| ObjectiveIn order to provide a direct evidence to settle the controversy concerning the role of nitric oxide (NO) in interaction with hydroxyl radical (·OH), the present study used an ideal model to systematically investigate the effect of NO on·OH-induced damage to biochemical components in traditional Chinese medicine (TCM), and then analyze its possible mechanism.Methods·OH produced by Fenton reaction and NO saturated aqueous solution reacted with glucose, fructose, galactose, xylose, sucrose, maltose, laminarin, pepsin, papain, linoleic acid emulsion as the substrates, respectively, so that we can investigate the effect of NO on·OH-induced damage to biochemical components in TCM. Furthermore, the detection of nitrous acid by ion chromatography, ABTS+· radical scavenging, and Fe2+chelation assays were conducted to explore the possible mechanism.ResultsThe data indicated that NO increased dose-dependently the protective percentages against·OH-induced damage to biochemical components in TCM. The IC50values of NO were calculated as0.13±0.01,0.06±0.01,0.08±0.01,0.07±0.01,0.26±0.01,0.07±0.01,0.06±0.01,0.12±0.01,0.07±0.01,0.04±0.01mmol/L, respectively for glucose, fructose, galactose, xylose, sucrose, maltose, laminarin, pepsin, papain, linoleic acid emulsion. And the IC50values of positive controls (Trolox/GSH) were calculated as0.58±0.01,0.55±0.03,0.70±0.04,1.18±0.06,3.55±0.14,1.03±0.08,1.06±0.09,1.96±0.12,2.74±0.04,0.54±0.04mmol/L, respectively for glucose, fructose, galactose, xylose, sucrose, maltose, laminarin, pepsin, papain, linoleic acid emulsion. In addition, nitrous acid has been detected in the solution of NO mixed with·OH radical by ion chromatography, and its concentration was calculated as0.680mmol/L. Further analysis suggested that NO could also effectively scavenge ABTS+· radicals (IC50=10.75±0.08μmol/L) and chelate Fe2+(IC50=372.09±.25μmol/L).ConclusionOn this basis, it can be concluded that NO as radical scavenger protects against·OH-induced damage to biochemical components in TCM, including sugar, protein and lipid. NO exerts its protective role via the reaction with·OH radical to produce nitrous acid (·OH+NO→HNO2), in which NO partly donates electron (e) to·OH radical. For the first time it proved that the above reaction in aqueous solution. NO binding to Fe2+may reduce the generation of hydroxyl radicals, so that it may reduce the damage of biochemical components in TCM. It is another way of protection with the biochemical components in TCM by NO. |
