III), Er(III), Ce(III)) και χρωμίου (Cr(III)) ως βασικοί πυρήνες βιολογικού ενδιαφέροντος (Μέρος Ι). Τα τριαδικά υβριδικά υλικά των μεταλλοϊόντων με τα φλαβονοειδή και τους χηλικοποιητές (1,10-φαινανθρολίνη (phen), 2,2’-διπυριδίνη (bipy)) έχουν χαρακτηριστεί πλήρως με FT-IR, ESI-MS, UV-Visible, φωταύγεια, και κρυσταλλογραφία ακτίνων Χ.Όσον αφορά στα νανοσωματίδια οργανικά (λιποσώματα), πολυμερικά (πολυ(ε-καπρολακτόνη), PCL, και χιτοζάνη, Ch), και ανόργανα (πυριτίας, SiO2), αυτά αποτέλεσαν αντικείμενο συστηματικής μελέτης για την αποσαφήνιση του τρόπου σύνθεσης και την απομόνωσή τους σε καλά καθορισμένα υβριδικά υλικά, συνοδευμένα από πλήρες φυσικο-χημικό προφίλ που επιβεβαιώνουν τη φύση και μορφολογία τους (Μέρος ΙΙ). Η ενθυλάκωση φλαβονοειδών, υδατοδιαλυτής βιοδιαθέσιμης πρόπολης, και φαρμακευτικών ουσιών (αμικασίνη (AS), κολιστίνη (CS)) στα προαναφερθέντα νανο- και μικρο- σωματίδια ποσοτικοποιήθηκε με οπτική φασματοσκοπία UV-Visible και χρωματογραφία αποκλεισμού μεγέθους (SEC).Περαιτέρω έρευνα των προαναφερθέντων σχετίζεται με την in vitro μελέτη των βιολογικών ιδιοτήτων αυτών των νέων υλικών σε κυτταρικούς στόχους που περιλαμβάνει: α) τη βιοτοξικότητα σε πρώιμους μυοβλάστες C2C12, β) τη τοξικότητα σε ώριμους μυοβλάστες C2C12, και γ) τη διερεύνηση της αντιοξειδωτικής δράσης παρουσία του γνωστού οξειδωτικού παράγοντα H2O2.Η συνολική αντιμετώπιση της ανάπτυξης νέων υβριδικών υλικών αποτελούμενων από φυσικά προϊόντα και ανόργανα συστατικά, έρχεται να απαντήσει σε βασικά και θεμελιώδη ερωτήματα αναφορικά με τη συμβολή α) ανόργανων παραγόντων, β) εξειδικευμένα τροποποιημένων φυσικών αντιοξειδωτικών και γ) καλά καθορισμένων ανόργανων-οργανικών συμπλόκων μορφών μεταλλοϊόντων και φλαβονοειδών, στην αντιοξειδωτική και εν δυνάμει προστατευτική ικανότητά τους σε ένα πολύπλοκο σύστημα, όπως η ανθρώπινη (παθο)φυσιολογία

Chromium Flavonoid Complexation in an Antioxidant Capacity Role

The plethora of flavonoid antioxidants in plant organisms, widespread in nature, and the appropriate metal ions known for their influence on biological processes constitute the crux of investigations toward the development of preventive metallodrugs and therapeutics in several human pathophysiologies. To that end, driven by the need to enhance the structural and (bio)chemical attributes of the flavonoid chrysin, as a metal ion complexation agent, thereby rendering it bioavailable toward oxidative stress, synthetic efforts in our lab targeted ternary Cr(III)-chrysin species in the presence of auxiliary aromatic N,N′-chelators. The crystalline metal-organic Cr(III)-chrysin-L (L = bipyridine (1) and phenanthroline (2)) compounds that arose were physicochemically characterized by elemental analysis, FT-IR, UV-Visible, ESI-MS, luminescence, and X-ray crystallography. The properties of these compounds in a solid state and in solution formulate a well-defined profile for the two species, thereby justifying their further use in biological experiments, intimately related to cellular processes on oxidative stress. Experiments in C2C12 myoblasts at the cellular level (a) focus on the antioxidant capacity of the Cr(III)-complexed flavonoids, emphasizing their distinct antiradical activity under oxidative stress conditions, and (b) exemplify the importance of structural speciation in Cr(III)-flavonoid interactions, thereby formulating correlations with the antioxidant activity of a bioavailable flavonoid toward cellular pathophysiologies, collectively supporting flavonoid introduction in new metallo-therapeutics

Antimicrobial Activity of Cobalt (II)-Citrate against Common Foodborne Pathogens and Its Potential for Incorporation into Food Packaging Material

Novel antimicrobial compounds can be added to foods directly or incorporated into packaging materials in order to improve food safety and shelf life. One such potential antimicrobial compound is the bioinorganic complex Co(II)-citrate (NH4)4[Co(C6H5O7)2] (Co-cit). Its antimicrobial activity against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa was investigated in solution, both alone and in combination with existing preservatives. The antimicrobial activity of poly(lactic acid) films (PLA) with incorporated Co-cit (23.3% w/w) against L. monocytogenes was determined using culture medium and model foods (slices of turkey ham and smoked salmon). In nutrient broth, without preservatives, all four bacteria were significantly (p < 0.05) inhibited by 0.5 mM Co-cit, and L. monocytogenes and P. aeruginosa were the most sensitive. The addition of preservatives to the broth increased the antimicrobial activity of Co-cit in many cases, but not in a way that was consistent between the different bacteria investigated and was likely due to additional physiological stress exerted on the cells rather than any effect on the activity of the Co-cit itself. PLA films with Co-cit were bacteriostatic against L. monocytogenes on artificial media and on foods. However, in the latter case, the PLA film itself was the main contributor to the inhibition. Composite PLA-(Co-cit) films exhibited antimicrobial activity against foodborne bacteria and have potential application as active packaging materials to enhance food safety

Antimicrobial Activity of Cobalt (II)-Citrate against Common Foodborne Pathogens and Its Potential for Incorporation into Food Packaging Material

Novel antimicrobial compounds can be added to foods directly or incorporated into packaging materials in order to improve food safety and shelf life. One such potential antimicrobial compound is the bioinorganic complex Co(II)-citrate (NH4)4[Co(C6H5O7)2] (Co-cit). Its antimicrobial activity against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa was investigated in solution, both alone and in combination with existing preservatives. The antimicrobial activity of poly(lactic acid) films (PLA) with incorporated Co-cit (23.3% w/w) against L. monocytogenes was determined using culture medium and model foods (slices of turkey ham and smoked salmon). In nutrient broth, without preservatives, all four bacteria were significantly (p L. monocytogenes and P. aeruginosa were the most sensitive. The addition of preservatives to the broth increased the antimicrobial activity of Co-cit in many cases, but not in a way that was consistent between the different bacteria investigated and was likely due to additional physiological stress exerted on the cells rather than any effect on the activity of the Co-cit itself. PLA films with Co-cit were bacteriostatic against L. monocytogenes on artificial media and on foods. However, in the latter case, the PLA film itself was the main contributor to the inhibition. Composite PLA-(Co-cit) films exhibited antimicrobial activity against foodborne bacteria and have potential application as active packaging materials to enhance food safety

Chemical and Biological Profiling of Fish and Seaweed Residues to Be Applied for Plant Fertilization

Brown algae and fish waste contain high-value compounds with potentially beneficial effects on plant growth. Several commercial fertilizer products are currently available, but the characteristics of the materials are usually not well-described. Fish and seaweed residues originating from the Norwegian coast are available, after industrial processing, which may be combined into complete fertilizers exerting additional effects on crop plants (biostimulants). In this study, raw samples of fish and seaweed residues were investigated using ecofriendly technologies (drying, leaching), targeting search and isolation of potential biostimulants, followed by physicochemical characterization (elemental analysis, UV–visible, FT-IR, ICP-MS, ICP-OES, electrical conductivity, pH, etc.). Organic solvent extractions were employed to determine the available mineral content, micro- and macro-nutrients, antioxidant compounds, and amino acid content by chemical hydrolysis. The in vitro biotoxicity profile (cell viability, morphology, migration) of the generated extracts was also perused, employing Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) along with sensitive neuronal eukaryotic cell lines N2a58 and SH-SY5Y, to assess their time- and concentration-dependent efficacy as antimicrobials and agents counteracting oxidative stress. The analytical composition of all raw materials showed that they contain important nutrients (K, P, Ca, N) as well as organic compounds and amino acids (Gly, Asp, Glu, Leu, Phe) capable of acting as plant biostimulants. Concurrently, the inherently high conductivity values and salt content necessitated leaching processes, which result in Na+ and K+ decreasing by more than ~60% and justifying further their use in soil treatment formulations. The aforementioned results and assertions, combined with physical measurements (pH, electrical conductivity, etc.) on naturally occurring and dried samples as well as green solvent extracts, formulated a physicochemical profile reflecting well-defined inorganic–organic species that might function as biostimulants. The collective physicochemical and biological properties support the notion that appropriate mixtures of marine organism residues may be efficient fertilizers for crop plants and concurrently possess biostimulant characteristics