Abstract:

In order to explore the effects of organic compounds on the bioavailability and toxicity of ferric salts, the media containing 1.5 mmol/L ferric chloride alone (as a control) or its respective mixtures with glucose, lactose, ascorbic acid and oxalic acid were used to incubate Caco-2 cells for 24 h, and after completion of the incubation, intracellular iron concentration characterizing bioavailability was measured and the cellular toxicity of ferric was assessed by MTT, lactate dehydrogenase (LDH) leakage, alkaline phosphatase (ALK) activity, superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity assays. Compared with the control medium, the cells incubated in the media containing ferric chloride/glucose, ferric chloride/lactose or ferric chloride/scorbic acid mixtures showed 2.57, 4.08 and 4.52-fold increases in iron bioavailability, respectively. However, the presence of oxalic acid in the control medium resulted in a decrease of iron bioavailability of the cells by 18.73%. Compared with the control medium, the cells incubated in the medium containing ferric chloride/ascorbic acid complex exhibited a significantly higher MTT absorbance (P ＜0.05) but a lower LDH leakage (P ＜0.05); in contrast, the medium containing ferric chloride/lactose mixture significantly improved LDH leakage (P ＜0.05). In addition, ferric chloride exhibited a reduction effect on the activities of SOD and ALK (P ＜0.01) when compared with deionized water. However, respective additions of these organic compounds could improve the activities of SOD and ALK. On the other hand, the medium containing ferric chloride/ascorbic acid mixture had a promoting effect on the activities of SOD, ALK and GSH-Px (P ＜0.05).

Key words: organic compound, ferric, bioavailability, toxicity