RESUMO
Electron-deficient chlorine covalently immobilised on an amido group of hyaluronic acid (HA) can be potentially exceptional for applications requiring biodegradable and biocompatible polymers with enhanced antibacterial or antiviral activity. This expectation is supported by the assumption that a small amount of HA chloramide (HACl) is formed in the extracellular matrix under inflammatory conditions by a reaction of endogenous HA with hypochlorous acid (HClO) generated by a myeloperoxidase/H2O2/Cl- system. HACl synthesis optimisation showed significant limitations of HClO as an oxidative agent where only lower degrees of substitution (DS) was achieved. Commercially available oxidative agents based on chlorinated isocyanuric acid were successfully tested, producing the HA chain with almost entirely chlorinated amidic groups. The structure of the final HACl was thoroughly studied using advanced 2-dimensional NMR methodologies and LC/MS. Stability of HACl at different temperatures was monitored over 12 months. Preliminary antimicrobial and antiviral tests demonstrated the potential of HACl for applications in biomedicine.
Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antivirais/farmacologia , Cloraminas/farmacologia , Ácido Hialurônico/química , Ácido Hipocloroso/química , Antibacterianos/química , Antifúngicos/química , Antivirais/química , Bactérias/efeitos dos fármacos , Cloraminas/química , Fungos/efeitos dos fármacos , Halogenação , Vírus/efeitos dos fármacosRESUMO
All-trans retinoic acid (ATRA) was grafted to hyaluronan (HA) via esterification. The reaction was mediated by mixed anhydrides. A perfect control of the degree of substitution (0.5-7.5%) was obtained by varying the molar ratio of retinoic acid in the feed. The degree of substitution plays a significant role in the long-term stability. The photodegradation of HA-ATRA upon UVA irradiation resulted in ß-ionone, ß-cyclocitral and 5,6-epoxy-(E)-retinoic acid. The photostability of the conjugate had increased with the combination with morin. The chemical structure of HA-ATRA and its degradation products was elucidated using NMR spectroscopy, SEC-MALLS, and gas chromatography-mass spectrometry (GC-MS). ATRA did not loss its biological activity after conjugation, as demonstrated by gene expression. The derivative was able to penetrate across the stratum corneum. Besides, HA-ATRA downregulated the expression of anti-inflammatory interleukins 6 and 8. HA-ATRA would be expected to be used for transdermal drug delivery or cosmetics.
Assuntos
Antioxidantes/farmacologia , Ácido Hialurônico/química , Pele/efeitos dos fármacos , Tretinoína/química , Administração Cutânea , Anidridos/química , Animais , Antioxidantes/química , Esterificação , Flavonoides/química , Ácido Hialurônico/síntese química , Ácido Hialurônico/farmacologia , Camundongos , Células NIH 3T3 , Norisoprenoides/química , Norisoprenoides/farmacologia , Fotólise/efeitos dos fármacos , Pele/efeitos da radiação , Tretinoína/síntese química , Tretinoína/farmacologia , Raios UltravioletaRESUMO
Conjugates of hyaluronic acid (HA) with biologically active molecules showed great potential in many applications. Oligomers of hyaluronic acid (oliHA) as possible regulators of biological processes and potential anti-cancer therapeutics, were reversibly attached via covalent bond on HA modified with an aldehyde group (HA-CHO) using bis-hydrazido or bis-oxyamino spacers. The structure of the final conjugates (HA-spacer-oliHA) was studied by advanced 2-dimensional NMR techniques in detail. The suggested synthetic strategy is simple, straightforward and can be used for the synthesis of various types of HA or oliHA conjugates. in vitro cytotoxicity assays showed selective activity of HA-spacer-oliHA conjugates against cancer cell lines in comparison with standard human fibroblasts.
