The Effects of Fulvic Acid on Copper Bioavailability to Porcine Oviductal Epithelial Cells

Abstract

This study assessed the effect of dissolved organic matter on the copper (Cu) bioavailability to mammalian cells, porcine oviductal epithelial cells (POEC), in order to imply its effect onto humans. Cu toxicity was investigated in the presence of with and without fulvic acid (FA). Dissociation and exchange rate constants were calculated by using competing ligand Chelex-100, and optical parameters were employed to help explain the complexation of their aromatic and aliphatic structures. Their morphological change was observed using transmission electron microscope (TEM), and Cu species were calculated using MINTEQA2 program. The results showed that the dissociation rate constant of Cu(2+)-FA was equal to 9.08 x 10(-4) s(-1), which was slower than the exchange rate at 1.95 x 10(-3) s(-1). Although Cu-FA was significantly absorbed into the cells higher than Cu(2+), it showed less damage than tested with Cu(2+). TEM and optical studies showed many aggregations around nucleus suggesting the amphipathic character of FA helped binging to the nuclear surfaces of both Cu-FA and FA treatments. Even though the MINTEQA2 calculations showed that there was free Cu(2+) in the mixed solutions around 39.2%, it could not bind with the cell surface. This suggested that the effect of FA was strong and had a lot of influence on the living surface of POEC, modifying the effect of Cu toxicity.