Stabilization of alpha-lipoic acid by complex formation with human serum albumin

Alpha lipoic acid (ALA) is produced in the human body and applied as an antioxidant drug in treatment of various diseases such as alcoholic liver disease, glaucoma, atherosclerosis, insulin resistance, neuropathy, neurodegenerative diseases and ischemia-reperfusion injury, diabetes and HIV. Currently, ALA is used as a dietary supplement. However, due to its poor water solubility and the instability against oxidation and thermal process, its application has been hampered. The distorted five membered ring of dithiolane may allow ALA to polymerize, especially during the thermal process at a temperature above its melting range (48–50 °C). The polymerization and oxidative degradation of ALA result in the loss of its bioactivity and formation of unpleasant sulfurous odor. The elimination rate of ALA with a biological half-life of less than 30 min hinders its clinical application. The thermal and oxidative stability, photochemical stability of alpha-lipoic acid (ALA) in aqueous dispersions were compared with complex human serum albumin. In the current study, the antioxidant activity of α-lipoic acid, human serum albumin (HSA), and the complex HSA-ALA were determined using ABTS* (2, 2‟-azino-bis 3-ethylbenzthiazoline-6- sulfonic acid) radical reaction scavenging. The results indicated that ALA complex with HSA was most stable against digestion. The HSA was an effective protecting agent for ALA in aqueous media, as well as a suitable delivery carrier for ALA in digestive tract.

کلیدواژه ها:

Alpha lipoic acid (α-LA) ، Antioxidant ، Scavenging test ، Reduced