The anti-inflammatory activity of natural allophane

This paper presents evidence of the novel anti-inflammatory properties of natural allophane collected from New Zealand, Japan, and Ecuador. Allophanes were assessed by (i) the mouse-ear edema method using 12-O-tetradecanoylphorbol-13-acetate (TPA) as inflammatory agent; and (ii) the myeloperoxidase (MPO) enzymatic-activity method. After 4 h, applying 1 mg ear− 1 allophane conveyed edema inhibition (EI; p ≤ 0.01) in up to 39%, while MPO content inhibition (CI) values surpassed 60%. Pearsonʹs correlation analysis between EI and MPO data showed that edema was mediated by the migration of neutrophils at t = 4 h (p < 0.05), but not at t = 24 h. The lack of variation in cellular migration with time was explained because of a reaction of zero-order kinetics. EPR spectra for allophanes showing higher anti-inflammatory activity denoted a broad signal centered at g = 2, and an intense spin–spin interaction, typical of a low-spin, octahedral Fe3 + environment (S = 1/2); and overlapping signals typical for Ni, with octahedral coordination, explained either by oxidation states + 1 (Ni1 +), + 3 (Ni3 +), or bulk Ni2 + ions.