Effect of organic co-solvents in the evaluation of the hydroxyl radical scavenging activity by the 2-deoxyribose degradation assay: The paradigmatic case of α-lipoic acid
| Autor: | Andrea Brizzolari, Mario C. Foti, Luciano Saso, Nima Razzaghi-Asl, Giuseppe Matteo Campisi, Enzo Santaniello |
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| Rok vydání: | 2016 |
| Předmět: |
Acetonitriles
Biophysics 010402 general chemistry 01 natural sciences Biochemistry chemistry.chemical_compound Reaction rate constant 2-Deoxyribose degradation assay Hydroxyl radical Scavenging activity scavenging activity Organic chemistry Solubility Organic Chemicals Acetonitrile Aqueous solution Thioctic Acid 010405 organic chemistry Deoxyribose Hydroxyl Radical Organic Chemistry Free Radical Scavengers 0104 chemical sciences 2-deoxyribose degradation assay hydroxyl radical lipoic acid acetonitrile Lipoic acid chemistry Polymerization Solvents Hydroxyl radical |
| Zdroj: | Biophysical chemistry 220 (2017): 1–6. doi:10.1016/j.bpc.2016.10.005 info:cnr-pdr/source/autori:Andrea Brizzolari, Giuseppe M. Campisi, Enzo Santaniello, Nima Razzaghi-Asl, Luciano Saso, Mario C. Foti/titolo:Effect of organic co-solvents in the evaluation of the hydroxyl radical scavenging activity by the 2-deoxyribose degradation assay: The paradigmatic case of ?-lipoic acid/doi:10.1016%2Fj.bpc.2016.10.005/rivista:Biophysical chemistry (Print)/anno:2017/pagina_da:1/pagina_a:6/intervallo_pagine:1–6/volume:220 |
| ISSN: | 1873-4200 |
| DOI: | 10.1016/j.bpc.2016.10.005 |
| Popis: | The 2-deoxyribose degradation assay (2-DR assay) is an in vitro method broadly used for evaluating the scavenging activity against the hydroxyl radical (HO ). One of the major drawbacks of the assay, however, is that only water soluble compounds can be tested for their radical-scavenging activity. Lipoic acid (LA) is an excellent scavenger of HO but it exhibits a low solubility in the aqueous milieu of the 2-DR assay and a high tendency to polymerize under a variety of conditions. We used LA as a paradigmatic substrate to evaluate the effect of several organic co-solvents in increasing its solubility. Most of these solvents, however, demonstrated to be potent scavengers of HO making their use in the 2-DR assay improper. On the other hand, acetonitrile showed a remarkably low reactivity toward HO (rate constant ~ 8.7 × 106 M− 1 s− 1) which allowed us to use it as a co-solvent in the preparation of stock solutions of LA ~ 5 mM. We therefore evaluated the radical-scavenging activity of LA by the 2-DR assay in a relatively large range of concentrations, 1–200 μM. We found that the rate constant for LA + HO is diffusion-controlled (~ 1 × 1010 M− 1 s− 1 in water at 25 °C) and uninfluenced by the presence of small quantities of acetonitrile. Therefore, the use of acetonitrile in the 2-DR assay does not interfere with the test and may increase the solubility of the radical scavengers. |
| Databáze: | OpenAIRE |
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