title: Oxidative stress inhibition and oxidant activity by fibrous clays.
abstract: Fibrous clays (sepiolite, palygorskite) are produced at 1.2m tonnes per year and have a wide range of industrial applications needing to replace long-fibre length asbestos. However, information on the beneficial effects of fibrous clays on health remains scarce. This paper reports on the effect of sepiolite (Vallecas, Spain) and palygorskite (Torrejón El Rubio, Spain) on cell damage via oxidative stress (determined as the progress of lipid peroxidation, LP). The extent of LP was assessed using the Thiobarbituric Acid Reactive Substances assay. The oxidant activity by fibrous clays was quantified using Electron-Paramagnetic Resonance. Sepiolite and palygorskite inhibited LP, whereby corresponding IC50 values were 6557±1024 and 4250±289μgmL(-1). As evidenced by dose-response experiments LP inhibition by palygorskite was surface-controlled. Fibrous clay surfaces did not stabilize HO species, except for suspensions containing 5000μgmL(-1). A strong oxidant (or weak anti-oxidant) activity favours the inhibition of LP by fibrous clays.
authors.affiliation: Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana Unidad Cuajimalpa, México City, Mexico; Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. Electronic address: jcervini@correo.cua.uam.mx.
authors.forename: Javiera
authors.initials: J
authors.lastname: Cervini-Silva
authors.affiliation: Laboratorio de Pruebas Biológicas, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria México City, Mexico.
authors.forename: Antonio
authors.initials: A
authors.lastname: Nieto-Camacho
authors.affiliation: Laboratorio de Resonancia Paramagnética Electrónica, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria México City, Mexico.
authors.forename: Virginia
authors.initials: V
authors.lastname: Gómez-Vidales
mesh_terms: D000538:Aluminum Silicates; D000077215:Clay; D015227:Lipid Peroxidation / Q000187:drug effects; D016877:Oxidants / Q000494:pharmacology*; D018384:Oxidative Stress
chemical_list: D000538:Aluminum Silicates; D016877:Oxidants; D000077215:Clay
keywords: Hydroxyl radicals; Silanol groups; Surface-controlled; Tetrahedron-inversion sites