title: Mechanistic characterization and inhibition of sphingomyelinase C over substituted Iron Schiff bases of chitosan adsorbed on glassy carbon electrode.
abstract: The medical treatment of laxoscelisms is based solely on supportive measures. Although equine antiserum for Sphingomyelinase C (SMASE) and D isomers are available, it is not used due to the risk of an anaphylactic reaction and its unproven efficacy. As potential enzyme inhibitors, derivatives of Iron chitosan complexes were studied (Shiff base having -R = -H, -Cl, -Br, -F, -OCH3, -CH3, -NO2). These chitosan complexes were chosen because they have revealed good results in medicine and catalysis due to their biodegradable characteristics and bioavailability. Besides considering that these complexes have not been studied in relation to this toxin. The mechanisms underlying the catalytic and catcher effects of Iron chitosan complexes were studied using electrochemistry, UV-Vis spectroscopy and microscopic assay at physiological pH. The electrochemical studies showed that one of seven Schiff bases of chitosan adsorbed on glassy carbon electrode was electrocatalytically active for the oxidation of sphingomyelinase at 1.27 V, and that allowed proposing a reaction scheme for SMASE oxidation by adsorbed Iron complexes. On the other hand, even though the spectroscopic studies indicated that there was no chemical bond formation between the complex and SMASE in solution, the microscopic studies showed that this complex proved to be a remarkable cellular protector in presence of the enzyme. In conclusion, Shiff base of chitosan with R = -CH3was the only active complex in front of sphingomyelinase C, protecting red blood cells, according to our electrochemical and microscopic studies.
authors.affiliation: Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad del Bío-Bío, Campus Fernando May, Av. Andrés Bello S/n, Chillán, Chile. Electronic address: ccaro@ubiobio.cl.
authors.forename: Claudia A
authors.initials: CA
authors.lastname: Caro
authors.affiliation: Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad del Bío-Bío, Campus Fernando May, Av. Andrés Bello S/n, Chillán, Chile.
authors.forename: Luis
authors.initials: L
authors.lastname: Lillo
authors.affiliation: Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad del Bío-Bío, Campus Fernando May, Av. Andrés Bello S/n, Chillán, Chile.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Valenzuela
authors.affiliation: Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad del Bío-Bío, Campus Fernando May, Av. Andrés Bello S/n, Chillán, Chile.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Cabello
mesh_terms: D000327:Adsorption; D055162:Biocatalysis; D002244:Carbon / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry / Q000378:metabolism*; D055664:Electrochemical Techniques; D004566:Electrodes; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000737:chemistry*; D010084:Oxidation-Reduction; D012545:Schiff Bases / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D056831:Coordination Complexes; D012545:Schiff Bases; D002244:Carbon; D048271:Chitosan; D007501:Iron; D013108:Sphingomyelin Phosphodiesterase
keywords: Erythrocyte's counting; Modified electrode; Schiff bases of chitosan; Sphingomyelinase C